Design of ferromagnetic shape memory alloy (FSMA) based spring actuators is discussed where a variety of design parameters are included, design of FSMA and FSMA composite, that of compact electromagnet, and the mode of deformation of a helical spring. Advantages of FSMA and FSMA composite are simple design, faster actuation speed large axial stroke and magnetic force.
A new first generation torque actuator based on ferromagnetic shape memory alloy composite is designed. The first generation actuator made of Fe bars and TiNi wires is successfully demonstrated. A simple model is proposed for prediction of angle of twist for a given constant load. The optimization of FSMA composite plate is made by a composite modeling under the constraints that the super-elastic SMA plate attains higher stress beyond the onset of the stress-induced martensite transformation while the ferromagnetic plate remains elastic.