Dent-repaired fatigue performance of thin sheet specimens under coupled multi-stage damage with impact and pre-fatigue was investigated. Different damage combinations of fatigue, impact and repair were performed to simulate actual service of aircraft. Residual fatigue life after repairing is 27.8% higher than that of unrepaired, axial strain field during fatigue loading is redistributed after repairing. Fatigue life reduction is found to be sensitive to damage sequence. For specimens with certain cycles of pre-fatigue, dent repairing could not restore fatigue life. A life prediction model based on strain distribution and damage accumulative theory is proposed, which is of strong engineering significance.

研究了具有冲击和预疲劳的多阶段耦合损伤下薄片试样的凹痕修复疲劳性能。进行了疲劳，冲击和修理的不同损害组合，以模拟飞机的实际服务。修复后的残余疲劳寿命比未修复的高27.8％，修复后重新分配了疲劳载荷期间的轴向应变场。发现减少疲劳寿命对损坏顺序很敏感。对于具有一定预疲劳周期的试样，凹痕修复无法恢复疲劳寿命。提出了一种基于应变分布和损伤累积理论的寿命预测模型，具有重要的工程意义。