The paper analyzes numerically the passages to the limit in the dynamic problem for a penny-shaped crack at the interface between dissimilar linear elastic, homogeneous, isotropic materials as either the frequency of harmonic load or the difference between the properties of the materials decreases. It is shown that as the frequency decreases, the solution of the dynamic problem tends to that of the static problem, and as the physical and mechanical properties of the materials become less different, the original problem goes into the dynamic problem for a crack in a homogeneous body Keywords: interface crack, harmonic load, boundary integral equations, passage to the limit
Introduction.Recently, there has been considerable success in the understanding of the deformation and fracture of piecewise-homogeneous cracked bodies under static loading [5,6,8,9,11]. Unfortunately, there are very few problem solutions for compound bodies with cracks under dynamic loading. This is because of the difficulty of describing dynamic processes. In [7], boundary integral equations were derived to solve a problem for a crack at the interface between two elastic half-spaces under dynamic loading. A numerical solution to a problem of elasticity for a circular crack at the interface under a harmonic load was first obtained in [4,12]. It was shown there that in the dynamic case, the stress-strain state of a compound body with an interfacial crack is greatly different from that of a homogeneous body with a crack.Note that reference solutions that could be used for comparison and validation purposes in solving new problems are usually not available. Therefore, solution reliability is an issue of extreme and current importance. As the frequency of loading tends to zero, dynamic solutions in solid mechanics are known to tend to the corresponding static solutions, which, thus, can be used for the validation of dynamic solutions [1,2]. In our recent publications, we examined the variation of forces at the front of a penny-shaped crack (for several pairs of materials [13,14]) and the displacement-discontinuity vector at the crack edges (for the pair of tungsten and aluminum [13]) with decreasing frequency of load, and compared the dynamic solution with the static one. As the difference in the physical and mechanical properties between the constituent materials decreases, problems for composite bodies go over into similar problems for continuous bodies, whose solutions can also be used as a reference.The present paper involves multiparameter numerical analysis of the passages to the limit in the dynamic problem for a penny-shaped crack at the interface between linear elastic, homogeneous, isotropic materials as either the frequency of harmonic load or the difference between the mechanical properties of the materials decreases. Special attention is focused on the variation in the normal and tangential displacements of the crack edges with decreasing difference between the mechanical properties of the materials.1. Problem Formulation. Consider, in...