摘要
目的更全面地掌握残余应力对焊接接头疲劳性能的具体影响。方法采用先进的连续损伤力学方法,深入研究对接焊接接头在循环载荷作用下的疲劳损伤演化过程。通过热-力耦合分析,以评估焊接工艺引起的残余应力,从而建立焊接接头在疲劳分析中使用的初始状态。同时,将耦合损伤循环塑性本构方程编写为ABAQUS用户材料子程序UMAT,建立循环载荷下的有限元模型。结果在前10个循环载荷作用下,焊接接头出现了明显的应力松弛现象,且疲劳损伤先缓慢增加,然后快速增加。在前几个循环内,疲劳损伤与循环次数呈现出线性关系,即随着循环次数的增加,疲劳损伤也逐渐累积。然而,当疲劳损伤达到0.25左右时,其增长速度显著加快,材料开始出现明显的性能下降,最终导致失效。结论这一研究成果能够更准确地预测焊接接头在循环载荷作用下的疲劳寿命,从而为工程实践提供有力的理论指导。
Thework aims to acquire a comprehensive understanding of the specific effect of residual stress on the fatigue behavior of welded joints.The advanced continuous damage mechanics method was adopted to study the fatigue damage evolution process in butt-welded joints under cyclic loading conditions.Thermal-mechanical coupling analysis was employed to assess the residual stresses introduced by the welding processes,thus establishing the initial state of the welded joints for fatigue analysis.Furthermore,a coupled damage cyclic plastic constitutive equation was implemented as a user-defined material subroutine(UMAT)in ABAQUS to develop a finite element model for simulating cyclic loading conditions.During the initial 10 loading cycles,the welded joint exhibited significant stress relaxation,and fatigue damage progressed initially at a slow rate,followed by a rapid acceleration.In the initial loading cycles,a linear relationship was observed between the fatigue damage and the number of cycles,indicating a gradual accumulation of fatigue damage with increasing cycle count.However,once the fatigue damage reached approximately 0.25,its growth rate underwent an obvious acceleration,signaling a significant degradation in material performance,ultimately leading to failure.The findings of this research provide an enhanced capability to predict the fatigue life of welded joints under cyclic loading conditions,offering valuable theoretical guidance for engineering applications.
作者
刘正阳
宋双印
谢蓉
于海洋
LIU Zhengyang;SONG Shuangyin;XIE Rong;YU Haiyang(Unit 91007,Fujian Ningde 355011,China;Shanghai Lingyao Marine Engineering Co.,Ltd.,Shanghai 201108,China)
出处
《装备环境工程》
CAS
2024年第10期137-142,共6页
Equipment Environmental Engineering
关键词
残余应力
焊接接头
疲劳损伤
损伤演化
本构方程
UMAT
residual stress
welded joints
fatigue damage
damage evolution
constitutive equations
UMAT
