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Prediction of the Residual Welding Stress in 2.25Cr-1Mo Steel by Taking into Account the Effect of the Solid-State Phase Transformations

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Acta Metallurgica Sinica(English Letters) 2013年第3期26卷 333-339页

作者： Dean DENG Yangang TONG Ninshu MA hidekazu murakawa College of Materials Science and Engineering Chongqing University State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology JWRI Osaka University11-1 MihogaokaIbaraki Osaka 567-0047 Japan

A computational approach based on the thermal elastic plastic finite element method was developed for predicting welding residual stress in low carbon alloyed steel welds by taking into account the effect of the solid-state phase transformations. The kinetics of phase transformations was described by Johnson Mehl Avrami Kolmogrov （JMAK） equation for bainitic transition and by Koistinen-Marburger （K-M） relationship for martensitic transition. Moreover, an additive rule depending on volumetric phase fraction was adopted to represent the material property changes during heating and cooling. Consequently, the residual welding stresses in a 2.25Cr1Mo steel TIG welded plate were computed. Early calculation results suggest that the bainitic and martensitic transformations took place in the weld the heat-affected zone drastically reduce the residual longitudinal tensile stress in the region.

关键词： Computational approach Numerical simulation Phase transformation Welding residual stress

Characteristic Tensor for Evaluation of Singular Stress Field Under Mixed-Mode Loadings

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Computer Modeling in Engineering & Sciences 2020年第2期122卷 415-432页

作者： Kei Saito Tei Hirashima Ninshu Ma hidekazu murakawa JSOL Corporation 2-5-24 HarumiChuo-kuTokyo104-0053Japan. Osaka University 11-1 MihogaokaIbarakiOsaka567-0047Japan.

A characteristic tensor is defined using stress tensor averaged in a small circular domain at the crack tip and multiplied by the root of domain *** possesses the original stress tensor characteristics and has a simple relationship with conventional fracture-mechanics ***,it can be used to estimate stress intensity factors(SIFs)for cracks of arbitrary shape subjected to multiaxial stress loads.A characteristic tensor can also be used to estimate SIFs for kinked *** study examines the relation between a characteristic tensor and SIFs to demonstrate the correlation between the characteristic tensor and fracture-mechanics ***,a single straight crack and a kinked crack of finite length existing in a twodimensional,infinite isotropic elastic body in a plane stress state,were considered to investigate the properties of the characteristic tensor under mixed-mode *** demonstrate the practical utility of the characteristic tensor,the stress distribution obtained through finite element analysis(FEA)was used to estimate mixed-mode SIFs,and the values of estimated SIFs were compared with those obtained using an analytical *** demonstrate that SIFs estimated under mixed-mode loadings exhibit a good agreement with the analytical *** indicates that the proposed characteristictensor-based approach is effective in extracting features of singular stress fields at crack tips,and can be employed to estimate values of fracture-mechanics parameters,such as *** to its simplicity,the proposed approach can be easily incorporated in commercial FE codes for practical applications to simulate the crack-growth problem under both static and dynamic loading *** excellent applicability of the characteristic tensor greatly contributes to efficiency of the design process in industries.

关键词： Characteristic tensor stress-intensity factor mixed-mode loading kinked crack.

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铝合金薄板固有变形逆解析方法的研究与开发

中国有色金属学报 2015年第11期25卷 3011-3018页

作者：梁伟邓德安 murakawa hidekazu 重庆交通大学机电与汽车工程学院重庆400074 哈尔滨工业大学先进焊接与连接国家重点实验室哈尔滨100051 重庆大学材料科学与工程学院重庆400044 Joining and Welding Research Institute Osaka University

为了获得可靠的铝合金焊接接头上固有变形,开发一种将实验与基于固有应变的有限元法(FEM)融为一体的新方法来获得接头的固有变形。为了澄清铝合金薄板焊接固有变形的分布特征,先采用热-弹-塑性有限元计算铝合金TIG重熔接头的焊接变形,... 详细信息

为了获得可靠的铝合金焊接接头上固有变形,开发一种将实验与基于固有应变的有限元法(FEM)融为一体的新方法来获得接头的固有变形。为了澄清铝合金薄板焊接固有变形的分布特征,先采用热-弹-塑性有限元计算铝合金TIG重熔接头的焊接变形,并建立固有变形在接头上的简化分布模型。其次,以该模型为基础,提出一种通过测量焊接接头上少数位置上焊前和焊后三维坐标来逆向求解固有变形的计算方法。最后,将利用该算法获得的铝合金薄板接头固有变形代入到基于固有应变理论的弹性有限元分析中,计算得到的焊接变形能较好地再现热-弹-塑性有限元方法计算得到的结果和实验结果。结果表明:采用提出的逆解析方法来获得铝合金接头的固有变形是有效可行的。

关键词：铝合金逆解析方法固有应变法热-弹-塑性有限元法薄板

Impact Strength Analysis of Plate Panels with Welding-Induced Residual Stress and Deformation

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World Journal of Mechanics 2016年第1期6卷 8-17页

作者： Yehia Abdel-Nasser Ninshu Ma Sherif Rashed hidekazu murakawa Naval Architecture and Marine Engineering Faculty of Engineering Alexandria University Alexandria Egypt Joining and Welding Research Institute Osaka University Osaka Japan

The paper describes the simulation of impact loads applied on plate panels with welding-induced residual stresses and deformation (WSD). Numerical simulations using FEM are carried out to study the influence of welding-induced residual stresses and deformation on the impact strength of plate panels. Welding is simulated using a three dimensional thermal mechanical coupled finite element method. The welding stress and deformation are taken as the initial imperfections in the impact strength analysis and their influence on the behavior of plate panels subjected to impact loadings. The impact loadings from the three directions, the lateral direction and two in-plane directions of the plate panels are studied. Results show a certain reduction in the impact strength due to the existence of welding stress and deformation in the plate panels. It is found that the reduction of impact force is strongly influenced by the welding deformation and the impact directions in the plate panels. This reduction is more significant when the impact force is in the lateral direction.

关键词： Lateral Impact In-Plane Impact Welding Deformation Plate Panels Impact Force FEM

Determination of local constitutive behavior and simulation on tensile test of 2219-T87 aluminum alloy GTAW joints

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Transactions of Nonferrous Metals Society of China 2015年第9期25卷 3072-3079页

作者：李艳军李权吴爱萍麻宁绪王国庆 hidekazu murakawa 鄢东洋吴会强清华大学机械工程系北京100084 清华大学摩擦学国家重点实验室北京100084 清华大学先进成形制造教育部重点实验室北京100084 Joining and Welding Research Institute Osaka University 中国运载火箭技术研究院北京100076

The local and global mechanical responses of gas tungsten arc welds（GTAW） of a 2219-T87 aluminum alloy were investigated with experiment and numerical *** image correlation（DIC） was used to access the local strain fields in transversely loaded welds and to determine the local stress-strain curves of various regions in the *** results show that the DIC method is efficient to acquire the local stress-strain curves but the curves of harder regions are incomplete because the stress and strain ranges are limited by the weakest *** appropriate extrapolation,the complete local stress-strain curves were acquired and proved to be effective to predict the tensile behavior of the welded *** the tensile process,the fracture initiates from the weld toes owing to their plastic strain concentrations and then propagates along the fusion line,finally propagates into the partially melted zone（PMZ）.

关键词： aluminum alloy tensile behavior digital image correlation constitutive behavior welded joint

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薄板焊接变形高精度预测方法的研究

船舶力学 2017年第4期21卷 437-442页

作者：梁伟马峰张渝村川英一重庆交通大学机电与车辆工程学院重庆400074 大阪大学接合科学研究所

采用固有应变方法预测焊接变形时,传统方法是把纵向收缩、横向收缩和角变形这三成分作为接头的固有变形来估算焊接变形。但是,由于薄板的刚度低,在纵向方向上的弯曲变形也较明显,采用传统方法会影响薄板焊接变形的预测精度。为提高精度... 详细信息

采用固有应变方法预测焊接变形时,传统方法是把纵向收缩、横向收缩和角变形这三成分作为接头的固有变形来估算焊接变形。但是,由于薄板的刚度低,在纵向方向上的弯曲变形也较明显,采用传统方法会影响薄板焊接变形的预测精度。为提高精度,文章对传统的方法进行了改进,开发了包括考虑纵向弯曲在内的四成分固有变形数值计算方法来预测薄板焊接变形。数值模拟结果表明:运用该方法预测薄板的焊接变形时,比传统的方法有更高的精度,而且预测结果与热弹塑性有限元的模拟结果十分吻合。

关键词：薄板焊接接头固有变形成分焊接变形预测精度

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焊接变形的高精度测量方法及预测方法研究

机械工程学报 2016年第16期52卷 65-70页

作者：梁伟夏洋冯伟村川英一重庆交通大学机电与汽车工程学院重庆400074 大阪大学接合科学研究所

基于有限元分析的固有变形逆解析方法是一种获取焊接接头固有变形的新方法。但是,采用该方法计算固有变形时,必须已知焊接前后焊接接头上少数点的三维坐标值。为了提高固有变形逆解析结果的精度,提出利用接触式三维坐标测量仪准确地获... 详细信息

基于有限元分析的固有变形逆解析方法是一种获取焊接接头固有变形的新方法。但是,采用该方法计算固有变形时,必须已知焊接前后焊接接头上少数点的三维坐标值。为了提高固有变形逆解析结果的精度,提出利用接触式三维坐标测量仪准确地获得焊件中面上三维坐标的新算法。该算法是通过在被焊件上加工小孔,在每一个小孔附近测量八个点的三维坐标,利用测量得到的坐标值确定小孔的中心位置。以2 mm和3 mm薄板表面堆焊焊接接头为例,以计算得到的小孔中心三维坐标为已知参数,基于逆解析方法求得了各成分固有变形,并采用固有应变法预测了2 mm和3 mm薄板焊接变形。通过比较分析发现,尽管焊件板厚只相差1 mm,但焊接变形的特征和变形量却有显著的差别,采用该测量方法及算法能获得焊接接头中面上较精确的三维坐标,基于逆解析方法获得的固有变形各成分有效准确。

关键词：变形测量固有变形逆解析焊接变形

熔池表面Marangoni力诱导的表面速度奇异现象

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西安交通大学学报 1999年第5期33卷 70-74页

作者：雷永平史耀武村川英一西安交通大学日本大阪大学

通过对焊接熔池流体流动与传热过程控制方程组、合金元素气化方程、Ｍａｒａｎｇｏｎｉ力方程以及其他辅助方程的耦合求解，定量计算了ＦｅＣｒＮｉＳ合金系中具有不同Ｓ含量时焊接熔池的表面温度分布和浮力、电磁力、Ｍａｒａｎ... 详细信息

通过对焊接熔池流体流动与传热过程控制方程组、合金元素气化方程、Ｍａｒａｎｇｏｎｉ力方程以及其他辅助方程的耦合求解，定量计算了ＦｅＣｒＮｉＳ合金系中具有不同Ｓ含量时焊接熔池的表面温度分布和浮力、电磁力、Ｍａｒａｎｇｏｎｉ力共同作用下的表面速度分布．结果表明，在微量的Ｓ含量条件下，熔池表面上的Ｍａｒａｎｇｏｎｉ力会出现一个最大值．随Ｓ含量增大，Ｍａｒａｎｇｏｎｉ力减小，Ｍａｒａｎｇｏｎｉ力的最大值对应的温度增大．在Ｍａｒａｎｇｏｎｉ力诱导下，熔池内会形成两个方向相反的涡流环路，它们具有不同的温度，并在熔池表面上逆向而流，相遇处产生很大的温度梯度，从而在该部位引发表面速度奇异峰值．当Ｓ含量较小时，表面速度奇异峰值发生在液相线前沿，当ｗ（Ｓ）大于０．０３％时，速度奇异性消失．

关键词：焊接熔池 Marangoni力表面速度分布表面温度

采用热弹塑性有限元方法预测低碳钢钢管焊接变形

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焊接学报 2006年第1期27卷 76-80页

作者：邓德安梁伟罗宇村川英一重庆大学机械工程学院重庆400044 大阪大学接合科学研究所上海交通大学船舶海洋及建筑工程学院上海200030

用有限元分析软件ABAQUS Code开发了用于模拟焊接温度场、焊接残余应力和焊接变形的热弹塑性有限元计算方法。通过建立三维有限元模型,预测了低碳钢钢管多层焊接时的温度场和焊接变形,并通过试验验证了所提出计算方法的精度和有效性。... 详细信息

用有限元分析软件ABAQUS Code开发了用于模拟焊接温度场、焊接残余应力和焊接变形的热弹塑性有限元计算方法。通过建立三维有限元模型,预测了低碳钢钢管多层焊接时的温度场和焊接变形,并通过试验验证了所提出计算方法的精度和有效性。结果表明,在多层焊接条件下,采用有限元方法计算得到的焊接变形与试验结果十分吻合。

关键词：焊接变形温度场有限元数值分析多层焊