Exploration of static equilibrium in elastically biased shape memory alloy components

摘要

In the past, several studies have explored the fundamentals and applications of deforming an elastic compo-nent using a shape memory alloy (SMA) component. Previous explorations have been primarily motivated bythe capability of SMA actuation against a spring biasing load and dynamic response where energy dissipationupon perturbation or thermal tunability is desired. This current work instead explores elastically biased SMAcomponents in the context of a static system, where both stress-induced and thermally-induced phase transfor-mations are employed to reproduce and improve upon the advantages of the shape memory eu000bect (SME). Whiledeformation of an SMA component utilizing stress-free SME can only be mechanically generated and thermallyrecovered, a system composed of an elastically biased SMA component can generate and recover deformationboth mechanically and thermally. Additionally, the applied stress necessary to induce deformation is thermallytunable in both systems, but the non-zero stress state of the elastically biased SMA component enables oper-ation at higher temperatures. This study also introduces employing the same antagonistic concept as a lowpower intensive two-way actuating system that utilizes impulsive" heating and cooling to generate and recoverdeformation, while the balance of internal reaction forces enables deformation to be maintained. In this work,experimental and nite element analysis (FEA) results will demonstrate the capabilities of an SMA componentbiased against a cantilevered beam composed of elastic material. The results from this investigation will alsointroduce an abstraction termed the equilibrium domain, which represents the range of equilibrium points instress-strain-temperature space.