Multiscale numerical modeling for thermal behavior of plain-woven composites with interfacial and internal defects

This paper predicted thermal responses of plain-woven composites with interfacial and internal defects based on the multi-scale simulation. The effective and localized responses of plain-woven composites are simulated through “bottom-up” homogenization and “top-down” localization across several scales. Periodic representative volume elements (RVEs) are extracted at micro-scale, meso-scale and macro-scale, respectively, to represent the entire composite arrays at distinct scales. The local behavior of RVEs is predicted by either finite element method (FEM) or the locally exact homogenization theory (LEHT), the latter of which is employed to simulate the effect of imperfect interface between fiber and matrix to avoid large-scale mesh refinement in FEM, especially at the vicinity of physical interphase/ cohesive damaged interface. Based on the localized temperature/heat flux distributions, the effect constitutive relations are introduced to predict the corresponding effective thermal coefficients. The accuracy and efficiency of the proposed method is verified by validating the predicted effective coefficients against the results in literature. Several microstructural parameters, including interfacial parameters, internal porosity volume fraction, as well as fiber contents are tested on the effective response and it is found that effective thermal conductivity of plain-woven composites varies greatly when the interfacial parameter of imperfect interface lied in range of “sensitivity zone”, while the thickness of physical interphase has less significant influence on the in-plane and out-of-plane thermal conductivities. More importantly, the reinforcing/weakening schemes of fiber or damaged interface are illustrated through recovering the local thermal distribution and demonstrating the significant interfacial effect. The model established in this paper can provide theoretical guidance for the neglected imperfect interface and internal defects in plain woven composites.