An analytical approach to the thermal residual stress problem in fiber-reinforced composites.

摘要

A pair of two new tensors called Generalized Plane Strain (GPS) tensors S and D is proposed for the concentric cylindrical inclusion problem. GPS tensors take the fiber volume fraction explicitly into account. When the cylindrical matrix is of infinite radius, tensor S reduces to the appropriate Eshelby's tensor. The GPS tensors provide a convenient form of solution to a class of problems involving eigen-strain, e.g., strain due to thermal expansion, phase transformation, plastic and misfit strain. Explicit expressions to evaluate thermal residual stresses in the matrix and the fiber using GPS tensors are developed for metallic/intermetallic matrix composites. Results are compared with Eshelby's infinite domain solution and Finite Element solution for SCS-6/Ti-24Al-11Nb composite. The method of superposition using GPS tensor is proposed for evaluating thermal residual stress distribution in a fiber reinforced composite with periodic arrays. The results compare very favorably with Finite Element solution. GPS tensors are also used in the evaluation of the effective material properties. We demonstrated the approach by studying two fiber reinforced composites, Graphite/Epoxy and Glass/Epoxy composites. A good agreement between analytical results using GPS tensor and experimental data was found. We also compared the results of using GPS tensor along with the original Eshelby's tensor and found that GPS tensor provides a better match with experimental data.