Investigating the dissipative effects of liquid-filled particle dampers using coupled DEM–SPH methods

One of the main disadvantages of solid-particle-filled dampers, generally called particle dampers (PDs), is that their performance is sensitive to vibration amplitude changes. The efficiency of PDs seems to reduce drastically with low intensity driving acceleration, especially when the acceleration level falls below that of gravity. In this paper, a new approach is investigated, in which the damper is filled with a combination of both solid and liquid fillings, in order to reduce such undesirable PD short comings. In order to quantify and understand the influence of various dissipation mechanisms, simulations were performed. The liquid motion is modeled using the smoothed particle hydrodynamics (SPH) method and the discrete element method (DEM) is used to model the motion of solid particles. In order to validate the simulation models, also a laboratory experiment was set up. This experiment consists of a damper, in this case a cylindrical acrylic container filled with spherical particles in combination with distilled water, mounted on a vertical leaf spring. By analyzing the free oscillation behavior of the leaf spring, the corresponding damper performance is characterized. The insights gained during experiments were then utilized to identify and validate the DEM and SPH models, respectively. Initially, damping behavior of dampers with solid filling and liquid filling are analyzed independent of each other. Then, these two configurations are compared with dampers with a combination of both solid and liquid fillings. In order to model solid–liquid dampers a coupled SPH–DEM approach is used. Experimental and simulation results show that dampers with a mixture of solid and liquid filling perform better than purely solid-filled or purely liquid-filled dampers, especially under low intensity driving accelerations. The main reasons behind this effect are believed to be that the solid particles with the additional hydraulic forces due to an added liquid are more agile leading to more relative motion and thereby leading to more energy dissipation. Moreover, the violent sloshing motion of the liquid through the tiny gaps, created by solid particles, also leads to more energy dissipation.