Shape Memory Alloy Actuated Switch (SMAAS)
Abstract
In the light of recent research advancements in the field of shape memory alloy (SMA) actuators and devices, an idea of employing shape memory alloys in an electric switching device emerged. In this SMA actuated switch, SMA members are used as resistively heated actuators to separate or engage electric contacts for load circuit(s). Advantages of using SMA actuators in electric switching include; no holding power requirement (unlike some electromagnetic and solid-state relays), low power losses at the contacts (using metallic contacts as opposed to semiconductor junctions) and ease of miniaturization. One potential application for this device is the smart photovoltaic nonplanar skin made of individual PV cells arranged together into pixels that can adapt to environmental conditions. One smart method of adaptation is to use miniature switches embedded onto the PV skin to group homogenous cells (according to exposure, solar intensity and other environmental conditions) to yield maximum energy harvest. Therefore, this research work investigates the feasibility of bi-stable shape memory alloy actuated switches and develops a framework for designing, optimizing and manufacturing them with respect to the intended application. In this thesis, 15 conceptual designs for the SMAAS (inspired by the literature and novel concepts) are presented, 5 of which were down-selected as having the most potential in terms of robustness, manufacturability and scalability. The governing equations for the SMAAS concepts are formulated in the form of analytical and empirical models. In addition, two functional proof of concept prototypes for the switch are presented in this document as well as case studies for the optimization and manufacturing of some of the down selected SMAAS concepts in the micro level. The outcome of this work is a proof of the feasibility of the SMAAS and its potential for miniaturization as well as the detailed design and manufacturing framework for SMA-based devices. An extension of this research work would be to develop and manufacture an energy-optimal micro SMAAS that satisfies the PV skin application’s constraints and objectives.
Citation
Raslan, Moustafa (2019). Shape Memory Alloy Actuated Switch (SMAAS). Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195919.