MEMBRANES USING NON-DIMENSIONAL DYNAMIC INFLUENCE

Some points will be discussed as follows. (1) Spurious eigensolution: It is interesting to "nd that all the examples in reference [1] are of the Dirichlet type. According to the theoretical derivation, the Neumann problem has the problems of spurious solutions using the imaginary-part formulation. We will prove that in the following. As mentioned earlier, spurious eigenvalues occur in the real-part of MRM formulation [9, 11, 12]. Also, the imaginary-part BEM results in spurious solutions [7]. Here, we will derive the true and spurious solutions in the discrete system analytically for a circular domain by using the non-dimensional in#uence function method [1] and the imaginary-part dual BEM [7] in a uni"ed way. The degenerate kernels and circulants areCOMMENTS ON &&VIBRATION ANALYSIS OF ARBITRARY SHAPE