Thermo-mechanical characterization of optical thin films filters deposited onto shape memory alloy micro-actuators

Abstract

Different optical thin films filters have been deposited by plasma techniques onto shape memory alloy micro-actuators controlled by the heating of laser irradiations. Thermomechanical cycles have been performed to investigate the stability of these optical filters. Excellent properties have been obtained with amorphous hydrogenated silicon/silica and amorphous hydrogenated silicon/plasma polymerized methacrylic acid-based filters; no degradation was observed after up to 50 000 cycles. Other silver/plasma polymerized methacrylic acid-based filters, which have a better selectivity and permit the use of more laser sources of different wavelengths for optical actuation, showed lower stability. The optical-filtering properties are lost during the thermomechanical cycles, due to a rearrangement of the silver atoms with heating. Thus, there is a trade-off between wavelength selectivity and the stability of the structures used for the optical control of the micro-actuators.

In-situ strain measurement of shape memory alloy fiber during the austenitic and martensitic phase transformation

“…By accurately controlling the heating temperature and driving voltage, the SMAs and SMAF can be served as an actuator. The loading-unloading behaviors of those smart materials have been comprehensively used in intelligent material and civil structures [10,11]. Pioneering SMAs researches associated with solid mechanics and material science have proposed in-depth theory and different receipt for optimizing the effects of strain and strain relief [12,13].…”

Thermo-mechanical behavior of shape memory alloy spring actuated using novel scanning technique powered by ytterbium doped continuous fiber laser

“…Many researchers have studied the shape recovery behavior i.e. thermally induced actuation, as shown in figure 1, using different heating methodologies, such as Joule heating [34][35][36][37][38][39], hot fluidic actuation [18,[40][41][42], laser actuation [43][44][45][46], electromagnetic heating [47,48] and RF electromagnetic actuation [49,50]. In general, Joule heating of SMA element is simple and used widely but requires electrical insulation from other metal/conductive components for safety and better energy efficiency.…”

“…However, to the best of authors' knowledge, there is no detailed study on the laser actuation of SMA under various parametric conditions. Moreover, the reported laser actuation studies have used constant exposure of laser irradiation over the SMA element for actuation [43][44][45][46]58]. Hence, it was decided to demonstrate the laser actuation of SMA element using novel scanning technique.…”