Experimental Study on Thermal Ratcheting Effect of NiTi Shape Memory Alloy

Shape memory cable net structure using the servo type driven of shape memory alloy (SMA) to achieve the orbit adjustment of surface precision of cable net structure. However, the SMA has to experience the long-term cyclic thermal load in space, which will produce the thermal ratcheting effect and reduce the adjusting ability of SMA. Therefore, this paper takes the SMA in shape memory cable net structure working in the bad environment of the space as the research object. The experimental study was carried out for the thermal ratcheting effect of SMA wire in the range of different pretensions and different temperatures. The results show that the cumulative evolution of residual martensite has important influence on the attenuation of tension force of wire and temperature evolution of austenite transformation and martensite transformation.