基于缺口应力法的焊接接头疲劳强度评估

摘要

在现有的焊接接头疲劳评估方法中,S-N曲线法的运用最为广泛,但是该方法主要考虑的结构的名义应力,很难运用到复杂结构或者复杂载荷下的求解.对于复杂接头形式的应力分析应根据其几何应力作必要的修正,缺口应力为含有缺口的复杂焊接接头的疲劳强度评估开辟了新的思路.以对接接头、纵向角接头以及T形接头为研究对象,根据IIW的相关规定,采用缺口应力评估焊接接头的疲劳强度.结果表明,采用缺口应力评估焊接接头疲劳强度时,疲劳数据的离散性较小;IIW推荐的缺口应力S-N曲线仅适用于角焊缝接头,但对对接接头的疲劳评估,得到的结果偏危险.%S-N curve is the most widely used among all the modern fatigue design concepts for welded structures .However ,this method mainly considers the nominal stress of the structure ,and it is diffi-cult to be used for the evaluation of complex structure or complex loads .As for the stress analysis of complex joints ,the correction according to the geometric stress is needed to be taken into account , and the notch stress method provides a novel idea for the fatigue strength assessment of complex wel-ded structures .Experimental fatigue data for butt welded joints ,longitudinal fillet joints ,and T-joints have been collected and studied .According to ⅡW recommendations ,the notch stress method has been used for the evaluation of the joints .The results show that ,the dispersion is less when the notch stress is used for the evaluation of welded joints .Meanwhile ,the S-N curve recommended by the IIW is suitable for the evaluation of fillet welded joints ,but the results will be dangerous for butt welded joints .