Finite element analysis of particle rebound characteristics

Abstract

In the present thesis, a study about the particle rebound characteristics is presented. The rebound of a spherical particle was analyzed in details and specifically the coefficient of restitution of a sphere colliding to a planar surface was investigated. This study has been conducted by carrying out a series of finite element simulations using the software package ANSYS Autodyn. In the first part of the work, a summary about the existing studies and the theoretical models is done. While the theoretical model for the elastic collisions was applied and validated, predicting the coefficient of restitution for collisions where plastic deformation is a more complex task. In the second part, the experimental results of an aluminum oxide particle colliding to an aluminum alloy target surface are provided. Using a finite element analysis software these results are reproduced. The selection of the equation of state and the strength model for each material has a strong role in the results. For both materials, the Shock equation of state is used. For the strength model, the Johnson-Cook and the Elastic model provided by the software are respectively used. The coincidence of the results obtained with the experimental values, confirm that the model proposed with ANSYS Autodyn fits the real behavior of the particle and therefore, it is validated to analyze other parameters. By fixing the velocity to 3.85 m/s and varying the impact angle, the effect of this second variable in the rebound is observed. To check how the impact velocity affects the rebound, the impact angle is set to 30º and 60º and the velocity is changed. After run of these simulations, the influence of the parameters such as the initial velocity, the impact angle or the coefficient of friction was obtained and analyzed.