焊接残余应力重分布与裂纹扩展的耦合分析  

Coupling analysis of welding residual stress redistribution and crack propagation

作　　者：高海洋 罗广恩[1] 郑新招 柴莹 GAO Hai-yang;LUO Guang-en;ZHENG Xin-zhao;CHAI Ying(School of Naval Architecture and Ocean Engineering,Jiangsu University of Science and Technology,Zhenjiang 212100,China)

机构地区：[1]江苏科技大学船舶与海洋工程学院,江苏镇江212100

出　　处：《船舶力学》2024年第11期1756-1767,共12页Journal of Ship Mechanics

基　　金：国家自然科学基金面上项目(52171312);水路交通控制全国重点实验室开放课题资助项目(QZ2022-Y012);2023江苏省工业和信息产业转型升级项目(苏财工贸〔2023〕60号)。

摘　　要：焊接残余应力对于焊接结构疲劳寿命影响明显,同时焊接残余应力并不是一成不变的,随着裂纹扩展会发生重分布。因此,开展焊接残余应力重分布和裂纹扩展的耦合研究对于准确预测焊接结构的疲劳寿命至关重要。本文基于热弹塑性有限元法与扩展有限元法(XFEM),提出考虑焊接残余应力重分布和裂纹扩展耦合的疲劳寿命分析方法。以TC4钛合金拉伸疲劳试样为例,结合扩展有限元法,研究焊接残余应力随裂纹扩展的重分布情况,循环迭代计算得到裂纹扩展过程中裂尖前方焊接残余应力分布,以及焊接残余应力重分布下的疲劳裂纹扩展a-N曲线。计算结果表明,裂尖处焊接残余应力会随裂纹扩展先增大后减小,相比于将焊接残余应力视为恒定值,考虑焊接残余应力重分布的扩展有限元疲劳寿命分析方法能更准确地预报焊接结构疲劳寿命。Welding residual stress has a significant impact on the fatigue life of a welding structure.Mean⁃while,welding residual stress is not invariable,but will be redistributed with crack propagation.Therefore,the coupling study of welding residual stress redistribution and crack propagation is very important to predict the fatigue life of a welded structure accurately.Based on thermal elastic-plastic finite element method and extended finite element method(XFEM),a fatigue life analysis method considering the coupling of residual stress redistribution and crack propagation was proposed in this paper.Taking the tensile fatigue sample of TC4 titanium alloy as an example,the redistribution of the welding residual stress along with crack propaga⁃tion was studied with the extended finite element method.The welding residual stress distribution in front of the crack tip during crack propagation and the fatigue crack propagation a-N curve under the redistribution of weld residual stress were calculated by cyclic iteration.The calculation results show that the welding resid⁃ual stress at the crack tip increases firstly and then decreases with the crack propagation.Compared with the results based on constant value of the residual stress,the extended finite element fatigue life analysis method considering the redistribution of the residual stress is more accurate to predict the fatigue lives of welding structures.

关 键 词：疲劳裂纹扩展 残余应力重分布 扩展有限元 TC4钛合金 

分 类 号：U661.43[交通运输工程—船舶及航道工程]