• SMA actuator.
• Shape Memory Alloys
• quasi one-dimensional constitutive model for SMA
• Ni-Ti behaviour
• Brinson’s model for designing SMA
• Solar panel deployment
• Thermomechanical model of SMA

It has been recognised that SMA materials have a significant potential for deployment actuators, the number of applications of SMA-based actuators to the present day is quite small, since a deeper understanding of Thermomechanical behaviour of SMA and how it might be exploited in the design of working actuators is necessary.
This Thesis Investigates structural behaviour of Ni-Ti alloy and by using a Ni-Ti Shape Memory spring Actuator, we develop a space application, i.e. Satellite solar panel deployment.
Even though many constitutive models have been developed the Thermomechanical behaviour of Shape Memory Alloys, we have taken a reference of L.C. Brinson’s phenomenological model (1993) for deeper understanding of Shape Memory Effect in all Transformation phases, i.e. Austenite, Twinned and De-Twinned Martensite.
After a clear understanding of Shape Memory Effect, we have Implemented the Brinson’s Mathematical model and compared with the standard results of Brinson’s approach and we have shown our Implemented model can reproduce accurately the Stress-Strain-Temperature plots.
Finally, in the application part we have used a Nitinol (Ni-Ti) wire and developed a One-way Spring actuator of length 152.4 cm, which can eventually deploy the satellite solar panel of area 0.3 square meter segmented plates, with the help of circular hinge mechanism of radius 6mm between them, by giving an input of 1 ampere current, and it takes 10.45 seconds deploy the panels.