Geometrically Linear and Nonlinear First-Ply Failure Loads of Composite Cylindrical Shells

Abstract

Review of the literature on first-ply failure of composite shells shows that research reports on first-ply failure of moderately thin, laminated composite cylindrical shell panels, using a geometrically nonlinear approach, are not available. The present paper aims to fill this deficiency. It uses a finite-element code developed using eight-noded, doubly-curved elements combined with modified Sanders’ first-approximation theory for thin shells and von Kármán-type nonlinear strains. The accuracy of the present geometric nonlinear and first-ply failure formulations are verified separately through solutions of two benchmark problems. Failure loads, failure modes (for individual stress or strain failure) or tendencies (for interactive stress failures), and the locations from where the failures initiate are reported. The results are discussed critically to formulate design guidelines, suggesting practical values for factors of safety applicable to failure loads. Such suggestions also consider the serviceability requirements.