摘要
对搅拌磨擦焊、TIG焊和激光焊进行数值模拟,得到焊接残余应力场.将残余应力场施加到线弹性断裂力学模型之中,运用J积分方法计算残余应力强度因子,并计算裂纹扩展速率,通过与试验结果和虚拟裂纹闭合法计算结果进行对比,验证了文中所使用方法的正确性.研究发现,残余应力强度因子的分布与残余应力分布形式相似.残余应力的引入,对应力比有较大影响,但随着应力比的增大,残余应力对应力比的影响逐渐减弱.焊接残余应力的引入缩短了焊接构件的使用寿命,当裂纹长度较小时,TIG焊接构件使用寿命比搅拌摩擦焊接构件和激光焊接构件使用寿命短.
Sequential coupled thermo-mechanical model and fracture mechanical model based on finite element method and J-integral method are established to calculate the residual stress and the stress intensity factor for friction stir welding,TIG and laser welding process,respectively. The commerical code NASGRO is used to predict the fatigue crack growth rate. This method is validated by comparing with the experimental data and results of the virtual crack closure technique method. The distribution of the residual stress intensity factor is similar with the residual stress profile and the residual stress has a significant impact on the effective stress ratio R. The influence decreases as the increase of the stress ratio. The residual stresses severely shorten the fatigue life of the plate,and the fatigue life of the plate welded with TIG technology is shorter than the ones of the plates welded with friction stir welding and laser welding.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2014年第10期29-32,36,114,共6页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(10802017)
国家重点基础研究发展计划资助项目(973计划
2010CB832704)
国家高技术研究发展计划资助项目(863计划
2012AA050901)
新世纪优秀人才支持计划资助项目(NCET-12-0075)
中央高校基本科研业务费专项资金资助项目
关键词
焊接残余应力场
J积分
残余应力强度因子
裂纹扩展速率
welding residual stresses
J-intergral
residual stress intensity factor
fatigue crack growth rate
