检索结果-南通市图书馆

Application of grey relational analysis in sheet metal forming for multi-response quality characteristics

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 805-811页

作者： XIE Yan-min yu Hu-ping CHEN Jun ruan xue-yu National Die ＆ Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

The theory of grey systems is a new technique for performing prediction, relational analysis and decision making in many areas. In this paper, the use of grey relational analysis for optimizing the square hole flanging process parameters with considerations of the multiple response (the average flanging height, regular flanging and maximum strain) is introduced. Various flanging parameters, such as the blank inner radius rb, blank inner width B0, are considered. An orthogonal array is used for the experimental design. Multiple response values are obtained using finite element analysis (FEA). Optimal process parameters are determined by the grey relational grade obtained from the grey relational analysis for multi-performance characteristics (flanging height, regular flanging and maximum strain). Analysis of variance (ANOVA) for the grey relational grade is implemented. The results showed good agreement with the experiment result. Grey relational analysis can be applied in multiple response optimi-zation designs.

关键词： Grey relational analysis Flanging Multiple response Optimization design

Dynamic Recrystallization Behavior of Microalloyed Forged Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2008年第3期15卷 78-81,91页

作者： WANG Jin CHEN Jun ZHAO Zhen ruan xue-yu National Die and Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

The dynamic recrystallization behavior of microalloyed forged steel was investigated with a compression test in the temperature range of 1 223-1 473 K and a strain rate of 0. 01-5 s^-1. Activation energy was calculated to be 305.9 kJ/mol by regression analysis. Modeling equations were developed to represent the dynamic recrystallization volume fraction and grain size. Parameters of the modeling equations were determined as a function of the Zener-Hollomon parameter. The developed modeling equation will be combined with finite element modeling to predict microstructural change during the hot forging processing.

关键词： microalloyed forged steel dynamic recrystallization flow stress

An analytical model for predicting sheet springback after V-bending

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 237-244页

作者： ZHANG Dong-juan CUI Zhen-shan CHEN Zhi-ying ruan xue-yu National Mold ＆ Die CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

Springback is caused by the redistribution of stress in sheet material after the tooling is removed. Precise prediction of sheet springback is very important in die design. Based on Hill’s yielding criterion and plane strain condition, an analytical model is proposed in this paper which takes into account the effects of contact pressure, the length of bending arm between the punch and die, transverse stress, neutral surface shifting and sheet thickness thinning on the sheet springback of V-bending. The predicted results by this analytical model indicated that the contact pressure and transverse stress have much effect on the springback when the bending ratio (the ratio of punch radius to sheet thickness) is less than five. The contact pressure declined when the length of bending arm goes up, which means that shorter length of bending arm will result in larger springback. The effect of neutral surface shifting on the springback is less than that of contact pressure and decreases with the bending ratio. However, this research showed that the influence of thickness thinning on the springback can be ignored. Comparison with finite element method (FEM) simu-lating results shows that the predicted results by the analytical model accord well with simulation results by FEM. In addition to that, the bending ability—the limit bending ratio for a given sheet thickness and material properties was also determined.

关键词： Springback V-bending Contact pressure Neutral surface shifting Transverse stress Bending ratio

Heat Treat ment of Die and Mould Oriented Concurrent Design

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2006年第1期13卷 40-43,74页

作者： LI Xiong ZHANG Hong bing ruan xue-yu LUO Zhong-hua ZHANG Yan Department of Plasticity Forming Engineering Shanghai Jiaotong University Shanghai 200030 China Department of Materials Engineering Shanghai Institute of Technology Shanghai 200235 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beiiing Beijing 100083 China

Many disadvantages exist in the traditional die design method which belongs to serial pattern. It is well known that heat treatment is highly important to the dies. A new idea of concurrent design for heat treatment process of die and mould was developed in order to overcome the existent shortcomings of heat treatment process. Heat treatment CAD/CAE was integrated with concurrent circumstance and the relevant model was built. These investigations can remarkably improve efficiency, reduce cost and ensure quality of R and D for products.

关键词： die design heat treatment mould

Ductile damage and simulation of fine-blanking process by FEM

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2000年第3期10卷 368-371页

作者： ZHANG Xing quan(张兴全) JIA Jian jun(贾建军) PENG Ying hong(彭颖红) ruan xue yu(阮雪榆) Shanghai Jiao Tong Univ Natl Die & Mold CAD Engn Res Ctr Shanghai 200030 Peoples R China

Based on the Curson Tvergaard void damage plastic potential equation and by using orthogonal rules of plastic material, the influence of void volume fraction on stress and strain fields was introduced into Levy Mises flow rules. The variation principle of rigid plastic material with void degradation was demonstrated. Furthermore, FEM equations coupled with damage factor were presented to study the void growth and the criterion to judge the damage was also given. Using the developed system, the fine blanking process was simulated and the sheared surface of the part edge was predicted. Meanwhile, the influence of process parameters, such as punch die clearance, V ring force, counter force, radius of punch and die edges, on the height and quality of the sheared surface was analyzed. The calculation results were compared with the experiments, which can be used to guide the design of fine blanking process.

关键词： fine blanking ductile fracture FEM simulation

Non-Steady Equilibrium during Pro-Eutectoid Ferrite Formation in Fe-0.2C Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2002年第2期9卷 28-32页

作者： ZHANG Hong-bing WU Rui-heng HSU T Y(XU Zu-yao) ruan xue-yu Shanghai Institute of Technology Shanghai Jiaotong University

As rolled microstructure and mechanical properties of a new kind of grain boundary allotriomorphic ferrite/granular bainite duplex steel plate and its crack propagation behavior were investigated in comparison with simple granular bainitic steel plate. These new duplex plate steels possess better combination of strength and toughness than granular bainite plate steels under the conditions of conventional rolling and air cooling. The observation of fatigue crack propagation behaviors showed that the existence of proper grain boundary allotriomorphic ferrite increases the compatible deformation ability of duplex microstructure and leads to the formation of crack branching and curving route, and it has an evidently blunting effect on microcrack tip and results in higher impact toughness. In addition, the new duplex steel plate also has good weldability as hot rolled high strength low alloy structural steel.

关键词： duplex microstructure grain boundary allotriomorphic ferrite granular bainite high strength steel weldability

在线全文

学校读者我要写书评

暂无评论

微小尺度流动应力波动尺度效应

上海交通大学学报 2006年第6期40卷 906-908页

作者：申昱于沪平阮雪榆上海交通大学国家模具CAD工程研究中心上海200030

通过对常温下具有不同晶粒直径的微型铜圆柱体进行镦粗实验,研究了微小尺度下流动应力波动尺度效应现象.结果表明,在应变量相同条件下,流动应力波动幅度随晶粒尺寸的增大而线性增大;在晶粒尺寸相同条件下,流动应力波动幅度随应变量的增... 详细信息

通过对常温下具有不同晶粒直径的微型铜圆柱体进行镦粗实验,研究了微小尺度下流动应力波动尺度效应现象.结果表明,在应变量相同条件下,流动应力波动幅度随晶粒尺寸的增大而线性增大;在晶粒尺寸相同条件下,流动应力波动幅度随应变量的增大而增大.基于晶体塑性理论及数理统计理论,建立了流动应力波动幅度与晶粒尺寸和坯料几何尺寸间的关系.

关键词：微成形尺度效应流动应力波动

在线全文

学校读者我要写书评

暂无评论

流动应力下降尺度效应的数值模拟

上海交通大学学报 2006年第10期40卷 1667-1670页

作者：申昱于沪平阮雪榆上海交通大学国家模具CAD工程研究中心上海200030

采用率相关晶体塑性本构关系及弹塑性大变形增量有限元方法,通过在晶粒尺寸相同条件下模拟不同尺寸微型铜圆柱体镦粗实验,对流动应力下降尺度效应现象进行了数值模拟研究,获得了与实验及表面层模型较为一致的结果.结果表明,随着坯料尺... 详细信息

采用率相关晶体塑性本构关系及弹塑性大变形增量有限元方法,通过在晶粒尺寸相同条件下模拟不同尺寸微型铜圆柱体镦粗实验,对流动应力下降尺度效应现象进行了数值模拟研究,获得了与实验及表面层模型较为一致的结果.结果表明,随着坯料尺寸的减小,流动应力逐渐下降;晶体塑性理论能够解释并描述流动应力下降尺度效应现象,并在一定程度上对流动应力下降幅度做出预测.

关键词：微成形尺度效应晶体塑性流动应力

在线全文

学校读者我要写书评

暂无评论

硬度转换的神经网络模型

上海交通大学学报 2000年第10期34卷 1376-1377,1381页

作者：王玉邢渊阮雪榆上海交通大学塑性成形工程系上海200030

基于人工神经网络理论 ,建立了各种硬度值之间相互转换的完整统一的神经网络模型 .该模型可实现各种硬度之间的线性与非线性映射 ,并对硬度表中没有的数据给出准确的预测 ,克服了查表法的不足 ,较线性回归具有更高的精度 .网络模型可嵌... 详细信息

基于人工神经网络理论 ,建立了各种硬度值之间相互转换的完整统一的神经网络模型 .该模型可实现各种硬度之间的线性与非线性映射 ,并对硬度表中没有的数据给出准确的预测 ,克服了查表法的不足 ,较线性回归具有更高的精度 .网络模型可嵌入机械 CAD系统中 ,方便地实现各种硬度之间的转换 .

关键词：硬度人工神经网络转换模型 CAD