对接接头焊趾应力集中有限元分析

Finite element analysis on stress concentration at weldtoe of butt-welded joints

研究焊缝几何参数对应力集中的影响,对于提高焊接结构疲劳强度有重要的意义。本文采用有限元方法,计算了双侧对称加强高和单侧加强高的对接接头焊趾处的应力集中系数,分析了几个主要参数,包括焊趾倾角、焊趾过渡圆弧半径和板厚对于应力集中系数的影响,研究了焊趾处应力集中沿板厚方向的变化情况,在分析大量计算结果的基础上给出了估算两种形式的对接接头应力集中系数的经验公式。结果表明,减小焊趾倾角,增大过渡圆弧半径,可以减缓焊趾处截面形状的变化,改善焊趾处的应力集中;板厚的增加使得应力集中系数增大。并且单侧加强高的对接接头应力集中系数小于双侧对称加强高对接接头的,其减小幅度只与兹有关。

It is significant to study the effect of the joint geometry parameters on stress concentration factor (SCF) for improving fatigue strength of welded structures. The SCFs of butt-welded joints for symmetrical and single side strengthening weld height were calculated respectively by FEM (finite element method). The effects of parameters such as weld bead flank angle, weld toe radius and plate thickness on the SCFs were analyzed, and the variation of stress concentration along the thickness direction at weld toe was studied. Base on the analysis of calculation results, the empirical formulas for evaluating the SCFs of two types of butt-welded joints were presented. The results show that it is possible to ease the variation of section shape and decrease the stress concentration factor of butt-welded joint by decreasing weld bead flank angle or/and increasing the weld toe radius, and the SCFs increase with the augment of plate thickness. The SCFs of single side strengthening height butt-weld joints are less than that of symmetrical ones, and the decreasing magnitude only depends on weld bead flank angle.