Überblick: Ratenunabhängige Prozesse
Zeitabhängige Prozesse in Physik, Biologie und Wirtschaft zeigen häufig ein ratenunabhängiges EingangsAusgangsVerhalten. Dies bedeutet, dass eine Umskalierung der Eingangsgröße bezüglich der Zeit zu einer gleichartigen Umskalierung der Ausgangsgröße des Prozesses führt.
In diesen Prozessen treten häufig Hystereseeffekte auf, die von einem dem Prozess innewohnenden Gedächtnis hervorgerufen werden.
Wird beispielsweise ein elastoplastischer Körper unter einer vorgegebenen Last verformt, so kann dieser verformt bleiben, wenn die Last wieder entfernt wird. Werden darüber hinaus periodische Lastwechsel betrachtet, kann eine Hysterese Schleife entstehen:
 Es können die ursprünglichen Variablen durch zusätzliche innere Variablen zur Beschreibung des momentanen Zustandes ergänzt werden, so dass eine Modellierung des Gedächtnisses nicht mehr benötigt wird. Bei dieser Strategie müssen die inneren Variablen explizit in der Formulierung des Löungsbegriffs der ratenunabhängige Systeme auftreten.
 Anderseits können in vielen Fällen HystereseOperatoren zur Beschreibung des EingangsAusgangsVerhaltens gefunden werden, die nur die ursprünglichen Variablen verwenden. Diese Strategie vermeidet das explizite Auftreten der inneren Variablen, führt aber zu einem Gedächtnis, das heißt, dass der Zustand zu einer Zeit von der gesamten Vorgeschichte abhängt.
Modellierung mit ratenunabhängigen Systemen
Ratenunabhängige Systeme sind ratenunabhängige quasistatische Evolutionsgleichungen, die mit einem Energiefunktional und einem Dissipationspotential formuliert werden, wobei das Dissipationspotential positiv homogen vom Grad eins bezüglich der Zeitableitungen der inneren Variable ist. Die Theorie geht dabei im Allgemeinen von der Darstellung mittels zusätzlicher innerer Variablen aus, so dass eine Evolutionstheorie im Zustandsraum entwickelt werden kann, die ohne Gedächtnisterme auskommt. Typische Evolutionsgleichungen lassen sich als Differentialinklusionen schreiben, die sich zum Beispiel aus einer Kräftebilanz zwischen dissipativen Kräften als Funktion der Zustandsänderungsrate und den Rückstellkräften ergibt. Dabei haben diese Evolutionsgleichungen häufig mehr als eine Lösung.
Die Analysis ratenunabhängiger Systeme kann auf die allgemeine Theorie dissipativer Evolutionssysteme zurückgreifen, wird aber erschwert durch den Umstand, dass Lösungen im Allgemeinen nicht mehr stetig sein müssen. Insbesondere bei nichtkonvexen Energiefunktionalen weisen typische Lösungen Sprünge auf, die geeignet modelliert werden müssen. Dies kann einerseits durch die Methode der vanishingviscosityMethode geschehen, wo eine physikalische (oder künstliche) Viskosität verwendet wird um stetige Lösungen zu erzeugen, deren Grenzwert dann den Lösungsbegriff definiert. Andererseits kann eine rein energetische Formulierung verwendet werden, bei der die dissipativen Kräfte durch ein Dissipationsabstandsfunktional beschrieben werden. Die sogenannten energetischen Lösungen werden durch eine stationäre globale Stabilitätsbedingung und eine Energiebilanzgleichung charakterisiert.
Modellierung mit HystereseOperatoren
HystereseOperatoren bilden zeitabhängige Funktionen, die sogenannten InputFunktionen, auf zeitabhängige Funktionen, die so genannten OutputFunktionen ab, wobei gilt:
 Der Operator ist ratenunabhängig: Für alle betrachteten InputFunktionen und zulässigen Zeittransformationen gilt: Betrachtet man die OutputFunktion, die sich für die zeitlich transformierte Version der InputFunktion ergibt, so ist diese gerade die zeitlich transformierte Version der OutputFunktion zur ursprünglichen InputFunktion.
 Der Operator ist kausal: Für jede der betrachteten InputFunktionen gilt: Für alle Zeiten hängt der Wert der OutputFunktion zu einer Zeit nur von den Werten der InputFunktion bis zu diesem Zeitpunkt ab.
Wenn Daten in Modellen mit HystereseOperatoren, wie z.B. solche für elektromagnetomechanische Komponenten, aus Messungen hergeleitet werden, so sind diese mit gewissen Unsicherheiten behaftet. Daher werden jetzt die Methoden der Uncertainty Quantification auf HystereseOperatoren und auf derartige Modelle angewendet, siehe z.B. Klein 2016.
Höhepunkte
Modellierung mit ratenunabhängigen Systemen
In den letzten Jahren konnte die Existenz energetischer Lösungen für rateunabhängige Systeme für breite Anwendungsklassen gezeigt werden, wie zum Beispiel in der ElastoPlastizität (auch mit großen Verzerrungen), in Formgedächtnislegierungen, in Schädigungsmodellen und der Rissausbreitung, siehe Mielke, Roubíček 2015.
Zusätzlich gelang es in einer großen abstrakten Klasse von ratenunabhängigen Systemen den vanishingviscosity Grenzwert mittels der neu entwickelten Klasse von balanced viscosity solutions exakt zu beschreiben, siehe Mielke, Rossi, Savaré 2016.
Modellierung mit HystereseOperatoren.
Es ist gelungen, ein Darstellungsresultat aus BrokateSprekels 1996 für HystereseOperatoren mit skalaren InputFunktionen auf HystereseOperatoren mit speziellen vektoriellen InputFunktionen zu übertragen und zu erweitern, siehe Klein 2014.
Es wurde für alle Erweiterungen des sogenannten sweeping process auf InputFunktionen mit beschränkter Variation bewiesen, dass die Erweiterung nicht stetig ist, wenn man den Urbildraum mit der strikten Topologie betrachtet und den Bildraum mit der L^{1}Topologie, siehe Klein, Recupero 2016.
Publikationen
Monografien

M. Dimian, P. Gurevich, O. Klein, D. Knees, D. Rachinskii, S. Tikhomirov, eds., MURPHYSHSFS2014: 7th International Workshop on MUltiRate Processes and HYSteresis (MURPHYS) & 2nd International Workshop on Hysteresis and SlowFast Systems (HSFS), 727 of Journal of Physics: Conference Series, IOP Publishing, 2016, 252 pages, (Collection Published).

A. Mielke, T. Roubíček, Rateindependent Systems. Theory and Application, 193 of Applied Mathematical Sciences, Springer International Publishing, New York, 2015, vii+660 pages, (Monograph Published).
Abstract
This monograph provides both an introduction to and a thorough exposition of the theory of rateindependent systems, which the authors have been working on with a lot of collaborators over 15 years. The focus is mostly on fully rateindependent systems, first on an abstract level either with or even without a linear structure, discussing various concepts of solutions with full mathematical rigor. Then, usefulness of the abstract concepts is demonstrated on the level of various applications primarily in continuum mechanics of solids, including suitable approximation strategies with guaranteed numerical stability and convergence. Particular applications concern inelastic processes such as plasticity, damage, phase transformations, or adhesivetype contacts both at small strains and at finite strains. A few other physical systems, e.g. magnetic or ferroelectric materials, and couplings to ratedependent thermodynamic models are considered as well. Selected applications are accompanied by numerical simulations illustrating both the models and the efficiency of computational algorithms. In this book, the mathematical framework for a rigorous mathematical treatment of "rateindependent systems" is presented in a comprehensive form for the first time. Researchers and graduate students in applied mathematics, engineering, and computational physics will find this timely and well written book useful. 
G. Dal Maso, A. Mielke, U. Stefanelli, eds., Rateindependent Evolutions, 6 (No. 1) of Discrete and Continuous Dynamical Systems  Series S, American Institute of Mathematical Sciences, Springfield, 2013, 275 pages, (Collection Published).

P. Colli, A. Damlamian, N. Kenmochi, M. Mimura, J. Sprekels, eds., Proceedings of International Conference on: Nonlinear Phenomena with Energy Dissipation: Mathematical Analysis, Modeling and Simulation, 29 of Gakuto International Series Mathematical Sciences and Applications, Gakkōtosho, Tokyo, 2008, 475 pages, (Collection Published).
Artikel in Referierten Journalen

E. Davoli, M. Kružík, P. Pelech, Separately global solutions to rateindependent processes in largestrain inelasticity, Nonlinear Analysis. An International Mathematical Journal, 215 (2022), 112668, DOI 0.1016/j.na.2021.112668 .
Abstract
In this paper, we introduce the notion of separately global solutions for largestrain rateindependent systems, and we provide an existence result for a model describing bulk damage. Our analysis covers nonconvex energies blowing up for extreme compressions, yields solutions excluding interpenetration of matter, and allows to handle nonlinear couplings of the deformation and the internal variable featuring both Eulerian and Lagrangian terms. In particular, motivated by the theory developed in Roubíček (2015) in the small strain setting, and for separately convex energies we provide a solution concept suitable for large strain inelasticity. 
M. Thomas, S. Tornquist, Discrete approximation of dynamic phasefield fracture in viscoelastic materials, Discrete and Continuous Dynamical Systems  Series S, 14 (2021), pp. 38653924, DOI 10.3934/dcdss.2021067 .
Abstract
This contribution deals with the analysis of models for phasefield fracture in viscoelastic materials with dynamic effects. The evolution of damage is handled in two different ways: As a viscous evolution with a quadratic dissipation potential and as a rateindependent law with a positively 1homogeneous dissipation potential. Both evolution laws encode a nonsmooth constraint that ensures the unidirectionality of damage, so that the material cannot heal. Suitable notions of solutions are introduced in both settings. Existence of solutions is obtained using a discrete approximation scheme both in space and time. Based on the convexity properties of the energy functional and on the regularity of the displacements thanks to their viscous evolution, also improved regularity results with respect to time are obtained for the internal variable: It is shown that the damage variable is continuous in time with values in the state space that guarantees finite values of the energy functional. 
A. Mielke, Relating a rateindependent system and a gradient system for the case of onehomogeneous potentials, Journal of Dynamics and Differential Equations, published online on 31.05.2021, DOI 10.1007/s10884021100073 .
Abstract
We consider a nonnegative and onehomogeneous energy functional $mathcal J$ on a Hilbert space. The paper provides an exact relation between the solutions of the associated gradientflow equations and the energetic solutions generated via the rateinpendent system given in terms of the timedependent functional $mathcal E(t,u)=t mathcal J(u)$ and the norm as a dissipation distance. The relation between the two flows is given via a solutiondependent reparametrization of time that can be guessed from the homogeneities of energy and dissipations in the two equations. We provide several examples including the totalvariation flow and show that equivalence of the two systems through a solution dependent reparametrization of the time. Making the relation mathematically rigorous includes a careful analysis of the jumps in energetic solutions which correspond to constantspeed intervals for the solutins of the gradientflow equation. As a major result we obtain a nontrivial existence and uniqueness result for the energetic rateindependent system. 
R. Rossi, U. Stefanelli, M. Thomas, Rateindependent evolution of sets, Discrete and Continuous Dynamical Systems  Series S, 14 (2021), pp. 89119 (published online in March 2020), DOI 10.3934/dcdss.2020304 .
Abstract
The goal of this work is to analyze a model for the rateindependent evolution of sets with finite perimeter. The evolution of the admissible sets is driven by that of a given timedependent set, which has to include the admissible sets and hence is to be understood as an external loading. The process is driven by the competition between perimeter minimization and minimization of volume changes. In the mathematical modeling of this process, we distinguish the adhesive case, in which the constraint that the (complement of) the `external load' contains the evolving sets is penalized by a term contributing to the driving energy functional, from the brittle case, enforcing this constraint. The existence of Energetic solutions for the adhesive system is proved by passing to the limit in the associated timeincremental minimization scheme. In the brittle case, this timediscretization procedure gives rise to evolving sets satisfying the stability condition, but it remains an open problem to additionally deduce energydissipation balance in the timecontinuous limit. This can be obtained under some suitable quantification of data. The properties of the brittle evolution law are illustrated by numerical examples in two space dimensions. 
M. Brokate, Newton and Bouligand derivatives of the scalar play and stop operator, Mathematical Modelling of Natural Phenomena, 15 (2020), pp. 51/151/34, DOI 10.1051/mmnp/2020013 .

O. Klein, D. Davino, C. Visone, On forward and inverse uncertainty quantification for models involving hysteresis operators, Mathematical Modelling of Natural Phenomena, 15 (2020), pp. 53/153/19, DOI https://doi.org/10.1051/mmnp/2020009 .
Abstract
Parameters within hysteresis operators modeling real world objects have to be identified from measurements and are therefore subject to corresponding errors. To investigate the influence of these errors, the methods of Uncertainty Quantification (UQ) are applied. 
G. Lazzaroni, R. Rossi, M. Thomas, R. Toader, Rateindependent damage in thermoviscoelastic materials with inertia, Journal of Dynamics and Differential Equations, 30 (2018), pp. 13111364, DOI 10.1007/s108840189666y .
Abstract
We present a model for rateindependent, unidirectional, partial damage in viscoelastic materials with inertia and thermal effects. The damage process is modeled by means of an internal variable, governed by a rateindependent flow rule. The heat equation and the momentum balance for the displacements are coupled in a highly nonlinear way. Our assumptions on the corresponding energy functional also comprise the case of the AmbrosioTortorelli phasefield model (without passage to the brittle limit). We discuss a suitable weak formulation and prove an existence theorem obtained with the aid of a (partially) decoupled timediscrete scheme and variational convergence methods. We also carry out the asymptotic analysis for vanishing viscosity and inertia and obtain a fully rateindependent limit model for displacements and damage, which is independent of temperature. 
M. Heida, A. Mielke, Averaging of timeperiodic dissipation potentials in rateindependent processes, Discrete and Continuous Dynamical Systems  Series S, 10 (2017), pp. 13031327.
Abstract
We study the existence and wellposedness of rateindependent systems (or hysteresis operators) with a dissipation potential that oscillates in time with period ε. In particular, for the case of quadratic energies in a Hilbert space, we study the averaging limit ε→0 and show that the effctive dissipation potential is given by the minimum of all friction thresholds in one period, more precisely as the intersection of all the characteristic domains. We show that the rates of the process do not converge weakly, hence our analysis uses the notion of energetic solutions and relies on a detailed estimates to obtain a suitable equicontinuity of the solutions in the limit ε→0. 
R. Rossi, M. Thomas, From adhesive to brittle delamination in viscoelastodynamics, Mathematical Models & Methods in Applied Sciences, 27 (2017), pp. 14891546, DOI 10.1142/S0218202517500257 .
Abstract
In this paper we analyze a system for brittle delamination between two viscoelastic bodies, also subject to inertia, which can be interpreted as a model for dynamic fracture. The rateindependent flow rule for the delamination parameter is coupled with the momentum balance for the displacement, including inertia. This model features a nonsmooth constraint ensuring the continuity of the displacements outside the crack set, which is marked by the support of the delamination parameter. A weak solvability concept, generalizing the notion of energetic solution for rateindependent systems to the present mixed ratedependent/rateindependent frame, is proposed. Via refined variational convergence techniques, existence of solutions is proved by passing to the limit in approximating systems which regularize the nonsmooth constraint by conditions for adhesive contact. The presence of the inertial term requires the design of suitable recovery spaces small enough to provide compactness but large enough to recover the information on the crack set in the limit. 
R. Rossi, M. Thomas, Coupling rateindependent and ratedependent processes: Existence results, SIAM Journal on Mathematical Analysis, 49 (2017), pp. 14191494.
Abstract
We address the analysis of an abstract system coupling a rateindependet process with a second order (in time) nonlinear evolution equation. We propose suitable weak solution concepts and obtain existence results by passing to the limit in carefully devised timediscretization schemes. Our arguments combine techniques from the theory of gradient systems with the toolbox for rateindependent evolution, thus reflecting the mixed character of the problem. Finally, we discuss applications to a class of rateindependent processes in viscoelastic solids with inertia, and to a recently proposed model for damage with plasticity. 
M. Thomas, Ch. Zanini, Cohesive zonetype delamination in viscoelasticity, Discrete and Continuous Dynamical Systems  Series S, 10 (2017), pp. 14871517, DOI 10.3934/dcdss.2017077 .
Abstract
We study a model for the rateindependent evolution of cohesive zone delamination in a viscoelastic solid, also exposed to dynamics effects. The main feature of this model, inspired by [Ortiz&Pandoli99Int.J.Numer.Meth.Eng.], is that the surface energy related to the crack opening depends on the history of the crack separation between the two sides of the crack path, and allows for different responses upon loading and unloading.
Due to the presence of multivalued and unbounded operators featuring nonpenetration and the `memory'constraint in the strong formulation of the problem, we prove existence of a weaker notion of solution, known as semistable energetic solution, pioneered in [Roubicek09M2AS] and refined in [Rossi&Thomas15WIASPreprint2113]. 
O. Klein, A representation result for rateindependent systems, Phys. B, 486 (2016), pp. 8183.

A. Mielke, R. Rossi, G. Savaré, Balanced viscosity (BV) solutions to infinitedimensional rateindependent systems, Journal of the European Mathematical Society (JEMS), 18 (2016), pp. 21072165.
Abstract
Balanced Viscosity solutions to rateindependent systems arise as limits of regularized rateindependent ows by adding a superlinear vanishingviscosity dissipation. We address the main issue of proving the existence of such limits for innitedimensional systems and of characterizing them by a couple of variational properties that combine a local stability condition and a balanced energydissipation identity. A careful description of the jump behavior of the solutions, of their dierentiability properties, and of their equivalent representation by time rescaling is also presented. Our techniques rely on a suitable chainrule inequality for functions of bounded variation in Banach spaces, on rened lower semicontinuitycompactness arguments, and on new BVestimates that are of independent interest. 
R. Rossi, M. Thomas, From an adhesive to a brittle delamination model in thermoviscoelasticity, ESAIM. Control, Optimisation and Calculus of Variations, 21 (2015), pp. 159.
Abstract
We address the analysis of a model for brittle delamination of two viscoelastic bodies, bonded along a prescribed surface. The model also encompasses thermal effects in the bulk. The related PDE system for the displacements, the absolute temperature, and the delamination variable has a highly nonlinear character. On the contact surface, it features frictionless Signorini conditions and a nonconvex, brittle constraint acting as a transmission condition for the displacements. We prove the existence of (weak/energetic) solutions to the associated Cauchy problem, by approximating it in two steps with suitably regularized problems. We perform the two consecutive passages to the limit via refined variational convergence techniques. 
T. Roubíček, M. Thomas, Ch. Panagiotopoulos, Stressdriven localsolution approach to quasistatic brittle delamination, Nonlinear Analysis. Real World Applications. An International Multidisciplinary Journal, 22 (2015), pp. 645663.
Abstract
A unilateral contact problem between elastic bodies at small strains glued by a brittle adhesive is addressed in the quasistatic rateindependent setting. The delamination process is modelled as governed by stresses rather than by energies. This results in a specific scaling of an approximating elastic adhesive contact problem, discretised by a semiimplicit scheme and regularized by a BVtype gradient term. An analytical zerodimensional example motivates the model and a specific localsolution concept. Twodimensional numerical simulations performed on an engineering benchmark problem of debonding a fiber in an elastic matrix further illustrate the validity of the model, convergence, and algorithmical efficiency even for very rigid adhesives with high elastic moduli. 
O. Klein, On the representation of hysteresis operators acting on vectorvalued, leftcontinuous and piecewise monotaffine and continuous functions, Discrete and Continuous Dynamical Systems, 35 (2015), pp. 25912614.
Abstract
In BrokateSprekels 1996, it is shown that hysteresis operators acting on scalarvalued, continuous, piecewise monotone input functions can be represented by functionals acting on alternating strings. In a number of recent papers, this representation result is extended to hysteresis operators dealing with input functions in a general topological vector space. The input functions have to be continuous and piecewise monotaffine, i.e., being piecewise the composition of two functions such that the output of a monotone increasing function is used as input for an affine function. In the current paper, a representation result is formulated for hysteresis operators dealing with input functions being leftcontinuous and piecewise monotaffine and continuous. The operators are generated by functions acting on an admissible subset of the set of all strings of pairs of elements of the vector space. of the set of all strings of pairs of elements of the vector space. 
O. Klein, A representation result for hysteresis operators with vector valued inputs and its application to models for magnetic materials, Phys. B, 435 (2014), pp. 113115.
Abstract
In this work, hysteresis operators mapping continuous vectorvalued input functions being piecewise monotaffine, i.e. being piecewise the composition of a monotone with an affine function, to vectorvalued output functions are considered. It is shown that the operator can be generated by a uniquely defined function on the convexity triple free strings. A formulation of a congruence property for periodic inputs is presented and reformulated as a condition for the generating string function. 
A. Mielke, S. Zelik, On the vanishingviscosity limit in parabolic systems with rateindependent dissipation terms, Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie V, XIII (2014), pp. 67135.
Abstract
We consider quasilinear parabolic systems with a nonsmooth rateindependent dissipation term in the limit of very slow loading rates, or equivalently with fixed loading and vanishing viscosity $varepsilon>0$. Because for nonconvex energies the solutions will develop jumps, we consider the vanishingviscosity limit for the graphs of the solutions in the extended state space in arclength parametrization, where the norm associated with the viscosity is used to keep the subdifferential structure of the problem. A crucial point in the analysis are new a priori estimates that are rate independent and that allows us to show that the total length of the graph remains bounded in the vanishingviscosity limit. To derive these estimates we combine parabolic regularity estimates with ideas from rateindependent systems. 
TH.I. Seidman, O. Klein, Periodic solutions of isotone hybrid systems, Discrete and Continuous Dynamical Systems. Series B. A Journal Bridging Mathematics and Sciences, 18 (2013), pp. 483493.
Abstract
Suggested by conversations in 1991 (Mark Krasnosel'skiĭ and Aleksei Pokrovskiĭ with TIS), this paper generalizes earlier work (Krasnosel'skiĭPokrovskiĭ 1974) of theirs by defining a setting of hybrid systems with isotone switching rules for a partially ordered set of modes and then obtaining a periodicity result in that context. An application is given to a partial differential equation modeling calcium release and diffusion in cardiac cells. 
D. Knees, R. Rossi, Ch. Zanini, A vanishing viscosity approach to a rateindependent damage model, Mathematical Models & Methods in Applied Sciences, 23 (2013), pp. 565616.
Abstract
We analyze a rateindependent model for damage evolution in elastic bodies. The central quantities are a stored energy functional and a dissipation functional, which is assumed to be positively homogeneous of degree one. Since the energy is not simultaneously (strictly) convex in the damage variable and the displacements, solutions may have jumps as a function of time. The latter circumstance makes it necessary to recur to suitable notions of weak solution. However, the bynow classical concept of global energetic solution fails to describe accurately the behavior of the system at jumps. Hence, we consider rateindependent damage models as limits of systems driven by viscous, ratedependent dissipation. We use a technique for taking the vanishing viscosity limit, which is based on arclength reparameterization. In this way, in the limit we obtain a novel formulation for the rateindependent damage model, which highlights the interplay of viscous and rateindependent effects in the jump regime, and provides a better description of the energetic behavior of the system at jumps. 
D. Knees, A. Schröder, Computational aspects of quasistatic crack propagation, Discrete and Continuous Dynamical Systems  Series S, 6 (2013), pp. 6399.
Abstract
The focus of this note lies on the numerical analysis of models describing the propagation of a single crack in a linearly elastic material. The evolution of the crack is modeled as a rateindependent process based on the Griffith criterion. We follow two different approaches for setting up mathematically well defined models: the global energetic approach and an approach based on a viscous regularization. We prove the convergence of solutions of fully discretized models (i.e. with respect to time and space) and derive relations between the discretization parameters (mesh size, time step size, viscosity parameter, crack increment) which guarantee the convergence of the schemes. Further, convergence rates are provided for the approximation of energy release rates by certain discrete energy release rates. Thereby we discuss both, models with selfcontact conditions on the crack faces as well as models with pure Neumann conditions on the crack faces. The convergence proofs rely on regularity estimates for the elastic fields close to the crack tip and local and global finite element error estimates. Finally the theoretical results are illustrated with some numerical calculations. 
M. Thomas, Quasistatic damage evolution with spatial BVregularization, Discrete and Continuous Dynamical Systems  Series S, 6 (2013), pp. 235255.
Abstract
An existence result for energetic solutions of rateindependent damage processes is established. We consider a body consisting of a physically linearly elastic material undergoing infinitesimally small deformations and partial damage. In [ThomasMielke10DamageZAMM] an existence result in the small strain setting was obtained under the assumption that the damage variable z satisfies z∈ W^{1,r}(Ω) with r∈(1,∞) for Ω⊂R^{d}. We now cover the case r=1. The lack of compactness in W^{1,1}(Ω) requires to do the analysis in BV(Ω). This setting allows it to consider damage variables with values in 0,1. We show that such a brittle damage model is obtained as the Γlimit of functionals of ModicaMortola type. 
M. Liero, Th. Roche, Rigorous derivation of a plate theory in linear elastoplasticity via $Gamma$convergence, NoDEA. Nonlinear Differential Equations and Applications, 19 (2012), pp. 437457.
Abstract
This paper deals with dimension reduction in linearized elastoplasticity in the rateindependent case. The reference configuration of the elastoplastic body is given by a twodimensional middle surface and a small but positive thickness. We derive a limiting model for the case in which the thickness of the plate tends to 0. This model contains membrane and plate deformations which are coupled via plastic strains. The convergence analysis is based on an abstract Gamma convergence theory for rateindependent evolution formulated in the framework of energetic solutions. This concept is based on an energystorage functional and a dissipation functional, such that the notion of solution is phrased in terms of a stability condition and an energy balance. 
A. Fiaschi, D. Knees, U. Stefanelli, Young measure quasistatic damage evolution, Archive for Rational Mechanics and Analysis, 203 (2012), pp. 415453.

S. Bartels, A. Mielke, T. Roubíček, Quasistatic smallstrain plasticity in the limit of vanishing hardening and its numerical approximation, SIAM Journal on Numerical Analysis, 50 (2012), pp. 951976.
Abstract
The quasistatic rateindependent evolution of the PragerZieglertype model of linearized plasticity with hardening is shown to converge to the rateindependent evolution of the PrandtlReuss elastic/perfectly plastic model. Based on the concept of energetic solutions we study the convergence of the solutions in the limit for hardening coefficients converging to 0 by using the abstract method of Gammaconvergence for rateindependent systems. An unconditionally convergent numerical scheme is devised and 2D and 3D numerical experiments are presented. A twosided energy inequality is a posteriori verified to document experimental convergence rates. 
O. Klein , Representation of hysteresis operators for vectorvalued inputs by functions on strings, Phys. B, 407 (2012), pp. 13991400.

O. Klein, Representation of hysteresis operators acting on vectorvalued monotaffine functions, Advances in Mathematical Sciences and Applications, 22 (2012), pp. 471500.
Abstract
In BrokateSprekels1996, it was shown that scalarvalued hysteresis operators for scalarvalued continuous piecewise monotone input functions can be uniquely represented by functionals defined on the set of all finite alternating strings of real numbers. Using this representation, various properties of these hysteresis operators were investigated. In this work, it is shown that a similar representation result can be derived for hysteresis operators dealing with inputs in a general topological linear vector space. Introducing a new class of functions, the socalled emphmonotaffine functions, which can be considered as a vector generalization of monotone scalar functions, and the convexity triple free strings on a vector space as a generalization of the alternating strings allows to formulate the corresponding representation result. As an example for the application of the representation result, a vectorial formulation of the second and third Madelung rule are discussed. 
A. Mielke, R. Rossi, G. Savaré, BV solutions and viscosity approximations of rateindependent systems, ESAIM. Control, Optimisation and Calculus of Variations, 18 (2012), pp. 3680.
Abstract
In the nonconvex case solutions of rateindependent systems may develop jumps as a function of time. To model such jumps, we adopt the philosophy that rate independence should be considered as limit of systems with smaller and smaller viscosity. For the finitedimensional case we study the vanishingviscosity limit of doubly nonlinear equations given in terms of a differentiable energy functional and a dissipation potential which is a viscous regularization of a given rateindependent dissipation potential. The resulting definition of `BV solutions' involves, in a nontrivial way, both the rateindependent and the viscous dissipation potential, which play a crucial role in the description of the associated jump trajectories. We shall prove a general convergence result for the timecontinuous and for the timediscretized viscous approximations and establish various properties of the limiting $BV$ solutions. In particular, we shall provide a careful description of the jumps and compare the new notion of solutions with the related concepts of energetic and local solutions to rateindependent systems. 
A. Mielke, R. Rossi, G. Savaré, Variational convergence of gradient flows and rateindependent evolutions in metric spaces, Milan Journal of Mathematics, 80 (2012), pp. 381410.
Abstract
We study the asymptotic behaviour of families of gradient flows in a general metric setting, when the metricdissipation potentials degenerate in the limit to a dissipation with linear growth. We present a general variational definition of BV solutions to metric evolutions, showing the different characterization of the solution in the absolutely continuous regime, on the singular Cantor part, and along the jump transitions. By using tools of metric analysis, BV functions and blowup by time rescaling, we show that this variational notion is stable with respect to a wide class of perturbations involving energies, distances, and dissipation potentials. As a particular application, we show that BV solutions to rateindependent problems arise naturally as a limit of pgradient flows, p>1, when the exponents p converge to 1. 
A. Mielke, T. Roubíček, M. Thomas, From damage to delamination in nonlinearly elastic materials at small strains, Journal of Elasticity. The Physical and Mathematical Science of Solids, 109 (2012), pp. 235273.
Abstract
Brittle Griffithtype delamination of compounds is deduced by means of Gammaconvergence from partial, isotropic damage of threespecimensandwichstructures by flattening the middle component to the thickness 0. The models used here allow for nonlinearly elastic materials at small strains and consider the processes to be unidirectional and rateindependent. The limit passage is performed via a double limit: first, we gain a delamination model involving the gradient of the delamination variable, which is essential to overcome the lack of a uniform coercivity arising from the passage from partial damage to delamination. Second, the delaminationgradient is supressed. Noninterpenetration and transmissionconditions along the interface are obtained. 
A. Mielke, L. Truskinovsky, From discrete viscoelasticity to continuum rateindependent plasticity: Rigorous results, Archive for Rational Mechanics and Analysis, 203 (2012), pp. 577619.
Abstract
We show that continuum models for ideal plasticity can be obtained as a rigorous mathematical limit starting from a discrete microscopic model describing a viscoelastic crystal lattice with quenched disorder. The constitutive structure changes as a result of two concurrent limiting procedures: the vanishingviscosity limit and the discrete to continuum limit. In the course of these limits a nonconvex elastic problem transforms into a convex elastic problem while the quadratic ratedependent dissipation of viscoelastic solid transforms into a singular rateindependent dissipation of an ideally plastic solid. In order to emphasize ideas we employ in our proofs the simplest prototypical system describing transformational plasticity of shapememory alloys. The approach, however, is sufficiently general and can be used for similar reductions in the cases of more general plasticity and damage models. 
A. Mielke, Emergence of rateindependent dissipation from viscous systems with wiggly energies, Continuum Mechanics and Thermodynamics, 24 (2012), pp. 591606.
Abstract
We consider the passage from viscous system to rateindependent system in the limit of vanishing viscosity and for wiggly energies. Our new convergence approach is based on the (R,R^{*}) formulation by De Giorgi, where we pass to the Γ limit in the dissipation functional. The difficulty is that the type of dissipation changes from a quadratic functional to one that is homogeneous of degree 1. The analysis uses the decomposition of the restoring force into a macroscopic part and a fluctuating part, where the latter is handled via homogenization. 
A. Mielke, Generalized PrandtlIshlinskii operators arising from homogenization and dimension reduction, Phys. B, 407 (2012), pp. 13301335.
Abstract
We consider rateindependent evolutionary systems over a physically domain Ω that are governed by simple hysteresis operators at each material point. For multiscale systems where ε denotes the ratio between the microscopic and the macroscopic length scale, we show that in the limit ε → 0 we are led to systems where the hysteresis operators at each macroscopic point is a generalized PrandtlIshlinskii operator 
M. Liero, A. Mielke, An evolutionary elastoplastic plate model derived via $Gamma$convergence, Mathematical Models & Methods in Applied Sciences, 21 (2011), pp. 19611986.
Abstract
This paper is devoted to dimension reduction for linearized elastoplasticity in the rateindependent case. The reference configuration of the threedimensional elastoplastic body has a twodimensional middle surface and a positive but small thickness. Under suitable scalings we derive a limiting model for the case in which the thickness of the plate tends to 0. This model contains membrane and plate deformations (linear KirchhoffLove plate), which are coupled via plastic strains. We establish strong convergence of the solutions in the natural energy space. The analysis uses an abstract Gammaconvergence theory for rateindependent evolutionary systems that is based on the notion of energetic solutions. This concept is formulated via an energystorage functional and a dissipation functional, such that energetic solutions are defined in terms of a stability condition and an energy balance. The Mosco convergence of the quadratic energystorage functional follows the arguments of the elastic case. To handle the evolutionary situation the interplay with the dissipation functional is controlled by cancellation properties for Moscoconvergent quadratic energies. 
A. Mielke, Formulation of thermoelastic dissipative material behavior using GENERIC, Continuum Mechanics and Thermodynamics, 23 (2011), pp. 233256.
Abstract
The theory of GENERIC (general equations for nonequilibrium reversible irreversibel coupling) is presented in a mathematical form. It is applied first to simple mechanical systems and then generalized to standard generalized materials. It is shown that nonisothermal viscoplasticity can be cast into the form of GENERIC, if the dissipative structure is generalized from linear functionals to the more general subdifferential of convex potentials. 
M. Thomas, A. Mielke, Damage of nonlinearly elastic materials at small strain  Existence and regularity results, ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik, 90 (2010), pp. 88112.
Abstract
In this paper an existence result for energetic solutions of rateindependent damage processes is established and the temporal regularity of the solution is discussed. We consider a body consisting of a physically nonlinearly elastic material undergoing small deformations and partial damage. The present work is a generalization of [MielkeRoubicek 2006] concerning the properties of the stored elastic energy density as well as the suitable Sobolev space for the damage variable: While previous work assumes that the damage variable z satisfies z ∈ W^1,r (Omega) with r>d for Omega ⊂ R^d, we can handle the case r>1 by a new technique for the construction of joint recovery sequences. Moreover, this work generalizes the temporal regularity results to physically nonlinearly elastic materials by analyzing Lipschitz and Höldercontinuity of solutions with respect to time. 
P. Gruber, D. Knees, S. Nesenenko, M. Thomas, Analytical and numerical aspects of timedependent models with internal variables, ZAMM. Zeitschrift für Angewandte Mathematik und Mechanik, 90 (2010), pp. 861902.
Abstract
In this paper some analytical and numerical aspects of timedependent models with internal variables are discussed. The focus lies on elasto/viscoplastic models of monotone type arising in the theory of inelastic behavior of materials. This class of problems includes the classical models of elastoplasticity with hardening and viscous models of the NortonHoff type. We discuss the existence theory for different models of monotone type, give an overview on spatial regularity results for solutions to such models and illustrate a numerical solution algorithm at an example. Finally, the relation to the energetic formulation for rateindependent processes is explained and temporal regularity results based on different convexity assumptions are presented. 
M. Eleuteri, J. Kopfová, P. Krejčí, Magnetohydrodynamic flow with hysteresis, SIAM Journal on Mathematical Analysis, 41 (2009), pp. 435464.
Abstract
We consider a model system describing the 2D flow of a conducting fluid surrounded by a ferromagnetic solid under the influence of the hysteretic response of the surrounding medium. We assume that this influence can be represented by the Preisach hysteresis operator. Existence and uniqueness of solutions for the resulting system of PDEs with hysteresis nonlinearities is established in the convexity domain of the Preisach operator. 
K. Kuhnen, P. Krejčí, Compensation of complex hysteresis and creep effects in piezoelectrically actuated systems  A new Preisach modeling approach, IEEE Transactions on Automatic Control. Institute of Electrical and Electronics Engineers, Inc., New York, NY (US). Control Systems Society., 54 (2009), pp. 537550.

P. Krejčí, M. Liero, Rate independent Kurzweil processes, Applications of Mathematics, 54 (2009), pp. 117145.
Abstract
The Kurzweil integral technique is applied to a class of rate independent processes with convex energy and discontinuous inputs. We prove existence, uniqueness, and continuous data dependence of solutions in $BV$ spaces. It is shown that in the context of elastoplasticity, the Kurzweil solutions coincide with natural limits of viscous regularizations when the viscosity coefficient tends to zero. The discontinuities produce an additional positive dissipation term, which is not homogeneous of degree one. 
M. Brokate, M. Eleuteri, P. Krejčí, On a model for electromagnetic processes inside and outside a ferromagnetic body, Mathematical Methods in the Applied Sciences, 31 (2008), pp. 15451567.

M. Eleuteri, J. Kopfová, P. Krejčí, On a model with hysteresis arising in magnetohydrodynamics, Phys. B, 403 (2008), pp. 448450.

M. Eleuteri, O. Klein, P. Krejčí, Outward pointing inverse Preisach operators, Phys. B, 403 (2008), pp. 254256.

P. Krejčí, K. Kuhnen, Existence, uniqueness and $L_infty$stability of the PrandtlIshlinskii hysteresis and creep compensator, European Journal of Control, 14 (2008), pp. 409417.

P. Krejčí, J. Sprekels, Clamped elasticideally plastic beams and PrandtlIshlinskii hysteresis operators, Discrete and Continuous Dynamical Systems  Series S, 1 (2008), pp. 283292.

P. Krejčí, A higher order energy bound in a singular Preisach circuit, Phys. B, 403 (2008), pp. 297300.

M. Eleuteri, P. Krejčí, An asymptotic convergence result for a system of partial differential equations with hysteresis, Communications on Pure and Applied Analysis, 6 (2007), pp. 11311143.

M. Eleuteri, Wellposedness results for a class of partial differential equations with hysteresis arising in electromagnetism, Nonlinear Analysis. Real World Applications. An International Multidisciplinary Journal, 8 (2007), pp. 14941511.

P. Krejčí, J. Sprekels, Elasticideally plastic beams and PrandtlIshlinskii hysteresis operators, Mathematical Methods in the Applied Sciences, 30 (2007), pp. 23712393.

P. Krejčí, J. Sprekels, Long time behaviour of a singular phase transition model, Discrete and Continuous Dynamical Systems, 15 (2006), pp. 11191135.

O. Klein, Asymptotic behaviour for a phasefield model with hysteresis in onedimensional thermoviscoplasticity, Applications of Mathematics, 49 (2004), pp. 309341.

P. Krejčí, J. Sprekels, Nonlocal phasefield models for nonisothermal phase transitions and hysteresis, Advances in Mathematical Sciences and Applications, 14 (2004), pp. 593612.

P. Krejčí, J. Sprekels, U. Stefanelli, Onedimensional thermoviscoplastic processes with hysteresis and phase transitions, Advances in Mathematical Sciences and Applications, 13 (2003), pp. 695712.

O. Klein, P. Krejčí, Outwards pointing hysteresis operators and asymptotic behaviour of evolution equations, Nonlinear Analysis. Real World Applications. An International Multidisciplinary Journal, 4 (2003), pp. 755785.

J. Sprekels, S. Zheng, Global existence and asymptotic behaviour for a nonlocal phasefield model for nonisothermal phase transitions, Journal of Mathematical Analysis and Applications, 279 (2003), pp. 97110.

N. Kenmochi, J. Sprekels, Phasefield systems with vectorial order parameters including diffusional hysteresis effects, Communications on Pure and Applied Analysis, 1 (2002), pp. 495511.

P. Krejčí, J. Sprekels, U. Stefanelli, Phasefield models with hysteresis in onedimensional thermoviscoplasticity, SIAM Journal on Mathematical Analysis, 34 (2002), pp. 409434.

P. Krejčí, J. Sprekels, Parabolic regularization of differential inclusions and the stop operator, Interfaces and Free Boundaries. Mathematical Modelling, Analysis and Computation, 4 (2002), pp. 423435.

J. Sprekels, P. Krejčí, Phasefield systems for multidimensional PrandtlIshlinskii operators with nonpolyhedral characteristics, Mathematical Methods in the Applied Sciences, 25 (2002), pp. 309325.

P. Krejčí, J. Sprekels, S. Zheng, Asymptotic behaviour for a phasefield system with hysteresis, Journal of Differential Equations, 175 (2001), pp. 88107.

P. Krejčí, J. Sprekels, On a class of multidimensional PrandtlIshlinskii operators, Phys. B, 306 (2001), pp. 185190.

P. Krejčí, J. Sprekels, A hysteresis approach to phasefield models, Nonlinear Analysis. Theory, Methods & Applications. An International Multidisciplinary Journal. Series A: Theory and Methods, 39 (2000), pp. 569586.

P. Krejčí, J. Sprekels, Phasefield models with hysteresis, Journal of Mathematical Analysis and Applications, 252 (2000), pp. 198219.

G. Gilardi, P. Krejčí, J. Sprekels, Hysteresis in phasefield models with thermal memory, Mathematical Methods in the Applied Sciences, 23 (2000), pp. 909922.
Beiträge zu Sammelwerken

R. Rossi, U. Stefanelli, M. Thomas, Rateindependent evolution of sets, in: Analysis of Evolutionary and Complex Systems: Issue on the Occasion of Alexander Mielke's 60th Birthday, M. Liero, S. Reichelt, G. Schneider, F. Theil, M. Thomas, eds., 14 of Discrete and Continuous Dynamical Systems  Series S, American Institute of Mathematical Sciences, Springfield, 2021, pp. 89119, DOI 10.3934/dcdss.2020304 .
Abstract
The goal of this work is to analyze a model for the rateindependent evolution of sets with finite perimeter. The evolution of the admissible sets is driven by that of (the complement of) a given timedependent set, which has to include the admissible sets and hence is to be understood as an external loading. The process is driven by the competition between perimeter minimization and minimization of volume changes.In the mathematical modeling of this process, we distinguish the adhesive case, in which the constraint that the (complement of) the `external load' contains the evolving sets is penalized by a term contributing to the driving energy functional, from the brittle case, enforcing this constraint. The existence of Energetic solutions for the adhesive system is proved by passing to the limit in the associated timeincremental minimization scheme. In the brittle case, this timediscretization procedure gives rise to evolving sets satisfying the stability condition, but it remains an open problem to additionally deduce energydissipation balance in the timecontinuous limit. This can be obtained under some suitable quantification of data. The properties of the brittle evolution law are illustrated by numerical examples in two space dimensions. 
O. Klein, On uncertainty quantification for models involving hysteresis operators, in: Extended Abstracts Spring 2018  Singularly Perturbed Systems, Multiscale Phenomena and Hysteresis: Theory and Applications, A. Korobeinikov, M. Caubergh, T. Lázaro, J. Sardanyés, eds., 11 of Research Perspectives CRM Barcelona, Birkhäuser, Cham, 2019, pp. 271275, DOI 10.1007/9783030252618 .

R. Rossi, M. Thomas, From nonlinear to linear elasticity in a coupled ratedependent/independent system for brittle delamination, in: Proceedings of the INdAMISIMM Workshop on Trends on Applications of Mathematics to Mechanics, Rome, Italy, September 2016, E. Rocca, U. Stefanelli, L. Truskinovsky, A. Visintin, eds., 27 of Springer INdAM Series, Springer International Publishing, Cham, 2018, pp. 127157, DOI 10.1007/9783319759401_7 .
Abstract
We revisit the weak, energetictype existence results obtained in [Rossi/ThomasESAIMCOCV21(1):159,2015] for a system for rateindependent, brittle delamination between two viscoelastic, physically nonlinear bulk materials and explain how to rigorously extend such results to the case of viscoelastic, linearly elastic bulk materials. Our approximation result is essentially based on deducing the Moscoconvergence of the functionals involved in the energetic formulation of the system. We apply this approximation result in two different situations: Firstly, to pass from a nonlinearly elastic to a linearly elastic, brittle model on the timecontinuous level, and secondly, to pass from a timediscrete to a timecontinuous model using an adhesive contact approximation of the brittle model, in combination with a vanishing, superquadratic regularization of the bulk energy. The latter approach is beneficial if the model also accounts for the evolution of temperature. 
S. Bartels, M. Milicevic, M. Thomas, Numerical approach to a model for quasistatic damage with spatial $BV$regularization, in: Proceedings of the INdAMISIMM Workshop on Trends on Applications of Mathematics to Mechanics, Rome, Italy, September 2016, E. Rocca, U. Stefanelli, L. Truskinovsky, A. Visintin, eds., 27 of Springer INdAM Series, Springer International Publishing, Cham, 2018, pp. 179203, DOI 10.1007/9783319759401_9 .
Abstract
We address a model for rateindependent, partial, isotropic damage in quasistatic small strain linear elasticity, featuring a damage variable with spatial BVregularization. Discrete solutions are obtained using an alternate timediscrete scheme and the VariableADMM algorithm to solve the constrained nonsmooth optimization problem that determines the damage variable at each time step. We prove convergence of the method and show that discrete solutions approximate a semistable energetic solution of the rateindependent system. Moreover, we present our numerical results for two benchmark problems. 
M. Thomas, A comparison of delamination models: Modeling, properties, and applications, in: Mathematical Analysis of Continuum Mechanics and Industrial Applications II, Proceedings of the International Conference CoMFoS16, P. VAN Meurs, M. Kimura, H. Notsu, eds., 30 of Mathematics for Industry, Springer Nature, Singapore, 2018, pp. 2738, DOI 10.1007/9789811062834_3 .
Abstract
This contribution presents recent results in the modeling and the analysis of delamination problems. It addresses adhesive contact, brittle, and cohesive zone models both in a quasistatic and a viscous, dynamic setting for the bulk part. Also different evolution laws for the delaminating surface are discussed. 
A. Mielke, Three examples concerning the interaction of dry friction and oscillations, in: Proceedings of the INdAMISIMM Workshop on Trends on Applications of Mathematics to Mechanics, Rome, Italy, September 2016, E. Rocca, U. Stefanelli, L. Truskinovsky, A. Visintin, eds., 27 of Springer INdAM Series, Springer International Publishing, Cham, 2018, pp. 159177, DOI 10.1007/9783319759401_8 .
Abstract
We discuss recent work concerning the interaction of dry friction, which is a rate independent effect, and temporal oscillations. First, we consider the temporal averaging of highly oscillatory friction coefficients. Here the effective dry friction is obtained as an infimal convolution. Second, we show that simple models with statedependent friction may induce a Hopf bifurcation, where constant shear rates give rise to periodic behavior where sticking phases alternate with sliding motion. The essential feature here is the dependence of the friction coefficient on the internal state, which has an internal relaxation time. Finally, we present a simple model for rocking toy animal where walking is made possible by a periodic motion of the body that unloads the legs to be moved. 
G. Lazzaroni, R. Rossi, M. Thomas, R. Toader, Some remarks on a model for rateindependent damage in thermoviscoelastodynamics, in: MURPHYSHSFS2014: 7th International Workshop on MUltiRate Processes and HYSteresis (MURPHYS) & 2nd International Workshop on Hysteresis and SlowFast Systems (HSFS), O. Klein, M. Dimian, P. Gurevich, D. Knees, D. Rachinskii, S. Tikhomirov, eds., 727 of Journal of Physics: Conference Series, IOP Publishing, 2016, pp. 012009/1012009/20.
Abstract
This note deals with the analysis of a model for partial damage, where the rateindependent, unidirectional flow rule for the damage variable is coupled with the ratedependent heat equation, and with the momentum balance featuring inertia and viscosity according to KelvinVoigt rheology. The results presented here combine the approach from [Roubíček M2AS'09, SIAM'10] with the methods from Lazzaroni/Rossi/Thomas/Toader [WIAS Preprint 2025]. The present analysis encompasses, differently from [Roubíček SIAM'10], the monotonicity in time of damage and the dependence of the viscous tensor on damage and temperature, and, unlike [WIAS Preprint 2025], a nonconstant heat capacity and a timedependent Dirichlet loading. 
O. Klein, V. Recupero, Hausdorff metric BV discontinuity of sweeping processes, in: MURPHYSHSFS2014: 7th International Workshop on MUltiRate Processes & HYSteresis (MURPHYS) & the 2nd International Workshop on Hysteresis and SlowFast Systems (HSFS), O. Klein, M. Dimian, P. Gurevich, D. Knees, D. Rachinskii, S. Tikhomirov, eds., 727 of Journal of Physics: Conference Series, 2016, pp. 012006/1012006/12, DOI 10.1088/17426596/727/1/012006 .
Abstract
Sweeping processes are a class of evolution differential inclusions arising in elastoplasticity and were introduced by J.J. Moreau in the early seventies. The solution operator of the sweeping processes represents a relevant example of emphrate independent operator containing as a particular case the so called emphplay operator which is widely used in hysteresis. The continuity properties of these operators were studied in several works. In this note we address the continuity with respect to the strict metric in the space of functions of bounded variation with values in the metric space of closed convex subsets of a Hilbert space. We provide a counterexample showing that the solution operator of the sweeping process is not continuous when its domain is endowed with the strict topology of $BV$ and its codomain is endowed with the $L^1$topology. This is at variance with the case of the play operator which instead is continuous in this sense. 
A. Mielke, Free energy, free entropy, and a gradient structure for thermoplasticity, in: Innovative Numerical Approaches for MultiField and MultiScale Problems. In Honor of Michael Ortiz's 60th Birthday, K. Weinberg, A. Pandolfi, eds., 81 of Lecture Notes in Applied and Computational Mechanics, Springer International Publishing Switzerland, Cham, 2016, pp. 135160.
Abstract
In the modeling of solids the free energy, the energy, and the entropy play a central role. We show that the free entropy, which is defined as the negative of the free energy divided by the temperature, is similarly important. The derivatives of the free energy are suitable thermodynamical driving forces for reversible (i.e. Hamiltonian) parts of the dynamics, while for the dissipative parts the derivatives of the free entropy are the correct driving forces. This difference does not matter for isothermal cases nor for local materials, but it is relevant in the nonisothermal case if the densities also depend on gradients, as is the case in gradient thermoplasticity.
Using the total entropy as a driving functional, we develop gradient structures for quasistatic thermoplasticity, which again features the role of the free entropy. The big advantage of the gradient structure is the possibility of deriving timeincremental minimization procedures, where the entropyproduction potential minus the total entropy is minimized with respect to the internal variables and the temperature.
We also highlight that the usage of an auxiliary temperature as an integrating factor in Yang/Stainier/Ortiz "A variational formulation of the coupled thermomechanical boundaryvalue problem for general dissipative solids" (J. Mech. Physics Solids, 54, 401424, 2006) serves exactly the purpose to transform the reversible driving forces, obtained from the free energy, into the needed irreversible driving forces, which should have been derived from the free entropy. This reconfirms the fact that only the usage of the free entropy as driving functional for dissipative processes allows us to derive a proper variational formulation. 
M. Thomas, Modeling and analysis of rateindependent damage and delamination processes, in: Proceedings of the 19th International Conference on Computer Methods in Mechanics (online only), 2011, pp. 16.

A. Mielke, Geometry and thermodynamics for the coupling of quantum mechanics and dissipative systems, in: Applied Dynamics and Geometric Mechanics, Workshop, August 1420, 2011, 8 of Oberwolfach Reports, Mathematisches Forschungsinstitut Oberwolfach, 2011, pp. 22602263.

M. Thomas, From damage to delamination in nonlinearly elastic materials at small strains, in: Microstructures in Solids: From Quantum Models to Continua, Workshop, March 1420, 2010, 7 of Oberwolfach Reports, Mathematisches Forschungsinstitut Oberwolfach, 2010, pp. 783785.

O. Klein, Outward pointing properties for vectorial hysteresis operators and some applications, in: International Workshop on MultiRate Processes and Hysteresis'', March 31  April 5, 2008, Cork, Ireland, M.P. Mortell, R.E. O'Malley, A. Pokrovskii, D. Rachinskii, V.A. Sobolev, eds., 138 of J. Phys.: Conf. Ser., Inst. Phys., 2008, pp. 012009/1012009/14.

P. Krejčí, Hysteresis rarefaction in the Riemann problem, in: International Workshop on MultiRate Processes and Hysteresis, March 31  April 5, 2008, Cork, Ireland, M.P. Mortell, R.E. O'Malley, A. Pokrovskii, D. Rachinskii, V.A. Sobolev, eds., 138 of J. Phys.: Conf. Ser., Inst. Phys., 2008, pp. 012010/1012010/10.

M. Eleuteri, An existence result for a P.D.E. with hysteresis, convection and a nonlinear boundary condition, in: Dynamical Systems, Differential Equations and Applications. Dedicated to the 6th AIMS Conference, Poitiers, France, B. Belinsky, K. Lan, X. Lu, A. Miranville, R. Shivaji, eds., American Institute of Mathematical Sciences, Springfield, 2007, pp. 344353.

M. Eleuteri, Some P.D.E.s with hysteresis, in: Free Boundary Problems. Theory and Applications, I.N. Figueiredo, J.F. Rodrigues, L. Santos, eds., 154 of Internat. Ser. Numer. Math., Birkhäuser, Basel, 2007, pp. 159168.

P. Krejčí, Asymptotic hysteresis patterns in a phase separation problem, in: Free Boundary Problems. Theory and Applications, I.N. Figueiredo, J.F. Rodrigues, L. Santos, eds., 154 of Internat. Ser. Numer. Math., Birkhäuser, Basel, 2007, pp. 283290.

M. Brokate, O. Klein, P. Krejčí, Outward pointing properties for Preisach operators, in: Proceedings of the Fifth International Symposium on Hysteresis and Micromagnetic Modeling, Budapest, Hungary, 30 May01 June 2005, A. Ivanyi, G. Kádár, eds., 372 of Phys. B, Elsevier, Amsterdam, 2006, pp. 58.

J. Sprekels, Asymptotic behavior of the stop hysteresis operator, in: Applications of Asymptotic Analysis, Workshop, June 1824, 2006, 3 of Oberwolfach Reports, Mathematisches Forschungsinstitut Oberwolfach, 2006, pp. 16961697.

O. Klein, P. Krejčí, Asymptotic behaviour of evolution equations involving outwards pointing hysteresis operators, in: Proceedings of the Fourth International Symposium on Hysteresis and Micromagnetic Modeling, Salamanca, Spain, 2830 May 2003, L. LopezDias, L. Torres, O. Alejos, eds., 343 of Physica B: Condensed Matter, Elsevier B.V., 2004, pp. 5358.

J. Sprekels, D. Tiba, Optimization of differential systems with hysteresis, in: Analysis and Optimization of Differential Systems, IFIP TC7/WG7.2 International Working Conference on Analysis and Optimization of Differential Systems, September 1014, 2002, Constanta, Romania, V. Barbu, I. Lasiecka, D. Tiba, C. Varsan, eds., Kluwer Academic Publishers, Boston, 2003, pp. 387398.

P. Krejčí, J. Sprekels, Phasefield systems and vector hysteresis operators, in: Free Boundary Problems: Theory and Applications II, N. Kenmochi, ed., 14 of Gakuto Int. Series Math. Sci. & Appl., Gakkōtosho, Tokyo, 2000, pp. 295310.
Preprints, Reports, Technical Reports

D.R.M. Renger, S. Schindler, Gradient flows for bounded linear evolution equations, Preprint no. 2881, WIAS, Berlin, 2021, DOI 10.20347/WIAS.PREPRINT.2881 .
Abstract, PDF (198 kByte)
We study linear evolution equations in separable Hilbert spaces defined by a bounded linear operator. We answer the question which of these equations can be written as a gradient flow, namely those for which the operator is real diagonalisable. The proof is constructive, from which we also derive geodesic lambdaconvexity. 
M. Heida, M. Thomas, GENERIC for dissipative solids with bulkinterface interaction, Preprint no. 2872, WIAS, Berlin, 2021, DOI 10.20347/WIAS.PREPRINT.2872 .
Abstract, PDF (322 kByte)
The modeling framework of GENERIC was originally introduced by Grmela and Öttinger for thermodynamically closed systems. It is phrased with the aid of the energy and entropy as driving functionals for reversible and dissipative processes and suitable geometric structures. Based on the definition functional derivatives we propose a GENERIC framework for systems with bulkinterface interaction and apply it to discuss the GENERIC structure of models for delamination processes. 
D. Peschka, M. Rosenau, Twophase flows for sedimentation of suspensions, Preprint no. 2743, WIAS, Berlin, 2020, DOI 10.20347/WIAS.PREPRINT.2743 .
Abstract, PDF (12 MByte)
We present a twophase flow model that arises from energeticvariational arguments and study its implication for the sedimentation of buoyant particles in a viscous fluid inside a HeleShaw cell and also compare corresponding simulation results to experiments. Based on a minimal dissipation argument, we provide a simplified 1D model applicable to sedimentation and study its properties and the numerical discretization. We also explore different aspects of its numerical discretization in 2D. The focus is on different possible stabilization techniques and their impact on the qualitative behavior of solutions. We use experimental data to verify some first qualitative model predictions and discuss these experiments for different stages of batch sedimentation. 
S. Bartels, M. Milicevic, M. Thomas, N. Weber, Fully discrete approximation of rateindependent damage models with gradient regularization, Preprint no. 2707, WIAS, Berlin, 2020, DOI 10.20347/WIAS.PREPRINT.2707 .
Abstract, PDF (3444 kByte)
This work provides a convergence analysis of a timediscrete scheme coupled with a finiteelement approximation in space for a model for partial, rateindependent damage featuring a gradient regularization as well as a nonsmooth constraint to account for the unidirectionality of the damage evolution. The numerical algorithm to solve the coupled problem of quasistatic small strain linear elasticity with rateindependent gradient damage is based on a Variable ADMMmethod to approximate the nonsmooth contribution. Spacediscretization is based on P1 finite elements and the algorithm directly couples the timestep size with the spatial grid size h. For a wide class of gradient regularizations, which allows both for Sobolev functions of integrability exponent r ∈ (1, ∞) and for BVfunctions, it is shown that solutions obtained with the algorithm approximate as h → 0 a semistable energetic solution of the original problem. The latter is characterized by a minimality property for the displacements, a semistability inequality for the damage variable and an energy dissipation estimate. Numerical benchmark experiments confirm the stability of the method.
Vorträge, Poster

TH. Eiter, On the timeperiodic Viscous flow outside a rotating body (online talk), SIAM Conference on Analysis of Partial Differential Equations, Minisymposium ``Recent Developments in the Mathematical Analysis of Viscous Fluids" (Online Event), March 14  18, 2022, Society for Industrial and Applied Mathematics, March 15, 2022.

P. Pelech, Separately global solutions to rateindependent systems  applications to largestrain deformations of damageable solids (online talk), 20th GAMM Seminar on Microstructures (Online Event), Technische Universität Wien, Austria, January 29, 2021.

P. Pelech , Separately global solutions to rateindependent systems  Applications to largestrain deformations of damageable solids (online talk), MS21: SIAM Conference on Mathematical Aspects of Materials Science, Minisymposium 33 ``Asymptotic Analysis of Variational Models in Solid Mechanics'' (Online Event), May 17  28, 2021, Society for Industrial and Applied Mathematics, May 24, 2021.

S. Tornquist, Analysis of dynamic phasefield fracture (online talk), 9th BMS Student Conference (Online Event), March 3  5, 2021, Berlin Mathematical School, March 4, 2021.

M. Thomas, Convergence analysis for fully discretized damage and phasefield fracture models (online talk), 15th International Conference on Free Boundary Problems: Theory and Applications 2021 (Online Event), September 13  17, 2021, WIAS Berlin, September 14, 2021.

P. Pelech, Separately global solutions to rateindependent systems  Applications to largestrain deformations of damageable solids (online talk), MA4M: Mathematical Analysis for Mechanics (Online Event), November 23  25, 2020, WIAS Berlin, November 23, 2020.

P. Pelech, Separately global solutions to rateindependent systems: Applications to largestrain deformations of damageable solids, Thematic Einstein Semester: Student Compact Course ``Variational Methods for Fluids and Solids'' (Online Event), October 12  23, 2020.

P. Pelech, Separately global solutions to rateindependent systems: Applications to largestrain deformations of damageable solids (online talk), Thematic Einstein Semester: Kickoff Conference (Online Event), October 26  30, 2020, WIAS Berlin, October 29, 2020.

S. Tornquist, Temporal regularity of solutions to a dynamic phasefield fracture model in viscoelastic materials (online talk), MA4M: Mathematical Analysis for Mechanics (Online Event), November 23  25, 2020, WIAS Berlin, November 23, 2020.

S. Tornquist, Dynamic phasefield fracture in viscoelastic materials (online talk), Thematic Einstein Semester on Energybased Mathematical Methods for Reactive Multiphase Flows: Student Compact Course ``Variational Methods for Fluids and Solids'' (Online Event), October 12  23, 2020, WIAS Berlin, October 14, 2020.

A. Zafferi, LagrangianEulerian reduction of GENERIC systems (online talk), Thematic Einstein Semester on Energybased Mathematical Methods for Reactive Multiphase Flows: Student Compact Course ``Variational Methods for Fluids and Solids'' (Online Event), October 12  23, 2020, WIAS Berlin, October 12, 2020.

M. Thomas, Nonlinear fracture dynamics: Modeling, analysis, approximation, and applications, Presentation of project proposals in SPP 2256 ``Variational Methods for Predicting Complex Phenomena in Engineering Structures and Materials'', Bad Honnef, January 30, 2020.

M. Thomas, Thermodynamical modelling via energy and entropy functionals (online talks), Thematic Einstein Semester on Energybased Mathematical Methods for Reactive Multiphase Flows: Student Compact Course ``Variational Methods for Fluids and Solids'' (Online Event), October 12  23, 2020, WIAS Berlin.

M. Thomas, WeierstraßGruppe "VolumenGrenzschichtProzesse", Sitzung des Wissenschaftlichen Beirats, WIAS Berlin, September 18, 2020.

M. Thomas, Analysis for the discrete approximation of gradientregularized damage models, Mathematics Seminar Brescia, Università degli Studi di Brescia, Italy, March 13, 2019.

M. Thomas, Analysis for the discrete approximation of gradientregularized damage models, PDE Afternoon, Universität Wien, Austria, April 10, 2019.

M. Thomas, Analytical and numerical aspects for the approximation of gradientregularized damage models, 9th International Congress on Industrial and Applied Mathematics (ICIAM 2019), Thematic Minisymposium MS A3226 ``PhaseField Models in Simulation and Optimization'', July 15  19, 2019, Valencia, Spain, July 17, 2019.

M. Thomas, Analytical and numerical aspects of rateindependent gradientregularized damage models, Conference ``Dynamics, Equations and Applications (DEA 2019)'', Session D444 ``Topics in the Mathematical Modelling of Solids'', September 16  20, 2019, AGH University of Science and Technology, Kraków, Poland, September 19, 2019.

M. Thomas, Coupling of rateindependent and ratedependent systems, MURPHYSHSFS 2019 Summer School on MultiRate Processes, SlowFast Systems and Hysteresis, June 17  19, 2019, Politecnico di Torino, Turin, Italy.

M. Thomas, Coupling of rateindependent and ratedependent systems with application to delamination processes in solids, Mathematics for Mechanics, October 29  November 1, 2019, Czech Academy of Sciences, Prague, Czech Republic, October 31, 2019.

M. Thomas, Coupling of rateindependent and ratedependent systems with application to delamination processes in solids, Seminar ``Applied and Computational Analysis'', University of Cambridge, UK, October 10, 2019.

M. Thomas, Rateindependent evolution of sets and application to fracture processes, 90th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2019), Section S14 ``Applied Analysis'', February 18  22, 2019, Technische Universität Wien, Austria, February 20, 2019.

S. Tornquist, Towards the analysis of dynamic phasefield fracture, Spring School on Variational Analysis 2019, Paseky, Czech Republic, May 19  25, 2019.

S. Tornquist, Towards the analysis of dynamic phasefield fracture, MURPHYSHSFS 2019 Summer School on MultiRate Processes, SlowFast Systems and Hysteresis, Turin, Italy, June 17  21, 2019.

M. Thomas, Analysis for the discrete approximation of damage and fracture, Applied Analysis Day, June 28  29, 2018, Technische Universität Dresden, Chair of Partial Differential Equations, June 29, 2018.

M. Thomas, Analysis for the discrete approximation of gradientregularized damage models, Workshop ``Women in Mathematical Materials Science'', November 5  6, 2018, Universität Regensburg, Fakultät für Mathematik, November 6, 2018.

M. Thomas, Analytical and numerical aspects of damage models, Berlin Dresden Prague Würzburg Workshop ``Mathematics of Continuum Mechanics'', November 29  30, 2018, Universität Würzburg, Institut für Mathematik, November 30, 2018.

M. Thomas, Rateindependent evolution of sets & applications to damage and delamination, PDEs Friends, June 21  22, 2018, Politecnico di Torino, Dipartimento di Scienze Matematiche ``Giuseppe Luigi Lagrange'', Italy, June 22, 2018.

O. Klein, On uncertainty quantification for models involving hysteresis operators, MURPHYSHSFS2018: Interdisciplinary Workshop on Multiple Scale Systems, Systems with Hysteresis and Trends in Dynamical Systems, May 28  June 1, 2018, Centre de Recerca Matemàtica (CRM), Barcelona, Spain, May 31, 2018.

M. Thomas, Rateindependent delamination processes in viscoelasticity, Miniworkshop on Dislocations, Plasticity, and Fracture, February 13  16, 2017, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy, February 15, 2017.

O. Klein, Uncertainty quantification for models involving hysteresis operators, Summer School on MultiRate Processes, SlowFast Systems and Hysteresis MURPHYSHSFS2017, June 19  23, 2017, DISMA Politecnico di Torino, Dipartimento di Scienze Matematiche ``Giuseppe Luigi Lagrange'', Italy.

A. Mielke, On selfinduced oscillations for friction reduction with applications to walking, Conference ``Dynamical Systems and Geometric Mechanics'', June 12  14, 2017, Technische Universität München, Zentrum für Mathematik, June 13, 2017.

A. Mielke, Oscillations in systems with hysteresis, SFB 910 Symposium ``Stability Versus Oscillations in Complex Systems'', Technische Universität Berlin, Institut für Theoretische Physik, February 10, 2017.

M. Heida, Stochastic homogenization of 1homogeneous functionals, 7th European Congress of Mathematics (7ECM), Minisymposium 29 ``Nonsmooth PDEs in the Modeling Damage, Delamination, and Fracture'', July 18  22, 2016, Technische Universität Berlin, July 22, 2016.

M. Heida, Stochastic homogenization of rateindependent systems, Berlin Dresden Prague Würzburg Workshop ``Homogenization and Related Topics'', Technische Universität Dresden, Fachbereich Mathematik, June 22, 2016.

M. Heida, Stochastic homogenization of rateindependent systems, Joint Annual Meeting of DMV and GAMM, Session ``Multiscales and Homogenization'', March 7  11, 2016, Technische Universität Braunschweig, Braunschweig, March 10, 2016.

M. Thomas, Coupling rateindependent and ratedependent processes: Delamination models in viscoelastodynamics, Oberseminar ``Mathematik in den Naturwissenschaften'', Universität Würzburg, Institut für Mathematik, June 10, 2016.

M. Thomas, Coupling rateindependent and ratedependent processes: Existence results, 7th European Congress of Mathematics (ECM), minisymposium ``Nonsmooth PDEs in the Modeling Damage, Delamination, and Fracture'', July 18  22, 2016, Technische Universität Berlin, Berlin, July 22, 2016.

M. Thomas, Energetic concepts for coupled rateindependent and ratedependent processes: Damage & delamination in viscoelastodynamics, International Conference ``Mathematical Analysis of Continuum Mechanics and Industrial Applications II'' (CoMFoS16), October 22  24, 2016, Kyushu University, Fukuoka, Japan.

M. Thomas, From adhesive contact to brittle delamination in viscoelastodynamics, The 11th AIMS Conference on Dynamical Systems, Differential Equations and Applications, special session ``Ratedependent and Rateindependent Evolution Problems in Continuum Mechanics: Analytical and Numerical Aspects'', July 1  5, 2016, The American Institute of Mathematical Sciences, Orlando (Florida), USA, July 4, 2016.

M. Thomas, From adhesive contact to brittle delamination in viscoelastodynamics, ERC Workshop on Modeling Materials and Fluids using Variational Methods, February 22  26, 2016, WIAS Berlin, Berlin, February 26, 2016.

M. Thomas, Nonsmooth PDEs in material failure: Towards dynamic fracture, Joint Annual Meeting of DMV and GAMM, Section 14 ``Applied Analysis'', March 7  11, 2016, Technische Universität Braunschweig, March 10, 2016.

M. Thomas, Rateindependent evolution of sets, INdAMISIMM Workshop on Trends on Applications of Mathematics to Mechanics, September 5  8, 2016, The International Society for the Interaction of Mechanics and Mathematics (ISIMM), Rome, Italy, September 6, 2016.

M. Thomas, Rateindependent evolution of sets & application to fracture processes, Seminar on Analysis, Kanazawa University, Institute of Science and Engineering, Kanazawa, Japan, October 28, 2016.

O. Klein, On uncertainty quantification for hysteresis operators, Silesian University, Mathematical Institute, Opava, Czech Republic, December 7, 2016.

O. Klein, Uncertainty quantification for hysteresis operators, 7th European Congress of Mathematics (7ECM), Minisymposium 29 ``Nonsmooth PDEs in the Modeling Damage, Delamination, and Fracture'', July 18  22, 2016, Technische Universität Berlin, July 22, 2016.

O. Klein, Uncertainty quantification for hysteresis operators and models for magnetomechanical hysteresis, Conference ``Advances in Magnetics'' (AIM) 2016, March 14  16, 2016, Bormio, Italy, March 14, 2016.

M. Landstorfer, Theory, structure and experimental justification of the metal/electrolyte interface, Minisymposium `` Recent Developments on Electrochemical Interface Modeling'' of the 8th International Congress on Industrial and Applied Mathematics (ICIAM 2015), August 10  14, 2015, International Council for Industrial and Applied Mathematics, Beijing, China, August 11, 2015.

M. Thomas, Analysis of nonsmooth PDE systems with application to material failuretowards dynamic fracture, Minisymposium ``Analysis of Nonsmooth PDE Systems with Application to Material Failure'' of the 8th International Congress on Industrial and Applied Mathematics (ICIAM 2015), August 10  14, 2015, International Council for Industrial and Applied Mathematics, Beijing, China, August 12, 2015.

M. Thomas, Coupling rateindependent and ratedependent processes: Existence results, Applied Mathematics Seminar, Università di Pavia, Dipartimento di Matematica, Pavia, Italy, March 5, 2015.

M. Thomas, Coupling rateindependent and ratedependent processes: Evolutionary Gammaconvergence results, 86th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2015), Session on Applied Analysis, March 23  27, 2015, Università del Salento, Lecce, Italy, March 26, 2015.

M. Thomas, Coupling rateindependent and ratedependent processes: Existence and evolutionary Gamma convergence, INdAM Workshop ``Special Materials in Complex Systems  SMaCS 2015'', May 18  22, 2015, Rome, Italy, May 19, 2015.

M. Thomas, Coupling rateindependent and ratedependent processes: Existence results, 86th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2015), GAMM Juniors Poster Session, Lecce, Italy, March 23  27, 2015.

M. Thomas, Evolutionary Gamma convergence with application to damage and delamination, Seminar DICATAM, Università di Brescia, Dipartimento di Matematica, Brescia, Italy, June 3, 2015.

M. Thomas, From adhesive contact to brittle delamination in viscoelastodynamics, 3rd Workshop of the GAMM Activity Group ``Analysis of Partial Differential Equations'', September 30  October 2, 2015, Universität Kassel, Institut für Mathematik, Kassel, October 2, 2015.

M. Thomas, Rateindependent damage models with spatial BVregularization  Existence & fine properties of solutions, Oberseminar ``Angewandte Analysis'', Universität Freiburg, Abteilung für Angewandte Mathematik, Freiburg, February 10, 2015.

O. Klein, A representation result for rateindependent systems, 10th International Symposium on Hysteresis Modeling and Micromagnetics (HMM), May 18  20, 2015, Iasi, Romania, May 19, 2015.

A. Mielke, A mathematical approach to finitestrain viscoplasticity, Intensive Period on Variational Methods for Plasticity and Dislocations, March 16  20, 2015, International School of Advanced Studies (SISSA), Trieste, Italy, March 20, 2015.

A. Mielke, Abstract approach to energetic solutions for rateindependent solutions, Intensive Period on Variational Methods for Plasticity and Dislocations, March 16  20, 2015, International School of Advanced Studies (SISSA), Trieste, Italy, March 18, 2015.

A. Mielke, Existence results in finitestrain elastoplasticity, Intensive Period on Variational Methods for Plasticity and Dislocations, March 16  20, 2015, International School of Advanced Studies (SISSA), Trieste, Italy, March 19, 2015.

A. Mielke, Mathematical modeling for finitestrain elastoplasticity, Intensive Period on Variational Methods for Plasticity and Dislocations, March 16  20, 2015, International School of Advanced Studies (SISSA), Trieste, Italy, March 16, 2015.

A. Mielke, The multiplicative strain decomposition in finitestrain elastoplasticity, Intensive Period on Variational Methods for Plasticity and Dislocations, March 16  20, 2015, International School of Advanced Studies (SISSA), Trieste, Italy, March 17, 2015.

M. Thomas, A stressdriven localsolution approach to quasistatic brittle delamination, The 10th AIMS Conference on Dynamical Systems, Differential Equations and Applications, Special Session 91: Variational Methods for Evolution Equations, July 7  11, 2014, Madrid, Spain, July 7, 2014.

M. Thomas, Existence & stability results for rateindependent processes in viscoelastic materials, Applied Mathematics Seminar, Università di Pavia, Dipartimento di Matematica, Italy, March 18, 2014.

M. Thomas, Existence and stability results for rateindependent processes in viscoelastic materials, Women in Partial Differential Equations & Calculus of Variations Workshop, March 6  8, 2014, University of Oxford, Mathematical Institute, UK, March 6, 2014.

M. Thomas, GENERIC for solids with dissipative interface processes, 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2014), GAMM Juniors' Poster Session, FriedrichAlexander Universität ErlangenNürnberg, March 10  14, 2014.

M. Thomas, Rateindependent systems with viscosity and inertia: Existence and evolutionary Gammaconvergence, Workshop ``Variational Methods for Evolution'', December 14  20, 2014, Mathematisches Forschungsinstitut Oberwolfach, December 18, 2014.

M. Thomas, Rateindependent, partial damage in thermoviscoelastic materials, 7th International Workshop on MultiRate Processes & Hysteresis, 2nd International Workshop on Hysteresis and SlowFast Systems (MURPHYSHSFS2014), April 7  11, 2014, WIAS Berlin, April 8, 2014.

M. Thomas, Rateindependent, partial damage in thermoviscoelastic materials with inertia, International Workshop ``Variational Modeling in Solid Mechanics'', September 22  24, 2014, University of Udine, Department of Mathematics and Informatics, Italy, September 23, 2014.

M. Thomas, Rateindependent, partial damage in thermoviscoelastic materials with inertia, Oberseminar ``Analysis und Angewandte Mathematik'', Universität Kassel, Institut für Mathematik, December 1, 2014.

M. Thomas, Stressdriven localsolution approach to quasistatic brittle delamination, 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2014), Session on Applied Analysis, March 10  14, 2014, FriedrichAlexander Universität ErlangenNürnberg, March 11, 2014.

O. Klein, Classification of hysteresis operators for vectorvalued inputs by using their representation as functions on strings, RIPE60  Rate Independent Processes and Evolution Workshop, June 24  26, 2014, Prague, Czech Republic, June 24, 2014.

O. Klein, Stringrepresentation of hysteresis operators acting on vectorvalued, leftcontinuous and piecewise monotaffine and continuous functions, MURPHYSHSFS2014, The 7th MultiRate Processes and Hysteresis Workshop, in conjunction with the Second International Workshop on Hysteresis and SlowFast Systems, April 7  11, 2014, Weierstrass Institute, Berlin, April 11, 2014.

A. Mielke, Modeling jumps in rateindependent systems using balancedviscosity solutions, 7th International Workshop on MultiRate Processes & Hysteresis, 2nd International Workshop on Hysteresis and SlowFast Systems (MURPHYSHSFS2014), April 7  11, 2014, WIAS Berlin, April 8, 2014.

S. Heinz, On a way to control oscillations for a special evolution equation, Conference ``Nonlinearities'', June 10  14, 2013, University of Warsaw, Institute of Mathematics, Male Ciche, Poland, June 11, 2013.

D. Knees, A vanishing viscosity approach to a rateindependent damage model, Seminar ``Wissenschaftliches Rechnen'', Technische Universität Dortmund, Fachbereich Mathematik, January 31, 2013.

D. Knees, Crack evolution models based on the Griffith criterion, Workshop on Mathematical Aspects of Continuum Mechanics, October 12  14, 2013, The Japan Society for Industrial and Applied Mathematics, Kanazawa, Japan, October 13, 2013.

D. Knees, Global spatial regularity results for crack with contact and application to a fracture evolution model, Oberseminar Nichtlineare Analysis, Universität Köln, Mathematisches Institut, October 28, 2013.

D. Knees, Modeling and analysis of crack evolution based on the Griffith criterion, Nonlinear Analysis Seminar, Keio University of Science, Yokohama, Japan, October 9, 2013.

D. Knees, On energy release rates for nonlinearly elastic materials, Workshop on Mathematical Aspects of Continuum Mechanics, October 12  14, 2013, The Japan Society for Industrial and Applied Mathematics, Kanazawa, Japan, October 12, 2013.

M. Thomas, A stressdriven local solution approach to quasistatic brittle delamination, BMS Intensive Course on Evolution Equations and their Applications, November 27  29, 2013, Technische Universität Berlin, Berlin Mathematical School, November 29, 2013.

M. Thomas, A stressdriven local solution approach to quasistatic brittle delamination, Seminar on Functional Analysis and Applications, International School of Advanced Studies (SISSA), Trieste, Italy, November 12, 2013.

M. Thomas, Existence & fine properties of solutions for rateindependent brittle damage models, Workshop for the Initiation of the GAMM Activity Group ``Analysis of Partial Differential Equations'', Regensburg, October 1  2, 2013.

M. Thomas, Fine properties of solutions for rateindependent brittle damage models, XXIII Convegno Nazionale di Calcolo delle Variazioni, Levico Terme, Italy, February 3  8, 2013.

M. Thomas, Local versus energetic solutions in rateindependent brittle delamination, DIMO2013  Diffuse Interface Models, September 10  13, 2013, Levico Terme, Italy, September 13, 2013.

M. Thomas, Rateindependent damage models with spatial BVregularization  Existence & fine properties of solutions, Oberseminar zur Analysis, Universität DuisburgEssen, Fachbereich Mathematik, Essen, January 24, 2013.

O. Klein, A representation result for hysteresis operators with vector valued inputs and its application to models for magnetic materials, 9th International Symposium on Hysteresis Modelling and Micromagnetics (HMM 2013), May 13  15, 2013, Taormina, Italy, May 13, 2013.

O. Klein, Representation of hysteresis operators for vectorvalued monotaffine inputs by functions on strings, Politecnico di Torino, DISMA Dipartimento di Scienze Matematiche ``Giuseppe Luigi Lagrange'', Italy, April 23, 2013.

A. Mielke, Emergence of rate independence in gradient flows with wiggly energies, SIAM Conference on Mathematical Aspects of Materials Science (MS13), Minisymposium ``The Origins of Hysteresis in Materials'' (MS56), June 9  12, 2013, Philadelphia, USA, June 12, 2013.

J. Sprekels, PrandtlIshlinskii operators and elastoplasticity, Spring School on ``Rateindependent Evolutions and Hysteresis Modelling'', May 27  31, 2013, Politecnico di Milano, Università degli Studi di Milano, Italy.

G. Witterstein, Compressible phase change flows and the existence of transition profiles, PDEs for multiphase advanced materials, ADMAT2012, September 17  21, 2012, Cortona, Italy, September 18, 2012.

P.É. Druet, Some problems associated with the second order optimal shape of a crystallisation interface, PDEs for multiphase advanced materials, ADMAT2012, September 17  21, 2012, Cortona, Italy, September 20, 2012.

D. Knees, A vanishing viscosity approach in fracture mechanics, Nonlocal Models and Peridynamics, November 5  7, 2012, Technische Universität Berlin, Institut für Mathematik, November 5, 2012.

M. Thomas, Analytical aspects of rateindependent damage models with spatial BVregularization, Seminar, SISSA  International School for Advanced Studies, Functional Analysis and Applications, Trieste, Italy, November 28, 2012.

M. Thomas, Mathematical methods in continuum mechanics of solids, COMMAS (Computational Mechanics of Materials and Structures) Summer School, October 8  12, 2012, Universität Stuttgart, Institut für Mechanik (Bauwesen).

W. Dreyer, Sharp limits of diffuse interface models in the context of energy storage problems, PDEs for Multiphase Advanced Materials (ADMAT2012), September 17  21, 2012, Cortona, Italy, September 18, 2012.

O. Klein, A representation result for hysteresis operators acting on vectorvalued continuous, piecewise monotaffine input functions, 6th International Workshop on MultiRate Processes and Hysteresis (MURPHYS 2012), May 21  24, 2012, Stefan cel Mare University, Suceava, Romania, May 22, 2012.

O. Klein, Representation of hysteresis operators for vectorvalued inputs by string functions, PDEs for multiphase advanced materials, ADMAT2012, September 17  21, 2012, Cortona, Italy, September 17, 2012.

A. Mielke, From smallstrain to finitestrain elastoplasticity via evolutionary Gamma convergence, Variational Models and Methods for Evolution, September 10  12, 2012, Centro Internazionale per la Ricerca Matematica (CIRM) and Istituto di Matematica Applicata e Tecnologie Informatiche/Consiglio Nazionale delle Ricerche (IMATICNR), Levico, Italy, September 11, 2012.

A. Mielke, Gamma convergence and evolution, International Conference ``Trends in Mathematical Analysis'', March 1  3, 2012, Politecnico di Milano, Dipartimento di Matematica ``F. Brioschi'', Italy, March 1, 2012.

A. Mielke, Smallstrain elastoplasticity is the evolutionary Gamma limit of finitestrain elastoplasticity, International Symposium on Trends in Applications of Mathematics to Mechanics (STAMM 2012), September 3  6, 2012, Israel Institute of Technology (Technion), Faculty of Aerospace Engineering, Haifa, September 4, 2012.

J. Sprekels, Mathematical modeling of hysteresis, Seminar ``Thermodynamische Modellierung und Analyse von Phasenübergängen'', WIAS, Berlin, November 13, 2012.

J. Sprekels, Mathematical modeling of hysteresis  Part II, Seminar ``Thermodynamische Modellierung und Analyse von Phasenübergängen'', WIAS, Berlin, December 11, 2012.

O. Klein, Representation of hysteresis operators for vectorvalued inputs by functions on strings, International Symposium on Hysteresis Modelling and Micromagnetics (HMM 2011), Levico (Trento), Italy, May 9  11, 2011.

A. Mielke, An evolutionary elastoplastic plate model obtained via Mosco convergence, 10th GAMM Seminar on Microstructures, January 20  22, 2011, Technische Universität Darmstadt, Fachbereich Mathematik, January 22, 2011.

A. Mielke, Complex hysteresis operators arising from homogenization and dimension reduction, 8th International Symposium on Hysteresis Modelling and Micromagnetics (HMM2011), Session ``Mathematics of Hysteresis II'', May 9  11, 2011, Università degli Studi di Trento, Centro Internazionale per la Ricerca Matematica, Levico Terme, Italy, May 10, 2011.

A. Mielke, Evolution for dissipative materials at finite strains, From Polymer Physics to Rubber Elasticity, January 17  19, 2011, Institut National de Recherche en Informatique et en Automatique (INRIA), Paris, France, January 19, 2011.

A. Mielke, Multiscale problems in systems driven by functionals, ISAMTopMath Summer School 2011 on Variational Methods, September 12  16, 2011, Technische Universität München, Fakultät für Mathematik.

M. Thomas, Modeling and analysis of rateindependent damage and delamination processes, 19th International Conference on Computer Methods in Mechanics, Minisymposium ``Growth Phenomena and Evolution of Microstructures. Applications in Solids'', May 9  12, 2011, Warsaw University of Technology, Poland, May 11, 2011.

O. Klein, Hysteresis operators for vectorvalued inputs and their representation by functions on strings, International Workshop on Hysteresis and SlowFast Systems (HSFS2011), December 12  14, 2011, Lutherstadt Wittenberg, December 14, 2011.

J. Sprekels, Phase field models and hysteresis operators, Trends in Thermodynamics and Materials Theory 2011, December 15  17, 2011, Technische Universität Berlin, December 16, 2011.

M. Liero, Rateindependent Kurzweil processes, Workshop ``Rateindependent Systems: Modeling, Analysis, and Computations'', August 30  September 3, 2010, Banff International Research Station for Mathematical Innovation and Discovery (BIRS), Canada, September 3, 2010.

A. Petrov, On a 3D model for shapememory alloys, Workshop ``Rateindependent Systems: Modeling, Analysis, and Computations'', August 30  September 3, 2010, Banff International Research Station for Mathematical Innovation and Discovery (BIRS), Canada, September 2, 2010.

M. Thomas, From damage to delamination in nonlinearly elastic materials, 6th Singular Days on Asymptotic Methods for PDEs, April 29  May 1, 2010, WIAS, May 1, 2010.

M. Thomas, From damage to delamination in nonlinearly elastic materials at small strains, Workshop ``Microstructures in Solids: From Quantum Models to Continua'', March 14  20, 2010, Mathematisches Forschungsinstitut Oberwolfach, March 18, 2010.

A. Mielke, A mathematical model for the evolution of microstructures in elastoplasticity, Fifth International Conference on Multiscale Materials Modeling, Symposium on Mathematical Methods, October 4  8, 2010, Fraunhofer Institut für Werkstoffmechanik (IWM), Freiburg, October 4, 2010.

A. Mielke, Rateindependent plasticity as Gamma limit of a slow viscous gradient flow for wiggly discrete energy, ZweiStädteKolloquium zur Analysis, FriedrichAlexanderUniversität ErlangenNürnberg, Fachbereich Mathematik, November 26, 2010.

A. Mielke, Rateindependent plasticity as Gamma limit of a slow viscous gradient flow for wiggly energies, Partial Differential Equations Seminar, University of Oxford & Queen's College, Centre for Nonlinear PDE, UK, February 22, 2010.

A. Mielke, Rateindependent plasticity as Gamma limit of a slow viscous gradient flow for wiggly energies, Nečas Seminar on Continuum Mechanics, Jindrich Nečas Center for Mathematical Modeling, Prague, Czech Republic, November 8, 2010.

M. Thomas, Rateindependent damage and delamination processes, Workshop ``Rateindependent Systems: Modeling, Analysis, and Computations'', August 30  September 3, 2010, Banff International Research Station for Mathematical Innovation and Discovery (BIRS), Canada, August 31, 2010.

O. Klein, Outward pointing properties for vectorial hysteresis operators and some applications, International Workshop on MultiRate Processes & Hysteresis, March 31  April 5, 2008, University College Cork, Ireland, April 4, 2008.

J. Sprekels, Oscillating elastoplastic bodies: Dimensional reduction, hysteresis operators, existence results, Direct, Inverse and Control Problems for PDE's (DICOP 08), September 22  26, 2008, Cortona, Italy, September 22, 2008.

J. Sprekels, Oscillating thin elastoplastic bodies: Dimensional reduction, hysteresis operators, existence results, Seminar Partial Differential Equations: Models and Applications, Università di Pavia, Dipartimento di Matematica ``F. Casorati'', Italy, May 20, 2008.

J. Sprekels, Models of phase transitions and hysteresis operators, Joint International Meeting UMIDMV 2007, Minisymposium ``Phase Transitions and Hysteresis in Free Boundary Problems'', June 18  22, 2007, Università degli Studi di Perugia, Dipartimento di Matematica e Informatica, Italy, June 21, 2007.

O. Klein, Asymptotic behavior for a phasefield model for thermoviscoplasticity involving outwards pointing hysteresis operators, 6th AIMS International Conference on Dynamical Systems, Differential Equations & Applications, June 25  28, 2006, Université de Poitiers, France, June 26, 2006.

O. Klein, Outwards pointing properties for Preisach operators, International Workshop on MultiRate Processes & Hysteresis (MURPHYS 2006), April 3  7, 2006, University College Cork, Ireland, April 4, 2006.

J. Sprekels, Asymptotics of the stop hysteresis operator, Workshop ``Applications of Asymptotic Analysis'', June 18  22, 2006, Mathematisches Forschungsinstitut Oberwolfach, June 21, 2006.

J. Sprekels, PrandtlIshlinskii hysteresis operators and 1D elastoplasticity, 6th AIMS International Conference on Dynamical Systems, Differential Equations & Applications, June 25  28, 2006, Université de Poitiers, France, June 26, 2006.

O. Klein, Outward pointing properties for Preisach operators, 5th International Symposium on Hysteresis and Micromagnetic Modeling (HMM 2005), May 30  June 1, 2005, Budapest, Hungary, May 30, 2005.

O. Klein, Asymptotic behaviour for a phasefield model with hysteresis in thermoviscoplasticity, INdAM Workshop ``Dissipative Models in Phase Transitions'', September 5  11, 2004, Cortona, Italy, September 9, 2004.

O. Klein, Longtime behaviour of solutions to equations involving outwards pointing hysteresis operators, International Workshop on Hysteresis & MultiScale Asymptotics (HAMSA 2004), March 17  21, 2004, University College Cork, Ireland, March 19, 2004.

J. Sprekels, On nonlocal phasefield models, Workshop ``Thermodynamische Materialtheorien'', December 12  15, 2004, Mathematisches Forschungsinstitut Oberwolfach, December 14, 2004.

O. Klein, Asymptotic behaviour of evolution equations involving outwards pointing hysteresis operators, 4th International Symposium on Hysteresis and Micromagnetic Modeling (HMM2003), May 28  30, 2003, Universidad de Salamanca, Departamento de Física Aplicada, Spain, May 30, 2003.

J. Sprekels, Mathematical modelling of hysteresis phenomena, February 18  20, 2003, Chiba University, Department of Mathematics, Japan.

J. Sprekels, Hysteresis operators in phasefield modelling, Workshop ``Phasenübergänge'', April 29  May 4, 2001, Mathematisches Forschungsinstitut Oberwolfach, May 1, 2001.

J. Sprekels, Hysteresis operators in phasefield systems, University of Warsaw, Interdisciplinary Centre for Mathematics and Computer Modelling, Poland, January 5, 2001.

J. Sprekels, On nonlocal phase transition models for nonconserved order parameters, Università di Pavia, Dipartimento di Matematica, Italy, September 19, 2001.

J. Sprekels, Phasefield systems and vector hysteresis operators, Workshop "`Phase Transitions and Interfaces in Evolution Equations: Analysis, Control and Approximation"', February 8  12, 2000, Santa Margherita Ligure, Italy, February 11, 2000.

J. Sprekels, Phasefield systems with hysteresis, Konferenz "`Evolution Equations 2000: Applications to Physics, Industry, Life Sciences and Economics"', October 30  31, 2000, Levico, Italy, October 30, 2000.
Preprints im Fremdverlag

A. Fiaschi, D. Knees, U. Stefanelli, Young measure quasistatic damage evolution, Preprint no. 28PV10/26/0, Istituto di Matematica Applicata e Technologie Informatiche, 2010.