Shape Memory Alloys (SMAs) as one of smart materials with special properties such as shape memory effect, superelasticity and high strength against external forces. These properties caused to apply these alloys in practical and commercial application in recent decades. Also some applications in micro systems have been developed based on SMAs. Nitinol is a famous SMA that presents considerable recoverable strain with high stress hysteresis during a loading-unloading cycle. This energy dissipating ability have been encouraged researchers to apply these alloys in practical applications as damper. Most of performed studies have been conducted base on applicable damping of crude shape of SMAs such wire and proposed mechanisms with SMAs are few. With consideration of this lack of researches, a new micro damper is designed, analyzed and manufactured. The point is to reach higher damping ability and exported displacement relative to behavior of SMA wires and similar damping systems. Two separated damping sets are employed in the same length of damper to increase exported displacement of mechanism. Each of these damping sets work on shaft movement to one side of its middle position. Each damping set includes two NiTi wires, one which is with initial strain and stress in equilibrium mode and the other one has maximum stress and strain in this position. With shaft movement first wire starts to lengthened and the other one starts to shortened. As a result of this operation, overall gained damping would be increased. Based on a thermomechanical model of NiTi wires, force-displacement behavior of damper have been simulated. It has been shown that the designed mechanism have ability to damp the energy with an equivalent viscous damping ratio of 11.8%. According to completed designed plan, a specimen of damper is manufactured and the procedure for assembly of components is presented. A tension-compression test is developed to investigate performance of the manufactured damper. Test result shows an equivalent viscous damping of 11.54%. Also the force-displacement behavior gained from test is in good conformity with simulation results. A parameter study is developed to find the effect of different parameters such as loading factors, dimensions and properties of NITi wires on damping, and optimum values of each parameter is introduced. Finally with consideration of flexibility of mechanism to make changes in dimension and the SMA wire leading to changes in performance condition of the damper, some commercial and practical applications are proposed. In this applications imported force of system, displacement, frequency and dimension are main factors that have been considered. Key Words: Shape Memory Alloys, Nitinol, Superelasticity, Equivalent Viscous Damping Ratio.
