Construction of a dynamic weight function from a finite-element solution for a cracked beam

An elastodynamic weight function for a cracked beam is shown to be determined by the elastodynamic stress intensity factor corresponding to a single crack-face loading of the beam. This weight function suffices to determine the time-dependent stress intensity factor corresponding to other dynamic loadings of the same cracked beam. The example of a center-cracked pinned-pinned beam serves to illustrate and verify the technique. The weight function is constructed from finite element results for the case of a step pressure distributed uniformly along the beam, and the case of a step load concentrated at the crack plane serves as an illustration of the efficacy of the weight function so constructed.