Modelling of nonlinear dampers under low-amplitude vibration

Particle dampers can suppress structural vibration over a broad range of frequencies, which makes them attractive in comparison to many other passive damping technologies. They constitute a cavity filled with particles. Energy dissipation from particle dampers depends on many parameters including, size of the cavity, diameter of the particles, shape of the damper, filling ratio, material properties of the particles and the volumetric ratio between the cavity and particles. Performance changes with the amplitude of the excitation and, to a lesser extent, the frequency. This study focuses on the energy dissipation in the granular material that fills particle dampers as the damper is subjected to low-amplitude dynamic load. The behaviour of this material is modelled using the Discrete Element Method (DEM) for a specific case: a tube-shaped cavity filled with spherical particles. An equivalent continuum model is proposed for the granular material and the Finite Element Method (FEM) is used to simulate the response of a damper subject to structural vibration. This study shows how the equivalent material model can be used to predict amplitude dependent behaviour in particle dampers under lowamplitude excitation.