Damping properties of foamed Aluminium

The mechanical damping properties of aluminium foams were measured. An experimental apparatus for measuring the loss factor avoiding parasitic damping is described. The difficulties, originating from random spatial density variations, are discussed. A procedure to overcome the problems is proposed and tested. The measured loss factors show that alumninium foams have a damping capacity which is enhanced in comparison with most massive cast aluminium alloys and increases with increasing,' porosity level.