Analysis of Heat Engines Driven by Different Actuators

<p dir="ltr">Artificial muscles have undergone significant advancements since the 1950s, leading to breakthroughs in various fields. These synthetic muscles draw inspiration from natural muscles and are created using materials like shape memory alloys, hydrogels, and twisted and coiled fibres. These muscles rely on external stimuli to change shape or volume and are attractive because they can be powered by waste energy sources like the heat from a car engine. The first aim of this thesis was to develop heat engines which exist in the literature, optimize them, and run them using the same shape memory alloy actuators to analyse if different engine geometry or design makes any difference in the engine output. Testing was completed on four different kinds of SMA heat engines, and a theoretical model was developed to predict the output of the offset heat engine based on the material properties and engine’s configuration. This model enabled the engine output to be estimated in terms of the maximum torque generated and the experimental results were then compared to verify the model predictions. Once the model was established, the heat engine’s design was improved based on the model predictions. Finally, the model allowed the engine to be redesigned to allow the SMA actuators to be replaced with Nylon 6,6 twisted and coiled actuators. For the first time a heat engine was demonstrated using these new types of actuators and the predicted engine’s output compared favourably with the results obtained experimentally.</p>