Abstract: The relationships among stress, strain, temperature and phase transformation of Cu-based shape memory alloy spring are investigated. The experimental results and their mechanisms are systematically analyzed. The results show that the relationships about stress-strain, stress-temperature and strain-temperature of SMA helical spring in the three basic application forms are non-linear, and Hooke’s law can not be directly used in design. Experimental results are very useful to reveal the actuating behaviors and to design actuators of SMA spring.

Key words: Actuator, Measure, Shape memory alloy, Thermomechanical property