The limitations of electrical resistance for accurate positioning of shape-memory actuators: The case of well-oriented CuZnAl single-crystals under uniaxial loading
Abstract The possibility of using the electrical resistance as a feedback signal for precise positioning in the design of compact shape-memory actuators was revised. The analysis was performed on well-oriented CuZnAl single crystalline shape-memory alloys subjected to uniaxial tensile loadings, combining direct strain measurements determined with an extensometer and the four-lead electrical resistance technique. In that way the relationship between strain and electrical resistance could be evaluated by formulating a physics based model that can be easily contrasted with the experimental characterization of a simple benchmark system. It was found that the model here developed provides general guidelines for the selection of a shape-memory material for positioning actuators and that the correlation between strain and electrical resistance is of rather limited precision, even for the simplest material case and loading condition analyzed. The effects of temperature, deformation rate, temperature dependence of the electrical resistivity of austenite and martensite phases and temperature dependence of the strain associated with the stress induced transformation were carefully characterized. Results suggest that the direct use of feedback from electrical resistance measurements for precise positioning is arguable unless materials with low hysteresis and low latent heat of transformation are used in combination with quasi-static operating conditions. Highlights The use of electrical resistance as a feedback signal for positioning of shape memory based actuators is critically revised. A physics-based model relating electrical resistance variation with strain for a single crystal benchmark case is presented. Even in the simplest case, a straightforward accurate correlation between strain and electrical resistance does not exist. Guidelines for selection of a shape memory material for actuator positioned through the electrical resistance are formulated. Graphical abstract [DISPLAY OMISSION]
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기