We develop novel shape memory alloy (SMA) film damper devices using the dissipative mechanisms of either the superelastic effect (SE) or thermal shape memory effect (SME). These effects result in a nonlinear stress-strain response and hysteresis allowing the engineering and control of dissipative processes at large stress and strain levels up to 500 MPa and 5%, respectively. Owing to the large surface-to volume ratio of SMA films rapid heat transfer leads to time constants in the millisecond regime. This enables a new generation of smart miniature damper systems for portable or mobile applications combining noise- and jerk-free operation. The figure shows a sketch of a miniature camera module to investigate the effect of SMA film damping and of suitable control strategies on the overall system dynamics.
|Sketch of a miniature camera module consisting of a platform that is controlled by SMA microdevices|
Ahmadi, Shahabeddin PhD student