Elastic-Plastic Constitutive Modeling and Experimental Observation of Some Steels for Phase Transformation Process under Multi-axial Stresses State

多轴应力状态下部分钢材相变过程的弹塑性本构建模及实验观察

• 批准号: 18560071
• 负责人: NAGAKI Shigeru
• 金额: $ 2.47万
• 依托单位: Tokyo University of Agriculture and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560071/
• 关键词: phase transformation; transformation plasticity; thermo-elasto-plasticity; constitutive equation; stress induced transformation; multi-axial stress state; 応力誘起変態; 熱処理; 変態塑性; 温度・伸び線図

In this project the response of phase-transforming steels under multi-axial stress state at elevated temperature is studied both theoretically and experimentally.The new biaxial loading equipment is developed, where tensile and torsional loads can be applied to the specimen independently at elevated temperature and the specimen can be cooled rapidly so that martensite and bainite transformations are observed. The dilatation-temperature diagram is obtained experimentally for SCM440 steel and it is found that the transformation temperature depends on both applied stress state and cooling rate. It is also fount that transformation plasticity is observed to occur for both tensile and torsional stresses and depends on stress state.The constitutive model for thermo-elastic-plastic behavior of some steels during phase transformation process is also proposed in terms of internal state variable theory, where the volume fraction of each phase is considered as an internal state variable. The explicit form of the evolutional equations for internal variables is derived. The coefficient of transformation plasticity is also identified within the proposed framework. Calculated results of the continuous cooling transformation (C-C-T) diagram and the isothermal time-temperature-transformation (T-T-T) diagram, together with the dilatation-temperature diagram show the stress dependency of phase transformation and are compared with experimental data for SCM440 steel.Applications of the theory to the cases of bending of locally heated plate are also presented. Stress, displacement and temperature distributions are numerically calculated by a finite element technique and compared with corresponding experimental results.

本项目从理论上和实验上研究了相变钢在高温多轴应力状态下的响应。开发了新型双轴加载装置，可以在高温下对试件独立施加拉伸和扭转载荷，并快速冷却试件，从而观察马氏体和贝氏体相变。通过实验获得了SCM440钢的膨胀-温度图，发现转变温度取决于施加的应力状态和冷却速率。还发现拉应力和扭转应力都会发生相变塑性，并且相变塑性取决于应力状态。还根据内部状态变量理论提出了某些钢在相变过程中热弹塑性行为的本构模型，其中将各相的体积分数视为内部状态变量。推导了内变量演化方程的显式形式。转变塑性系数也在所提出的框架内确定。连续冷却转变（C-C-T）图和等温时间-温度-转变（T-T-T）图以及膨胀-温度图的计算结果显示了相变的应力依赖性，并与SCM440钢的实验数据进行了比较。还介绍了该理论在局部加热板弯曲情况下的应用。通过有限元技术对应力、位移和温度分布进行数值计算，并与相应的实验结果进行比较。

项目成果

局所加熱下における板材の曲げ変形と熱弾塑性解析

板材局部加热弯曲变形及热弹塑性分析

• 发表时间: 2007
• 期刊: 日本機械学会講演論文集 No.070-1
• 作者: 金子豊;樋渡保秋;小原勝彦;浅富士夫;Takashi Nagatani;Takashi Nagatani;Takashi Nagatani;Takashi Nagatani;Takashi Nagatani;Zhanpeng Lu;Zhanpeng Lu;Takashi Nagatani;Zhanpeng Lu;Takashi Nagatani;Zhanpeng Lu;Takashi Nagatani;Z. Lu;Takashi Nagatani;Takashi Nagatani;Z. Lu;Zhanpeng Lu;Zhanpeng Lu;Zhanpeng Lu;Zhanpeng Lu;Zhanpeng Lu;Zhanpeng Lu;津司 和哉;Zhanpeng Lu;椋野昇平・木元岳史・佐久間淳・大下賢一・長岐滋
• 通讯作者: 椋野昇平・木元岳史・佐久間淳・大下賢一・長岐滋

Deformation of the plate during localized heating and thermo-elasto-plastic analysis

局部加热和热弹塑性分析期间板的变形

• 发表时间: 2007
• 期刊: Proc. 2007 Annual Meeting of JSME No. 070-1
• 作者: S.;Mukuno;T.;Kimoto;A.;Sakuma;K.;Ohosita;S.;Nagaki
• 通讯作者: Nagaki