Asymmetrical Bending Model for NiTi Shape Memory Wires: Numerical Simulations and Experimental Analysis

Strain ◽  
2011 ◽  
Vol 47 (3) ◽  
pp. 255-267 ◽  
Author(s):  
S. De la Flor ◽  
C. Urbina ◽  
F. Ferrando
Keyword(s):  
Numerical Simulations ◽  
Shape Memory ◽  
Experimental Analysis ◽  
Asymmetrical Bending

Systems Actuated by Shape Memory Alloys: Identification and Modeling

2021 ◽  
Vol 1 (2) ◽  
pp. 12-20
Author(s):  
Najmeh Keshtkar ◽  
Johannes Mersch ◽  
Konrad Katzer ◽  
Felix Lohse ◽  
Lars Natkowski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Numerical Simulations ◽  
Shape Memory ◽  
Transfer Equation ◽  
Mechanical Parameters ◽  
Heat Transfer Equation ◽  
The Mathematical Model

This paper presents the identification of thermal and mechanical parameters of shape memory alloys by using the heat transfer equation and a constitutive model. The identified parameters are then used to describe the mathematical model of a fiber-elastomer composite embedded with shape memory alloys. To verify the validity of the obtained equations, numerical simulations of the SMA temperature and composite bending are carried out and compared with the experimental results.

QUASIPASSIVITY-BASED ROBUST NONLINEAR FLAP POSITIONING CONTROL USING SHAPE MEMORY ALLOY MICRO-ACTUATORS

2005 ◽  
Vol 29 (2) ◽  
pp. 143-161
Author(s):  
Nicolas Léchevin ◽  
Camille Alain Rabbath ◽  
Frank Wong ◽  
O. Boissonneault
Keyword(s):  
Shape Memory Alloy ◽  
Nonlinear Control ◽  
Numerical Simulations ◽  
Shape Memory ◽  
Position Control ◽  
Tracking Error ◽  
Constitutive Law ◽  
Control Law ◽  
Ultimate Boundedness ◽  
Feedback Connection

This paper proposes a quasipassivity-based robust nonlinear control law ensuring position control of a rotary flap by means of an antagonist-type shape memory alloy microactuator. The control system employs variable-structure control to obtain robust performance, phase-lead compensation to quasipassivate the shape memory alloy dynamics and quasipassivity-based analysis to warrant robust ultimate boundedness of system trajectories. The feedback connection of the two paths leads to ultimate boundedness of tracking error trajectories of the plant despite uncertainties in the dynamic loads affecting the leading edge flap and in the friction found in the actuator. Since accurate numerical simulations and development of new concepts of microactuators based on shape memory alloys require a tractable, constitutive law accurately describing the relationship between force, displacement and temperature in the material, the paper also presents a hybrid micro-macro-mechanical shape memory alloy constitutive model. This model is based on a combination of structural modeling on a microscopic scale and transformation kinetics modeling on a macroscopic scale. The proposed control law and hybrid micro-macro-mechanical model are placed in closed-loop by means of numerical simulations that demonstrate the validity of the nonlinear control scheme.

A Classification of Shallow Water Resonant Sloshing in a Rectangular Tank

2013 ◽  
Author(s):  
Benjamin Bouscasse ◽  
Andrea Colagrossi ◽  
Matteo Antuono ◽  
Claudio Lugni
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Shallow Water ◽  
Convergence Analysis ◽  
Experimental Analysis ◽  
Large Amplitude ◽  
Large Range ◽  
Water Regimes ◽  
Sph Model

A numerical and experimental analysis of sloshing phenomena (i.e. violent fluid motions inside a tank) has been conducted in shallow water regimes. A large range of experimental data from moderate to large amplitude sway motions has been considered for different filling heights. The numerical simulations, performed through a δ-SPH model, aim to cover the configurations where no experiments were available and provide an exhaustive description of the shallow-water sloshing motion. A convergence analysis for non breaking and breaking cases has also been presented.

Experimental investigation of vibration reduction using shape memory alloys

2012 ◽  
Vol 24 (2) ◽  
pp. 247-261 ◽  
Author(s):  
Ricardo AA Aguiar ◽  
Marcelo A Savi ◽  
Pedro MCL Pacheco
Keyword(s):  
Dynamical Systems ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Experimental Analysis ◽  
Vibration Reduction ◽  
Dynamical Response ◽  
Temperature Variations ◽  
Experimental Apparatus

Smart materials have a growing technological importance due to their unique thermomechanical characteristics. Shape memory alloys belong to this class of materials being easy to manufacture, relatively lightweight, and able to produce high forces or displacements with low power consumption. These aspects could be exploited in different applications including vibration control. Nevertheless, literature presents only a few references concerning the experimental analysis of shape memory alloy dynamical systems. This contribution deals with the experimental analysis of shape memory alloy dynamical systems by considering an experimental apparatus consisted of low-friction cars free to move in a rail. A shaker that provides harmonic forcing excites the system. The vibration analysis reveals that shape memory alloy elements introduce complex behaviors to the system and that different thermomechanical loadings are of concern showing the main aspects of the shape memory alloy dynamical response. Special attention is dedicated to the analysis of vibration reduction that can be achieved by considering different approaches exploiting either temperature variations promoted by electric current changes or vibration absorber techniques. The results establish that adaptability due to temperature variations is defined by a competition between stiffness and hysteretic behavior changes.

scholarly journals Experimental analysis of the quasi-static and dynamic torsional behaviour of shape memory alloys

2012 ◽  
Vol 49 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Olivier Doaré ◽  
Alessandro Sbarra ◽  
Cyril Touzé ◽  
Mohamed Ould Moussa ◽  
Ziad Moumni
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Experimental Analysis
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