Campagnolo Alberto, Ferro Paolo, Romanin Luca, Meneghetti Giovanni
Department of Industrial Engineering, University of Padova, 35131 Padova, Italy.
Department of Management and Engineering, University of Padova, 36100 Vicenza, Italy.
Materials (Basel). 2021 Feb 8;14(4):812. doi: 10.3390/ma14040812.
Approaches based on calculating Residual Notch Stress Intensity Factors (R-NSIFs) assume the weld toe to be a sharp V-notch that gives rise to a residual singular stress distribution close to the weld toe. Once R-NSIFs are determined, they might be included in local fatigue criteria for the structural strength assessment of welded joints based on NSIFs due to external cyclic loading. However, the numerical calculation of R-NSIFs through finite element (FE) simulations of the welding process requires extremely refined meshes to properly capture the residual stress singularity. In this context, the Peak Stress Method (PSM) has recently been adopted to estimate R-NSIFs due to residual stresses by means of coarse meshes of 2D 4-node plane or 3D 8-node brick elements. The aim of this work is to investigate the applicability of the PSM to estimate R-NSIFs in a butt-welded joint using coarse meshes of 3D 10-node tetra elements. The R-NSIF distribution at the weld toe line is estimated by applying the PSM to coarse meshes of 3D 10-node tetra elements, and the results are in agreement with those obtained using 3D 8-node brick elements. Accordingly, the PSM based on tetra elements further enhances the rapid estimation of R-NSIFs using coarse meshes and could be effective in analyzing complex 3D joint geometries.
基于计算残余切口应力强度因子（R-NSIFs）的方法假定焊趾为尖锐的V形切口，这会在靠近焊趾处产生残余奇异应力分布。一旦确定了R-NSIFs，它们可能会被纳入基于外部循环载荷引起的NSIFs的焊接接头结构强度评估的局部疲劳准则中。然而，通过焊接过程的有限元（FE）模拟对R-NSIFs进行数值计算需要极其精细的网格才能正确捕捉残余应力奇异性。在此背景下，峰值应力法（PSM）最近已被用于通过二维4节点平面或三维8节点砖单元的粗网格来估计由残余应力引起的R-NSIFs。这项工作的目的是研究PSM在使用三维10节点四面体单元的粗网格估计对接焊接接头中R-NSIFs的适用性。通过将PSM应用于三维10节点四面体单元的粗网格来估计焊趾线处的R-NSIF分布，结果与使用三维8节点砖单元获得的结果一致。因此，基于四面体单元的PSM进一步提高了使用粗网格快速估计R-NSIFs的能力，并且在分析复杂的三维接头几何形状时可能是有效的。
