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Forming limits and constitutive modeling of steel tube for automotive parts

汽车零部件钢管的成形极限及本构建模

基本信息

批准号：
17560628
负责人：
KUWABARA Toshihiko
金额：
$ 2.24万
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：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

The present study aims to clarify the nature of the path-dependence of forming limit stresses from a view point of the phenomenological plasticity analysis.In this analysis we use a non-normality flow rule proposed by Kuroda and Tvergaard (2001). This flow rule assumes a non-linear dependence of the plastic strain rate D^P on the total strain rate D, where D is decomposed asD=D^e +D^P=D^e+^^・ΦN^P (1)where e and p indicate the elastic and plastic part of strain. N^P defines the direction of D^P, ^^・Φ is a non-negative overstress function for rate-dependent cases. State variables of the material are assumed to be Cauchy stress tensor, σ, and the orthonormal vectors n, defined along the axes of orthotropy, and equivalent strain ^^-ε. These variable are calculated using following equations:^^。σ=^^・σ-ω・σ+σ・ω=C^<+e>:D^e=C:D-^^・ΦC^e : N^P (2)^^・n_i=ω・n_i (3)^^-ε=∫^^<・->εdt, ^^<・->ε=√<2/3>^^・Φ (4)where C^e is the fourth order elastic moduli tensor. With a superposed o denoting an objective rat … More e with respect to the spin ω and the superposed dot denoting a material time derivative, the elasticity relation is assumed to be given by Hooke's law.The limits to formability are simulated using the M-K model both for proportional loading and two types of combined loadings : one type includes unloading between the first and second loadings while the other type does not include unloading. The strain paths for each combined loading are almost identical, while the resulting stress paths are significantly different. The effects of changing stress/strain paths on the FLC and FLSC are discussed in detail by observing the strain localization process for each case. A basic question is: Is the forming limit stress always path-independent, irrespective of stress/strain paths? If so, why? If not, what makes the forming limit stress path-dependent?The forming limit stresses calculated for combined loading A agree well with those calculated for the linear stress paths, while the forming limit curves in strain space depend strongly on the strain paths. The forming limit stresses calculated for the combined loading B do not, however, coincide with those calculated for the linear stress paths. Less

本文采用黑田和Tvergaard（2001）提出的非正态流动法则，从唯象塑性分析的角度阐明了成形极限应力的路径依赖性。该流动法则假设塑性应变速率D^P与总应变速率D之间存在非线性关系，其中D被分解为D =D^e +D^P=D^e+^^·ΦN^P（1）其中e和p表示应变的弹性和塑性部分。N^P定义了D^P的方向，对于速率相关的情况，Φ是非负的过应力函数。材料的状态变量被假定为柯西应力张量σ，以及沿正交各向异性轴沿着定义的正交向量n，以及等效应变^^-ε。这些变量使用以下等式计算：σ=^^·σ-ω·σ+σ·ω=C^<+e>：D^e=C：D-^^·ΦC^e：N^P（2）^^·n_i=ω·n_i（3）^^-ε=∫^^<·->εdt，^^<·->ε=√<2/3>^^·Φ（4）其中C^e是四阶弹性模量张量。叠加的o表示客观率 ...更多信息 e关于自旋ω和表示材料时间导数的叠加点，假定弹性关系由虎克定律给出，用M-K模型模拟了比例加载和两种组合加载（一种在第一次加载和第二次加载之间卸载，另一种不卸载）下的成形极限。每种组合载荷的应变路径几乎相同，而产生的应力路径则明显不同。通过观察每种情况下的应变局部化过程，详细讨论了改变应力/应变路径对FLC和FLSC的影响。一个基本的问题是：成形极限应力是否总是与路径无关，而与应力/应变路径无关？如果是，为什么？如果不是，是什么使成形极限应力路径依赖？复合载荷A下的成形极限应力与线性应力路径下的成形极限应力吻合较好，而应变空间中的成形极限曲线强烈依赖于应变路径。但是，对于组合载荷B计算的成形极限应力与线性应力路径计算的成形极限应力不一致。少

项目成果

期刊论文数量（12）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

各種負荷経路における鋼管の成形限界 -第1報線形応力経路における成形限界の測定と解析-

各种载荷路径下钢管的成形极限第1部分：线性应力路径下成形极限的测量与分析

DOI：
发表时间：
2005
期刊：
第55回塑性加工連合講演会論文集
影响因子：
0
作者：
桑原利彦;吉田健吾
通讯作者：
吉田健吾

成形限界応力線のひずみ経路依存性に関する実験検証

形成临界应力线的应变路径依赖性的实验验证

DOI：
发表时间：
2005
期刊：
日本機械学会東北支部第41期秋季講演会講演論文集 2
影响因子：
0
作者：
吉田健吾;桑原利彦
通讯作者：
桑原利彦

Advanced in experiments on metal sheets and tubes in support of constitutive modeling and forming simulations

金属板材和管材实验取得进展，支持本构建模和成形模拟

DOI：
发表时间：
2007
期刊：
International Journal of Plasticity 23-3
影响因子：
0
作者：
M.Adachi;K.Okuyama;足立元明;Toshihiko Kuwabara;Kengo Yoshida;Kengo Yoshida;Toshihiko Kuwabara
通讯作者：
Toshihiko Kuwabara

複合応力経路下における鋼管およびアルミニウム合金管の成形限界

复杂应力路径下钢管和铝合金管的成形极限