Development of a NiTi actuator using a two-way shape memory effect induced by compressive loading cycles

NiTi can produce a large force per unit volume and operate with a simple mechanism. For these reasons, it has been widely researched for application as an actuator. In this study, preliminary research to develop a NiTi linear actuator using a two-way shape memory process is conducted. Compression tests on a NiTi cylinder to investigate basic compressive properties are performed and recovery stresses to evaluate the actuating capacity are measured. The one-way shape memory process requires compressive loading and unloading but the two-way recovery does not. Hence, a two-way recovery can be utilized more conveniently compared to a one-way process. Additionally, bolt-fracturing tests are performed to confirm the possibility of NiTi actuators. The bolts are fractured successfully using both one-way and two-way shape memory effects.