In-phase thermomechanical fatigue damage evolution of long fiber-reinforced ceramic-matrix composites using fatigue hysteresis-based damage parameters

摘要

Under in-phase (IP) thermomechanical fatigue (TMF) loading, the thermal cyclic temperature changes with decreasing or increasing applied stress upon unloading or loading, and the fiber/matrix interface shear stress in the long fiber-reinforced ceramic-matrix composites (CMCs) changes with applied cycles. In this paper, the in-phase TMF damage evolution of CMCs has been investigated, considering the coupling effects of TMF loading stress level, thermal cyclic temperature and applied cycles. The interface debonding and sliding lengths are determined based the thermomechanical micromechanical stress field and the fracture mechanics approach. The relationships between the TMF hysteresis parameters, interface damage, thermal cyclic temperature and applied cycles have been developed. The damage accumulation processes subjected to in-phase TMF for different fibers volume fraction, peak stress, matrix crack spacing, interface properties and thermal cyclic temperature range have been analyzed. The distinction of the damage evolution between the in-phase TMF and isothermal fatigue (IF) loading at the same applied stress has been analyzed. The damage evolution of cross-ply CMCs subjected to the in-phase TMF and IF loading have been predicted. (C) 2018 Elsevier Ltd. All rights reserved.