An empirical formula for predicting the collapse strength of composite cylindrical-shell structures under external pressure loads

This paper derives an empirical formula for predicting the collapse strength of composite cylindrical-shell structures under external hydrostatic pressure loads as a function of geometric dimensions and layered angles, where the effects of initial manufacturing imperfections are implicitly taken into account. A series of experiments are undertaken on [+/-theta/90] (FW) filament-wound-type composite cylindrical-shell models subjected to collapse pressure loads. A total of 20 composite cylindrical-shell models are tested to derive the empirical formula, which is validated by comparison with experimental data, existing design formulas of ASME 2007 and NASA SP-8700, and solutions of the nonlinear finite element method. It is concluded that the proposed formula accurately predicts the collapse pressure loads of filament-wound composite cylinders and will thus aid the safety design of composite cylindrical shell-structures under external pressure loads.