We first formulate the mixed backward in time problem in the context of thermoelasticity for dipolar materials. To prove the consistency of this mixed problem, our first main result is regarding the uniqueness of the solution for this problem. This is obtained based on some auxiliary results, namely, four integral identities. The second main result is regarding the temporal behavior of our thermoelastic body with a dipolar structure. This behavior is studied by means of some relations on a partition of various parts of the energy associated to the solution of the problem.

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In this study we want to extend the results of B. Straughan, which quite recently addressed the issue of double porosity structure for classical elastic bodies. In this case, the double porosity structure of the body is not influenced by the displacement field, which is not consistent with reality. For the mixed initial boundary value problem in the context of micropolar bodies with double porosity, we prove the existence of the solution, its uniqueness as well as some considerations on stability of solution.

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Engineering practice imposes an increased rigidity of mechanical elements that are parts of machinery or equipment used in practice. Circular plates are such elements, especially used in many common applications, which is why the increase in mechanical properties of circular plates in engineering is connected with the weight optimization problem. The paper makes a study of such a composite plate, proposes and validates a constructive solution capable of increasing the stiffness of this piece. The finite element method is used for the composite panel analysis, and experimental measurements allow us to take information concerning of the magnitude of this rigidity.

An important stage in an analysis of a multibody system (MBS) with elastic elements by the finite element method is the assembly of the equations of motion for the whole system. This assembly, which seems like an empirical process as it is applied and described, is in fact the result of applying variational formulations to the whole considered system, putting together all the finite elements used in modeling and introducing constraints between the elements, which are, in general, nonholonomic. In the paper, we apply the method of Maggi's equations to realize the assembly of the equations of motion for a planar mechanical systems using finite two-dimensional elements. This presents some advantages in the case of mechanical systems with nonholonomic liaisons.

The paper aims to study a plane system with bars, with certain symmetries. Such problems can be encountered frequently in industry and civil engineering. Considerations related to the economy of the design process, constructive simplicity, cost and logistics make the use of identical parts a frequent procedure. The paper aims to determine the properties of the eigenvalues and eigenmodes for transverse and torsional vibrations of a mechanical system where two of the three component bars are identical. The determination of these properties allows the calculus effort and the computation time and thus increases the accuracy of the results in such matters.

Our study is dedicated to the problem with initial and boundary conditions in the theory of thermoelasticity for micropolar materials with pores. We obtain some results regarding the existence and uniqueness of a finite energy solution of this mixed problem by generalizing the corresponding results obtained by Dafermos in the context of classical elasticity. In some specific conditions we prove some properties regarding the possibility to control the finite energy solution.