计及焊接变形的薄板对接焊缝疲劳热点应力分析

Fatigue assessment of butt-weld joint in thin plate accounting for initial deformation

为减轻重量及降低能耗,超大型船舶的上层建筑开始尝试使用薄板焊接结构.然而现行的各国船级社规范不允许使用小于5 mm的薄板,其主要原因是薄板焊接变形对结构疲劳强度的影响机理尚未明晰.以某在建巨型豪华游轮上层建筑的甲板分段为研究对象,通过三维激光扫描该对接焊结构实体并获取整体焊接变形数据,采用高阶多项式拟合得到该结构的初始焊接变形,利用通用有限元程序ANSYS对计及焊接变形的结构进行建模分析,并获取了焊缝周围疲劳热点应力的分布;提出了更加接近真实薄板焊接变形的拟合方法;探讨了焊接变形对疲劳热点应力分布的影响.

To improve energy efficiency,structural lightweight has gained wide attention. For shipbuilding,thin welded structure is widely used as superstructure. Since the influence of welding deformation on the fatigue strength of thin welded structure is unknown,classification rules do not allow using plate with thickness smaller than 5 mm. Based on the case on a cruise ship deck,the initial welding deformation is fitted at multiple sections. The finite element software ANSYS 15. 0 is used to obtain the strain and hotspot stress at the specified section. The results show that the effect of welding deformation on the fatigue strength of welded structures can be well evaluated.