基于扭转试验的大变形本构关系分析

研究采用实心圆轴扭转试验标定大变形弹塑性本构关系时客观应力导数的影响问题.给出了在实心圆轴扭转试验中,几种常用旋率的具体形式.应用等向强化的J2流动塑性理论,建立了以扭转试验的应力-应变曲线为基准的,分别由Oldroyd、广义Jaumann应力导数和相对于变形率标架旋率的应力导数表述的大变形弹塑性本构关系.所得各本构关系中的塑性刚度函数与由Jaumann客观应力导数给出的塑性刚度函数形式相同,说明用扭转试验标定大变形弹塑性本构关系时,塑性刚度函数不受客观应力导数的影响,本构形式相对稳定.

Analysis of large strain constitutive relationship based on torsion test

The effect of objective stress rates on constitutive model based on solid cylinder torsion test was discussed.Several objective spins of solid cylinder torsion deformation were rendered and the large deformation elastoviscoplastic constitutive relationships were derived for the Oldroyd stress rate,the generalizing Jaumann stress rate and the stress rate with respect to the spin of the frame of deformation rate with the aid of stress-strain curve from torsion test.Isotropic hardening model and J_2 flowing plasticity theory are employed in this paper.The obtained plastic rigidity function of constitutive models is the same as that of Jaumann stress rate.It is concluded that objective stress rate has no affect on plastic rigidity function if torsion test is used to discuss large deformation constitutive model.