颗粒弹塑性碰撞理论模型

以Hertz弹性接触力学为基础,假设材料为弹塑性强化材料,并考虑接触压力作用下颗粒球体接触面上材料进入塑性阶段后的应力调整与释放,提出了一种新的颗粒弹塑性接触理论。以此为基础,在准静态假设的基础上,研究了颗粒间的弹塑性碰撞问题,推导了相应的计算公式,并与其它弹塑性接触模型进行了比较。结果表明:按照该文模型预测的荷载变位曲线介于Hertz弹性解和Thornton解之间;强化系数越高,荷载变位曲线越接近Hertz弹性解,强化系数越低,越接近Thornton解,Thornton模型为该文模型的一个特例。在颗粒弹塑性碰撞过程中,本文理论预测的冲击力远远小于Hertz弹性解的预测结果,更与实际情况相符。

THEORETICAL MODEL ON ELASTIC-PLASTIC GRANULE IMPACT

Base on the Hertz contact mechanics, assuming the materials as elastic-plastic hardening, and considering the adjustment and release of contact stress on the plastic contact region, a new granule elastic-plastic contact theory has been suggested. Then, the elastic-plastic impact among granules has been investigated under the material’s quasi-static hypothesis. At last a corresponding formula is given and compared with other models. The results have shown that the force-deformation relation locates between the curves following Hertz theory and Thornton theory according to new model. It also clearly shows the curve will approach closer to the Hertz solution when the hardening coefficient becomes higher and to the Thornton solution when hardening coefficient is lower, so the Thornton model is a special case of this model. In fact, the impact pressure predicted with the new model is far smaller than the Hertz elastic solution and more conformable to reality.