A model for shape memory alloy beams accounting for tensile compressive asymmetry

2019 ◽  
Vol 30 (18-19) ◽  
pp. 2697-2715 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Ziad Moumni
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Solid Phase ◽  
Constitutive Relations ◽  
Beam Theory ◽  
Element Analysis ◽  
Proposed Model ◽  
The Finite Element Analysis ◽  
Tension And Compression ◽  
Asymmetric Shape

A new analytical model is derived for cantilever beams made from superelastic shape memory alloy and subjected to tip load. The deformation of the beam is described based on Timoshenko beam theory using constitutive relations that account for asymmetric shape memory alloy response in tension and compression. Analytical moment and shear force equations are developed and the position of the neutral axis and the different solid phase regions in the beam are tracked throughout a full loading–unloading cycle. Validation of the proposed model is carried out against data from the literature and from the finite element analysis considering tensile–compressive asymmetry in shape memory alloy behavior.

Bending theory for laminated composite cantilever beams with multiple embedded shape memory alloy layers

2019 ◽  
Vol 30 (10) ◽  
pp. 1549-1568 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Numerical Solutions ◽  
Phase Distribution ◽  
Solid Phase ◽  
Axial Stress ◽  
Laminated Composite ◽  
Beam Theory ◽  
Cantilever Beams ◽  
Element Analysis

In this article, a new analytical model is proposed for laminated composite cantilever beams consisting of multiple alternating superelastic shape memory alloy and elastic layers. The model is based on the Zaki–Moumni model for shape memory alloys combined with Timoshenko’s beam theory. The Zaki–Moumni model accounts for solid phase transformation as well as detwinning and reorientation of martensite under multiaxial thermomechanical loading conditions. Mathematical formulas are first derived to characterize the evolution of the solid phase structure within the beam with a prescribed load at the tip during loading and unloading. Analytical moment–curvature and shear force–shear strain relations are then obtained following the strength of materials approach. The present work is the first to fully develop the nonlinear expressions of the axial stress in terms of the distance from the neutral plane and to allow the description of the phase distribution in both the longitudinal and the transverse directions in the beam as the load evolves. The proposed model is validated against finite element analysis and high-accuracy numerical solutions. The influence of temperature and the number of shape memory alloy layers on the superelastic behavior of the laminate is also investigated.

scholarly journals Modeling the behavior of bilayer shape memory alloy/functionally graded material beams considering asymmetric shape memory alloy response

2019 ◽  
Vol 31 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer ◽  
Quan Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Functionally Graded Material ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Alloy Layer ◽  
Functionally Graded ◽  
Tension And Compression ◽  
Graded Material ◽  
Asymmetric Shape

A new model is proposed to describe the response of laminated composite beams consisting of one shape memory alloy layer and one functionally graded material layer. The model accounts for asymmetry in tension and compression of the shape memory alloy behavior and successfully describes the dependence of the position of the neutral surface on phase transformation within the shape memory alloy and on the load direction. Moreover, the model is capable of describing the response of the composite beam to both loading and unloading cases. In particular, the derivation of the equations governing the behavior of the beam during unloading is presented for the first time. The effect of the functionally graded material gradient index and of temperature on the neutral axis deviation and on the overall behavior of the beam is also discussed. The results obtained using the model are shown to fit three-dimensional finite element simulations of the same beam.

Experimental Research of PFD-SMA Support System

2011 ◽  
Vol 71-78 ◽  
pp. 4521-4524 ◽  
Author(s):  
Ji Gang Zhang ◽  
Yan Mei Liu ◽  
Yuan Feng Gao ◽  
Jian Han
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Support System ◽  
Load Force ◽  
Element Analysis ◽  
Test Study ◽  
Force Increase ◽  
The Finite Element Analysis ◽  
Good Energy

Pall-typed dampers(PFD) have good energy dissipation, and shape memory alloy(SMA) brace has good super-elastic performance, so the PFD-SMA support system is put forward. Through the test study of PFD-SMA support system, analyze the influence to its hysteretic characteristic by preload force of Pall-typed frictional damper, the stiffness and length parameters of shape memory alloy support. The test results show that PFD-SMA support system s have good energy dissipation and good reposition due to its super-elastic performance, with pre-load force increase, its super-elastic performance acts better, its hysteretic curve show super-elastic performance too, and it verifies the correctness of the finite element analysis.

Analytical model for a superelastic Timoshenko shape memory alloy beam subjected to a loading–unloading cycle

2018 ◽  
Vol 29 (20) ◽  
pp. 3902-3922 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Analytical Model ◽  
Solid Phase ◽  
Three Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

We propose a new analytical model for a superelastic shape memory alloy prismatic cantilever beam subjected to a concentrated force at the tip. The force is gradually increased and then removed and the corresponding distribution of phase transformation fields in the beam is determined, analytically, in both the transverse and longitudinal directions. Analytical moment–curvature and shear force–shear strain relations are also derived during loading and unloading of the beam. The proposed model is validated against an exact numerical beam model as well as a three-dimensional finite element analysis model for the same beam, with very good agreement in each case. Moreover, an experiment is proposed and carried out to characterize the load–deflection response of a shape memory alloy beam under the same boundary conditions as those considered in deriving the model. The obtained response is in good agreement with the analytical model as well as three-dimensional finite element analysis simulations. The analytical method provides a direct mathematical way for describing the material and structural properties of the beam and the distribution of the different solid phase regions as they change under the influence of an applied load and allows the determination of details such as the boundaries of solid phase regions immediately and accurately using equations. The same would require postprocessing at possibly significant computational cost and personal effort if finite element analysis or similar numerical methods are used.

Bending of Superelastic Shape Memory Alloy Tubes

2011 ◽  
Author(s):  
Benjamin Reedlunn ◽  
Christopher Churchill ◽  
Emily Nelson ◽  
Samantha Daly ◽  
John Shaw
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Response ◽  
Surface Displacement ◽  
Beam Theory ◽  
Image Correlation ◽  
Reasonable Assumption ◽  
Significant Shift ◽  
Localized Deformation ◽  
Tension And Compression

Many shape memory alloy (SMA) applications exploit superelasticity in a bending mode, yet the large displacements and rotations associated with bending of slender structures make controlled experiments difficult. A custom pure bending fixture was built to perform experiments on superelastic NiTi tubes. To understand the bending results, the tubes were also characterized in uniaxial tension and compression, where a custom fixture was utilized to avoid buckling. In addition to measuring the global mechanical response, stereo digital image correlation (DIC) was used in all the experiments to capture the local surface displacement and strain fields. Consistent with the tension/compression data, our bending experiments showed a significant shift of the neutral axis towards the compression side. Also, the tube had strain localization on the tension side, but no such localization on the compression side. Detailed analysis of the strain distribution across the tube diameter revealed that the usual assumption of beam theory, that plane sections remain plane, did not hold along the tension side. Averaged over a few diameters of gage length, plane sections remain plane is a reasonable assumption and can be used to predict the global moment–curvature response. However, this assumption should be used with caution since it can under/over predict local strains by as much as 2× due to the localized deformation morphology.

Asymmetric bending response of shape memory alloy beam with functionally graded porosity

2020 ◽  
Vol 31 (16) ◽  
pp. 1935-1949
Author(s):  
Pouya Fahimi ◽  
Amin Hajarian ◽  
Amir Hossein Eskandari ◽  
Ali Taheri ◽  
Mostafa Baghani
Keyword(s):  
Shape Memory Alloy ◽  
Analytical Solution ◽  
Shape Memory ◽  
Functionally Graded ◽  
Element Analysis ◽  
Bending Analysis ◽  
Significant Difference ◽  
Porosity Coefficient ◽  
Dimensional Finite Element ◽  
Tension And Compression

In this study, an innovative semi-analytical model is presented to simulate the bending behavior of a shape memory alloy porous beam throughout loading and unloading cycles. The basis of the proposed method is the improved Brinson model which can capture the asymmetry behaviors of shape memory alloys in tension and compression. The comparison of the semi-analytical solution with two-dimensional finite element analysis results for both symmetric and asymmetric models of a homogeneous shape memory alloy beam is presented for model validation. Afterward, bending analysis of shape memory alloy beams with uniform porosity and functionally grading porosity is studied. For this purpose, first, the bending analysis of a shape memory alloy beam with uniform porosity is investigated to show the effects of porosity coefficient on the free tip deflection and slope. Then, the bending analysis of a shape memory alloy beam with functionally grading porosity is simulated. Reported findings with respect to symmetric and asymmetric models indicate that raising the porosity coefficient brings about an increase in deflection and slope. Also, it highlights the significant difference between the results of the asymmetric and symmetric models. The proposed semi-analytical solution can be utilized as an efficient tool for studying the effects of changing any of the porosity coefficient, the geometry, and material of shape memory alloy beams.

A Constitutive Description for Shape Memory Alloys with Phase Transformation Microstructure

2011 ◽  
Vol 52-54 ◽  
pp. 192-197
Author(s):  
Wei Guo Li ◽  
Xiang He Peng ◽  
Wen Li Pi
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Phase ◽  
Experimental Results ◽  
Niti Shape Memory Alloy ◽  
Element Analysis ◽  
Proposed Model ◽  
The Finite Element Analysis ◽  
Two Phases ◽  
Incremental Form

An incremental form of constitutive model is proposed for shape memory alloys using the modified strain based on experimental results and the finite element analysis, taking into account of the laminar microstructure, the thickness of martensite phase lamina and the interaction between the two phases. The pseudoelastisity of NiTi shape memory alloy micro-tube subjected to pure tension and pure torsion are analyzed and compared with the experimental results respectively. It can be seen that the pseudoelastic behavior, especially the stress drop during tension processes, can be well described with the proposed model.

Finite Element Analysis of Removable Shape Memory Alloy Pipe Joint’s Cone Sealing Performance

2015 ◽  
Vol 817 ◽  
pp. 685-689
Author(s):  
Bin Zhou ◽  
Fu Shun Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Contact Stress ◽  
Structural Parameters ◽  
Cone Angle ◽  
Element Analysis ◽  
Sealing Performance ◽  
The Finite Element Analysis

According to the behavior of shape memory alloys, a structure of removable shape memory alloy pipe joint was designed. The contact manner of two parts of this structure is cone-globe. Cone-globe sealing is the key point of this structure’s sealing. Therefore the finite element analysis software ANSYS was used to simulate and calculate the sealing. The result shows that the width of the sealing surface and the contact stress altered with the change of structural parameters, which affected the sealing most. According to the value of the sealing surface’s width and the contact stress, the structural parameters including cone angle can be definitely settled.

Modeling of Electrical Resistivity Evolution Using Free Energy Analysis for NiTi Shape Memory Alloy Wires

2011 ◽  
Vol 311-313 ◽  
pp. 2282-2285
Author(s):  
Jian Jun Zhang
Keyword(s):  
Electrical Resistivity ◽  
Free Energy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Free Energy Change ◽  
Energy Change ◽  
Niti Shape Memory Alloy ◽  
Scanning Calorimetry ◽  
Proposed Model ◽  
Free Energy Analysis

This paper presents a transformation kinetics model of NiTi shape memory alloy (SMA) wires based on electrical resistivity (ER) derivative study under the assumption that the derivative of electrical resistivity with respect to temperature is in linear relationship with the derivative of free energy change with respect to temperature. Free energy change and electrical resistivity properties of SMA are analyzed based on differential scanning calorimetry (DSC) experiments during phase transformation. The simulated evolution of electrical resistivity during thermomechanical transformation is presented using the proposed model.

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