Thermodynamics with Internal State Variables
TL;DR: In this paper, the authors study the thermodynamics of nonlinear materials with internal state variables whose temporal evolution is governed by ordinary differential equations, and employ a method developed by Coleman and Noll to find the general restrictions which the Clausius-Duhem inequality places on response functions.
Abstract: This is a study of the thermodynamics of nonlinear materials with internal state variables whose temporal evolution is governed by ordinary differential equations. After employing a method developed by Coleman and Noll to find the general restrictions which the Clausius—Duhem inequality places on response functions, we analyze various types of dynamical stability that can be exhibited by solutions of the internal evolution equations. We also discuss integral dissipation inequalities, conditions under which temperatures can be associated with internal states, and the forms taken by response functions when the material is a fluid.
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TL;DR: In this article, the theoretical foundations of constitutive relations at finite strain for a class of solids exhibiting inelasticity as a consequence of specific structural rearrangements, on the microscale, of constituent elements of material.
Abstract: This paper is a study of the theoretical foundations of constitutive relations at finite strain for a class of solids exhibiting inelasticity as a consequence of specific structural rearrangements, on the microscale, of constituent elements of material. Metals deforming plastically through dislocation motion are of this class and form the primary application of the theory. The development is in terms of a general internal-variable thermodynamic formalism for description of the microstructural rearrangements, and it is shown how metal plasticity may be so characterized. The principal result is in the normality structure which is shown to arise in macroscopic constitutive laws when each of the local microstructural rearrangements proceeds at a rate governed by its associated thermodynamic force. This provides a theoretical framework for time-dependent inelastic behavior in terms of a “flow potential”, and reduces to statements on normality of strain increments to yield surfaces in the time-independent case. Conventional characterizations of the stress-state dependence of metallic slip are noted to be in accord with this concept of associated forces governing rates, so that the resulting normality structure may be considered directly applicable to metal plasticity.
1,573 citations
Cites background from "Thermodynamics with Internal State ..."
...…variables to averaging variables The restrictions on kinetic equations implied in (3 1) and (32) parallel those in other internal-variable treatments of inelasticity (e.g. DE GROOT and MAZUR (1962), COLEMAN and GURTIN (1967)), at least when these are specialized to homogeneous deformation....
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TL;DR: In this article, a dual framework for elastic cap damage was proposed, where a strain-and a stress-based approach was employed, and a viscous regularization of strain-based, rate-independent damage models was also developed.
1,158 citations
TL;DR: In this paper, a constitutive model for anisotropic damage is developed to describe the elastic-brittle behavior of fiber-reinforced composites and the corresponding rate-equations are subjected to the laws of thermomechanics.
1,099 citations
TL;DR: In this paper, a fully three-dimensional finite-strain viscoelastic model is developed, characterized by general anisotropic response, uncoupled bulk and deviatoric response over any range of deformations, general relaxation functions, and recovery of finite elasticity for very fast or very slow processes; in particular, classical models of rubber elasticity (e.g. Mooney-Rivlin).
Abstract: A fully three-dimensional finite-strain viscoelastic model is developed, characterized by: (i) general anisotropic response, (ii) uncoupled bulk and deviatoric response over any range of deformations, (iii) general relaxation functions, and (iv) recovery of finite elasticity for very fast or very slow processes; in particular, classical models of rubber elasticity (e.g. Mooney-Rivlin). Continuum damage mechanics is employed to develop a simple isotropic damage mechanism, which incorporates softening behavior under deformation, and leads to progressive degradation of the storage modulus in a cyclic test with increasing amplitude (Mullins' effect). A numerical integration procedure is proposed which trivially satisfies objectivity and bypasses the use of midpoint configurations. The resulting algorithm can be exactly linearized in closed form, and leads to symmetric tangent moduli. Quasi-incompressible response is accounted for within the context of a three-field variational formulation of the Hu-Washizu type.
911 citations
TL;DR: In this paper, an energy-based coupled elastoplastic damage theory for ductile and brittle materials is presented, which employs irreversible thermodynamics and internal state variable theory for damage.
865 citations
References
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Book•
01 Jan 1964
TL;DR: In this article, the Poincare-Bendixson theory is used to explain the existence of linear differential equations and the use of Implicity Function and fixed point Theorems.
Abstract: Foreword to the Classics Edition Preface to the First Edition Preface to the Second Edition Errata I: Preliminaries II: Existence III: Differential In qualities and Uniqueness IV: Linear Differential Equations V: Dependence on Initial Conditions and Parameters VI: Total and Partial Differential Equations VII: The Poincare-Bendixson Theory VIII: Plane Stationary Points IX: Invariant Manifolds and Linearizations X: Perturbed Linear Systems XI: Linear Second Order Equations XII: Use of Implicity Function and Fixed Point Theorems XIII: Dichotomies for Solutions of Linear Equations XIV: Miscellany on Monotomy Hints for Exercises References Index.
9,036 citations
Book•
01 Jan 1948
TL;DR: In this article, the authors proposed a method to compressible ecoulement for compressible compressible and supersonique and onde de choc Reference Record created on 2005-11-18, modified on 2016-08-08
Abstract: Keywords: ecoulement : compressible ; ecoulement : supersonique ; onde de : choc Reference Record created on 2005-11-18, modified on 2016-08-08
3,239 citations
TL;DR: The basic physical concepts of classical continuum mechanics are body, configuration of a body, and force system acting on a body as mentioned in this paper, which can be expressed as follows: a body is regarded as a smooth manifold whose elements are the material points; a configuration is defined as a mapping of the body into a three-dimensional Euclidean space, and a force system is defined to be a vector-valued function defined for pairs of bodies.
Abstract: The basic physical concepts of classical continuum mechanics are body, configuration of a body, and force system acting on a body. In a formal rational development of the subject, one first tries to state precisely what mathematical entities represent these physical concepts: a body is regarded to be a smooth manifold whose elements are the material points; a configuration is defined as a mapping of the body into a three-dimensional Euclidean space, and a force system is defined to be a vector-valued function defined for pairs of bodies1. Once these concepts are made precise one can proceed to the statement of general principles, such as the principle of objectivity or the law of balance of linear momentum, and to the statement of specific constitutive assumptions, such as the assertion that a force system can be resolved into body forces with a mass density and contact forces with a surface density, or the assertion that the contact forces at a material point depend on certain local properties of the configuration at the point. While the general principles are the same for all work in classical continuum mechanics, the constitutive assumptions vary with the application in mind and serve to define the material under consideration.
1,885 citations