A method is described for obtaining the displacements (and hence the stresses) of a linear elastic system under a given transient load in a more accurate and more expeditious manner than is possible by the standard method. For simplicity, ho account is taken of damping forces in describing the method.

The method is of interest to engineers and others who require to obtain numerical answers to problems of the type described above. It depends upon the fact that in many practical cases of transient loads the inertia forces in the series of normal modes of an elastic system converge rapidly, compared with the series of “normal” loadings in terms of which the spatial distribution of the applied load can be expressed.