双向应力场下对接接头裂尖应力强度因子研究

Study on Stress Intensity Factor of Crack Tip for Butt Joint Under Bidirectional Stress Field

裂纹尖端的应力强度因子K是判断裂纹扩展和结构断裂的重要参数,准确描述对接接头焊趾附近裂纹尖端的应力强度因子,在研究焊接接头裂纹扩展速率中显得尤为重要.以对接接头为研究对象,考虑焊接残余应力、压弯双向应力等对应力强度因子的影响,提出了适用于双向应力场下裂纹尖端的应力强度因子计算公式,并对该公式进行验证.结果表明,修正的应力强度因子计算公式更能准确预测疲劳裂纹扩展速率.

The stress intensity factor K at the crack tip is an important parameter to judge the crack propagation and structural fracture.It is particularly important to accurately describe the stress intensity factor at the crack tip near the weld toe of butt joint in studying the crack propagation rate of welded joint.Taking butt joint as the research object,considering the influence of welding residual stress,compressive-bending loads on stress intensity factor,a stress intensity factor calculation formula suitable for crack tip under biaxial stress field was proposed and verified.The results show that the modified stress intensity factor formula can more accurately predict the fatigue crack growth rate.