Smart Damping Treatment for Flexible Structure

1994 ◽  
Vol 360 ◽  
Author(s):  
Q. Chen ◽  
C. Levy
Keyword(s):  
Differential Equation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loss Factor ◽  
Alloy Layer ◽  
Viscoelastic Layer ◽  
Flexible Structure ◽  
Recovery Stress ◽  
Governing Differential Equation ◽  
The Mathematical Model

AbstractThe mathematical model of a flexible cantilever beam with a constrained viscoelastic layer and shape memory alloy layer called smart damping treatment (SDT) is presented. It is shown that a change of the elastic modulus of the shape memory alloy layer will affect the system loss factor and resonance frequency. The recovery stress of the SMA layer leads to an inhomogeneity in the governing differential equation. The recovery stress also functions as an excitation to the system. The effects of the different parameters found in the analysis are discussed in the paper.

Experimental Analysis of Smart Structure with Damping Treatment and SMA

1996 ◽  
Vol 459 ◽  
Author(s):  
Q. Chen ◽  
J. Ma ◽  
C. Levy
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Effects ◽  
Loss Factor ◽  
Alloy Layer ◽  
Smart Structure ◽  
Viscoelastic Layer ◽  
Heat Cycling ◽  
Damping Materials ◽  
System Frequency

ABSTRACTThe experimental results of a flexible cantilever beam with constrained viscoelastic layer and shape memory alloy layer called smart damping treatment (SDT) are presented. The upper side of the beam is bonded with a viscoelastic layer and then covered with a constraining layer. The lower side is bonded with a shape memory alloy layer, which is used as an actuator. The elastic modulus and loss factor of damping materials are functions of the temperature. The temperature effects on system frequency and loss factor due to heat cycling of SMA layer are evaluated here. It is found that temperature plays an important role on system frequency and loss factor, and thus the temperature effects must be included when discussing such an structure.

scholarly journals Mechanical Consequences of Dynamically Loaded NiTi Wires under Typical Actuator Conditions in Rehabilitation and Neuroscience

2021 ◽  
Vol 12 (1) ◽  
pp. 4
Author(s):  
Umut D. Çakmak ◽  
Zoltán Major ◽  
Michael Fischlschweiger
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Storage Modulus ◽  
Loss Factor ◽  
Empirical Relation ◽  
Material Behavior ◽  
Chemical Compositions ◽  
Loading Frequency ◽  
Frequency Dependency ◽  
Controlled Conditions

In the field of rehabilitation and neuroscience, shape memory alloys play a crucial role as lightweight actuators. Devices are exploiting the shape memory effect by transforming heat into mechanical work. In rehabilitation applications, dynamic loading of the respective device occurs, which in turn influences the mechanical consequences of the phase transforming alloy. Hence in this work, dynamic thermomechanical material behavior of temperature-triggered phase transforming NiTi shape memory alloy (SMA) wires with different chemical compositions and geometries was experimentally investigated. Storage modulus and mechanical loss factor of NiTi alloys at different temperatures and loading frequencies were analyzed under force-controlled conditions. Counterintuitive storage modulus- and loss factor-dependent trends regarding the loading frequency dependency of the mechanical properties on the materials’ composition and geometry were, hence, obtained. It was revealed that loss factors showed a pronounced loading frequency dependency, whereas the storage modulus was not affected. It was shown that force-controlled conditions led to a lower storage modulus than expected. Furthermore, it turned out that a simple empirical relation could capture the characteristic temperature dependency of the storage modulus, which is an important input relation for modeling the rehabilitation device behavior under different dynamic and temperature loading conditions, taking directly into account the material behavior of the shape memory alloy.

Optimal H∞ Control of Structural Vibrations Using Shape Memory Alloy Actuators

1999 ◽  
Author(s):  
Jian Sun ◽  
Ali R. Shahin
Keyword(s):  
Mathematical Model ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Model Uncertainty ◽  
High Frequency ◽  
Structural Vibrations ◽  
Design Procedures ◽  
Sma Actuators ◽  
Temperature Dynamics ◽  
The Mathematical Model

Abstract This paper investigates robust control problem of structural vibrations using shape memory alloy (SMA) wires as actuators. The mathematical model for these SMA actuators is derived with emphasis in model uncertainty. The linearization of the relation between stress and temperature dynamics of SMA actuators is analyzed for active control. To handle the uncertainties caused by the linearization and the neglected high frequency dynamics, optimal H∞ control was employed to design a controller. An example is used to demonstrate the design procedures and the control system is tested in a nonlinear environment.

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.

scholarly journals A Soft Five-Fingered Hand Actuated by Shape Memory Alloy Wires: Design, Manufacturing, and Evaluation

2020 ◽  
Vol 7 ◽  
Author(s):  
Filomena Simone ◽  
Gianluca Rizzello ◽  
Stefan Seelecke ◽  
Paul Motzki
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Force Measurement ◽  
Optimal Placement ◽  
Flexible Structure ◽  
Flexible Joints ◽  
3D Printed

This work presents a novel five-fingered soft hand prototype actuated by Shape Memory Alloy (SMA) wires. The use of thin (100 μm diameter) SMA wire actuators, in conjunction with an entirely 3D printed hand skeleton, guarantees an overall lightweight and flexible structure capable of silent motion. To enable high forces with sufficiently high actuation speed at each fingertip, bundles of welded actuated SMA wires are used. In order to increase the compliance of each finger, flexible joints from superelastic SMA wires are inserted between each phalanx. The resulting system is a versatile hand prototype having intrinsically elastic fingers, which is capable to grasp several types of objects with a considerable force. The paper starts with the description of the finger hand design, along with practical considerations for the optimal placement of the superelastic SMA in the soft joint. The maximum achievable displacement of each finger phalanx is measured together with the phalanxes dynamic responsiveness at different power stimuli. Several force measurement are also realized at each finger phalanx. The versatility of the prototype is finally demonstrated by presenting several possible hand configurations while handling objects with different sizes and shapes.

scholarly journals Modeling the behavior of bilayer shape memory alloy/functionally graded material beams considering asymmetric shape memory alloy response

2019 ◽  
Vol 31 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Nguyen Van Viet ◽  
Wael Zaki ◽  
Rehan Umer ◽  
Quan Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Functionally Graded Material ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Alloy Layer ◽  
Functionally Graded ◽  
Tension And Compression ◽  
Graded Material ◽  
Asymmetric Shape

A new model is proposed to describe the response of laminated composite beams consisting of one shape memory alloy layer and one functionally graded material layer. The model accounts for asymmetry in tension and compression of the shape memory alloy behavior and successfully describes the dependence of the position of the neutral surface on phase transformation within the shape memory alloy and on the load direction. Moreover, the model is capable of describing the response of the composite beam to both loading and unloading cases. In particular, the derivation of the equations governing the behavior of the beam during unloading is presented for the first time. The effect of the functionally graded material gradient index and of temperature on the neutral axis deviation and on the overall behavior of the beam is also discussed. The results obtained using the model are shown to fit three-dimensional finite element simulations of the same beam.

scholarly journals Recovery Stress of TiNi Shape Memory Alloy. 2nd Report. Properties under Constant Maximum Strain.

1994 ◽  
Vol 60 (569) ◽  
pp. 120-125 ◽  
Author(s):  
Ping-Hua Lin ◽  
Hisaaki Tobushi ◽  
Kimio Kimura ◽  
Hiroyuki Iwanaga ◽  
Takeharu Hattori
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Maximum Strain ◽  
Recovery Stress ◽  
Constant Maximum

Influence of Processing State on Recovery Stress in NiTiNb Shape Memory Alloy

2014 ◽  
Vol 875-877 ◽  
pp. 1525-1528 ◽  
Author(s):  
Er Min Wang ◽  
Qi Hu Hong ◽  
Zhi Ming Ni ◽  
Jin Han
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Stress Level ◽  
Microstructure Evolution ◽  
Hot Rolling ◽  
Cold Drawing ◽  
Eutectic Microstructure ◽  
Recovery Stress ◽  
Tini Phase

Self-made tension machine was used to measure the evolution of recovery stress under different processing state for NiTiNb alloy. Then, SEM was used to investigate the microstructure evolution. The results show that the range of the highest recovery stress for forged NiTiNb alloy is between 210-215MPa. Otherwise, the recovery stress level of the samples enduring cold drawing and hot rolling is basically same, which all belong to the rage of 210-220MPa. After forging, the firstly precipitated TiNi phase particles become fine, only 5-8μm. The Nb tablets in eutectic microstructure, which originally contributed between TiNi phase particles, appear spheroidization.

Robust position regulation of a shape memory alloy wire actuator

2002 ◽  
Vol 216 (3) ◽  
pp. 301-308 ◽  
Author(s):  
G Song
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Position Control ◽  
High Strain ◽  
Sliding Mode ◽  
Recovery Stress ◽  
High Recovery ◽  
Robust Controller ◽  
Alloy Wire ◽  
Position Regulation

This paper presents design and experiment results of active position control of a shape memory alloy (SMA) wire actuator using a sliding mode based robust approach. In this research, an SMA wire was chosen as an actuating element for position control owing to its high recovery stress (gt;500MPa) and tolerance to high strain (up to 5 per cent). To compensate for the inherent non-linearity associated with the SMA, a sliding mode based robust controller was designed and implemented actively to control the position of the SMA wire actuator. Experiments demonstrated the effectiveness of the robust control. For a 12 in long SMA wire actuator, the position can be controlled within 30m.

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