Member of technical staff, Sandia National Laboratories, Albuquerque, NM
A development program for spherical composite pressure vessels with burst pressures as high as 430 MPa (62.5 ksi) is described. Vessels were fabricated by filament-winding Kevlar 49/epoxy over thin seamless copper liners. Two configurations of stainless steel fill stems were evaluated both experimentally and analytically. Finite-element techniques were used to compute stress concentrations produced in the liner and composite shell as a result of the fill-stem geometry. An analytical model was used to estimate vessel pressure-strain response and predict burst pressure as a function of composite and liner properties, composite fiber volume fraction vf, and the composite shell's outer to inner radius ratio β. This model predicts a nonlinear relationship between the burst pressure and β, and at a given β a strong dependence of burst pressure on vf. Experimental data confirmed the predicted dependence of burst pressure on fiber volume fraction. In addition, predicted values of surface strain and burst pressures were in fair agreement with experimental data.
Paper ID: CTR10877J