Theoretical Post-Yielding Behavior of Composite Laminates Part II-Inelastic Macromechanics

This is the second of two papers which present the results of an investi gation that relates the post-yielding mechanical behavior of symmetric laminates, made from unidirectional composites, to the non-linearities in the fiber and matrix materials. The analysis consists of a single ply and a laminate analysis. The single ply portion uses a finite element idealization of the minimum repeating segment of each unidirectional layer as a means of deriving the required ply properties. The laminate portion considers each ply as a homogeneous anisotropic layer, in the context of a conven tional laminate analysis. The manner in which these two approaches are combined and their application to a particular boron/epoxy system is dis cussed here. This type of analysis is useful for verifying stability or deflec tion margins and accurately enforcing a variety of strength criteria.