Simulation analysis of thermal stress/strain of single fiber and multi-fiber composites caused by elevated environment temperature

Abstract

To study thermal expansion problem caused by environment temperature changes during service life, single and multi-fiber finite element models were established to investigate thermal stress/strain of composite. Single fiber model was shown that longitudinal thermal stress/strain distribution of fiber or matrix is uniform, but stress/strain distribution of transverse direction was more complex than longitudinal direction. Furthermore, longitudinal and transverse thermal stress at composite free end zone is higher than that of in inner zone. Then the influence of different fiber arrangement on thermal stress was discussed by finite element model of multi-fiber composite. It indicated that damage initiation would emerge at somewhere randomly in fiber regular arrangement model. But in fiber random arrangement model, initial damage will concentrate on interface of fiber-rich zone. In addition, thermal expansion model in this paper may provide simple and practical method to calculate thermal stress/strain, so as to prevent matrix cracking or interface debonding due to thermal stress concentration.