基于结构完整性评定方法和有限元分析并考虑焊接残余应力的焊接缺陷评估(英文)

Defect assessment of welded specimen considering weld induced residual stresses using SINTAP procedure and FEA

采用欧共体提出的结构完整性评定方法(SINTAP)与有限元分析(FEA)方法,结合焊接残余应力对存在横向贯穿裂纹的ASTMA36钢板和7075-T7351铝合金板对接焊接头的缺陷进行评估。由SINTAP方法、FEA或者实验得到焊接产生的纵向残余应力曲线。该残余应力曲线与SINTAP方法中得到的梯形残余应力拟合较好。计算了3种不同情况下的裂纹长度和残余应力强度因子(SIF),并与通过有限元分析得到的结果相比较,绘制了残余应力强度因子与裂纹长度的关系曲线。利用该图可以计算包括残余应力和力学载荷的总的SIF,比较了总的SIF与损伤容限分析法得到的材料断裂韧性。绘制了焊接态的、力学载荷的和存在残余应力情况下的不同裂纹尺寸的7075-T7351铝合金板的失效评估图,以确定在某特殊裂纹尺寸和力学载荷下的安全水平。

The defect assessment in butt-welded joint of ASTM A36 steel plates and 7075-T7351 aluminum alloy plates containing transverse through thickness crack was analyzed using SINTAP procedure and FEA incorporating weld induced residual stresses. Weld induced longitudinal residual stress profile can be obtained through SINTAP procedure, FEA or experimental analysis. This residual stress profile can be fitted with the trapezoidal residual stress profile available in SINTAP. For three different cases, crack length and residual stress intensity factor （SIF） are calculated and its comparison with the results obtained through FEA is plotted with respect to crack length. The stress intensity factor for mechanical loading is also plotted in the same graph. Using this graphical plot, the total SIF, including residual stress and mechanical loading, can be calculated for any particular crack size. The total SIF can be compared with the fracture toughness of the material for damage tolerance analysis. Also a failure assessment diagram is drawn for welded 7075-T7351 aluminum alloy plates with different crack sizes for as-welded （only residual stress） and mechanical loading along with the existing weld induced residual stresses to show the safety level for a particular crack size and mechanical loading.