Numerical Incorporation of the Damaging Effects of Residual Stresses in the Multiaxial Fatigue Assessment of Welded Components and Structures

焊接部件和结构多轴疲劳评估中残余应力破坏效应的数值结合

• 批准号: 271548146
• 负责人: Dr.-Ing. Majid Farajian
• 金额: --
• 依托单位: Lehigh University
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/271548146?language=en
• 关键词: Numerical; Incorporation; Damaging; Effects; Residual

The evaluation of the service life of welded joints under multiaxial loading is still associated with large uncertainties due to various influencing factors on the fatigue behavior. The extent to which the welding residual stress field influences the multiaxial stress state and consequently the fatigue damage mechanisms is still a matter of debate. The reason for this is that in the previous studies for the multiaxial fatigue analysis of welds either the welded specimens were stress relieved or very high tensile residual stresses at fatigue crack initiation sites were postulated without any experimental determination. A further difficulty in the evaluation of residual stresses is that these are subject to change during the stress, so that even a precise determination of the initial residual stresses may represent only the first step towards the fatigue assessment. The circumstances described have led to the fact that in the design of fatigue loaded welded structures conservative assessment methods are recommended in the current regulations, for which the suspected high stresses are made responsible. A scientific and engineering solution to reduce this design conservatism is the development of a validated computational approach in order to incorporate the damaging effects of the welding residual stress field in fatigue assessment methods.The proposed research project will therefore address this issue and has two main objectives:1. Observational and experimental studies on the influence of welding residual stresses on the axial and multiaxial fatigue crack behavior in tubular welded specimens.2. Numerical incorporation of the damaging effects of residual stresses into a proper fatigue damage model for accurate life time assessments of welded joints.Tubular welded specimens out of S355J2H are planned to be fatigue tested under axial, torsional and axial-torsional loading (LCF, HCF) in as-welded and stress relieved conditions. Through numerical incorporation of the calculated welding residual stress fields into critical fatigue damage models, the fatigue life of the welded specimens is going to be assessed and compared with the experiment. By developing a computational approach for the quantification of the influence of residual stresses on the fatigue life of welds and the appropriate recommendation for design guidelines, the lightweight potentials of construction materials could be exhausted. After a successful completion of the project, appropriate engineering guidelines and regulations for the fatigue assessment of welds under multiaxial loading with a realistic consideration of the residual stress influence in service life would be available.

多轴载荷下焊接接头疲劳寿命的评估仍然存在很大的不确定性，因为影响疲劳行为的因素很多。焊接残余应力场在多大程度上影响多轴应力状态，从而影响疲劳损伤机制仍然是一个有争议的问题。其原因是，在以前的研究中的多轴疲劳分析的焊接试样的应力消除或非常高的拉伸残余应力在疲劳裂纹萌生部位假设没有任何实验测定。残余应力评估的另一个困难是，残余应力在应力作用过程中会发生变化，因此，即使精确确定初始残余应力，也只是疲劳评估的第一步。所述情况导致了这样一个事实，即在疲劳加载焊接结构的设计中，现行法规建议采用保守的评估方法，怀疑高应力是造成这种情况的原因。一个科学的和工程的解决方案，以减少这种设计保守性是一个有效的计算方法，以将焊接残余应力场的破坏性影响的疲劳评估methods.The拟议的研究项目将解决这个问题，因此有两个主要目标的发展：1。对焊接残余应力对管状焊接接头轴向和多轴疲劳裂纹行为的影响进行了观测和实验研究.将残余应力的损伤效应数值化地纳入适当的疲劳损伤模型中，以准确评估焊接接头的寿命。计划对S355J2H的管状焊接试样在焊接状态和应力消除状态下进行轴向、扭转和轴向扭转载荷（LCF、HCF）下的疲劳试验。通过将计算得到的焊接残余应力场与临界疲劳损伤模型进行数值结合，对焊接试件的疲劳寿命进行评估，并与试验结果进行比较。通过开发一种计算方法来量化残余应力对焊缝疲劳寿命的影响，并为设计准则提供适当的建议，可以充分利用建筑材料的轻量化潜力。在项目成功完成后，将提供适当的工程准则和条例，用于在多轴载荷下对焊缝进行疲劳评估，并现实地考虑到残余应力对使用寿命的影响。

项目成果

Modelling and Experimental Validation of Material Deformation at Different Zones of Welded Structural-Steel under Multiaxial Loading

多轴载荷下焊接结构钢不同区域材料变形的建模和实验验证

• DOI: 10.1016/j.msea.2021.140826
• 发表时间: 2021
• 期刊: Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
• 影响因子: 6.4
• 作者: Hemmesi K;Holey H;Elmoghazy A;Böhm R;Farajian M;Schulze V.
• 通讯作者: Schulze V.

Numerical studies of welding residual stresses in tubular joints and experimental validations by means of x-ray and neutron diffraction analysis

• DOI: 10.1016/j.matdes.2017.03.088
• 发表时间: 2017-07-15
• 期刊: MATERIALS & DESIGN
• 影响因子: 8.4
• 作者: Hemmesi, Kimiya;Farajian, Majid;Boin, Mirko
• 通讯作者: Boin, Mirko

Application of the critical plane approach to the torsional fatigue assessment of welds considering the effect of residual stresses

考虑残余应力影响的临界平面方法在焊缝扭转疲劳评估中的应用

• DOI: 10.1016/j.ijfatigue.2017.01.023
• 发表时间: 2017
• 期刊: International Journal of Fatigue
• 影响因子: 6
• 作者: Hemmesi K;Farajian M;Fatemi A.
• 通讯作者: Fatemi A.

Numerical Welding Simulation as a Basis for Structural Integrity Assessment of Structures: Microstructure and Residual Stresses

数值焊接模拟作为结构完整性评估的基础：微观结构和残余应力

• DOI: 10.5772/intechopen.74466
• 发表时间: 2018
• 作者: Hemmesi K;Farajian M.
• 通讯作者: Farajian M.

Numerical evaluation of surface welding residual stress behavior under multiaxial mechanical loading and experimental validations

• DOI: 10.1016/j.ijmecsci.2019.105127
• 发表时间: 2020-02-15
• 期刊: INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
• 影响因子: 7.3
• 作者: Hemmesi, Kimiya;Mallet, Pierre;Farajian, Majid
• 通讯作者: Farajian, Majid