Improvement of Shape Memory Alloy (NiTi) Actuation Frequency Using Highly Thermally Conductive Metal Layer

In this paper, we investigate a novel passive approach to improve the actuation frequency of Shape Memory Alloys (SMAs) with the Kirigami-inspired design using a thin layer of highly thermally conductive material. By depositing an 80 nm layer of gold on the SMA surface, we aimed to enhance the overall thermal conductivity and consequently reduce both heating and cooling times of the SMA elements. The experimental results demonstrate a significant improvement (~ 25<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup>) in both heating and cooling times, thereby enhancing the actuation frequency of the SMA samples. We also developed a thermal model for the Kirigami-inspired SMA structure and compared with the experimental results to gain a deeper understanding of the structure's thermal behavior. This comparison helps to validate the model and provides insights into the heat transfer dynamics of the SMA actuator.