【摘要】 为考核层合结构复材风扇叶片在1.5倍离心载荷下的低周疲劳寿命，制备一批风扇叶片，在薄弱部位取样。通过建立层合结构风扇叶片有限元模型，模拟榫头的应力状态，从而确定拉伸载荷水平，开展拉-拉载荷低周疲劳测试。在相邻铺层间引入内聚力单元，并考虑榫头试样单向带面内损伤，模拟损伤变量随循环数累积的过程，增加虚拟拉伸载荷，得到榫头低周疲劳失效时刻的损伤状态。试验结果说明榫头元件形成分层裂纹的平均寿命为17 207次循环，首次出现分层裂纹的位置基本一致。数值仿真结果表明榫头单向带基体和层间损伤累积引起裂纹扩展，导致低周疲劳失效。本研究可为建立层合结构复材风扇叶片低周疲劳寿命试验流程和疲劳失效判据提供支撑。更多还原

【Abstract】 To validate the low cycle fatigue(LCF) life of laminated composite fan blade at 1.5 fold nominal design speed, multiple fan blades were manufactured, and dovetail specimens were sampled at one of weak locations of fan blade to conduct tension-tension fatigue test. The correspodning finite element model was established to simulate the reaction forces in blade root regions, thus the maximum longitudinal forces applied to dovetail elements were determined. By introducing cohesive elements between adjacent layers and considering in-plane damage of laminas, the maximum load in the sinuisoidal spectrum was dynamiclly enlarged so that the actual static reaction forces in simulations caused the propagation of cracks similar to those in the test. The evolution of damage variables in terms of loading cycles were effectively represented, and the multiple damage modes were obtained when fatigue failure occurred under the circumstance that no design curves were currently available to formulate ther relationship. Test results showed that the average loading cycle was 17 207 until the delamination cracks appeared within the dovetail body. There was small dispersity regarding the locations of damage onset and propagation. Numerical results showed that the tensile matrix and the interlaminar debonding were the dominating damage modes that led to the ultimate low cycle fatigue failure. This study will support the establishment of low cycle fatigue test process and fatigue failure criterion.更多还原