基于热点应力的焊缝疲劳强度评定研究

为解决名义应力法在焊接结构疲劳强度评定中应用的局限性,全面介绍和分析了当前国际上研究较多的基于热点应力的焊接板结构焊缝疲劳强度评定方法。主要包括热点应力定义、组成及其类型,热点应力的外推法确定及相应的有限元建模原则,DNV推荐的热点应力S—N曲线和经典的焊接结构疲劳强度评定及寿命预测算法。在机车车辆焊接承载部件的疲劳分析中,合理应用热点应力法以补充和完善名义应力评定,对提高评定及寿命预测精度具有较为现实的实用价值。

Study of fatigue strength assessment of welds based on hot spot stress

In order to avoid the limitation of nominal stress method applied in fatigue strength assessment for welded structures,the assessing method based on hot spot stress for plated welded structures was introduced and analyzed generally. The following points were mainly included: the concept and form of hot spot stress and hot spot types,the extrapolation methods for determination of hot spot stress and relevant principles for finite element modeling,the hot spot S-N curve according to DNV and the classical arithmetic of fatigue strength assessment and life prediction for welded structures. It is practical to improve the precision of assessment and life prediction by using the hot spot stress method in rolling stock welded load-carrying structures together with the nominal stress method properly.