Frequency and amplitude dependent behaviour of tangled metal wire dampers

Tangled metal wire (TMW) is an energy dissipating material, composed of spring-like wires. Friction in the material microstructure introduces damping in the system. A set of displacement controlled quasistatic and dynamic compression tests were carried out and the nonlinear hysteretic load displacement behaviour was observed. The quasi-static tests revealed rate-dependent material behaviour, whereas the results from the dynamic tests indicated the existence of frequency and amplitude dependency for both the average dynamic stiffness and the damping. These phenomena are not in agreement with the classical Coulomb friction behaviour, which may indicate that viscous effects are also acting in the system. Interestingly, the rate-dependency that occurred in the quasi-static tests was found to be in agreement with the results of the dynamic tests. This paper discusses the microstructural properties in relation to the behaviour observed in experiments.