Calculation method for predicting elastic behavior of compressible-incompressible composite material

Abstract

The invention discloses a calculation method for predicting the elastic behavior of a compressible-incompressible composite material, and belongs to the field of composite material calculation, and the method comprises the steps: 1, marking the attributes of a unit material, and distributing the to-be-solved variables of the unit; 2, obtaining a discrete format of an elastic equation of the compressible-incompressible double-layer composite material; and step 3, obtaining the central stress of the unit. According to the method, the problems of shear self-locking occurring when the FEM is used for solving the incompressible material problem and false stress concentration occurring when the FEM is used for solving the composite material can be avoided, the elastic behavior prediction of the incompressible-compressible double-layer composite material can be realized, the elastic distribution of different material domains can be directly obtained, iterative calculation is not needed, the calculation result is stable, the program implementation is simple, and the method is suitable for popularization and application. And a functional incompressible-compressible material can be directly solved.

Description

technical field [0001] The invention relates to the field of composite material calculation, and more specifically, to a calculation method for predicting the elastic behavior of compressible-incompressible composite materials. Background technique [0002] With the continuous development of rubber-like materials (polymers, living tissues, functional materials) in engineering and biomedical fields, and incompressible materials may exhibit completely different mechanical properties from compressible materials, the problem of linear elasticity of incompressible materials The research has become a hot issue concerned by scholars from all walks of life. Incompressibility means that the volume of an object remains unchanged under any stress state (isovolumetric deformation). Poisson's ratio for an isotropic incompressible elastic body with a finite modulus ν Equal to 0.5, the expression form is that the bulk modulus of the elastic body is infinite, and only volume deformation c...

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Problems solved by technology

[0003] At present, the research on the linear elasticity of incompressible materials mostly uses analytical methods, finite element (FEM), and lattice-type / lattice-type finite volume methods (CC-FVM / CV-FVM) for calculation, mainly for isotropic homogeneous The existing problems of mass / functional gradient incompressible materials mainly include: 1. When FEM calculates the elastic problems of composite materials or incompressible materials, there will be non-physical oscillation of the stress along the thickness direction near the material interface or the self-locking problem of unit shear ;2. The analytical method is only suitable for simple structure distribution and material distribution, and the real material structure cannot be calculated; 3. When CC-FVM calculates the elastic problem of composite materials, false stress jumps appear at the material interface

Compared with the above methods, CV-FEM shows better calculation performance in calculating functional materials and compressible materials, which can effectively avoid false stress and shear self-locking phenomenon. However, this method is currently suitable for calculating compressible or compressible materials. Elasticity problems with incompressible material distributions cannot yet be calculated for elastic problems with compressible-incompressible (or compressible-nearly incompressible) bilayer composite structures (see figure 1 )

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