Yield Hypersurfaces of a Three-Layer Composite Shell With a Fiber-Reinforced Middle Layer

Abstract

Plastic yield conditions for three-layer fibrous composite shells and plates, whose middle layer (matrix) is reiforced with thin fibers and outer ones (coverings) are homogeneous and isotropic, are determined. It is assumed that the matrix, fibers, and coverings are perfectly plastic (without hardening) and their properties in tension and compression are different. The fibers and coverings are thin to an extent their transverse dimensions can be neglected. The contact between the covering and matrix and between the matrix and fibers is perfect. It is also assumed that neutral surfaces arise in the construction, whose strain rate grows linearly with distance from the surfaces. Expressions for the yield hypersurfaces in terms of bending moments and membrane forces are derived.