Damping of honeycomb sandwich beams

An experimental investigation was carried out on the damping behaviour of laminated honeycomb cantilever beams with fine solder balls enclosed in the cells as dampers. Attenuation was achieved through the exchange of momentum between the balls and the beam. The effect of the mass ratio (i.e. the number of balls to be enclosed in each honeycomb cell) was studied by varying the number of balls used. The damping variation was found to be effective in reducing the amplitude without significantly shifting the natural frequency of the cantilever. However, an optimal mass ratio could not be determined as the effect is monotonic and the insertion of balls leads to an increase of total mass. Peeling tests after the vibration show that the cyclic impact of the inserted balls with the face sheets of the beam does not deteriorate the bonding strength. (C) 2000 published by Elsevier Science S.A.