Methodology for the estimation of material damping as applied to superelastic shape memory alloy mini-springs

This work presents an experimental methodology to estimate the material damping of superelastic helical mini-springs fabricated with superelastic shape memory alloys (SMA-SE). Moreover, the methodology provides a relatively inexpensive means for investigating the dynamic thermomechanical behavior of the NiTi SMA-SE mini-springs tested. This methodology is based on a resonance test in which the device is subjected to a mechanical reference system. We observed that four parallel mini-springs, each with a 0.033 g mass, have the capacity to reduce up to 6 dB of displacement amplitude (which represents an increase of 102% in hysteretic damping) in a mechanical system with a mass of 1485 g. Furthermore, a simplified analytical model is proposed based on observation of the frequency response function (FRF) of the mechanical system with the SMA-SE mini-springs.