推进剂贮箱金属焊接件疲劳裂纹对应力强度因子影响的数值分析

卫星推进剂贮箱的焊接质量直接影响卫星的寿命和可靠性。文章通过仿真分析研究焊接残余应力对贮箱上已存在裂纹的影响。首先针对球壳模型和平板模型分别计算焊接残余应力，然后在应力强度值最大的危险区域引入裂纹，对不同角度和尺寸系数的裂纹对应力强度因子影响的数值和变化趋势进行分析。研究表明：起主要作用的是应力强度因子KI；KII受角度影响相对较大；KI和KII的最小值都在裂纹中心处；KIII基本随归一化裂纹前沿数值增加而增加。

Numerical analysis of fatigue crack vs. stress impact factor of metal welded joint for satellite propellant tank

The welding quality of the propellant tank has a significant effect to the life and the reliability of satellites. To study the influence of the residual welding stress on the fatigue crack on the tank, the welding residual stress is first calculated with a spherical and a planer model, respectively. The stress intensity factors of three kinds are introduced to investigate the relations between the shape factors of the crack on the most vulnerable area with the highest stress intensity. The values and the variation trend of the crack’s stress intensity factors against the crack morphology are obtained. It’s shown that among the three SIFs, KI plays a most important role; KII is subjected more to the crack angle; the value of KI and KII both reaches its minimum at the center of the crack; and the value of KIII basically increases with the normalized front of the crack.