Duo features of shape memory wire for resonant force sensing

Abstract

The design and demonstration of a new version of the force measurement system based on the resonance principle by involving shape memory alloy (SMA) is presented. The sensor design enables an electromechanically functional resonator comprising the cantilever beam as the vibratory structural element and the Joule heated SMA as an actuating element. The actuation frequency of the SMA wire is improved up to 5.5 Hz by the optimized activation parameters and an appropriate biasing element. The choice of design attributes of the sensing module is made based on the analysis of the associated technical parameters with different dimensions of the constituents of the sensing assembly. The sensing module that adopts the least stiff configuration by the series arrangement of the active SMA and passive elastic cantilever element is modeled mathematically. The dual/twin phenomena of the SMA wire featured by both, actuation that creates resonance in the structure and self-sensing that senses the resonance state, is deployed. The sensor possesses static sensing capabilities and detects force in the range of 0.785 N to 2.45 N and this scheme of force measurement could be a stand-alone unit, besides is adaptable as an application-specific sensor in the analysis of large flexible structures.