Open AccessA Model for FGM/SMA Bilayer Beams Accounting for Asymmetric SMA Behavior
Author(s) -
Wael Zaki,
Nguyễn Văn Việt
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/855/1/012011
Subject(s) - neutral plane , materials science , neutral axis , shape memory alloy , beam (structure) , structural engineering , constitutive equation , deflection (physics) , timoshenko beam theory , finite element method , sma* , mechanics , cantilever , composite material , classical mechanics , physics , mathematics , engineering , combinatorics
A new model is proposed for bilayer cantilever beams consisting of shape memory alloy (SMA) and functionally graded material (FGM) layers and subjected to loading at the tip. The model accounts for tensile-compressive SMA behavior through the use of an appropriate set of constitutive relations and considers the deformation of the beam within the frame of the Timoshenko beam theory. The derivation of the model proceeds by first determining the correct sequence in which different solid phase structures develop within the SMA layer as the load is applied, resulting in the formation of distinct solid phase regions. The boundaries separating these regions are then located and used in deriving appropriate moment and shear force equations throughout a complete loading-unloading cycle. The model is capable of tracking the deviation of the neutral surface with respect to the mid-plane and the distribution of martensite in the beam as the load varies. The nonlinear variation of stress and strain in a cross section of the beam is also considered. Results of beam deflection and neutral surface deviation are presented and validated against finite element simulations of a 3D model of a beam consisting of a Nitinol and CNT-reinforced layers.