Abstract

In the present work, the effects of material properties of the interfacial layer (or coating) on the stress distributions in unidirectional fibrous composites subjected to a thermal loading are elastic–plastically analysed based on a a four-phase model consisting of fibre, coating, matrix and surrounding body. A linear strain-hardening stress-plastic strain relation with temperature independence is proposed to describe the plastic behaviour of the coating. The governing equation for the coating is established and its closed form solution is obtained based upon the Tresca's yield criterion and the associated flow rule. Some numerical examples are provided to illustrate the effect of the material properties of the coating on the stress distributions in the composites. The results indicate that the use of a plastically deformable coating with a combination of material properties that is able to smooth out the property mismatches between fibre and matrix can reduce the stresses in the coating and the associated risk of interfacial failure under thermal loading.