Discrete element method model and damping performance of bean bag dampers

• The DEM model of BBD is established.
• The effects of structural parameters on damping effect of BBD are studied.
• The tightness of BBD is quantitatively described.
• The effects of structural parameters on the tightness of BBD are studied.

Bean bag dampers (BBDs) have been widely applied in engineering to attenuate the vibration of a structural system, but the theoretical analysis on BBDs has been scarcely reported because of their nonlinear damping performance and complex mechanism. In this work, a three-dimensional model of a BBD was established based on the discrete element method (DEM); its flexible boundary was discretized. The model was verified by comparing simulation with test data. Based on the model, the selection of proper particle diameter on the flexible boundary of the BBD was discussed first, and then the effects of internal particle size of the BBD, the BBD׳s tightness and the gap between BBD and the inner wall of its enclosure on the energy dissipation capacity were studied. Moreover, the filling ratio of BBD (total internal particles׳ volume/the flexible boundary׳s capacity) was defined to quantitatively describe the tightness of BBD, and the effects of the internal particle size, the natural frequency of primary system and the enclosure size on the optimum tightness of the BBD were also considered. The results can be used as a guide in the design of BBDs.