葵花籽压榨过程中的塑性模型

Plasticity Model for Pressing of Sunflower Seeds

对葵花籽散粒体侧限压榨下的应力-应变关系和侧向压力进行了试验。根据侧限压榨符合三次幂曲线模型的试验结果,采用Kuhn屈服准则并结合实际侧限压榨过程中的粘弹塑性过程,确定主要塑性模型的参数,建立了基于增量理论的葵花籽散粒体侧限压榨本构方程。并通过试验得出了葵花籽应变的理论计算值与试验实测值最大相对误差为19.7%,平均相对误差5.3%,验证了基于Kuhn屈服准则建立的压榨模型能较好地描述葵花籽压榨过程中的塑性变形。

The experiments for stress-strain and lateral pressure of sunflower seeds by uniaxial pressing were carried out. The results show that sunflower seeds conform to the model of three power curve. By using of Kuhn＇s yield criterion, plasticity constitutive equations were developed. Sunflower seed strain of theoretical and experimental value of the actual value of the maximum relative error is 19.7%, with an average error of 5.3 %. The constitutive model can show a better description of sunflower seeds in the press process of plastic deformation. Kuhn＇s yield criterion can be used as theoretical basis for plasticity model of sunflower seeds.