Voloshko O. Analysis of zones at the tip of the crack in a thin layer, which connects two isotropic materials

The objects are the zones at the tip of the crack at the interface of isotropic half-planes and in a thin layer of isotropic composite. The aim is the development of the methods of pre-fracture zones investigation for a crack in a thin interlayer of isotropic composite and an interface crack investigation in elastoplasic bodies under mechanical loads. Methods of theory of complex variable functions and finite element. By using of the finite element method stress state at the crack tip is studied and the contact zone lengths, the crack opening displacement and the values of the J-integral are found. The mathematical models, which take into account of the nonuniform stresses distribution at the crack continuations, are developed for the analytical study of an isotropic composite with a crack in an interlayer. The problems of linear relationship are formulated and solved analytically. The equations for determination of the pre-fracture zones lengths as well as the expressions of the crack opening displacement and the J-integral are obtained. For the case of the identical material components the approximated function for determination of the distributions of the normal stress are constructed. The effect of geometrical and mechanical properties of the composite as well as the external loads on the main fracture parameters is studied. Application spheres are training courses, machine and instrument-making industries.