Effect Of Shape Memory Alloy Wires Research Articles

Investigation of the damping behavior of shape memory alloy-nitinol reinforced composite

The use of Shape Memory Alloy (SMA) recently increased in smart structures. It is essential to investigate the impact of viscoelastic material, and transformation temperatures of SMA on dynamic behavior, especially the damping capability of the SMA reinforced composite. In this paper, the damping constants of SMA and viscoelastic material are evaluated experimentally, and a damping model based on experimental results is proposed for the composite. The effect of SMA wires in combination and selective activation has been studied using the proposed model and validated experimentally. It has been observed that damping predicted by the model is close to damping calculated by experimentation. Also, damping varies with the transformation temperatures of SMA. Thus, dynamic control of the SMA reinforced composite is feasible by controlling transformation temperature. The composite studied in this work can shift the damping by 9.58% by activating all nitinol wires.

Frequency Response of Sandwich Beam Embedded with Shape Memory Alloy Wires

Experimental investigation of the dynamic behavior of sandwich beam and an embedded with shape memory alloy (SMA) wires are deliberated. In this study wires composition of Ni 56.2% remaining Ti were used for vibration control. These wires were inserted in sandwich beam with its neutral axis. The wires are embedded along a length of beam and beam is sandwiched between two copper plates. The beam is tested for free boundary condition and observed natural frequency when the stiffness of beam is changed by actuating the wire with electric current. This paper depicts the frequency response of beam due to embedded SMA wires. Effect of SMA wires on natural frequency and damping factor are examined. The maximum frequency is obtained at 1.5 amps after that frequency continuously decreases because of increase in temperature of the beam.

A study on the deflection of shape memory alloy (SMA) reinforced thermo-viscoelastic beam

The deflection of an epoxy beam with embedded shape memory alloy (SMA) wires subjected to lateral load and transient ambient temperature is predicted. The SMA wires, which are located at the neutral surface of the beam, are embedded inside the sleeves and fixed externally at two ends. Brinson's one-dimensional constitutive relation is used for the analysis of SMA wires. The stiffening effect of SMA wires on the beam is modeled by an elastic foundation. The epoxy beam is assumed to obey the principle of thermo-rheological simple material. A recursive formula is used to account for thermo-viscoelastic behavior of the epoxy beam. The deflection of beams with simply supported and clamped boundary conditions are analyzed and the results for simply supported beam compare well with our previous test data.