Fatigue-related damping in some cellular metallic materials

Damping in cellular metallic materials is enhanced by localised stresses in comparison with the corresponding dense materials. A pronounced increase in damping with the amplitude of vibration interferes with an additional time dependence due to fatigue processes. This effect, attributed to growth and movement of cracks, is observed in Al- and Zn-based foams, porous steel and titanium. A model of this contribution to amplitude dependent damping is discussed using a simulation of experimental data for a porous 316L (FeNiCr) steel.