Wave-number-based assessment of the doubly asymptotic approximation. II. Frequency and time domain response

In part I, the surface variational principle (SVP) and the doubly asymptoti c approximation (DAA) were used to generate alternative descriptions of the frequency domain wet surface impedance. These are used here to obtain alte rnative descriptions of the displacement field in slender hemicapped cylind rical shells. This field is represented as a decomposition into a two-dimen sional wave-number space. The responses that are obtained are frequency dom ain transfer functions for a point force at the midplane, evaluated for a d iscrete set of frequencies. Solutions obtained from first-and second-order versions of DAA are compared to the SVP result. Then temporal responses are obtained by using an inverse fast Fourier transform to evaluate the convol ution of the transfer functions with a prototypical temporal excitation. Th e results reveal that DAA and SVP differ most in the vicinity of fluid-load ed resonances. The largest disagreement is encountered for the axisymmetric portion of the response. It is shown that DAA often greatly underpredicts peak displacements and accelerations, but a few cases lead to overpredictio n. (C) 2000 Acoustical Society of America. [S0001-4966(00)05403-5].