不等厚板对接焊疲劳寿命结构形状影响分析

Impact Analysis of Structural Shape Fatigue Life of Butt Weld between Plates of Unequal Thickness

从焊接部位局部应力集中的角度分析了不等厚板在不同焊接形式下的疲劳寿命。利用有限元法求解了20种具有不同焊接对齐方式、焊趾角和厚板削薄段斜度的球形封头和简体对接焊结构在承受循环载荷作用下的局部应力，参照修正的Goodman理。论和JB4732——1995《钢制压力容器——分析设计标准》得到焊接结构的等效疲劳应力幅和疲劳寿命。结果表明，不等厚板对接焊时，对齐方式和焊趾角对焊缝区域的局部应力集中和结构的疲劳寿命有显著影响，而厚板削薄段斜度在1：4～1：3对应力集中和疲劳寿命影响不大。

The fatigue life of different welding shapes between plates of unequal thickness in pressure vessel was investigated from the point of local stress concentration at welding position. Under cyclic loading, local stress of 20 types of butt welding structure between dome head and cylinder, with different alignment mode, flank angle of welding toe and slope of shaving segment, was solved by finite element method. Referring to extended Goodman theory and national standard of JB/T 4732--1995 steel pressure vessel standard of design by analysis,the equal fatigue stress amplitude and fatigue life of these welding structures were obtained. The results demonstrate that alignment mode and flank angle of welding toe have significant influence on the local stress concentration at welding position and fatigue life of the welding structure, while, the slope of shaving segment, from 1 ： 4 to 1 ： 3, has trivial impact to the stress concentration and fatigue life.