Study on the Prediction Method Considered Interaction between Normal and Shear Deformations in Nonlinear S-S Behavior of Glass Fabric Composites

摘要

Many models concernig the nonlinear stress-strain (S-S) relationship of FRP have been proposed. To the authors' knowledge, no interactions between normal and normal and shear stress were assumed in most of them. However, in the previous our study shows that the interaction between normal and shear stesses exists. In this study we propose a new model considering the interactions between normal and shear stresses for the nonlinear S-S relationship of fiber composites using fabrics. This model consists of springs and friction elements which are parallelly combined for each stress axis. The friction elements represent the interaction between normal and shear stresses. Both surfaces on yield and failure criteria are assumed ellipsoidal to estimate the S-S curves and stresses as failure of composites at multi-axial stess state. Stress field is also assumed that the stresses as failure of composites at multi-axial stess state. Stress field is also assumed that the stress state expanded as a concentric ellipsoid from yield to failure stresses. The shape of ellipsoid was determined by the experimental results in both uniaxial tension and pure tosion loading tests. Moreover, the S-S relationship under low cyclic loading was also represented by this spring-friction model. And the calculated results by using this model well agreed with the experimental results under biaxial proportional and cyclic loading.