Numerical and Experimental Characterizations of Damping Properties of SMAs Composite for Vibration Control Systems

Abstract

Shape memory alloys (SMAs) are very interesting smart materials not only for their shape memory and superelastic effects but also because of their significant intrinsic damping capacity. The latter is exhibited upon martensitic transformations and especially in martensitic state. The combination of these SMA properties with the mechanical and the lightweight of fiberglass-reinforced polymer (FGRP) is a promising solution for manufacturing of innovative composites for vibration suppression in structural applications. CuZnAl sheets, after laser patterning, were embedded in a laminated composite between a thick FGRP core and two thin outer layers with the aim of maximizing the damping capacity of the beam for passive vibration suppression. The selected SMA Cu66Zn24Al10 at.% was prepared by vacuum induction melting; the ingot was subsequently hot-and-cold rolled down to 0.2 mm thickness tape. The choice of a copper alloy is related to some advantages in comparison with NiTiCu SMA alloys, which was tested for the similar presented application in a previous study: lower cost, higher storage modulus and consequently higher damping properties in martensitic state. The patterning of the SMA sheets was performed by means of a pulsed fiber laser. After the laser processing, the SMA sheets were heat treated to obtain the desired martensitic state at room temperature. The transformation temperatures were measured by differential scanning calorimetry (DSC). The damping properties were determined, at room temperature, on full-scale sheet, using a universal testing machine (MTS), with cyclic tensile tests at different deformation amplitudes. Damping properties were also determined as a function of the temperature on miniature samples with a dynamical mechanical analyzer (DMA). Numerical modeling of the laminated composite, done with finite element method analysis and modal strain energy approaches, was performed to estimate the corresponding total damping capacity and then compared to experimental results.