Abstract
The fatigue life of conventional heat-engines using shape memory alloy (SMA) wire is too short (less than 10^5 cycles). Therefore, SMA heat engines do not come into practical use. This study proposes the new SMA heat engine using SMA spiral spring actuators expected to have a longer fatigue life. In this study, the new SMA heat engine has been built and the engine performance has been investigated. The SMA spiral springs are fabricated from the SMA ribbon by heat-treatment. The chemical composition of the SMA ribbon is Ti-49.9at%Ni. The dimension of the SMA ribbon is 1000mm in length, 6.8mm in breadth and 0.15mm in thickness. The SMA heat engine is driven by hot (353K) and cold (293K) water. It is confirmed that the SMA heat engine can continue to work by continuous thermal cycling. The maximum output power of the engine is 139.4mW.
