Pages 141-148
The behavior of a crack in an elastic strip under pre-stretching load is atudied using the proposed interface element. For this study, the critical pre-stretching load at which the crack becomes unstable is computed as a static problem first. Then, based on the knowledge obtained for the stability of the crack, the speed of the crack propagating in the pre-stretched plate with an initial crack at the center is clarified. Especially the influences of various factors, such as the pre-stretching, the surface energy, the bonding strength and the size of element on the crack speed under steady propagation are investigated. Through this study it is found that the behavior of the simulated crack at the onset of the instability can be divided into the stress controlled and the energy controlled types. When the surface energy is small, the scale parameter of the interface potential is large and the mesh size is sufficiently small the behavior of the crack becomes the energy controlled type. In case of the energy controlled type the speed of the crack under steady state is determined only by the surface energy. The influence of the bonding strength and the mesh division is small. As for the pre-stretching, the crack speed increases with the pre-stretching and it converges to Layleigh wave speed.
