Tracking and Vibration Control of Flexible Robots Using Shape Memory Alloys

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.

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Case Studies of Seismic Vibration Control of Civil Structures Using Shape Memory Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.5427 ◽

2011 ◽

Vol 243-249 ◽

pp. 5427-5434

Author(s):

Hui Qian ◽

Hong Nan Li ◽

Di Cui ◽

Huai Chen

Keyword(s):

Reinforced Concrete ◽

Energy Dissipation ◽

Shape Memory Alloys ◽

Shape Memory ◽

Vibration Control ◽

Case Studies ◽

Precast Concrete ◽

Reinforced Concrete Beams ◽

Seismic Vibration ◽

Concrete Members

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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Seismic Vibration Control of Structures Using Superelastic Shape Memory Alloys

Shape Memory Alloys ◽

10.5772/9797 ◽

2010 ◽

Author(s):

Hongnan Li ◽

Hui Qi

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Vibration Control ◽

Seismic Vibration

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

Volume 1: Active Materials, Mechanics and Behavior; Modeling, Simulation and Control ◽

10.1115/smasis2009-1431 ◽

2009 ◽

Author(s):

Srikrishna Doraiswamy ◽

Mrinal Iyer ◽

Arun R. Srinivasa ◽

Srinivasan M. Sivakumar

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Vibration Control ◽

Stress And Strain ◽

Preisach Model ◽

Thermomechanical Response ◽

Superelastic Behavior ◽

Seismic Applications

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.

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