The dynamical problem for the infinite elastic layer with a cylindrical cavity

Abstract

The wave field of an infinite elastic layer weakened by a cylindrical cavity is constructed. The ideal contact conditions are given on the upper layer’s face and bottom face is rigidly fixed. The normal dynamic tensile load is applied to a cylindrical cavity’s surface at the initial moment of time. The Laplace and finite sin- and cos- Fourier integral transforms are applied successively directly to axisymmetric equations of motion and to the boundary conditions, on the contrary to the traditional approaches, when integral transforms are applied to solutions’ representation through harmonic and biharmonic functions. This operation leads to a one-dimensional vector inhomogeneous boundary value problem with respect to unknown displacements’ transformations. The problem is solved using a matrix differential calculus, which leads to an integral equation solved with a method of orthogonal polynomials. The field of initial displacements is derived after application of inverse integral transforms. The case of the steady-state oscillations was investigated. The normal stress on the rigidly fixed face of the elastic layer is constructed and investigated depending on the mechanical and dynamic parameters. Formulas for determining the normal stress for large values ​​of natural vibration frequencies were constructed.