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The formation mechanism and the influence factor of residual stress in machining

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 265-269 doi: 10.1007/s11465-014-0311-0

摘要:

Residual stresses generated in cutting process have important influences on workpiece performance. The paper presents a method of theoretical analysis in order to explicate the formation mechanism of residual stresses in cutting. An important conclusion is drawn that the accumulated plastic strain is the main factor which determines the nature and the magnitude of surface residual stresses in the workpiece. On the basis of the analytical model for residual stress, a series of simulations for residual stress prediction during cutting AISI 1045 steel are implemented in order to obtain the influences of cutting speed, depth of cut and tool edge radius on surface residual stress in the workpiece. And these influences are explained from the perspective of formation mechanism of residual stress in cutting. The conclusions have good applicability and can be used to guide the parameters selection in actual production.

关键词: residual stress     analytical model     strain     plastic     cutting parameter    

Improved analytical model for residual stress prediction in orthogonal cutting

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 249-256 doi: 10.1007/s11465-014-0310-1

摘要:

The analytical model of residual stress in orthogonal cutting proposed by Jiann is an important tool for residual stress prediction in orthogonal cutting. In application of the model, a problem of low precision of the surface residual stress prediction is found. By theoretical analysis, several shortages of Jiann’s model are picked out, including: inappropriate boundary conditions, unreasonable calculation method of thermal stress, ignorance of stress constraint and cyclic loading algorithm. These shortages may directly lead to the low precision of the surface residual stress prediction. To eliminate these shortages and make the prediction more accurate, an improved model is proposed. In this model, a new contact boundary condition between tool and workpiece is used to make it in accord with the real cutting process; an improved calculation method of thermal stress is adopted; a stress constraint is added according to the volume-constancy of plastic deformation; and the accumulative effect of the stresses during cyclic loading is considered. At last, an experiment for measuring residual stress in cutting AISI 1045 steel is conducted. Also, Jiann’s model and the improved model are simulated under the same conditions with cutting experiment. The comparisons show that the surface residual stresses predicted by the improved model is closer to the experimental results than the results predicted by Jiann’s model.

关键词: residual stress     analytical model     orthogonal cutting     cutting force     cutting temperature    

Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

《机械工程前沿(英文)》 2020年 第15卷 第3期   页码 475-483 doi: 10.1007/s11465-020-0590-6

摘要: In this study, the micro curing residual stresses of carbon fiber-reinforced thermoset polymer (CFRP) composites are evaluated using a multiscale modeling method. A thermochemical coupling model is developed at the macroscale level to obtain the distributions of temperature and degree of cure. Meanwhile, a representative volume element model of the composites is established at the microscale level. By introducing the information from the macroscale perspective, the curing residual stresses are calculated using the microscale model. The evolution of curing residual stresses reveals the interaction mechanism of fiber, matrix, and interphase period during the curing process. Results show that the curing residual stresses mostly present a tensile state in the matrix and a compressive state in the fiber. Furthermore, the curing residual stresses at different locations in the composites are calculated and discussed. Simulation results provide an important guideline for the analysis and design of CFRP composite structures.

关键词: CFRP     curing residual stress     multiscale modeling     finite element method    

Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics and structural analyses

Jinya KATSUYAMA, Shumpei UNO, Tadashi WATANABE, Yinsheng LI

《机械工程前沿(英文)》 2018年 第13卷 第4期   页码 563-570 doi: 10.1007/s11465-018-0487-9

摘要:

The thermal hydraulic (TH) behavior of coo-lant water is a key factor in the structural integrity assessments on reactor pressure vessels (RPVs) of pressurized water reactors (PWRs) under pressurized thermal shock (PTS) events, because the TH behavior may affect the loading conditions in the assessment. From the viewpoint of TH behavior, configuration of plant equipment and their dimensions, and operator action time considerably influence various parameters, such as the temperature and flow rate of coolant water and inner pressure. In this study, to investigate the influence of the operator action time on TH behavior during a PTS event, we developed an analysis model for a typical Japanese PWR plant, including the RPV and the main components of both primary and secondary systems, and performed TH analyses by using a system analysis code called RELAP5. We applied two different operator action times based on the Japanese and the United States (US) rules: Operators may act after 10 min (Japanese rules) and 30 min (the US rules) after the occurrence of PTS events. Based on the results of TH analysis with different operator action times, we also performed structural analyses for evaluating thermal-stress distributions in the RPV during PTS events as loading conditions in the structural integrity assessment. From the analysis results, it was clarified that differences in operator action times significantly affect TH behavior and loading conditions, as the Japanese rule may lead to lower stresses than that under the US rule because an earlier operator action caused lower pressure in the RPV.

关键词: structural integrity     reactor pressure vessel     pressurized thermal shock     thermal hydraulic analysis     pressurized water reactor     weld residual stress    

Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 595-608 doi: 10.1007/s11709-021-0720-1

摘要: The effective notch stress approach for evaluating the fatigue strength of rib–deck welds requires notch stress concentration factors obtained from complex finite element analysis. To improve the efficiency of the approach, the notch stress concentration factors for three typical fatigue-cracking modes (i.e., root–toe, root–deck, and toe–deck cracking modes) were thoroughly investigated in this study. First, we developed a model for investigating the effective notch stress in rib–deck welds. Then, we performed a parametric analysis to investigate the effects of multiple geometric parameters of a rib–deck weld on the notch stress concentration factors. On this basis, the multiple linear stepwise regression analysis was performed to obtain the optimal regression functions for predicting the notch stress concentration factors. Finally, we employed the proposed formulas in a case study. The notch stress concentration factors estimated from the developed formulas show agree well with the finite element analysis results. The results of the case study demonstrate the feasibility and reliability of the proposed formulas. It also shows that the fatigue design curve of FAT225 seems to be conservative for evaluating the fatigue strength of rib–deck welds.

关键词: notch stress concentration factor     rib–deck weld     parametric analysis     regression analysis     parametric equation    

decouple the contributions of friction and plastic deformation to machined surface temperatures and residualstress patterns in finish dry cutting

Subhash ANURAG, Yuebin GUO,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 247-255 doi: 10.1007/s11465-010-0097-7

摘要: Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement. Furthermore, the individual contribution of tool/work friction and plastic deformation of work materials to surface temperature is very difficult to quantify because the measured temperature is always the resultant temperature. This lack of understanding on the temperature distribution blocks the design of effective cutting tool geometries and materials to minimize surface temperature. This study provides a finite element method based on a predictive model to decouple the contributions of tool/work friction and material plastic deformation to surface temperature in a dry cutting process. The study shows that the plastic deformation of work material contributes to the majority of surface temperature, whereas the tool/work friction contribution is secondary. High temperatures are produced when more materials are plowed under the cutting edge. A large tool/work friction leads to higher surface temperatures, and the use of a cutting tool with physical properties in process simulation significantly improves the accuracy of predicted surface temperatures. Residual stress reversal from subsurface maximum residual to surface maximum residual stress may occur when tool/work friction increases.

关键词: surface temperature     friction     residual stress     finite element analysis (FEA)     dry cutting     tool property    

impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residualstress

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0701-7

摘要: The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles, but its riveting connection remains a problem. To address this problem, this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method, analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy (Mg/Al) assembled wheel, and constructed some major evaluation indicators. The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints. The punching riveting process parameters of the assembled wheel joints were defined as design variables, and the fatigue and impact performance of the assembled wheel was defined as the optimization objective. The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment, grey relational analysis, analytic hierarchy process, principal component analysis, and entropy weighting methods. The optimization results of the three weighting methods were compared, and the optimal combination of design variables was determined. The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.

关键词: magnesium/aluminum assembled wheel     riveting residual stress     fatigue analysis     impact analysis     multi-objective optimization    

石化特种设备中的硫化氢应力腐蚀与残余应力

张亦良,徐金泉,王羽辞

《中国工程科学》 2009年 第11卷 第8期   页码 38-43

摘要:

针对石化特种设备中硫化氢(H2S)应力腐蚀问题现状,综合比较了国际权威机构NACE,EFC以及ISO发布的最新标准、规范,对H2S应力腐蚀的环境界定、试验方法、影响因素、应力腐蚀评价准则及对材料的要求等做了扼要的综述。同时对焊接残余应力的产生、测定方法、消除措施等进行了论述,列举了实际参与研究的发生应力腐蚀容器的实例及残余应力的影响。

关键词: H2S应力腐蚀     规范指南     评价准则     焊接残余应力    

An improved algorithm for McDowell’s analytical model of residual stress

null

《机械工程前沿(英文)》 2014年 第9卷 第2期   页码 150-155 doi: 10.1007/s11465-014-0295-9

摘要:

The analytical model for two-dimensional elastoplastic rolling/sliding contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volume-constancy of plastic deformation, an improved algorithm for McDowell’s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell’s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell’s model under the same simulation conditions.

关键词: residual stress     McDowell’s model     volume-constancy of plastic deformation     FEM     elastoplastic rolling/sliding contact    

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 217-223 doi: 10.1007/s11709-012-0169-3

摘要: Welding residual stress is one of the main concerns for fabrication and operation of steel structures due to its potential effect on structural integrity. This paper focuses on the effect of welding residual stress on the ductile crack growth resistance of circumferentially cracked steel pipes. Two-dimensional axi-symmetry model has been used to simulate the pipe. Residual stresses were introduced into the model by using so-called eigenstrain method. The complete Gurson model has been employed to calculate the ductile crack growth resistance. Results show that residual stresses reduce the ductile crack growth resistance. However, the effect of residual stresses on ductile crack growth resistance decreases with the increase of crack growth. The effect of residual stress has also been investigated for cases with different initial void volume fraction, material hardening and crack sizes.

关键词: residual stress     ductile crack growth resistance     complete Gurson model     eigenstrain method    

基于变形力监测数据的残余应力场推断和表征方法

赵智伟, 刘长青, 李迎光, James Gao

《工程(英文)》 2023年 第22卷 第3期   页码 49-59 doi: 10.1016/j.eng.2022.07.018

摘要:

残余应力是材料的基本属性之一,与零件的几何/尺寸稳定性和疲劳寿命直接相关。针对具有高精度要求的大型零件,其残余应力场的准确测量和预测一直是一个挑战。目前的残余应力场测量技术分为基于应变的有损法以及效率和精度较低的无损法。本文提出了一种基于变形力推断残余应力场的无损法。本方法通过能够反映去除材料后不平衡残余应力场整体效应的变形力来推断零件的残余应力场。利用虚功原理建立了变形力与残余应力场之间的力学关系,并引入正则化方法求解残余应力场。为验证方法的有效性,本文进行了理论验证和实际实验验证。实验结果表明,该方法对于大型结构件的残余应力场测量具有可靠的精度和灵活性。在数字化和智能制造的趋势下,该方法的基本原理为利用加工监测数据预测和补偿由残余应力引起的零件加工变形提供了重要参考。

关键词: 残余应力场     精密加工     变形力     反问题     在位测量    

An adaptive sliding mode control technology for weld seam tracking

Jie LIU,Youmin HU,Bo WU,Kaibo ZHOU,Mingfeng GE

《机械工程前沿(英文)》 2015年 第10卷 第1期   页码 95-101 doi: 10.1007/s11465-015-0332-3

摘要:

A novel adaptive sliding mode control algorithm is derived to deal with seam tracking control problem of welding robotic manipulator, during the process of large-scale structure component welding. The proposed algorithm does not require the precise dynamic model, and is more practical. Its robustness is verified by the Lyapunov stability theory. The analytical results show that the proposed algorithm enables better high-precision tracking performance with chattering-free than traditional sliding mode control algorithm under various disturbances.

关键词: weld seam tracking     welding robotic manipulator     adaptive control     sliding mode control    

激光相变热处理对TC4电子束焊缝残余应力的影响

鲁金忠,张永康,孔德军,任旭东,邹世坤,王西昌

《中国工程科学》 2007年 第9卷 第5期   页码 72-76

摘要:

利用CO2激光相变热处理技术对TC4钛合金电子束焊缝进行了处理,研究了激光功率、光斑直径、辅助气体等激光工艺参数对电子束焊缝残余应力分布的影响。实验结果表明,激光相变热处理改善了焊缝残余应力的分布,使焊缝表面残余应力由拉应力转变为压应力,其压应力值随着激光功率的增加而增大,随着激光光斑直径的减小而增加;辅助气体为O2时残余压应力值比辅助气体为N2大30~40MPa,激光相变热处理显著提高了TC4钛合金电子束焊缝的残余压应力及其使用寿命。

关键词: 激光相变热处理     TC4钛合金     电子束焊缝     残余应力    

TA2板料激光热应力弯曲成形及其力学性能研究

周益军,张永康,游文明

《中国工程科学》 2007年 第9卷 第10期   页码 40-44

摘要:

用HVS-1000显微硬度测试仪、X-350A型X射线应力测定仪,以2.5 kW SM2000SM快轴流CO2激光器对0.6 mm厚的TA2板料进行扫描,按照正交试验理论安排成形工艺参数,研究了TA2板料弯曲成形时主要工艺参数对弯曲角度的影响,以及试样表面残余应力的分布和试样断面上的显微硬度变化。结果表明:正交试验中的4个工艺参数的作用是不同的,按其变化对弯曲变形量影响的大小排序,依次是扫描次数、光斑直径、激光束功率、扫描速度;成形参数对试样表面的残余应力分布也存在一定的影响;试样变形区断面上的显微硬度变化呈现出一定的规律。

关键词: 激光技术     热应力     板料弯曲成形     残余应力     显微硬度    

Application of metal magnetic memory test in failure analysis and safety evaluation of vessels

Yiliang ZHANG, Song YANG, Xuedong XU

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 40-48 doi: 10.1007/s11465-009-0003-3

摘要: Metal magnetic memory test (MMMT), which is a new subject in the field of nondestructive examination, can determine regions of stress concentration by testing the distribution of the magnetic field of metal structures so as to effectively diagnose premature defects. MMMT and other test methods are applied in the study to put a propylene purifier of a temperature-jump accident and a leaked ammonia vessel through safety evaluation. Results are as follows: The margin of safety declines after the purifier is overburnt; several stress concentrations are observed within the overburnt area and the level of stress concentration rises after one-month operation; and overpressure operation of the purifier must be strictly avoided and carefully monitored during later operation. Cracks are observed on the ammonia vessel after one year’s service. Extremely high residual stress is the primary cause of cracks. After four years in service, the residual stresses existing in the area of the base metal and weld zone are still greater than 0.5 , which results in numerous cracks due to stress corrosion. From the MMMT result of the ammonia vessel’s defects, it can be seen that the derivative of magnetic density (d p/d ) is an important reference variable. Within the 31 leakage points, 67.7% of them whose dHp/dx values are more than 10, and 96.8% of them whose dHp/dx values are more than 8.

关键词: Metal magnetic memory test (MMMT)     nondestructive testing (NDT)     residual stress     propylene purifier     ammonia vessel    

标题 作者 时间 类型 操作

The formation mechanism and the influence factor of residual stress in machining

null

期刊论文

Improved analytical model for residual stress prediction in orthogonal cutting

null

期刊论文

Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

期刊论文

Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics and structural analyses

Jinya KATSUYAMA, Shumpei UNO, Tadashi WATANABE, Yinsheng LI

期刊论文

Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

期刊论文

decouple the contributions of friction and plastic deformation to machined surface temperatures and residualstress patterns in finish dry cutting

Subhash ANURAG, Yuebin GUO,

期刊论文

impact analysis and multi-objective optimization design of Mg/Al assembled wheel considering riveting residualstress

期刊论文

石化特种设备中的硫化氢应力腐蚀与残余应力

张亦良,徐金泉,王羽辞

期刊论文

An improved algorithm for McDowell’s analytical model of residual stress

null

期刊论文

Influence of welding residual stresses on the ductile crack growth resistance of circumferentially cracked

Xiaobo REN, Odd M. AKSELSEN, B?rd NYHUS, Zhiliang ZHANG

期刊论文

基于变形力监测数据的残余应力场推断和表征方法

赵智伟, 刘长青, 李迎光, James Gao

期刊论文

An adaptive sliding mode control technology for weld seam tracking

Jie LIU,Youmin HU,Bo WU,Kaibo ZHOU,Mingfeng GE

期刊论文

激光相变热处理对TC4电子束焊缝残余应力的影响

鲁金忠,张永康,孔德军,任旭东,邹世坤,王西昌

期刊论文

TA2板料激光热应力弯曲成形及其力学性能研究

周益军,张永康,游文明

期刊论文

Application of metal magnetic memory test in failure analysis and safety evaluation of vessels

Yiliang ZHANG, Song YANG, Xuedong XU

期刊论文