Concept and preliminary design of SMA bimetallic strip smart actuator for space adaptive structures

This paper presents a novel concept of bimetallic strip smart actuator (BSSA) based on shape memory alloy (SMA) for space adaptive structures. Its preliminary design and analysis are studied to verify the BSSA is capable of good output power and displacement. The BSSA mainly consists of SMA and metal sheets. A SMA sheet with pre-stretch is the driving element, whereas the metal sheet is the passive component. The SMA sheet shortens when it is heated by heating sheets pasted on the SMA sheets. By contrast, SMA sheet elongates when it is cooled or not heated. The BSSA starts to work when the SMA sheet elongates or shortens. Properties of the BSSA including static stiffness, driving torque, and output angle are also analyzed by building the related theoretical models. To verify these theoretical analyses, a prototype of the actuator is designed and manufactured. Groups of tests are conducted. The test and analysis results show that the BSSA has simple structures, good load bearing capacity, sufficient output ability, and large driving torque thereby being potentially applied in adaptive structures for space tasks.