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You In the absence of an electric field a mathematical model describing the ferroelastic response of complete ferroelectrics ferroelastics on action of mechanical stresses is proposed. The modeling is based on the concept of a "ferroelastic" element, similar to the theory of plasticity where used the Saint-Venant element of "dry friction". The constitutive relations for elastic and residual strains are constructed. The dependence of elastic compliance on the main values of the tensor of residual strains is established. For residual strains, the constitutive relations are obtained in differentials. The obtained constitutive equations can be used in finite element analysis of irreversible processes of deformation of polycrystalline ferroelastics. A number of numerical experiments were performed, which showed good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The article presents a method for calculating the strength of concrete elements with non-metallic fiber, rod and external reinforcement. The algorithm and the calculation program are shown, which are based on the use of a nonlinear deformation model of the normal section of such elements, taking into account the real deformation properties of materials under static and short-term dynamic loading. [ABSTRACT FROM AUTHOR]

To create protective elements, information is needed on the resistance of various combinations of metal, ceramic, and heterogeneous plates, including layered ones, both in contact and with spacing. In addition, an intensive process is underway to create complex materials such as cermet composites. In this work, for verification of the code, numerical calculations of the breakdown of both monolithic and layered steel barriers by a striker with an ogival nose are performed. A series of 2D and 3D calculations for modeling the processes of penetrating heterogeneous barriers has been performed. It is shown that the resistance of heterogeneous barriers to penetration by a rigid striker is approximately the same, whereas the impact of a deformable striker on heterogeneous barriers shows that the resistance of layered barriers is lower compared to a monolithic barrier, and spacing of layers reduces the resistance of the barrier. [ABSTRACT FROM AUTHOR]

The generality of localization of plastic deformation, which is observed at the stage of linear work hardening for HCP, BCC and FCC monoand polycrystals of pure metals and alloys, is considered. It was found previously that the motion rate of localized flow autowave is related to the reciprocal value of the work hardening coefficient by a linear law, which is universal in character. This is further substantiated by the results of the given study. The waves of plastic flow localization are found to have dispersion law. It has been established that in order to address the autowave of localized deformation, a quasi-particle may be introduced. The quasi-particle's characteristics have been defined. [ABSTRACT FROM AUTHOR]

Deformation and fracture of metal-ceramic composites and coatings under quasistatic tension, compression, shear, and during cooling from the melt to room temperatures are numerically investigated. Dynamic and quasistatic boundary-value problems are solved in twoand three-dimensional formulations by the finite-difference and finite-element methods. Constitutive models include the isotropic hardening of aluminum and fracture of ceramic particles. Composite microstructure is taken into account explicitly. Analysis of the fracture in composites is carried out, with the residual stresses being not taken into consideration. Origination of cracks in the near-interface regions of bulk tension and their propagation in ceramic particles are investigated. Residual stresses formed during cooling of the composites are calculated for different volume fractions of particles. [ABSTRACT FROM AUTHOR]

A micromechanical model is developed to predict the deformation behavior of additively manufactured aluminum alloys. Three-dimensional models of grain structures typical for different microregions of the melt pool are generated by the step-by-step packing method. A crystal plasticity-based constitutive model accounting for the elastic-plastic anisotropy of face-centered cubic crystals is employed to simulate the microscale deformation in an additively manufactured aluminum alloy under loading. The grain shape and texture effects on the plastic strain localization patterns are analyzed. [ABSTRACT FROM AUTHOR]

The paper presents the comparison of the energy absorption by perfect and amorphized nanorods under the cyclic loading. The calculations have been carried out with the molecular dynamic modeling. The cyclic loading is modeled by a periodical shift of a movable clamp along the X axis. The calculations are performed for the maximal clamp shift in respect to the equilibrium state, which corresponds to the relative deformation (equal to 0.3%). Frequencies varied from 0.085 THz to 10 THz. It has been discovered that both the dramatic growth of the maximal dispersion of atomic planes, and the dramatic growth of amplification of the maximal dispersion of atomic planes can be used as an index of the irreversible transformation of the crystal structure in the physical system differing from the perfect nanosized crystal. General behavior of the studied systems more depends on cyclic loading parameters than on the object crystal structure. Under the cyclic loading modeled with the aid of the periodical shift of the movable clamp, the frequency makes the critical impact on the results. [ABSTRACT FROM AUTHOR]

A theoretical study of the deformation and fracture behavior of Ni3Al alloy under shock loading has been carried out. The finite element method simulation was used within the approach that combined modeling in terms of the dislocation kinetics of alloys with the L12 superstructure and the mechanics of a deformable solid. The dislocation kinetic model of the alloys with the Ll2 superstructure defined the hardening of Ni3Al punch and plate materials, while the model of the mechanics of a deformable solid described deformation of the macrovolume. [ABSTRACT FROM AUTHOR]

This work is devoted to the improvement mathematical apparatus for describing the stress-strain state of structures made of heterogeneous materials and modeling the processes of their deformation under load. The proposed mathematical model establishes the relationship between the components of the macrostrains tensor and the components of the macrostress tensor and explicitly takes into account the heterogeneity of the material. The model can be used in finite-elemental software packages. [ABSTRACT FROM AUTHOR]