• [2012-08-07]

  Date posted: August 2, 2012 Impact and Rebound of Thin-walled Spheres and Rings

Title：<span verdana','sans-serif';="" mso-bidi-font-family:="" 宋体"="" lang="EN-US"> Impact and Rebound of Thin-walled Spheres and Rings

<span verdana','sans-serif';="" mso-bidi-font-family:="" 宋体"="" lang="EN-US">Speaker：Prof. T.X. Yu

Professor Emeritus, Department of Mechanical Engineering Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong, China E-mail:  metxyu（at）ust.hk

Host：Linghui Duan

Time：14:30~16:00 pm

Date：August9, 2012

Venue：Conference Room 212, Building No.1, Engineering College   Abstract：The dynamic crushing and subsequent rebound of thin-walled spheres and circular rings colliding onto a rigid wall are studied. Dynamic experiments of ping pong balls were first conducted. After the governing non-dimensional parameter groups are identified, the effects of the thickness-to-radius ratio of spheres and rings, their material properties and the impact velocity on their dynamic deformation mode are systematically investigated by FE simulation. In case of the impact of thin-walled spheres, the transition from axisymmetric dimpling to non-axisymmetric deformation with multiple lobes is found to depend on the relative thickness of spheres and impact velocity; while the coefficient of restitution almost merely depends on the impact velocity. In case of the impact of thin rings, a simple theoretical model is proposed, which catches the main features of the dynamic deformation mechanisms of circular rings. The results of this study would be useful for characterizing the energy absorption capacity of thin-walled spheres and rings after impact, and helpful for understanding the rebound behavior of hollow balls in games and sports.