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In this paper we approach the linear mixed problem with initial and boundary values for a Cosserat body which is elastic and has pores. We coupled the equations characterizing the pores evolution with basic equations that describing the elastic deformations of the Cosserat body. The coupling is done by means of predetermined coefficients. To prove the continuous dependence of the solutions, we introduce an adequate measure which is useful in obtaining of some estimations with respect to the gradient of elastic deformations and regarding the gradient of a specific the application, introduced to characterize the behavior of the pores. [ABSTRACT FROM AUTHOR]

In this paper first we formulate the mixed problem with initial and boundary values in the context of the porous Cosserat thermoelastic bodies micropolar material with voids. WE have included among the independent constitutive variables the derivative with respect to time of the voids (pores) function. Under the conditions in which we imposed average restrictions on the functions used, we formulated and demonstrated the uniqueness of the solution to the mentioned mixed problem and we did a short analysis on the dilatational waves in this kind of media. [ABSTRACT FROM AUTHOR]

In our study we construct a boundary value problem in elasticity of porous piezoelectric bodies with a dipolar structure To construct an eigenvalue problem in this context, we consider two operators defined on adequate Hilbert spaces. We prove that the two operators are positive and self adjoint, which allowed us to show that any eigenvalue is a real number and two eigenfunctions which correspond to two distinct eigenvalues are orthogonal. With the help of a Rayleigh quotient type functional, a variational formulation for the eigenvalue problem is given. Finally, we consider a disturbation analysis in a particular case. It must be emphasized that the porous piezoelectric bodies with dipolar structure addressed in this study are considered in their general form, i.e.,inhomogeneous and anisotropic. [ABSTRACT FROM AUTHOR]

In our study, we adapt certain basic results from the abstract theory of differential equations of the elliptic type with the purpose to deduce some basic results in the case of a concrete type of media. Namely, after the boundary values problem is formulated in the context of elasticity of Cosserat bodies with voids, some results on existence of a generalized solution and the uniqueness of this solution are proven. [ABSTRACT FROM AUTHOR]

First we construct the boundary value problem in the context of the elastostatics of elastic orthotropic beams, which are loaded on the ends and on the lateral surface. Then we determine the solution of this problem with the help of some functions of stress. In this way we find an extension of Prandtl's method and, in the same time, an natural extension of the known Almansi's problem from the classical plane problem of torsion. [ABSTRACT FROM AUTHOR]

This study is concerned with the theory of Cosserat thermoelastic media, whose micro-particles possess microtemperatures. The mixed initial boundary value problem considered in this context is transformed in a temporally evolutionary equation on a Hilbert space. Using some results from the theory of semigroups, the existence and uniqueness of solution is proved. In the same manner, it approached the continuous dependence of the solution upon initial data and loads. From what we have studied, neither on the internet nor in the databases, we have not found qualitative issues addressed regarding the mixed problem in the context of the theory of thermoelasticity of Cosserat environments, in which the contribution of inner structure and microtemperatures are taken into account. [ABSTRACT FROM AUTHOR]

In this study, we consider the final boundary value problem for a thermoelastic Cosserat material. With the help of a simple translation, our final problem is transformed in a usual mixed problem with boundary relations and initial data. For this new problem, we obtain some theorems of uniqueness of solutions. For this, we do not use any law of conservation of energy, as is usually done to obtain a result of uniqueness. Moreover, we do not need assumptions to ensure the boundedness of the tensors which characterize thermoelastic coefficients. [ABSTRACT FROM AUTHOR]

In this study, we approach the strain gradient thermoelasticity of bodies with microtemperatures. We define the internal energy corresponding to an arbitrary solution of the mixed problem with boundary and initial values, considered in the context of strain gradient thermoelasticity of bodies with microtemperatures. The Cesaro means of different parts of the internal energy are considered. In our main result, we prove the asymptotic equipartition of the strain and kinetic energies, in the case t → ∞ . [ABSTRACT FROM AUTHOR]

Our study is dedicated to a composite, which, in fact, is a mixture of two thermoelastic micropolar bodies. We formulate the mixed initial boundary value problem in this context and define the domain of influence for given data. For any solution of the mixed problem we associate a measure and prove a second-order differential inequality for it. Based on the maximum principle for the heat equation and on the second-order differential inequality, we establish an estimate which proves that the thermal and the mechanical effects, at large distance from the domain of influence, are dominated by an exponential decay. [ABSTRACT FROM AUTHOR]

• Displacements, microdeformations, temperature and microtemperatures are coupled in a multiphysics process. • Existence, uniqueness and continuous dependence results are shown for the mathematical model. • The plane strain problem is studied by the finite element method. In this study we formulate the mixed initial boundary value problem for a dipolar thermoelastic material whose micro-particles possess microtemperatures. Then this mixed problem is transformed in a Cauchy problem attached to a temporally equation of evolution on a specific Hilbert space, which will be suitably chosen. As such, we will be able to use certain results specific to the theory of the semigroups of contractions in order to obtain the existence and uniqueness of the solution for our problem. The theory of semigroups also facilitates our approach regarding the continuous dependence of the solution upon initial data and loads. Finally, we reduce our model to the isotropic case and perform numerical simulations for the corresponding system of partial differential equations by means of the finite element method. [ABSTRACT FROM AUTHOR]

In our study, we consider the linear mixed initial boundary value problem for a porous elastic body having a dipolar structure. The equations that describe the elastic dipolar deformations are coupled with the equations which describe the evolution of the voids by means of certain coefficients. Our main result proves the continuous dependence of solutions for the mixed problem with regard to the coefficients which perform this coupling. Using an adequate measure, we can evaluate the continuous dependence by means of some estimate regarding the gradient of deformations and the gradient of the function that describes the evolution of the voids. [ABSTRACT FROM AUTHOR]

Our study is concerned with the initial boundary value problem in the context of the thermoelastostatics of dipolar bodies. We will derive a result which describes the exponential spatial decay of solutions of this problem. We will also find a superior limit for the amplitude, which is dependent on the initial and boundary conditions. [ABSTRACT FROM AUTHOR]

This study is concerned with the mixed initial boundary value problem for a dipolar body in the context of the thermoelastic theory proposed by Green and Naghdi. For the solutions of this problem we prove a result of Hölder's-type stability on the supply terms. We impose middle restrictions on the thermoelastic coefficients, which are common in continuum mechanics. For the same conditions we propose a continuous dependence result with regard to the initial data. [ABSTRACT FROM AUTHOR]

In this paper we derive some identities for the solution of the problem of homogeneous and anisotropic micropolar thermoelasticity. These can be applied to proving uniqueness of the solution of the corresponding boundary initial value problem. [ABSTRACT FROM AUTHOR]

First, we formulate the mixed initial boundary value problem in the theory of thermoelastic microstretch bodies having certain internal state variables. Then by using some approachable computing techniques and the known Gronwall's inequality we will prove that the presence of internal state variables do not inuence the uniqueness of solution of the mixed problem. [ABSTRACT FROM AUTHOR]

We consider a porous thermoelastic body, including voidage time derivative among the independent constitutive variables. For the initial boundary value problem of such materials, we analyze the temporal behaviour of the solutions. To this aim we use the Cesaro means for the components of energy and prove the asymptotic equipartition in mean of the kinetic and strain energies. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with microstretch thermoelastic materials. For the mixed initial boundary value problem defined in this context, we prove that the Cesaro means of the kinetic and strain energies of a solution with finite energy become asymptotic equal as time tends to infinity. [Copyright &y& Elsevier]

Abstract: In the present paper we generalize the results obtained by Iesan and Quintanilla for microstretch elastic bodies in order to cover dipolar elastic materials with stretch. For the boundary value problem considered in this context, we prove a generalized existence result and, also, an extension of the principle of minimum potential energy. [Copyright &y& Elsevier]

The objective of our study is to explain a boundary value problem, so called Saint-Venant relaxed problem, from the linear theory of Elasticity. We study the torsion of a cylindrical bar, by means of the torsion function, in the special case when the cross-section of the bar is conic. The bounary value problem, in this context, has been successfully solved. Also, we prove that there is no other cross section for what the considered problem has a solution. [ABSTRACT FROM AUTHOR]

Reports on the application of the theory of semigroups of operators in order to obtain the existence and uniqueness of solutions for the mixed initial-boundary value problems in thermoelasticity of dipolar bodies. Continuous dependence of the solutions upon initial data and supply terms; Variables that describe the deformation of a dipolar medium.

In this paper, we consider the mixed initial boundary value problem in the context of a thermoelastic porous body having a dipolar structure. We intend to analyze the rate of decay of solutions to this problem to ensure that in a finite time, they become null. In our main result, we find that the combined contribution of the dipolar constitution of the body together with voids dissipation and thermal behavior cannot cause vanishing of the deformations in a finite time. [ABSTRACT FROM AUTHOR]

With a wide applicability in solid state mechanics, the theory of continuous dipolar materials with voids is a distinctive part of microstructure theory, a theory that emerged with the necessity of eliminating the discrepancies between the classical theory and its experimental applications. These inconsistencies are caused by the influence of the microstructure of materials on the general deformations of the bodies, such as ceramics, graphite or polymers. In the present work, we study the mixed boundary value problem with initial data for the thermoelasticity of three-phase-lag dipolar materials with voids, in order to obtain the corresponding constitutive laws, using the same method as in the classical elasticity. By going deeper into the study of these materials, we achieve a uniqueness result and a reciprocal relation, using less common methods, like the dissipative inequality regarding the result of uniqueness. Along with these aspects, we demonstrate a variational principle for anisotropic and non-homogeneous materials, derived from a well-known variational principle, but studied in the context of thermoelasticity of three-phase-lag dipolar materials with voids. [ABSTRACT FROM AUTHOR]