Control of Wave Propagation in Composite Rods Using Shape Memory Inserts: Theory and Experiments

Abstract

Longitudinal wave propagation is controlled using shape memory inserts placed along rods. The inserts act as sources of impedance mismatch with tunable characteristics. Such characteristics are attributed to the unique behavior of the shape memory alloy whereby the elastic modulus significantly increases as the alloy undergoes a phase transformation from martensite to austenite. With such controllable capability, the inserts can introduce the proper impedance mismatch necessary to impede the wave propagation along the rods. A spectral finite element model is developed to accurately reproduce the wave propagation phenomena inside the composite rod and to model its dynamic behavior with a significantly reduced number of elements. The theoretical predictions are compared with the experimental performance of rods with one, two, and three shape memory inserts. The behavior of the composite is evaluated at different activation temperatures of the shape memory material. The obtained results indicate significant attenuation of the wave propagation inside the composites with increasing operating temperature. Both experimental and theoretical results demonstrate the effectiveness and potential of composites with tunable impedance mismatch sources in controlling wave propagation in rods.