基于Lemaitre and Chaboche非线性随动强化和等向强化理论,提出了一种有效的背应力修正方法,采用Mises屈服准则,建立了复杂加载模式下非线性混合强化材料模型(M-NH)的弹塑性应力应变本构关系,采用高效的Backward Euler切向预测径向返回...基于Lemaitre and Chaboche非线性随动强化和等向强化理论,提出了一种有效的背应力修正方法,采用Mises屈服准则,建立了复杂加载模式下非线性混合强化材料模型(M-NH)的弹塑性应力应变本构关系,采用高效的Backward Euler切向预测径向返回算法给出应力应变增量的计算,引入最小二乘法根据单轴拉伸实验数据点获得材料的硬化模型参数。为了计算背应力及弹塑性刚度矩阵开发了Fortran程序,编制了M-NH模型的实现代码。针对采用本模型获得的单轴拉伸应力应变曲线,分析了材料相关硬化参数对曲线变化趋势的影响。本模型及Chaboche1991、Basu&Voyiadjis强化模型分别与Chaboche的实验数据对比表明,基于M-NH获得的计算数据与实验结果更为接近。展开更多
Temperature-dependent elastic viscoplastic material model was used for the numerical simulation of the friction stir welding process. The non-elastic response of the rate-dependent material in the large deformation pr...Temperature-dependent elastic viscoplastic material model was used for the numerical simulation of the friction stir welding process. The non-elastic response of the rate-dependent material in the large deformation problems was calculated by using the closest point algorithm. The numerical results show that the shape of the equivalent plastic strain looks like onion rings and the spacing of the rings is approximately equal to the forward movement of the tool in one rotation. The equivalent plastic strain is increased with the increase of viscosity coefficient due to the increase of friction stress in the pin-plate interface. The region which is influenced by the rotating tool is decreased with the decrease of viscosity coefficient. The radial and circumferential stresses in front of the pin are greater than the ones behind the pin. This difference can be reduced with the decrease of viscosity.展开更多
文摘基于Lemaitre and Chaboche非线性随动强化和等向强化理论,提出了一种有效的背应力修正方法,采用Mises屈服准则,建立了复杂加载模式下非线性混合强化材料模型(M-NH)的弹塑性应力应变本构关系,采用高效的Backward Euler切向预测径向返回算法给出应力应变增量的计算,引入最小二乘法根据单轴拉伸实验数据点获得材料的硬化模型参数。为了计算背应力及弹塑性刚度矩阵开发了Fortran程序,编制了M-NH模型的实现代码。针对采用本模型获得的单轴拉伸应力应变曲线,分析了材料相关硬化参数对曲线变化趋势的影响。本模型及Chaboche1991、Basu&Voyiadjis强化模型分别与Chaboche的实验数据对比表明,基于M-NH获得的计算数据与实验结果更为接近。
基金Porjects(10225212 10421002+1 种基金 10302007) supported by the National Natural Science Foundation of China Project supported by the Program of Changjiang Scholars and the Innovative Research Team in University of China(PCSIRT) and Project(2005CB321704) supported by the National Basic Research Program of China
文摘Temperature-dependent elastic viscoplastic material model was used for the numerical simulation of the friction stir welding process. The non-elastic response of the rate-dependent material in the large deformation problems was calculated by using the closest point algorithm. The numerical results show that the shape of the equivalent plastic strain looks like onion rings and the spacing of the rings is approximately equal to the forward movement of the tool in one rotation. The equivalent plastic strain is increased with the increase of viscosity coefficient due to the increase of friction stress in the pin-plate interface. The region which is influenced by the rotating tool is decreased with the decrease of viscosity coefficient. The radial and circumferential stresses in front of the pin are greater than the ones behind the pin. This difference can be reduced with the decrease of viscosity.
