scholarly journals On Existence and Approximation for a 3D Model of Thermally Induced Phase Transformations in Shape-Memory Alloys

2009 ◽  
Vol 41 (4) ◽  
pp. 1388-1414 ◽  
Author(s):  
Alexander Mielke ◽  
Laetitia Paoli ◽  
Adrien Petrov
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phase Transformations ◽  
3D Model ◽  
Thermally Induced

scholarly journals Existence and approximation for a 3D model of thermally-induced phase transformations in shape-memory alloys

PAMM ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 10395-10396 ◽  
Author(s):  
Alexander Mielke ◽  
Laetitia Paoli ◽  
Adrien Petrov
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phase Transformations ◽  
3D Model ◽  
Thermally Induced

A phenomenological model for thermally-induced hysteresis in polycrystalline shape memory alloys with internal loops

2021 ◽  
pp. 1045389X2110482
Author(s):  
Yuxiang Han ◽  
Haoyuan Du ◽  
Linxiang Wang ◽  
Roderick Melnik
Keyword(s):  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Phenomenological Model ◽  
Landau Theory ◽  
Thermally Induced ◽  
First Order ◽  
Proposed Model ◽  
Crystal Model ◽  
Hysteretic Response

In the current study, a 1-D phenomenological model is constructed to capture the temperature-induced hysteretic response in polycrystalline shape memory alloys (SMAs). The martensitic and austenitic transformations are regarded as the first-order transitions. A differential single-crystal model is formulated on the basis of Landau theory. It is assumed that the transformation temperatures follow the normal distribution among the grains due to the anisotropic stress field developed in the material. The polycrystalline hysteretic response is expressed as the integration of single-crystal responses. Besides, the prediction strategy for incomplete transitions is presented, and the first-order reversal curves are obtained via density reassignment. The proposed model is numerically implemented for validation. Comparisons between the modeling results and the experimental ones demonstrate the capability of the proposed model in addressing the hysteresis in thermally-induced phase transformations.

Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts

2018 ◽  
Vol 30 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Venkata Siva C Chillara ◽  
Leon M Headings ◽  
Ryohei Tsuruta ◽  
Eiji Itakura ◽  
Umesh Gandhi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Building Blocks ◽  
Smart Composite ◽  
Thermally Induced ◽  
One Dimensional ◽  
Flat Shape

This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.

scholarly journals Phase Equilibria and Phase Transformations in New B2-type Ferromagnetic Shape Memory Alloys of Co-Ni-Ga and Co-Ni-Al Systems

2001 ◽  
Vol 42 (11) ◽  
pp. 2472-2475 ◽  
Author(s):  
Katsunari Oikawa ◽  
Takuya Ota ◽  
Fumihiko Gejima ◽  
Toshihiro Ohmori ◽  
Ryosuke Kainuma ◽  
...  
Keyword(s):  
Phase Equilibria ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phase Transformations ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory
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