The θ scheme for time-domain BEM/FEM coupling applied to the 2-D scaler wave equation

There exist quite a number of published papers showing that BEM/FEM coupling in time domain is a robust procedure leading to great computer time savings for infinite domain analyses. However, in many cases, the procedures presented so far have considered only constant time interpolation for BEM tractions, otherwise one may have (mainly in bounded domains) strong oscillations which invalidate the results. In this paper, such a limitation is overcome by employing the linear theta method which consists, basically, of computing the response at the time t(n+1) from the response previously computed at the time t(n+theta) theta greater than or equal to 1.0. This procedure is implicitly incorporated into the BEM algorithm in the coupled BEM/FEM process presented here, i.e. the response is calculated directly at time t(n+1). Proceeding this way, it becomes possible to adopt the Newmark scheme in the FEM algorithm. Two examples are presented in order to validate the formulation. Copyright (C) 2000 John Wiley & Sons, Ltd.