The transient problem of a traction free half-space containing a subsurface semi-infinite crack subjected to dynamic antiplane loading on the crack faces has been investigated to gain insight into the phenomenon of the interaction of stress waves with material defects. A specific loading condition, namely a pair of concentrated point loadings applied on the crack faces, is considered in detail. The transient solutions are determined by superposition of a fundamental solution in the Laplace transform domain. The fundamental solution to be used is the problem for applying exponentially distributed traction in the Laplace transform domain on the crack faces. The exact closed form transient solutions of dynamic stress intensity factors are obtained and are expressed in a very simple formulation in this study. These solutions are valid for an infinite length of time and have accounted for the contributions of an infinite number of waves. Numerical results of dynamic stress intensity factors are obtained which indicate that the major contributions are due to the first few waves.
International Journal of Engineering Science 34(13), pp.1507-1517