Energy dissipation in head-on collisions of spheres
Energy dissipation in head-on collisions of spheres
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DOI：
10.1088/0022-3727/46/43/435303
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发表时间：
2013-10-30
影响因子：
3.4
通讯作者：
Tielens, A. G. G. M.
中科院分区：
文献类型：
--
作者：
Krijt, S.;Guettler, C.;Tielens, A. G. G. M.
球体之间的碰撞是各种科学问题的常见因素，而恢复系数 (COR) 是描述其结果的关键参数。我们提出了一种新的碰撞模型，该模型自洽地处理粘附和粘弹性，同时假设塑性变形引起的能量损失是相加的。结果表明，粘弹性可以显着增加碰撞中耗散的能量，从而提高粘附速度。此外，远高于粘着速度的碰撞仍然是耗散的。我们系统地将模型与大量已发表的实验室实验进行比较，以证明其普遍适用性。该模型能够很好地再现实验中测量的冲击速度和 COR 之间的重要关系，涵盖广泛的材料、颗粒尺寸和碰撞速度。此外，这些曲线的拟合参数提供了物理参数，例如表面能、屈服强度和特征粘性松弛时间。我们的结果表明，为了正确描述球体碰撞中的动能损失，需要所有三个方面——粘附、粘弹性耗散和塑性变形。
Collisions between spheres are a common ingredient in a variety of scientific problems, and the coefficient of restitution (COR) is a key parameter to describe their outcome. We present a new collision model that treats adhesion and viscoelasticity self-consistently, while energy losses arising from plastic deformation are assumed to be additive. Results show that viscoelasticity can significantly increase the energy that is dissipated in a collision, enhancing the sticking velocity. Furthermore, collisions well above the sticking velocity remain dissipative. We systemically compare the model to a large and unbiased set of published laboratory experiments to show its general applicability. The model is well capable of reproducing the important relation between impact velocity and COR as measured in the experiments, covering a wide range of materials, particle sizes, and collision velocities. Furthermore, the fitting parameters from those curves provide physical parameters such as the surface energy, yield strength, and characteristic viscous relaxation time. Our results show that all three aspects-adhesion, viscoelastic dissipation and plastic deformation-are required for a proper description of the kinetic energy losses in sphere collisions.