DYNAMICS OF SUBMERGED SHELLS OF ARBITRARY GEOMETRY USING IMPROVED TRANSMITTING BOUNDARIES

The dynamics of shells of arbitrary geometry submerged in an acoustic medium has attracted attention for many decades. Only a finite region of the finite fluid domain can be modelled in the numerical analysis. The artificial surface encompassing the finite region is called the tr uncation surface, on which the transmitting boundary condition is used . The classical plane wave, cylindrical wave and spherical wave approx imations are the first generation approximations. The residual variabl e method has made it possible to develop second generation improved tr ansmitting boundary conditions in Cartesian, cylindrical and spherical coordinates. A general purpose finite element program, in which both the classical and improved transmitting boundary conditions have been incorporated, has been coded and verified. The response of a point exc ited submerged ellipsoidal shell is studied. The ellipsoidal shell is enclosed in a spherical truncation surface. The numerical results on t he apex deflection are presented and they are compared with that of th e spherical shell. (C) 1997 Civil-Comp Ltd and Elsevier Science Ltd.