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

在这个项目中，我们主要取得了以下两个成果。(1)旋转铝合金圆盘的撞击现象：利用电动机带动铝合金圆盘旋转，通过弹簧机构加速，使铝合金圆盘撞击固体靶。使用高速摄像机分析了圆盘的旋转和平移运动。同时，一个圆柱形的铝合金靶与应变片在其表面上被用来测量冲击引起的应变和应力。此外，冲击代码AUTODYN-2D用于数值模拟。通过这种方式，特别是旋转对恢复系数和冲击力的影响进行了详细的研究，并获得了非常有趣的行为。（2）颗粒聚集的冲击现象。将尼龙球在容器中二维和三维排列，形成颗粒聚集体。然后，一个球形钢弹丸以不同的撞击速度和撞击角度撞击聚集体。使用高速摄像机分析了这些粒子的运动。采用离散元法对颗粒运动和应力波传播进行了数值模拟。在这种情况下，由于物体进行旋转运动和平移运动，因此旋转的颗粒之间的接触机制和恢复系数特别重要。因此，上述旋转体的冲击现象的结果。

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.