Evaluation of various approximate analyses for plain weave composites

The literature contains a variety of analyses for analyzing plain weave com posites. These differ in both geometric approximation and assumptions about stress and strain distribution. Herein the weave geometry for-a wide range of waviness was described using three-dimensional finite element meshes. T hese meshes were used with various stress and strain assumptions to determi ne how these assumptions affect predicted in-plane extensional stiffness. A ssumptions about stress and strain can be tied to whether an analysis is eq uivalent to a virtual work, complementary virtual work, or hybrid formulati on. Since these variational principles have well understood convergence beh avior, it is easy to explain the observed effects of the various assumption s. The results indicate that sometimes accurate predictions for particular cases result from cancellation of errors, rather than sound formulation.