Finite element analyses on three-point low-cyclic bending fatigue of 3-D braided composite materials at microstructure level

摘要: Abstract This paper presents numerical analyses of fatigue behaviors three-dimensional (3-D) 4-step rectangular braided composite material under three-point low-cyclic bending. A microstructure model the 3-D was established to calculate bending deformation and failure with a finite element method (FEM). The stiffness degradation morphologies were obtained from FEM results compared those experimental. stress distributions, hysteresis failures fiber tows resins at different parts have been collected calculations analyze mechanisms. influences preform on damage discussed. It is found that surface yarns share more loads than inner part. concentration appeared regions larger changes tow orientation angles. evolutions also used explain mechanical degradation. crack generation damages development early stages followed by propagation afterwards. series evolution loading cycles unveil From investigation, resistance could be optimized improving decreasing change