Dynamic responses of a layered medium subjected to anti-plane loadings

The dynamic response of a layered medium subjected to anti-plane loadings i s investigated in this study. An effective analytical method is used to pre sent transient full field solutions in the layered medium. The boundary val ue problem is solved using Laplace transform with respect to time and Fouri er transform with respect to space. The transient response is then implemen ted analytically by Cagniard's method that obviates the contour integration difficulties and whose terms represent successively reflected and transmit ted waves. The static solution is obtained by the extreme case of transient response while the time is sufficiently long. The objective in this study is to investigate the transition phenomena from transient response to stati c value. The numerical examples of a layered half-space are illustrated and discussed in detail. It is found that the characteristic time of the trans ition not only depends on the distance between source and receiver but also is strongly related to the wave velocities of layer and half-space. Furthe rmore, very interesting transition behavior is observed when the layer has faster wave velocity than the half-space. (C) 2001 Elsevier Science Ltd. Al l rights reserved.