Particle Dampers – Vibration Modification by Distributed Dissipation originating from Complex Particle Shapes and Fluid/Solid Interactions

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The application of particle dampers is a promising alternative for the modification of vibrations. Particle dampers are working over a large frequency range, they cover additional functions like minimizing noise or being a load bearing part, whereas they are very robust and are applicable over a larger temperature range. Several physical phenomena playing an important role for particle dampers and are interacting to fulfill the features of the damper. Until now there is no satisfying predictive simulation approach which takes the interaction of all those physical processes into account and in doing so is useable for a proper investigation for the understanding of particle dampers.The aim of this project is the more profound understanding of particle dampers for an optimal design. One of the important points for the functionality of a particle damper are the numerous contacts in between the particles and the housing. Therefore, in this project the particles are modeled with the Discrete Element Method (DEM). Due to its mesh-free character it is possible to model the large transient displacements of the particle pile. For influencing the dissipation simple spheres are replaced with non-convex particles. In a first step an algorithm for applying friction between those particles will be developed. A proper scientific investigation is often based on two pillars: simulation and experiment. We want to carry out small experiments in every working task; active experiments with stimulation via a shaker and passive ones with a pendulum. Besides the complex shape of the particles we want to develop a new method to predict the production of sound due to the impact of particles. In doing so, it is possible to optimize a smarter damper which is used for reducing the noise of a working machine, regarding the noise level by itself and simultaneously the resulting energy dissipation. Another point is the filling of the damper consisting of a mixture of solid particles and a fluid. Therefore, the experience in coupling a fluid (modeled by Smoothed Particle Hydrodynamics) with particles will be used to develop a new approach for coupling non-convex particles with a fluid. This approach is used to investigate the potential improvement of energy dissipation when a certain amount of fluid is added. Damage plays an important role in many technical applications. Last but not least we want to implement a simple damage approach into the DEM, between adjacent particles and also the housing and in this way to investigate the influence of damage to the damping.