The effective design of bean bag as a vibroimpact damper

The technique of a bean bag damper has been effectively applied in many eng ineering fields to control the vibroimpact of a structural system. In this study, the basic parameters responsible for the design of an effective bean bag: the size of beans, the mass ratio of the bean bag to the structure to which it is attached, the clearance distance and the position of the bag, are studied by both theoretical and experimental analyses. These will provi de a better understanding of the performance of the bean bag for optimisati on of damper design. It was found that reducing the size of beans would inc rease the exchange of momentum in the system due to the increase in the eff ective contact areas. Within the range of mass ratios studied, the damping performance of the damper was found to improve with higher mass ratios. The re was an optimum clearance for any specific damper whereby the maximum att enuation could be achieved. The position of the bag with respect to nodes a nd antipodes of the primary structure determined the magnitude of attenuati on attainable. Furthermore, the limitations of bean bags have been identifi ed and a general criteria for the design of a bean bag damper has been form ulated based on the study undertaken. It was shown that an appropriately co nfigured bean bag damper was capable of reducing the amplitude of vibration by 80% to 90%.