A coupled thermomechanical beam finite element for the simulation of shape memory alloy actuators

Abstract

The proposed article describes the development of a new beam finite element for the coupled thermomechanical analysis of shape memory alloy actuators. The element is formulated, assuming coupled equilibrium equations for the thermoelastic stresses and thermal loads. Displacements and temperature are treated as internal degrees of freedom giving the ability to predict the coupled thermal–displacement response of a shape memory alloy beam. The constitutive shape memory alloy model of Lagoudas and coworkers is implemented in the formulation. A generalized beam theory is formulated assuming shear deformation with a cubic temperature field through the thickness. The new element is capable to simulate heat transfer phenomena, electric Joule heating as direct input, and heat convection effects. The coupling between mechanical and thermal equilibrium equations due to endothermic/exothermic martensitic transformation procedures is also included. Numerical results and evaluations of the developed beam element are presented for the thermomechanical response of shape memory alloy wire actuators and an adaptive strip subject to various types of applied thermal loading and heat convection conditions. The effect of coupling terms on the prediction of shape memory alloy actuator response is also evaluated.

A coupled layered thermomechanical shape memory alloy beam element with enhanced higher order temperature field approximations

“…Yang and Xu (2011) subsequently extended the previous work to include the 2D form of the heat equation and demonstrated the capabilities of the new beam FE to capture the coupled thermomechanical response of beams subject to bending under different load rates and a variety of applied boundary conditions. Solomou et al (2014) reported a thermomechanically coupled element for single-layered SMA beams which combined the first-order shear deformation theory (FSDT) and a third-order temperature field to capture the temperature distribution through the thickness of the beam.…”

“…Building on the previous work of Solomou et al (2014), the development and numerical validation of a new multi-field thermomechanically coupled layered beam FE is described herein. A new beam formulation is developed which admits various layers of SMA and passive materials through the thickness and assumes a sixth-order temperature field to better capture highly asymmetric temperature distributions through the thickness of the structure.…”

Shape control and design of aeronautical configurations using shape memory alloy actuators

“…The authors verified that the wing can sustain the aerodynamic pres sure under different flight conditions, without any weight increase or stiffness loss compared to other conventional actuators. Solo mou et al [12] developed a beam element that incorporates the thermo mechanical properties of SMA wire actuators. The study of [13] followed these developments, coupled the FE model with a lower fidelity fluid solver and performed a fluid structure inter action (FSI) study for a hinged flap configuration and a segmented airfoil, targeting wind turbine applications.…”

Numerical analysis on thermo-mechanical behavior of shape memory alloy strip with two-way shape memory effect

“…The phase transformation in SMAs is accompanied by the internal energy changes. The energy conservation equation can be written as (Solomou et al, 2014)…”

“…Shape memory alloys (SMAs) present one type of some promising metals known as ''active'' or ''multifunctional'' materials (Hartl et al, 2010). They have been applied in variety of practical applications due to their shape memory effect (SME), pseudoelastic behavior (PE), high damping capacity, and good biocompatibility (Solomou et al, 2014). SMAs have the ability to recover seemingly permanent strain via stress-induced or temperature-induced phase transformation.…”