Research of acoustic emissions from the system of complanary cracks

The dynamic problem of the displacement field in an elastic half-space caused by the timesteady displacement of the surfaces of the system of disc-shaped coplanar cracks is solved. The solutions are obtained by the method of boundary integral equations. The dependences of elastic displacements on the surface of the half-space on the wave number, the number of defects and the depths of their occurrence are constructed.

Exterior boundaries of the objects in modeling with finite element method

The problems of wave field modeling with finite element method in unbounded domains and methods to deal with them are analyzed. To obtain optimal solution, using of infinite elements is proposed on the boundaries of the modeled area combined with standard finite-element modeling inside the area. It is important however to choose the shape functions of infinite elements depended on the conditions of wave decay at infinity.