Abstract: In this paper, the general formulation of a new proposed iteration algorithm of mixed BEM/FEM for eigenvalue problems of elastodynamics is described. Approximate fundamental solutions of elastodynamics are adopted in the normal mixed BEM/FEM equations. The accuracy of solutions is progressively improved by the iteration procedure. Not only could the awkwardness of non-algebraic eigenvalue equations be avoided but also the accuracy of numerical solutions is almost independent of the interior meshing. All these give many advantages in numerical calculation. The algorithm is applied to free torsional vibration analysis of bodies of revolution. A few cases are studied. All of the numerical results are very good.

Key words: mixed BEM/FEM formulation, iteration, free vibration, bodies of revolution, eigenvalue, crack, stress intensity factor