A Thermodynamically Based Model of the Superelastic Behavior of Shape Memory Alloys Using a Discrete Preisach Model

Author(s):  
Srikrishna Doraiswamy ◽  
Mrinal Iyer ◽  
Arun R. Srinivasa ◽  
Srinivasan M. Sivakumar

Shape Memory Alloys are increasingly being used in aeronautic [1], vibration control and seismic applications [2–6]. These applications require models that faithfully represent the full thermomechanical response of SMA wires but which at the same time are simple and fast to implement. In this paper we present a model for the superelastic behavior of Shape Memory Alloys that combines a thermodynamical framework with a Preisach model. This approach allows us to easily account for both stress and strain controlled responses as well as changes in termperature in a simple and straightforward way.

2000 ◽  
Author(s):  
Pavlin B. Entchev ◽  
Dimitris C. Lagoudas ◽  
Muhammad A. Qidwai ◽  
Virginia G. DeGiorgi

1993 ◽  
Vol 115 (1) ◽  
pp. 129-135 ◽  
Author(s):  
C. Liang ◽  
C. A. Rogers

Shape memory alloys (SMAs) have several unique characteristics, including their Young’s modulus-temperature relations, shape memory effects, and damping characteristics. The Young’s modulus of the high-temperature austenite of SMAs is about three to four times as large as that of low-temperature martensite. Therefore, a spring made of shape memory alloy can change its spring constant by a factor of three to four. Since a shape memory alloy spring can vary its spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, it may be useful in adaptive vibration control. Some vibration control concepts utilizing the unique characteristics of SMAs will be presented in this paper. Shape memory alloy springs have been used as actuators in many applications although their use in the vibration control area is very recent. Since shape memory alloys differ from conventional alloy materials in many ways, the traditional design approach for springs is not completely suitable for designing SMA springs. Some design approaches based upon linear theory have been proposed for shape memory alloy springs. A more accurate design method for SMA springs based on a new nonlinear thermomechanical constitutive relation of SMA is also presented in this paper.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Liberty Deberg ◽  
Masood Taheri Andani ◽  
Milad Hosseinipour ◽  
Mohammad Elahinia

Shape memory alloys (SMAs) provide compact and effective actuation for a variety of mechanical systems. In this work, the distinguished superelastic behavior of these materials is utilized to develop a passive ankle foot orthosis to address the drop foot disability. Design, modeling, and experimental evaluation of an SMA orthosis employed in an ankle foot orthosis (AFO) are presented in this paper. To evaluate the improvements achieved with this new device, a prototype is fabricated and motion analysis is performed on a drop foot patient. Results are presented to demonstrate the performance of the proposed orthosis.


2003 ◽  
Vol 112 ◽  
pp. 205-208 ◽  
Author(s):  
S. Arbab Chirani ◽  
D. Aleong ◽  
C. Dumont ◽  
D. McDowell ◽  
E. Patoor

2020 ◽  
Vol 776 ◽  
pp. 139025
Author(s):  
Victor A. L'vov ◽  
Anna Kosogor ◽  
Serafima I. Palamarchuk ◽  
Gregory Gerstein ◽  
Hans J. Maier

2006 ◽  
Vol 11 (6) ◽  
pp. 690-698 ◽  
Author(s):  
Shuzhi Sam Ge ◽  
Keng Peng Tee ◽  
Ivan E. Vahhi ◽  
Francis E. H. Tay

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. 855-858 ◽  
Author(s):  
Ji Xia ◽  
Yuki Noguchi ◽  
Xiao Xu ◽  
Takumi Odaira ◽  
Yuta Kimura ◽  
...  

Shape memory alloys recover their original shape after deformation, making them useful for a variety of specialized applications. Superelastic behavior begins at the critical stress, which tends to increase with increasing temperature for metal shape memory alloys. Temperature dependence is a common feature that often restricts the use of metal shape memory alloys in applications. We discovered an iron-based superelastic alloy system in which the critical stress can be optimized. Our Fe-Mn-Al-Cr-Ni alloys have a controllable temperature dependence that goes from positive to negative, depending on the chromium content. This phenomenon includes a temperature-invariant stress dependence. This behavior is highly desirable for a range of outer space–based and other applications that involve large temperature fluctuations.


2011 ◽  
Vol 243-249 ◽  
pp. 5427-5434
Author(s):  
Hui Qian ◽  
Hong Nan Li ◽  
Di Cui ◽  
Huai Chen

Shape memory alloys (SMAs) are unique class materials that have the ability to undergo large deformations, while returning to their undeformed shape through either the applications of heat (SME) or removal of stress (SE). The unique properties lead to their wide applications in the biomedical, mechanical, aerospace, commercial industries, and recently in civil engineering. The paper presents two case studies of structural seismic vibration control using SMAs. The first one is a study of the SMA reinforced RC members. Two innovative applications in RC members, such as SMA-based Precast Concrete Frame Connection (SMA-PCFC), and SMA reinforced RC short column, were proposed. Moreover, the self-rehabilitation properties of SMAs-based Intelligent Reinforced Concrete Beams (SMA-IRCBs) were further experimentally investigated. The results show that SMAs can improve the mechanical properties of concrete members. SMA reinforced RC members have unique seismic performance compared to ordinarily steel reinforced concrete members. The second one is a study of the structural energy dissipation system using SMAs damping device. An innovative hybrid SMAs friction device (HSMAFD) which consists of pre-tensioned superelastic SMA wires and friction devices (FD) was presented. The results of cyclic tensile tests show that the HSMAFD exhibits stable large energy dissipation capacity and re-centering feature. The effectiveness of the HSMAFD in reducing horizontal response of structures subjected to strong seismic excitations was verified through shaking table tests carried out on a reduced-scale symmetric steel frame model with and without the HSMAFD.


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