Mechanical properties identification and design optimization of nitinol shape memory alloy microactuators

Abstract

Microactuators are essential elements of MEMS and are widely used in these devices. Microgrippers, micropositioners, microfixtures, micropumps and microvalves are well-known applications of microstructures. In this paper, the design optimization of shape memory alloy microactuators is discussed. Four different configurations of microactuator with variable geometrical parameters, generating different levels of displacement and force, are designed and analysed. In order to determine the optimum values of parameters for each microactuator, statistical design of experiments (DOE) is used. For this purpose, the Souza et al constitutive model (1988 Eur. J. Mech. A 17 789-806) is adapted for use in finite element analysis software. Mechanical properties of the SMA are identified by performing experimental tests on Ti-49.8%Ni. Finally, the specific energy of each microactuator is determined using the calibrated model and regression analysis. Moreover, the characteristic curve of each microactuator is obtained and with this virtual tool one can choose a microactuator with the desired force and displacement. The methodology discussed in this paper can be used as a reference to design appropriate microactuators for different MEMS applications producing various ranges of displacement and force.

Caracterización de las SMAs y sus aplicaciones: Una revisión

“…Figura 2: Gráfica del comportamiento de tensión-deformación de un SMA, modificada de (Salehi et al, 2013).…”

Kinetic Solar Skin: A Responsive Folding Technique

“…While the creased sheets' kinematics is at the basis of the geometric issue, kinetics implies the use of micro actuators able to activate self-folding [15]. The adaptive Mashrabiya solar screen, which is the main stand out feature of the Abu Dhabi Al-Bahar Towers, well represents a type of Origami-based shading device [16].…”

Modeling, validation, and testing of a Ti-49.8%Ni shape memory actuator

“…This model was developed within the theory of irreversible thermodynamics in the realm of the small deformation regime. Implementation of the integration algorithm within a user-defined subroutine UMAT in the commercial nonlinear finite element software ABAQUS/Standard enables solving different kinds of boundary value problems, as well (Arghavani et al, 2010(Arghavani et al, , 2011Salehi et al, 2014). It should be noted that the model has been implemented as UMAT in ABAQUS software by Jamal Arghavani.…”