Study on contact fracture and shock phenomena of high-speed rotating condensed matter due to high-speed impact

在本项目中，我们主要取得了以下两方面的成果：(1)旋转铝合金圆盘的撞击现象，铝合金圆盘由电机旋转，由弹簧机构加速，撞击固体靶板。利用高速摄像机分析了圆盘的转动和平移运动。同时，用表面带有应变片的圆柱形铝合金靶板测量了冲击应变和应力。同时，采用激波程序AUTODYN-2D进行了数值模拟。用这种方法，特别是详细地研究了旋转对恢复系数和撞击力的影响，得到了非常有趣的行为。这一结果对高速旋转机械中出现的各种冲击现象是有用的。(2)颗粒聚集的冲击现象。尼龙制成的球体在容器中二维和三维排列形成颗粒聚集。然后，以不同的撞击速度和撞击角对球形钢弹撞击聚集体。使用高速摄像机分析了这些粒子的运动。同时，将离散单元法应用于颗粒运动和应力波传播的数值模拟。在这种情况下，由于物体在平移运动的同时也作旋转运动，所以旋转的粒子之间的接触机制和恢复系数就显得尤为重要。因此，上述旋转物体撞击现象的结果。

In this project, we obtained mainly the following two results.(1) Impact phenomena of rotating aluminum alloy circular disks.Aluminum alloy circular disks that are rotated by an electric motor and accelerated by a spring mechanism were impacted on a solid target. The rotational and translational motions of disks were analyzed using a high-speed video camera. Simultaneously, a cylindrical aluminum alloy target with strain gauges on its surface was used to measure impact-induced strains and stresses. Also, shock code AUTODYN-2D was used for numerical simulations. In this way, particularly the effect of rotation on the coefficient of restitution and impact forces was investigated minutely and very interesting behavior was obtained. The present result is useful for various impact phenomena appearing in high-speed rotating machines(2) Shock phenomena of particulate aggregation.Spheres made of nylon were arranged two-dimensionally and three-dimensionally in a vessel to from a particulate aggregation. Then, a spherical steel projectile was impinged to the aggregation at various impact velocities and impact angles. The motion of these particles was analyzed using high-speed video cameras. Also, discrete element method (DEM) was applied to numerical simulations on the motion of particles and stress wave propagation. In this case, since articles make rotational motion together with translational motion, contact mechanism and coefficient of restitution between particles that are rotating are particularly important. Therefore, the result of the impact phenomena of rotating bodies mentioned above.