Weft direction tension-tension fatigue responses of layer-to-layer 3D angle-interlock woven composites at room and elevated temperatures

摘要

Elevated fatigue behaviors of resin matrix composites are considerable key to the application of aeroengine that requires fatigue resistance at elevated temperature. However, undeniably, very few studies are focused on this issue, thereby resulting in limitation applications of resin matrix composites in aeroengine components, i.e. blades and case. In this work, the fatigue responses of layer-to-layer 3D angle-interlock woven composites (2.5DWC) were experimentally and numerically studied at room and elevated temperatures. Experimental results show that the weft direction fatigue lives at 20 °C and 180 °C experienced a relatively short cycle (less than 10~4 cycles) prior to the failure. But, once the stress level declined to a threshold value (dropped by 1-2%), the fatigue limitation would be activated, regardless of temperature. Moreover, the residual strength at 20 °C or 180 °C was reinforced compared to the static strength. Considering the fatigue data and fracture morphology, probable damage mechanisms corresponding to temperature-dependent weft direction fatigue behaviors of 2.5DWC were proposed. A temperature-dependent fatigue life prediction model of 2.5DWC was proposed, based on which the weft direction fatigue lives, damage propagation processes and residual stiffnesses of 2.5DWC at 20 °C and 180 °C were predicted.