EFFICIENCY OF VIBRATIONAL-ENERGY DISSIPATION BY MOVING SHOT

The paper presents measuring methods and measurement results of vibrat ion damping of shot-filled containers with some empty volume as the sh ot damper clearance. The energy dissipation by shot depends on two phe nomena: the internal and the external (container walls) impacts of sho t particles associated usually with their internal and external fricti on. This is the working principle of the single-/multi-mass impact dam pers and the shot vibration damper as well. It is shown in the paper t hat the additional loss factor introduced by the shot moving in the pr operly shaped container is on the order of half of shot mass reduced t o the primary system modal mass. It may be even twice more if the ener gy dissipation by shot friction will be fully utilized. This depends m ainly on the motion condition of shot inside a container. It was shown in the paper also that loose shot or better shot tightly packed in a plastic bag or mesh can fulfill this condition. Shot dampers can work efficiently in a broad range of acceleration and frequency and need no t be maintained. Due to this it may be very convenient to apply them t o structural vibration problems.