Role of Microstructure in the Thermomechanical Behavior of SMA Composites

1999 ◽  
Vol 121 (1) ◽  
pp. 86-92 ◽  
Author(s):  
Gu Quan Song ◽  
Qing Ping Sun ◽  
M. Cherkaoui
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Volume Fraction ◽  
Numerical Study ◽  
Thermomechanical Behavior ◽  
Stress And Strain ◽  
Strengthening Effect ◽  
Microstructure Design ◽  
Quantitative Basis

A numerical study on the role of microstructure in the thermomechanical behavior of shape memory alloy (SMA) composites under uniaxial tension is performed. The simulation is based on the micromechanics model established recently by the authors. The influence of the shape and volume fraction of SMA on the overall behavior of the composite as well as on the internal stress and strain evolution is investigated. The strengthening effect of SMA on ductile matrix is illustrated. The obtained results demonstrate several interesting features of the new composite and may serve as a quantitative basis for the microstructure design of this composite in the future.

An Experimental and Numerical Study of Shape Memory Alloy-Based Tensegrity/Origami Structures

2015 ◽  
Author(s):  
John L. Rohmer ◽  
Edwin A. Peraza Hernandez ◽  
Robert E. Skelton ◽  
Darren J. Hartl ◽  
Dimitris C. Lagoudas
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Numerical Study ◽  
Double Helix ◽  
Initial Study ◽  
Element Analysis ◽  
Novel Concept ◽  
Minimal Mass ◽  
And Function

This paper presents an initial experimental and numerical study on a novel concept of integrated tensegrity/origami morphing structures. Both tensegrity and origami are known for their potential transformative roles in applications in fields which exist at the interplay of shape, size, and function. Their integration, proposed here for the first time, is based on the interest in uniting the strengths of origami (membrane integration and folding capabilities) with the strengths of tensegrity (minimal mass and controllable rigidity). In order to achieve morphing capabilities while retaining low mass, the considered structures possess intrinsic material actuation provided by shape memory alloy (SMA) members. Two different representative structures of the proposed concept are studied. The first corresponds to a tensegrity/origami cylinder based on the double-helix tensegrity topology. Shape memory alloy wires play the role of the tensile members of the tensegrity structure while foldable surface components play the role of compressive members. The second structure corresponds to a tensegrity plate, which although not having a continuous dense surface, can be morphed in novel ways using origami principles. Fabrication of experimental prototypes and evaluation of the observed structural transformation are presented. Finite element analysis is performed to numerically evaluate the characteristics of the novel proposed structures. This initial study shows that the integration of tensegrity and origami results in a powerful combination that provides structural stability, flexibility in design and lightweight actuation mechanisms while allowing for significant deflections during morphing.

scholarly journals The Role of Nickel-titanium Shape Memory Alloy Embracing Fixator in Determination of the Implantation Angle of Hip Tumor Prosthesis Stem Following Tumor Resection and the Analysis of Its Efficacy: a Retrospective Study

2021 ◽  
Author(s):  
Yang Wang ◽  
Panyu Zhou ◽  
Demeng Xia ◽  
Yunyun Wang ◽  
Sheng Wang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tumor Resection ◽  
Hip Dislocation ◽  
Nickel Titanium ◽  
Prosthetic Replacement ◽  
Limb Function ◽  
Tumor Prosthesis

Abstract Background: To explore the role of nickel-titanium(NiTi) shape memory alloy embracing fixator in determination of implantation angle of hip tumor prosthesis stem and analyze its efficacy. Methods: 36 patients with proximal femur tumor were treated with extended tumor resection and prosthetic replacement. 14 patients received prosthetic replacements with the embracing fixators fixing between the junction of the prosthesis stem and the femur temporarily, while the other 22 patients received the same replacements but without the fixators. Following aspects were compared: occurrence of complications, limb function and active hip ROM.Results: There are fewer cases of hip dislocation in the group received prosthetic replacements with the use of embracing fixators. Occurrence of deep infection presented no difference between the two groups. Better limb function and higher active range of motion (ROM) on abduction or flexion were also found in the group using embracing fixators. Conclusion: Ni-Ti shape memory alloy embracing fixator plays a key part in assisting the accurate implantation angle of the prosthesis stem in the prosthetic replacement. The prosthesis stem can be adjusted to the optimal angle with the help of the embracing fixator. Patients have lower chance of dislocation, better limb function, and higher active hip ROM. Trial registration: retrospectively registered.

Role of Shape Memory Alloy Wires as a SENSAPTIC HMI Device

2020 ◽  
Vol 20 (12) ◽  
pp. 6422-6431
Author(s):  
D. Josephine Selvarani Ruth ◽  
K. Dhanalakshmi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory

Effect of the Addition of Gd on Ni53Mn22Co6Ga19 High-Temperature Shape Memory Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 2095-2098
Author(s):  
Yun Qing Ma ◽  
Shui Yuan Yang ◽  
San Li Lai ◽  
Shi Wen Tian ◽  
Cui Ping Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Earth Element ◽  
Stress And Strain ◽  
Martensitic Transformation Temperature ◽  
Rich Phase ◽  
Shape Memory Properties

The rare earth element Gd is added to Ni53Mn22Co6Ga19 high-temperature shape memory alloy to refine the grain size and adjust the distribution of γ phase, and their microstructure, martensitic transformation behaviors, mechanical and shape memory properties were investigated. The results show that the grain size is obviously decreased and the γ phase tends to segregate at grain boundaries with increasing Gd content. Small amounts of Gd-rich phase were formed with 0.1 at.% Gd addition. The martensitic transformation temperature abruptly increases with 0.1 at.% Gd addition, then almost keeps constant with further increasing Gd content. The addition of 0.1 at.% Gd is proved to be beneficial to both tensile stress and strain before fracture, but negative to the shape-memory effect.

Viscoelastic behavior of epoxy resin reinforced with shape-memory-alloy wires

2020 ◽  
pp. 1045389X2097549
Author(s):  
Niloufar Bagheri ◽  
Mahmood M Shokrieh ◽  
Ali Saeedi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Epoxy Resin ◽  
Volume Fraction ◽  
Niti Alloy ◽  
Micromechanical Model ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Reinforced Polymer ◽  
Small Volume Fraction

The effect of NiTi alloy long wires on the viscoelastic behavior of epoxy resin was investigated by utilizing the dynamic mechanical analysis (DMA) and a novel micromechanical model. The present model is capable of predicting the viscoelastic properties of the shape-memory-alloy (SMA) reinforced polymer as a function of the SMA volume fraction, initial martensite volume fraction, pre-strain level in wires, and the temperature variations. The model was verified by conducting experiments. Good agreement between the theoretical and experimental results was achieved. A parametric study was also performed to investigate the effect of SMA parameters. According to the results, by the addition of a small volume fraction of SMA, the storage modulus of the composite increases significantly, especially at higher temperatures. Moreover, applying a 4% pre-strain caused a 10% increase in the maximum value of the loss factor of the SMA reinforced epoxy in comparison with the 0% pre-strained SMA reinforced epoxy.

scholarly journals The Instability Improvement of the Symmetric Angle-Ply and Cross-Ply Composite Plates with Shape Memory Alloy Using Finite Element Method

2014 ◽  
Vol 6 ◽  
pp. 632825 ◽  
Author(s):  
Zainudin A. Rasid ◽  
Rizal Zahari ◽  
Amran Ayob
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Element Formulation ◽  
Recovery Stress ◽  
Buckling Behavior ◽  
Post Buckling

Shape memory alloy (SMA) wires were embedded within laminated composite plates to take advantage of the shape memory effect property of the SMA in improving post-buckling behavior of composite plates. A nonlinear finite element formulation was developed for this study. The plate-bending formulation used in this study was developed based on the first order shear deformation theory, where the von Karman's nonlinear moderate strain terms were added to the strain equations. The effect of the SMA was captured by adding recovery stress term in the constitutive equation of the SMA composite plates. Values of the recovery stress of the SMA were determined using Brinson's model. Using the principle of virtual work and the total Lagrangian approach, the final finite element nonlinear governing equation for the post-buckling of SMA composite plates was derived. Buckling and post-buckling analyses were then conducted on the symmetric angle-ply and cross-ply SMA composite plates. The effect of several parameters such as the activation temperature, volume fraction, and the initial strain of the SMA on the post-buckling behavior of the SMA composite plates were studied. It was found that significant improvements in the post-buckling behavior for composite plates can be attained.

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