Investigating thermal residual stress effect on mechanical behaviors of fiber composites with different fiber arrays

This study aims to investigate the thermal residual stress effect on the constitutive behaviors of fiber composites with three different fiber arrays, i.e., square edge packing, square diagonal packing, and hexagonal packing. The repeating unit cell (RUC) containing fiber and matrix phase was employed to describe the mechanical behaviors of fiber composites. For the fiber phase, it was assumed to be linear elastic, whereas the matrix was a nonlinear material. The generalized method of cell (GMC) micromechanical model originally proposed by Paley and Aboudi [Paley M, Aboudi J. Micromechanical analysis of composites by the generalized cells model. Mech Mater 1992; 14(2):127–39] was extended to include the thermal–mechanical behavior, from which the thermal residual stress within the fiber and matrix phases was calculated. Through numerical iteration, the constitutive relations of the composites in the presence of residual stress were established. Results show that for the composites with square edge packing, the mechanical behaviors are affected appreciably by the thermal residual stress. On the other hand, the composites with hexagonal packing and square diagonal packing are relatively less sensitive to the thermal residual stress.