In order to improve the damage tolerance ability of aircraft skin, the superiority of laser cladding aluminum alloy structures for crack resistance is investigated by establishing a three-dimensional (3D) finite element simulation model based on the double ellipsoid heat source and sequentially coupled thermal-mechanical analysis (SCTMA) method. The temperature field and residual stress field under different laser power, laser scanning velocity, laser cladding length, laser cladding patterns and laser cladding angles are investigated to evaluate the effectiveness of fatigue life improvement. Stress intensity factors are calculated by M-integral method and fatigue life is estimated by Paris equation, respectively. The results show that the laser cladding samples achieve the best crack resistance performance at laser power of 1400 W and laser scanning velocity of 10 mm/s. The fatigue life for the sample of cladding coating length of 50 mm is 2.93 times than that of the untreated sample. The linear pattern shows a better crack resistance performance than other patterns and the best crack resistance performance is achieved when the cladding angle of linear pattern is “0”. The results demonstrate that the fatigue life of samples after being laser cladding treated is significantly higher than that of untreated samples, which benefits from the residual compressive stress induced by laser cladding process. The higher laser power or lower laser scanning velocity can improve the fatigue life of laser treated samples. The fatigue life of samples can be affected by laser parameters, laser cladding patterns and angles.

为了提高飞机蒙皮的损伤承受能力，通过建立基于双椭球热源的三维有限元仿真模型并依次耦合热力，研究了激光熔覆铝合金结构抗裂性的优越性。机械分析（SCTMA）方法。研究了不同激光功率，激光扫描速度，激光熔覆长度，激光熔覆图案和激光熔覆角度下的温度场和残余应力场，以评价改善疲劳寿命的有效性。应力强度因子通过M积分法计算，疲劳寿命通过Paris方程估算。结果表明，在1400激光功率下，激光熔覆样品具有最佳的抗裂性能。 W和激光扫描速度为 10mm / s。熔覆层长度为50 mm的样品的疲劳寿命 是未处理样品的2.93倍。线性图案显示出比其他图案更好的抗裂性能，并且当线性图案的包角为“ 0”时，可以获得最佳的抗裂性能。结果表明，激光熔覆处理后样品的疲劳寿命明显高于未处理的样品，这归因于激光熔覆过程中产生的残余压应力。较高的激光功率或较低的激光扫描速度可以提高激光处理样品的疲劳寿命。样品的疲劳寿命会受到激光参数，激光熔覆图案和角度的影响。