Modal pencil method for the radiation of guided wave fields in finite isotropic plates validated by a transient spectral finite element method

•A semi-analytical model for GW radiation in isotropic finite-sized plate is derived.•Sources are described as arbitrary distributions of surface stresses.•Fields result from the superposition of modal contributions (direct and reflected).•Wave paths between source and calculation points can be arbitrary long at no cost.•The model is validated by comparison of its predictions with FE computations. Elastic guided waves (GW) can be profitably used in non-destructive evaluation and in structural health monitoring of plate-like structures. Nevertheless, the multi-modal and dispersive behaviour of GW often leads to difficult interpretation of typically measured time-dependent signals. The development of efficient simulation tools appears necessary to better understand complex phenomena involved and to optimize testing configurations. Here, a semi-analytical modal method is proposed to compute GW displacement fields in finite plates radiated by an arbitrary finite-sized source of surface stresses. It takes into account GW reflections and mode conversions at plate boundaries. As far as computation efficiency is concerned, this method is independent of the length of propagation paths, allowing to efficiently address configurations involving long range propagation. Predicted results are given as sums of modal contributions to ease their interpretation. The model is validated by comparing its predictions to those computed by a transient finite-element code.