Wave Diffraction by a Crack: Finite Element Simulations

The two-dimensional problem of a plane longitudinal stress wave diffracted by a straight crack is simulated by the finite element method. Time-dependent stress-intensity factors are computed with the aid of a crack-tip singularity element. Numerical results are obtained from two finite-element models using both consistent-mass and lumped-mass matrices and two different sizes of time step in the time-integration algorithm. The problem is simulated by application of two different superposition schemes. In one case the finite element model is loaded on a boundary remote from the crack; in the other case the model is excited through loading of the crack face. Computed stress-intensity factors are in good agreement with an existing analytical solution.