A validated model for induction heating of shape memory alloy actuators

Abstract

Shape memory alloy (SMA) actuators deliver high forces while being compact and reliable, making them ideal for consideration in aerospace applications. One disadvantage of these thermally driven actuators is their slow cyclic time response compared to conventional actuators. Induction heating has recently been proposed to quickly heat SMA components. However efforts to date have been purely empirical. The present work approachs this problem in a computational manner by developing a finite element model of induction heating in which the time-harmonic electromagnetic equations are solved for the Joule heat power field, the energy equation is solved for the temperature field, and the linear momentum equations are solved to find the stress, displacement, and internal state variable fields. The combined model was implemented in Abaqus using a Python script approach and applied to SMA torque tube and beam actuators. The model has also been used to examine magnetic flux concentrators to improve the induction systems performance. Induction heating experiments were performed using the SMA torque tube, and the model agreed well with the experiments.

Studies on development of NiTi-integrated optical fiber sensor and its life cycle behavior

“…Thus, it consequently leads to varying displacement on the tip of optic fiber at the free end due to a thermo-elastic effect. A sequence of potential difference has been applied with varying voltage, current, and frequency for obtaining their actuation response and to study its dynamic displacement characteristics during real-time experimentation (Potapov and Da Silva, 2000; Saunders et al, 2016).…”

Effect of stress redistribution during thermal actuation of shape memory alloys in notched cylindrical bars

“…In the following paper, the stress redistribution due to the phase transformation in notched cylindrical SMA specimens will be analyzed by utilizing the SMA constitutive model developed by Lagoudas et al (2012). This model has been utilized by a number of studies in order to predict the thermomechanical behavior of various SMA compositions and structures (Baxevanis et al, 2012; Hernandez et al, 2013; Masood et al, 2013; Saunders et al, 2016; Scalet et al, 2016; Teeriaho, 2013) and has shown generally good agreement when compared to experimental studies. For modeling purposes, the constitutive model utilized assumes that the phase transformation occurs in a decentralized manner, in that although the local crystal structure is either austenite or martensite, the model assumes that the crystallographic information is smeared out such that a martensitic volume fraction can be defined.…”

Induction heating of a shape memory alloy beam

“…Joule heating is a good candidate to decrease the heating time [2]. The induction heating has been evaluated for wires, as well as tubes in torsion and recently considered in the case of beams [3] but only in the case of small deformations (i.e. with linear strain-displacement equations).…”