基于NSIF的应变能密度法评估焊接接头疲劳强度（英文）

Fatigue Strength Assessment of Welded Joints Using Strain Energy Density Method Based on NSIF

本文介绍了一种基于切口应力强度因子的应变能密度法来评估焊接接头的疲劳强度。该方法将焊接接头简化成尖锐的V型切口。切口尖端应力的奇异性与切口的张开角度有关,切口尖端附近的应力分布可以用切口应力强度因子来描述。切口应力强度因子的计算需要精细的网格划分,在不同的切口张开角度下计算得到的切口应力强度因子之间是无法直接进行比较的。本文基于切口应力强度因子,研究了以R为临界半径的扇形面积内的应变能密度。经验证,应变能密度法不依赖于网格尺寸,包含了焊接接头局部焊接参数等影响,能够准确描述焊趾附近高应力区的应力分布,对于焊接接头疲劳强度的评估具有一定的工程应用价值。

A strain energy density method based on Notch Stress Intensity Factors(NSIF) to assess fatigue strength of welded joints is presented. This method simply treats welded joints as V-shaped notches. The stress field close to the notch tip is singular and related to the notch opening angle. The stress distribution of the notch tip can be described by the NSIF. The calculation of the NSIF needs refined mesh, and two calculated NSIFs of different notch opening angles cannot be compared with each other directly. Based on the NSIF, the strain energy density in a sector of critical radius R is studied. It is validated that the method presented in this paper is independent of mesh sizes and contains the effect of local welding parameters of the welded joints. The method can accurately describe the stress distribution in the highly stressed zones located at the weld toes, and can be used in engineering to assess the fatigue strength of welded joints.