ASA 127th Meeting M.I.T. 1994 June 6-10

2pSA8. Reflection of axisymmetric waves from an arbitrary termination of a fluid-loaded semi-infinite cylindrical shell.

J. Gregory McDaniel

P. W. Smith, Jr.

Kevin D. LePage

Bolt Beranek and Newman, Inc., 70 Fawcett St., Cambridge, MA 02138

This work proposes an approximate theory for the reflection of axisymmetric waves on a semi-infinite fluid-loaded shell from an arbitrary termination. The reflected and incident waves are described by wave numbers and wave shapes derived from the standard thin-shell equations for an infinite shell with fluid loading. The termination is characterized by an admittance matrix that relates stress resultants within the shell wall to axial, radial, and rotational velocities of the midsurface. The admittance matrix is determined for arbitrary terminations by finite element experiments on a fluid-loaded finite shell. An example focusing on variations in the axial admittance shows the effect of added mass at the termination. Results include the reflection and coupling between surface, longitudinal, and evanescent waves. [Work supported by ONR.]