Transient Response of Viscoplastic and Viscoelastic Shells Submerged in Fluid Media

The transient fluid-shell interaction problem is investigated for thin shells constructed of other than linearly elastic materials. Specifically, solutions are developed in terms of elementary functions for the transient responses of impulsively loaded, fluid-surrounded spherical shells constructed of either viscoplastic or viscoelastic materials. In all cases the fluid medium surrounding the shell is taken as inviscid and compressible and only spherically symmetric shell motions and radiation of sound into the surrounding medium are considered. It is found that the influence of material strain hardening and strain-rate sensitivity can be significant in reducing fluid-shell displacement responses. Further, limited investigations for viscoelastic materials indicate that for higher loss materials, displacement response of the shell is significantly altered by the inclusion of the viscoelastic behavior.