Mathematical Model of the Foundation From Orthotropic Layers Considering Their Deforma-Tional Pseudonhomogeneity

The article considers the problem of finding the parameters of the stress-strain state (SSS) of a half-space consisting of several layers of various orthotropic materials, whose physical and mechanical characteristics exhibit a significant dependence on the magnitude of stresses, under the influence of uniformly distributed pressure on a rectangular area of a rigid stamp. To build a computational model, a finite element (FE) model was used, based on a modification of an isoparametric FE in the form of a tetrahedron, without intermediate nodes with three nodal degrees of freedom. To describe the process of nonlinear deformation of a half-space, new effective constitutive relations are used that describe the mechanical behavior of orthotropic materials, constructed within the framework of the theory of normalized stress spaces. The calculated parameters of the stress-strain state were compared with the results obtained on the basis of theories proposed by other well-known authors, as well as on the basis of the classical theory, without taking into account the effects associated with resistance differences. The result of the analysis of the data obtained by the authors is a comparison of the theories used, and a conclusion is drawn about the need to consider the non-classical properties of materials.