振動荷重を利用した溶接残留応力の低減法 : 一定の溶接条件下における検討

抄録

Welding is widely used for construction of many structures. It is well known that residual stress exists nearby the bead because of locally given heat. Since tensile residual stress on the surface degrades fatigue strength, some methods for reduction of residual stress have been presented. In this paper, a new method is proposed in which vibrational load is applied during welding operation for reduction of residual stress without heat treatment. Advantage of this method is that vibrational load is generated by a small shaker. It is clarified experimentally that tensile residual stress near the bead can be reduced when this method is used. Experimental results are qualitatively explained by an analytical method. Using the analytical model with preloaded spring having elasto-plastic characteristic and considering change of dynamic characteristics during welding, reduction of residual stress can be evaluated. It is assumed that reduction of residual stress is caused by local plstic deformation because of low yield stress during solidification of welded metal. The proposed method is expected to be practical.