Recent developments in local concepts of fatigue assessment of welded joints
Recent developments in local concepts of fatigue assessment of welded joints
复制标题
DOI：
10.1016/j.ijfatigue.2008.05.019
复制
发表时间：
2009-01-01
影响因子：
6
通讯作者：
Fricke, W.
中科院分区：
文献类型：
--
作者：
Radaj, D.;Sonsino, C. M.;Fricke, W.
回顾了最近提出的结构应力或应变概念、缺口应力或应变概念（也称为“局部应力或应变概念”）以及焊接接头疲劳评估断裂力学概念的一些修改或变体，而更广泛的背景在最近重新发布和实施的标准工作中提出。首先描述的结构应力概念基于跨板厚度或沿着预期裂纹路径的应力分布的线性化，或者基于焊趾下方 1 毫米深度的结构应力。结构应力是根据设计 S-N 曲线定义和设置的。提出了薄钢板和铝合金焊接接头的进一步结构应力概念。在弹性缺口应力概念中，概述了参考缺口半径 rho(r) = 1 mm 的变体，最近也针对板厚 t >= 5 mm 的铝合金焊接接头进行了验证，以及小尺寸参考缺口半径 rho(r) = 0.05 mm 的变体，适用于薄板材料的焊接接头。弹塑性缺口应变概念适用于从熔核边缘处的小尺寸钥匙孔缺口开始的点焊拉伸剪切样本。回顾了与钢和铝合金缝焊接头的裂纹萌生相关并外推至最终断裂的新型缺口应力强度因子（NSIF）方法。最后描述了最近开发的点焊裂纹扩展方法。 (C) 2008 Elsevier Ltd. 保留所有权利。
Several lately proposed modifications or variants of the structural stress or strain concepts, of the notch stress or strain concepts (also termed 'local stress or strain concepts') and of the fracture mechanics concepts of fatigue assessment of welded joints are reviewed, whereas the wider context is presented in a recently republished and actualised standard work. The structural stress concepts described first are based on a linearisation of the stress distribution across the plate thickness or along the anticipated crack path and, alternatively, on the structural stress 1 mm in depth below the weld toe. The structural stress is defined and set against design S-N curves. A further structural stress concept is presented for welded joints in thin-sheet steels and aluminium alloys. Among the elastic notch stress concepts, the variant with the reference notch radius, rho(r) = 1 mm, recently verified also for welded joints in aluminium alloys with plate thicknesses t >= 5 mm and the variant with a small-size reference notch radius, rho(r) = 0.05 mm, applicable to welded joints in thin-sheet materials, are outlined. The elastic-plastic notch strain concept is applied to a spot-welded tensile-shear specimen starting from a small-size keyhole notch at the nugget edge. The novel notch stress intensity factor (NSIF) approach relating to crack initiation and extrapolated to final fracture of seam-welded joints in steels and in aluminium alloys is reviewed. A more recently developed crack propagation approach for spot welds is finally described. (C) 2008 Elsevier Ltd. All rights reserved.