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Local fracture properties and dissimilar weld integrity in nuclear power plants

Guozhen WANG, Haitao WANG, Fuzhen XUAN, Shantung TU, Changjun LIU

《机械工程前沿（英文）》 2013年 第8卷 第3期   页码 283-290 doi: 10.1007/s11465-013-0250-1

摘要：

In this paper, the local fracture properties in a Alloy52M dissimilar metal welded joint (DMWJ) between A508 ferritic steel and 316 L stainless steel in nuclear power plants were investigated by using the single-edge notched bend (SENB) specimens, and their use in integrity assessment of DMWJ structures was analyzed. The results show that the local fracture resistance in the DMWJ is determined by local fracture mechanism, and which is mainly related to the microstructures and local strength mismatches of materials at the crack locations. The initial cracks always grow towards the materials with lower strength, and the crack path deviation is mainly controlled by the local strength mismatch. If the local fracture properties could not be used for cracks in the heat affected zones (HAZs), interface and near interface zones, the use of the fracture properties ( -resistance curves) of base metals or weld metals following present codes will unavoidably produce non-conservative (unsafe) or excessive conservative assessment results. In most cases, the assessment results will be potentially unsafe. Therefore, it is recommended to obtain and use local mechanical and fracture properties in the integrity assessment of DMWJs.

关键词： local fracture properties     dissimilar metal welded joint     integrity assessment     strength mismatch     crack growth path    

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Structure and performance of welding joint of Q235 steel welded by SHS welding

Junzhi HU, Sumei WANG, Xiaoli ZHAO, Shilin ZHU, Botao YU,

《机械工程前沿（英文）》 2010年 第5卷 第2期   页码 189-193 doi: 10.1007/s11465-010-0003-3

摘要： A self-propagating high-temperature synthesis (SHS) welding-pen that can weld steel workpiece from 6 to 10 mm is developed and welds the Q235 steel. The structure and properties of the welding joint are studied. The result indicates that this type of welding is melting and the fusion zone is clear. The tensile-strength of the welding joint is 283 MPa, flexural strength is 628 MPa, impact toughness is 46.43 J·cm, and the microhardness of the welding joint and fusion zone are 230 HV and 255.6€HV, respectively. The mircohardness of the fusion zone and the welding line are higher than that of the matrix.

关键词： self-propagating high-temperature synthesis (SHS) welding     welding line     structure and performance     melting    

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Review on electromagnetic welding of dissimilar materials

K. SHANTHALA,T. N. SREENIVASA

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 363-373 doi: 10.1007/s11465-016-0375-0

摘要：

Electromagnetic welding (EMW) is a high-speed joining technique that is used to join similar or dissimilar metals, as well as metals to non-metals. This technique uses electromagnetic force to mainly join conductive materials. Unlike conventional joining processes, the weld interface does not melt, thus keeping the material properties intact. Extremely high velocity and strain rate involved in the process facilitate extending the EMW technique for joining several materials. In this paper, the research and progress in electromagnetic welding are reviewed from various perspectives to provide a basis for further research.

关键词： electromagnetic     welding     impact     dissimilar materials    

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Joint effects of Penta-BDE and heavy metals on

Baohua TANG, Lingyan ZHU, Qixing ZHOU

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 99-110 doi: 10.1007/s11783-010-0260-8

摘要： The joint toxicity of Penta-BDE (Pe-BDE) and heavy metals including cadmium and copper on ( ) was evaluated on the basis of determining the 48 h survival, antioxidative enzyme responses, and lipid peroxidation. The response was classified as additive, greater than additive, or less than additive by comparing the measured “toxic units, TU” with one. Based on the survival of , less-than-additive interactions were found in most of mixtures treatments. This may be attributed to the different toxicity mechanism between Pe-BDE and metals. Cu and Cd played a greater role in toxicity than what Pe-BDE did. As for the superoxide dismutase (SOD) and catalase (CAT) activity, most response was less than additive. For the glutathione -transferases (GST) activity, most of the greater-than-additive responses were found in the Cu plus Pe-BDE treatments, but the additive responses occurred in Cd plus Pe-BDE treatments and binary metal treatments. For lipid peroxide levels, which were measured as malondialdehyde (MDA) levels, less-than-additive response occurred in the 50% Cd plus 50% Cu and ternary mixture treatments. Results suggested that Pe-BDE, Cd, and Cu could induce different patterns of antioxidant enzyme responses, such as antioxidant/prooxidant responses, depending on their capability to produce reactive oxygen species and antioxidant enzymes to detoxify them.

关键词： polybrominated diphenyl ethers (PBDEs)     heavy metal     mixture toxicity     toxic units (TUs)     antioxidant enzyme     lipid peroxidation    

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Investigation of fatigue resistance of fillet-welded tube connection details for sign support structures

Hyungjoo CHOI, Husam NAJM

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 199-214 doi: 10.1007/s11709-019-0592-9

摘要： Stiffened and unstiffened fillet-welded tube-to-transverse plate connection details are widely used for mast-arm and base-plate connections for highway sign structures. However, due to repetitive wind loads, cyclic fatigue stresses are induced and they are the primary source of failure in welded connections at these locations. The resistance of fatigue critical details has been an on-going research topic because of limited experimental results and the variability in existing fatigue testing results. The main objective of this study is to evaluate fatigue resistance of fillet-welded tube connection details by utilizing the advanced fatigue tool in ANSYS Workbench platform. Finite Element (FE) models development and model validation using existing test data was presented. The resulting fatigue resistance from FE analysis was expressed in terms of fatigue life, fatigue damage, and fatigue safety factor to determine the fatigue performance of fillet-welded connections. Existing fatigue test data was grouped to perform a synthetic analysis and then analysis results were provided to determine input data and fatigue limit for the fatigue module. The local stress level at fatigue critical locations was evaluated using a static FE model for different number of stiffeners and boundary conditions. The results of this investigation provides fatigue resistance of fillet-welded connection details in the form of fatigue life, fatigue damage and safety factor for various connection parameters and structural conditions.

关键词： fatigue     weld connections     base plate     fillet welds    

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Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

《结构与土木工程前沿（英文）》   页码 901-914 doi: 10.1007/s11709-023-0915-8

摘要： The integrity and bearing capacity of segment joints in shield tunnels are associated closely with the mechanical properties of the joints. This study focuses on the mechanical characteristics and mechanism of a bolted circumferential joint during the entire bearing process. Simplified analytical algorithms for four stress stages are established to describe the bearing behaviors of the joint under a compressive bending load. A height adjustment coefficient, α, for the outer concrete compression zone is introduced into a simplified analytical model. Factors affecting α are determined, and the degree of influence of these factors is investigated via orthogonal numerical simulations. The numerical results show that α can be specified as approximately 0.2 for most metro shield tunnels in China. Subsequently, a case study is performed to verify the rationality of the simplified theoretical analysis for the segment joint via numerical simulations and experiments. Using the proposed simplified analytical algorithms, a parametric investigation is conducted to discuss the factors affecting the ultimate compressive bending capacity of the joint. The method for optimizing the joint flexural stiffness is clarified. The results of this study can provide a theoretical basis for optimizing the design and prediciting the damage of bolted segment joints in shield tunnels.

关键词： shield tunnel     segment joint     joint structural model     failure mechanism    

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Finite element analysis on the seismic behavior of side joint of Prefabricated Cage System in prefabricated

Yunlin LIU, Shitao ZHU

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1095-1104 doi: 10.1007/s11709-019-0538-2

摘要： The Prefabricated Cage System (PCS) has the advantages of high bearing capacity and good ductility. Meanwhile, it is convenient for factory production and it is beneficial to the cost savings, construction period shortening. Side joint is the weak region of PCS concrete frame and has great influence on seismic behavior of the whole structure. Thus systematically study on the seismic behavior of PCS concrete side joint is necessary. This paper presents a finite element study on behavior of the side joint under seismic loading. In the finite element model, PCS concrete and the reinforced concrete (RC) is modeled by the solid element and fiber-beam element, respectively. The numerical results is compared with the experimental results and it is found that the results of model based on fiber-beam element is in better agreement with the experimental results than solid element model. In addition, the overall seismic behavior of the side joints in PCS concrete is better than that of the RC with the same strength.

关键词： PCS concrete side joint     numerical simulation     fiber-beam element joint model     solid element joint model     seismic behavior    

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700 °C 及以上蒸汽温度下先进USC发电厂用耐热材料的研究和开发 Review

Fujio Abe

《工程（英文）》 2015年 第1卷 第2期   页码 211-224 doi: 10.15302/J-ENG-2015031

摘要：

欧洲、美国、日本已开展蒸汽温度为700 °C 及以上的先进超超临界(A-USC) 发电厂用材料开发项目，以实现更高能效和低二氧化碳排放量。近年来中国、印度等也开展了上述项目的开发和研究。这些项目涉及采用镍基合金更换马氏体9%~12%Cr 钢以用于最高温度的锅炉和涡轮部件，从而在700 °C 及以上温度下提供充足的蠕变强度。为尽量减少对昂贵的镍基合金的需求，马氏体9%~12%Cr 钢可用于A-USC 电厂中的次高温部件(最高温度不超过650 °C)。本文综述了A-USC 电厂厚型材锅炉和涡轮部件用镍基合金和马氏体9%~12%Cr 钢的研究和开发，主要关注高温下基底金属和焊缝的长期蠕变断裂强度、焊缝强度损失、蠕变疲劳性质和显微结构演化。

关键词： 镍基合金     9 %~12 % Cr 钢     蠕变强度     蠕变疲劳性质     焊缝     晶界     显微结构     &gamma     &prime     M23C6 碳化物    

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Dynamic characteristics of a magnetorheological pin joint for civil structures

Yancheng LI,Jianchun LI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 15-33 doi: 10.1007/s11465-014-0283-0

摘要：

Magnetorheological (MR) pin joint is a novel device in which its joint moment resistance can be controlled in real-time by altering the applied magnetic field. The smart pin joint is intended to be used as a controllable connector between the columns and beams of a civil structure to instantaneously shift the structural natural frequencies in order to avoid resonance and therefore to reduce unwanted vibrations and hence prevent structural damage. As an intrinsically nonlinear device, modelling of this MR fluid based device is a challenging task and makes the design of a suitable control algorithm a cumbersome situation. Aimed at its application in civil structure, the main purpose of this paper is to test and characterise the hysteretic behaviour of MR pin joint. A test scheme is designed to obtain the dynamic performance of MR pin joint in the dominant earthquake frequency range. Some unique phenomena different from those of MR damper are observed through the experimental testing. A computationally-efficient model is proposed by introducing a hyperbolic element to accurately reproduce its dynamic behaviour and to further facilitate the design of a suitable control algorithm. Comprehensive investigations on the model accuracy and dependences of the proposed model on loading condition (frequency and amplitude) and input current level are reported in the last section of this paper.

关键词： Magnetorheological pin joint     hyperbolic hysteresis model experimental testing frequency dependence    

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基于人体髋关节转动中心分析的髋关节外骨骼仿生设计 Article

Wei YANG,Can-jun YANG,Ting XU

《信息与电子工程前沿（英文）》 2016年 第17卷 第8期   页码 792-802 doi: 10.1631/FITEE.1500286

摘要： 为了改善外骨骼穿戴舒适性，本文提出了一种基于人机物理交互优化的外骨骼设计方法。该方法通过设计外骨骼髋关节，使其保证人体髋关节运动时外骨骼髋关节转动中心能跟随人体髋关节转动中心的运动轨迹。当人体髋关节运动时，通过实验测量和计算可以得到其转动中心轨迹。本文设计的外骨骼髋关节运动机构能在人体髋关节屈曲/伸展和外展/内收时，保证转动中心都能够包容人体髋关节转动中心运动范围。同时，所设计的外骨骼髋关节被应用到下肢步行康复训练外骨骼中。通过人机接触力实验可知，与传统设计外骨骼髋关节进行相比，本文设计的仿生髋关节外骨骼在髋关节屈曲/伸展和内收/外展时分别可以减小24.1%和76.0%的人机接触力。这一结果证明仿生设计髋关节外骨骼更具穿戴舒适性，更符合人机工程学的设计要求。最后，本文通过建立人机闭式链模型进一步分析了仿生设计对于人体髋关节内力的影响，并验证该设计能减少关节内力作用。

关键词： 髋关节外骨骼；髋关节中心；柔顺关节；人机交互力    

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Identification of dynamic stiffness matrix of bearing joint region

Feng HU, Bo WU, Youmin HU, Tielin SHI

《机械工程前沿（英文）》 2009年 第4卷 第3期   页码 289-299 doi: 10.1007/s11465-009-0064-3

摘要： The paper proposes an identification method of the dynamic stiffness matrix of a bearing joint region on the basis of theoretical analysis and experiments. The author deduces an identification model of the dynamic stiffness matrix from the synthetic substructure method. The dynamic stiffness matrix of the bearing joint region can be identified by measuring the matrix of frequency response function (FRFs) of the substructure (axle) and whole structure (assembly of the axle, bearing, and bearing housing) in different positions. Considering difficulty in measuring angular displacement, applying moment, and directly measuring relevant FRFs of rotational degree of freedom, the author employs an accurately calibrated finite element model of the unconstrained structure for indirect estimation. With experiments and simulation analysis, FRFs related with translational degree of freedom, which is estimated through the finite element model, agrees with experimental results, and there is very high reliability in the identified dynamic stiffness matrix of the bearing joint region.

关键词： frequency response function (FRFs)     dynamic stiffness     finite element     synthetic substructure method     joint region    

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Joint slip investigation based on finite element modelling verified by experimental results on wind turbine

Saleh YAGHOOBI, Ahmad SHOOSHTARI

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 341-351 doi: 10.1007/s11709-017-0393-y

摘要：

Slippage corresponds to the relative displacement of a bolted joint subjected to shear loads since the construction clearance between the bolt shank and the bolthole at assembly can cause joint slip. Deflections of towers with joint slippage effects is up to 1.9 times greater than the displacements obtained by linear analytical methods. In this study, 8 different types of joints are modelled and studied in the finite element program, and the results are verified by the experimental results which have been done in the laboratory. Moreover, several types of joints have been modelled and studied and load-deformation curves have also been presented. Finally, joint slip data for different types of angles, bolt diameter and bolt arrangements are generated. Thereupon, damping ratios (z) for different types of connections are reported. The study can be useful to help in designing of wind turbine towers with a higher level of accuracy and safety.

关键词： Joint slip     cyclic loading     Finite element modelling     Experimental joint behavior     damping ratios (   

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Strength of tubular welded joints of roof trusses in Shanghai Qizhong Tennis Center

TONG Lewei, GU Min, CHEN Yiyi, ZHOU Liying, SUN Jiandong, CHEN Yangji, LIN Yingru, LIN Gao

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 30-36 doi: 10.1007/s11709-008-0010-1

摘要： Static strength of multi-planar welded joints with seven brace members and one chord member made of circular hollow sections is investigated in the paper, based on the engineering practice of moveable roof trusses of Shanghai Qizhong Tennis Center. Firstly, comparative experiments were carried out on two model joints with a scale of 1:3. One joint was not reinforced, whereas the other was reinforced with ring stiffeners inside the chord member. Failure mode, stress distribution, plastic-zone development and ultimate load capacity of the joints were investigated, and effects of the ring stiffeners on the joint behavior were observed through the experiments. Secondly, finite element analysis of both the tested model joints was performed. The calculation results are in a good agreement with the experimental results, which indicated that the numerical analysis was quite effective. Finally, the strategy for enhancing strength of the complicated joint is discussed. Parameters study on the constructional details of ring stiffeners was carried out using FE method. The present research shows the multi-planar circular hollow section joint with high ratio of diameter to thickness of the chord and multiple braces is liable to chord plasticity under axial tension and compression on the braces. For the design of the joint, it is suggested that the ring stiffeners are installed insider the chord to meet needs of enough stiffness and strength. Both position and number of the stiffeners should be carefully determined based on the axial forces on the braces and their diameters. The stiffener thickness should not be less than the chord thickness, and the diameter of the hole at the center of the stiffener should not be greater than half of the chord diameter.

关键词： diameter     numerical analysis     calculation     thickness     engineering    

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Ultrasonic assisted EDM: Effect of the workpiece vibration in the machining characteristics of FW4 WeldedMetal

Mohammadreza SHABGARD, Hamed KAKOLVAND, Mirsadegh SEYEDZAVVAR, Ramin Mohammadpour SHOTORBANI

《机械工程前沿（英文）》 2011年 第6卷 第4期   页码 419-428 doi: 10.1007/s11465-011-0246-7

摘要：

This paper presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of ultrasonic vibration of workpiece on the characteristics of Electrical Discharge Machining (EDM) process of FW4 Welding Metal in comparison with the conventional EDM process. The studied process characteristics included the material removal rate (MRR), tool wear ratio (TWR), and surface roughness (Ra and Rmax) of the workpiece after the EDM and ultrasonic assisted EDM (US-EDM) processes. The experiments performed under the designed full factorial procedure and the considered EDM input parameters included pulse on-time and pulse current. The experimental results show that in short pulse on-times, material removal rate in the US-EDM process is approximately quadruple than that of the EDM process. On the contrary, in the long pulse on-times, ultrasonic vibration of work??piece leads to the reduction in the MRR. On the other hand, in short pulse on-times, the TWR in the US-EDM process is lower than that of in the EDM process, and this condition reverses with increase in the pulse on-time. Furthermore, the surface roughness of the workpiece machined by EDM process is slightly lower than that of applied to the US-EDM process.

关键词： electrical discharge machining (EDM)     material removal rate (MRR)     tool wear ratio (TWR)     surface roughness    

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General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0681-7

摘要： The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inverse kinematics problems, and there is no common approach to solve arbitrary three-joint subproblems in an arbitrary postural relationship. The novel algebraic geometric (NAG) methods that obtain the general closed-form inverse kinematics for all types of three-joint subproblems are presented in this paper. The geometric and algebraic constraints are used as the conditions precedent to solve the inverse kinematics of three-joint subproblems. The NAG methods can be applied in the inverse kinematics of three-joint subproblems in an arbitrary postural relationship. The inverse kinematics simulations of all three-joint subproblems are implemented, and simulation results indicating that the inverse solutions are consistent with the given joint angles validate the general closed-form inverse kinematics. Huaque III minimally invasive surgical robot is used as the experimental platform for the simulation, and a master–slave tracking experiment is conducted to verify the NAG methods. The simulation result shows the inverse solutions and six sets given joint angles are consistent. Additionally, the mean and maximum of the master–slave tracking experiment for the closed-form solution are 0.1486 and 0.4777 mm, respectively, while the mean and maximum of the master–slave tracking experiment for the compensation method are 0.3188 and 0.6394 mm, respectively. The experiments results demonstrate that the closed-form solution is superior to the compensation method. The results verify the proposed general closed-form inverse kinematics based on the NAG methods.

关键词： inverse kinematics     Paden–Kahan subproblems     three-joint subproblems     product of exponential     closed-form solution    

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标题 作者 时间 类型 操作

Local fracture properties and dissimilar weld integrity in nuclear power plants

Guozhen WANG, Haitao WANG, Fuzhen XUAN, Shantung TU, Changjun LIU

期刊论文

Structure and performance of welding joint of Q235 steel welded by SHS welding

Junzhi HU, Sumei WANG, Xiaoli ZHAO, Shilin ZHU, Botao YU,

期刊论文

Review on electromagnetic welding of dissimilar materials

K. SHANTHALA,T. N. SREENIVASA

期刊论文

Joint effects of Penta-BDE and heavy metals on

Baohua TANG, Lingyan ZHU, Qixing ZHOU

期刊论文

Investigation of fatigue resistance of fillet-welded tube connection details for sign support structures

Hyungjoo CHOI, Husam NAJM

期刊论文

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

期刊论文

Finite element analysis on the seismic behavior of side joint of Prefabricated Cage System in prefabricated

Yunlin LIU, Shitao ZHU

期刊论文

700 °C 及以上蒸汽温度下先进USC发电厂用耐热材料的研究和开发

Fujio Abe

期刊论文

Dynamic characteristics of a magnetorheological pin joint for civil structures

Yancheng LI,Jianchun LI

期刊论文

基于人体髋关节转动中心分析的髋关节外骨骼仿生设计

Wei YANG,Can-jun YANG,Ting XU

期刊论文

Identification of dynamic stiffness matrix of bearing joint region

Feng HU, Bo WU, Youmin HU, Tielin SHI

期刊论文

Joint slip investigation based on finite element modelling verified by experimental results on wind turbine

Saleh YAGHOOBI, Ahmad SHOOSHTARI

期刊论文

Strength of tubular welded joints of roof trusses in Shanghai Qizhong Tennis Center

TONG Lewei, GU Min, CHEN Yiyi, ZHOU Liying, SUN Jiandong, CHEN Yangji, LIN Yingru, LIN Gao

期刊论文

Ultrasonic assisted EDM: Effect of the workpiece vibration in the machining characteristics of FW4 WeldedMetal

Mohammadreza SHABGARD, Hamed KAKOLVAND, Mirsadegh SEYEDZAVVAR, Ramin Mohammadpour SHOTORBANI

期刊论文

General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of

期刊论文