Several new formulations are proposed to overcome the multi- frequency and non-uniqueness problems of the boundary element method in elastodynamics. For the multi-frequency problem, two improved boundary element techniques are proposed to make the analysis for an entire frequency spectrum possible and practical. The first technique is to interpolate the "neutralized" boundary element coefficient matrices in the frequency domain; the second technique is to interpolate the Green function in the spatial domain. Both techniques are suitable for vectorization and parallelization on supercomputers. For the non-uniqueness problem, two "enhanced CHIEF" methods are proposed to ensure the uniqueness and accuracy of the boundary element solution for an exterior wave propagation problem. Vectorized and parallelized codes based on the proposed formulations will also be made. Application areas include structural vibration, elastic wave propagation and earth- structure interaction.
