Experimental Study and Modeling of a TiNi Shape Memory Alloy Wire Actuator

Abstract

Shape memory alloys (SMA) are often used as actuators in miniature articulated devices. In this paper, a single TiNi SMA wire loaded by a mass is studied as a basic actuator controlled by Joule's effect. First, we describe an experimental study of the wire (150,m in diameter) under coupled stress and temperature actions for different thermal input velocities in order to analyze its dynamical behavior. In the case of static loadings, modeling is performed with a macroscopic description of the thermomechanical behavior preformed by Leclercq and Lexcellent (1996). Then, the heat equation integration is sufficient to take into account the thermal input velocities. Comparison between experiment and modeling is fairly correct.

A three‐dimensional model describing stress‐temperature induced solid phase transformations: thermomechanical coupling and hybrid composite applications

“…Up to now, in our knowledge, a big effort has been devoted to investigate experimentally the behaviour of always new invented composites [52][53][54], while only few researchers tried to predict numerically the experimental response and to design new devices. Among them, Venkatesh et al [27] use a simple beam finite element to predict active vibration control possibilities for planar mechanisms with Ni-Ti reinforced composite; Thompson et al [55] use standard finite element analysis to investigate the active buckling control of stiffened panels by embedded SMA rods; Ro et al [56] propose a finite element model to study the static and dynamic characteristics of Ni-Ti-reinforced composite plates; Hurlbut et al [57] implement a 3D SMA constitutive model within a shell based finite element code and study a passive vibration isolator; Benzaoui et al [58] study experimentally and numerically the behaviour of a basic actuator consisting in a single Ni-Ti SMA wire loaded by a mass; de Blonk et al [59] model the deflection of a flexible rod with embedded two way shape memory actuators; Lagoudas et al [60] model a thermoelectrically cooled thin SMA layer extensional actuator; Ostachowicz et al [61] present finite element governing equations and solution procedures to study natural frequencies of SMA fibre-reinforced composite plate; Su et al [62] propose a 2D constitutive model for a SMA reinforced composite laminated plate; Baz et al [63] study experimentally and numerically the shape control of a SMA reinforced composite beam through SMA strips thermally trained to provide and memorize controlled transverse deflections; Lau et al [64] present an analytical model for the evaluation of natural frequencies of glass fibre composite beams with embedded SMA wires. These works suggest that a properly developed computational tool can be useful to support the design of advanced hybrid composites exploiting the SMA features.…”

Phase transitions in shape memory alloys with hyperbolic heat conduction and differential-algebraic models

“…In comparison with other actuating and sensing materials SMAs can offer a number of new important properties such as relatively large reversible strains, high stress, large reversible changes of physical and mechanical characteristics, high damping capacity. However, the adequate modelling of the thermomechanical behaviour of SMAs remains a difficult task due to a strongly nonlinear character of this behaviour including hysteresis loops [1,6,10,24,33,39]. Note that the non-convexity of the free energy function ''is dictated by the molecular structure of the metallic lattice'' which has a highly symmetric phase (austenite) and a less symmetric phase (martensite) capable of twinning [23].…”

Modeling of a new SMA micro-actuator for active endoscopy applications

“…The choosen approach is based on the Helmholtz free energy expression of the different phases mixture: austenite, self accommodating martensite and stress induced martensite (Benzaoui et al, 1997). This approach gives an one-dimension prediction of the SMA behavior, e.g.…”