Sub-Structure Pseudo-Dynamic Response Test of a Pseudo-Elastic Bracing System Made of Shape Memory Alloy

2005 ◽  
Vol 297-300 ◽  
pp. 628-634 ◽  
Author(s):  
Kenichi Ohi ◽  
Jae Hyouk Choi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Original Position ◽  
Small Displacement ◽  
Structural System ◽  
Dynamic Tests ◽  
System A ◽  
Hysteretic Damper ◽  
Bracing System ◽  
Fail Safe

This paper deals with shape memory alloy. As a first step to assess the applicability of this kind of alloy in a structural system, a tension bar made of this kind of alloy that exhibits pseudo-elasticity at room temperature is used herein as a passive bracing system. This paper describes sub-structure pseudo-dynamic tests on pseudo-elastic bracing system with hysteretic damper. A pseudo-elastic bracing system is better to be used with other hysteretic elements such as a hysteretic damper. A damper provides energy dissipation within small displacement levels, and a pseudo-elastic bracing system works in turn as a back-up/fail-safe system when an accidental failure of damper or damper interface occurs, and also it helps to pull back the structure to the original position by uninstalling the damper after earthquake.

scholarly journals Dynamic Characteristics of Hanging Truss Having Shape Memory Alloy Wires

2017 ◽  
Vol 7 (2) ◽  
pp. 6 ◽  
Author(s):  
Xuan Zhang ◽  
Kazuyuki Hanahara ◽  
Yukio Tada
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Dynamic Characteristics ◽  
Dynamic Problem ◽  
Vibration Isolation ◽  
Mechanical Characteristics ◽  
Structural System ◽  
Vibration Attenuation ◽  
Calculation Process ◽  
Absorption Characteristics

In this study, we discuss the dynamics of a type of hanging truss structural system consisting of rigid and wire members, part of which are SMA (shape memory alloy) wires. This kind of truss structure has the capability of vibration isolation and absorption. Characteristics of zero compressive stiffness of wire members, SMA wire members and hanging configuration of the structure itself contribute to the effect of vibration isolation. The hysteretic loop of SMA wires plays a significant role in vibration attenuation. Mathematical models for this kind of dynamic problem are developed. Calculation process is introduced to take into account the mechanical characteristics of SMA and wire members. Dynamic characteristics are discussed; simultaneously, the effects of vibration isolation and attenuation have been confirmed. On the basis of the numerical calculations, advantages of combinations of various types of wire members, including the truss units having no bracing wires have been demonstrated. 

scholarly journals Experimental Design Validation of Tilting Calibration Mechanism by Using Shape Memory Alloy Spring Actuator

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Hyun-Ung Oh ◽  
Myeong-Jae Lee ◽  
Taegyu Kim
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Random Vibration ◽  
Dual Function ◽  
Test Results ◽  
Mechanical Constraints ◽  
Function Test ◽  
Sma Spring ◽  
Fail Safe ◽  
Imaging Sensor

A tilting calibration mechanism is periodically deployed to view the reference temperature target during on-board calibration of a spaceborne imaging sensor and stowed after calibration. In the present work, we have proposed a new design strategy using a shape memory alloy (SMA) spring as an actuator that provides a fail-safe function to prevent the blocking of the main optical path when the mechanical driving part of the mechanism is stopped at a certain position during on-board calibration. Although a launch locking device was not considered in the design, this approach makes it possible to impose mechanical constraints on the driving part of the mechanism in severe launch vibration environments. The effectiveness of the proposed design was experimentally validated by a deploying and stowing function test and launch vibration environment tests such as a sine burst test, a random vibration test, and a pyroshock simulating impulse shock test. The test results demonstrated that the mechanism fulfills all the required functions for on-board calibration. The use of an SMA spring actuator was proved effective for implementing the dual function of a fail-safe in an emergency phase and a mechanical constraint on the driving part of the mechanism in severe launch vibration environment.

scholarly journals Behaviour of Superelastic Nickel Titanium Shape Memory Alloy Material under Uniaxial Testing and its Potential in Civil Engineering

2018 ◽  
Vol 203 ◽  
pp. 06005
Author(s):  
Azmi Mohammad Hassan ◽  
Raizal Saifulnaz Muhammad Rashid ◽  
Nazirah Ahmad ◽  
Shahria Alam ◽  
Farzad Hejazi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Structural Characteristics ◽  
Nickel Titanium ◽  
Life Extension ◽  
Structural Safety ◽  
Structural System ◽  
Finish Temperature

Smart structures are defined as structures that able to adapt and maintain structural characteristics in dealing with changes of external disturbance, environment and unexpected severe loadings. This ability will lead to improve structural safety, serviceability and structural life extension. Shape memory alloys is one of the smart materials which has potential to be integrated in structural system to provide functions such as sensing, actuation, self-adapting and healing of the structures. The unique characteristic of shape memory alloys material is the ability to ‘remember’ its original shape after deformation. Nickel Titanium superelastic shape memory alloy wire is popular and widely used in many engineering fields and owned fully recovery of maximum strain of 6%-13.5% which is among the best shape recovery limit in alloy materials. The austenite finish temperature plays important role in stress-strain behaviour of superelastic shape memory alloys where higher stress required to complete martensite transformation with the increase of austenite finish temperature. The similar behaviour also is observed in the case of higher strain rate. The behaviour of superelastic shape memory alloys need to be studied before implementing in the structural system, so the targeted improvement for the structural system can be achieved.

Optimal design of a hanging truss with shape memory alloy wires

2020 ◽  
Vol 44 (1) ◽  
pp. 95-107
Author(s):  
Xuan Zhang ◽  
Kazuyuki Hanahara ◽  
Yukio Tada ◽  
Zhiyong Pei ◽  
Zhe Li ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Vibration Amplitude ◽  
Vibration Isolation ◽  
Point Of View ◽  
Optimal Solutions ◽  
Sectional Area ◽  
Structural System ◽  
Column Type ◽  
Transmission Reduction

In this study, we discuss the dynamic problem of a column-type hanging truss structural system with pseudo-elastic shape memory alloy (SMA) bracing wires. In the case where the sectional area values of the bracing SMA wire members are small enough to be negligible, it is close to the situation where there are no braces. In the case where the sectional area values of the bracing SMA wire members are large enough not to be negligible, the vibration amplitude of the peripheral end apparatus is suppressed from the deformation point of view. In addition, energy attenuation efficiency is improved with larger sectional area values because of the hysteretic characteristic of SMA. Small sectional area values of the bracing SMA wire members near the support ceiling or peripheral end are beneficial to vibration transmission reduction. These findings indicate that the placement and sectional area values of SMA wire members are both significant from the viewpoint of suppression of influence of the support ceiling vibration of the hanging truss. In this study, we obtain the optimal sectional area values of the SMA wire bracing members for the objectives of vibration isolation and attenuation. We discuss influences of different vibration conditions on the optimal solutions.

Development of a Shape Memory Alloy Actuated Catheter for Cardiovascular Procedures

2008 ◽  
Author(s):  
Arun S. Veeramani ◽  
John H. Crews ◽  
Gregory D. Buckner ◽  
Stephen B. Owen ◽  
Richard C. Cook ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Pid Control ◽  
Experimental Validation ◽  
Imaging System ◽  
System A ◽  
Atrial Ablation ◽  
Simulation Results ◽  
Hysteretic Characteristics ◽  
Memory Characteristics

This research highlights the design, fabrication and experimental validation of a Shape Memory Alloy (SMA) actuated robotic catheter. The prototype consists of four SMA tendons that actuate a central tubular substructure in two orthogonal directions. The experimental shape memory characteristics are used to optimize the design. Joule heating is used to generate tip deflections and the experimental bending characteristics are obtained using a dual camera imaging system. These measurements reveal important nonlinearities and hysteretic characteristics of the system. A dynamic model of the system is developed to describe the SMA-effected bending mechanics, and simulation results are compared to experimental measurements for model validation. The applicability of this technology to cardiovascular procedures, like atrial ablation, is demonstrated through precise tracking of trajectories using PID control.

Early Mobilization Using Heat Treated Shape Memory Alloy (SMA) for Rehabilitation Phases

2016 ◽  
Vol 724 ◽  
pp. 112-116 ◽  
Author(s):  
Ahmad Majdi Abdul-Rani ◽  
Subramaniam Krishnan ◽  
T. Nagarajan ◽  
T.V.V.L.N. Rao ◽  
Ramanathan Ramiah ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Manufacturing Industry ◽  
Medical Engineering ◽  
Early Mobilization ◽  
Original Position ◽  
Foot Diseases ◽  
Heat Treated ◽  
Mechanical Procedure ◽  
Effective Use

Shape Memory Alloy (SMA) is a material with the ability to return to its original position, when being subjected to an appropriate thermo mechanical procedure. SMA find very wide applications in various facets of robotic and bio medical engineering. In this paper, review on ankle/foot diseases and the effective use of heat treated SMA was carried out. The manufacturing industry normally uses a range of between 200°C to 400°C to shape any biomedical product which has been used as the benchmark temperature throughout this research. The results suggested that annealing of 200°C produced the best suited for generating substantial displacement which can promote early rehabilitation of ankle/foot.

An innovative seismic-resilient bridge with shape memory alloy-washer-based footing rocking RC piers

2020 ◽  
pp. 1045389X2096316
Author(s):  
Yue Zheng ◽  
Cheng Fang ◽  
Dong Liang ◽  
Ruiqin Sun
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Damage Control ◽  
Load Resistance ◽  
System Level ◽  
Superior Performance ◽  
Static Tests ◽  
System A ◽  
Fixed Base ◽  
Bridge System

This study proposes a new footing rocking pier which employs shape memory alloy (SMA) washers as its kernel elements. Apart from providing self-centering capability and energy dissipation, the SMA washers enable a “limited rocking” behavior for the pier, helping enhance the seismic resilience of the bridges. The study commences with quasi-static tests on SMA washer groups with various stack patterns. Subsequently, a 1/4 scale SMA-washer-based rocking pier specimen is tested. Following the experimental study, a bridge system adopting the SMA-washer-based rocking pier is carefully designed. An iterative seismic design approach is proposed for the rocking pier, followed by a system level analysis on the entire bridge system. A suite of ground motions corresponding to two intensity levels are considered. The performance of the innovative bridge is also compared with a conventional bridge with fixed-base piers. The results reveal that the new system exhibits superior performance to the conventional bridge in terms of pier damage control, which is achieved with acceptable sacrifice of other performance indices such as bearing displacement and peak drift ratio. A further parametric study suggests that the response of the bridge with the proposed pier is related to the load resistance and deformability of the SMA washers.

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