Cumulative fatigue damage for 3-D angle-interlock woven composite under three-point bending cyclic loading

This article presents the quantitative characterization of cumulative fatigue damage behavior for the three-dimensional angle-interlock woven composite undergoing three-point bending cyclic loading. The S–N curve was obtained to demonstrate the fatigue life of the three-dimensional angle-interlock woven composite under different stress levels. The increment of cycles for each 5% interval of stress level was reported to show the difference of fatigue resistance performances of the three-dimensional angle-interlock woven composite among the high, middle, and low intervals of stress level. In addition, the Cumulative Fatigue Damage versus Number of Cycles (D–N) curve and the Deflection Index versus Number of Cycles (F–N) curve were deduced to characterize the three-stage cumulative fatigue damage. Furthermore, the damage morphologies of the three-dimensional angle-interlock woven composite after fatigue tests were photographed to compare with those in quasi-static test. The cracks initiation and propagation in the three-dimensional angle-interlock woven composite during the process of cyclic loading were summarized to find the mechanisms of fatigue damage development.