Mesoscale analysis of ply-cracked composite laminates under in-plane and flexural thermo-mechanical loading

Abstract This article presents a finite element model to predict the thermo-mechanical behavior of ply-cracked composite laminates from their discrete structure at the ply level, i.e., the mesostructure, utilizing the second order homogenization method. With the assumption that the cracks are statistically regularly distributed within a composite laminate, the homogenization theory for periodic materials can be employed. Thus, instead of considering the whole laminate under thermo-mechanical loading, a significantly less computationally demanding analysis can be done on a repeated unit cell (RUC). Finite element analyses are performed to determine the accurate stress fields in the RUC under in-plane and flexural out-of-plane loading. During these analyses, the periodic boundary conditions are imposed on the surfaces of the RUC. The macroscopic thermoelastic properties are then derived from the stress/strain fields in the RUC by means of the numerical homogenization scheme. The physical fidelity of the proposed model is shown by good agreement between the predicted thermo-mechanical properties of the considered ply-cracked composite laminates and the corresponding data from experiments and analytical methods. In addition, insightful analyses of ply-cracked laminates with one or more off-axis plies are also conducted. Results from these analyses have been rarely reported in literature and can be utilized for benchmark solutions.