ANFIS Driven Strain Control of Thin-Shape Memory Alloy Wires Using Seebeck Voltage of a Shape Memory Alloy–Constantan Thermocouple

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
V. V. N. Sriram Malladi ◽  
Pablo A. Tarazaga
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Supply Voltage ◽  
Hysteretic Behavior ◽  
Time Shift ◽  
Anfis Model ◽  
Inference System ◽  
Actuator Nonlinearities ◽  
Adaptive Neurofuzzy Inference System ◽  
The Relationship

Shape memory alloy (SMA) actuators exhibit considerable hysteresis between the supply voltage (conventionally used in resistive heating) and strain characteristics of the SMA. Hence, it is not easy to control the strain of a thin-SMA wire, unless a model is developed that can match the actuator's nonlinearities for predicting the supply voltage required by the SMA system accurately. The work presented in this paper proposes the use of a black-box technique called the adaptive neurofuzzy inference system (ANFIS) to study the hysteretic behavior of SMAs. The input parameters for such an ANFIS model would be a physical variable at time t and at a time t + n, where n is a time shift. The present work studies the effect of a time shift on the actuator nonlinearities for two ANFIS models. One of the models studies the relationship between the desired displacement of an SMA and the supply voltage across the SMA, while the other model predicts the actual displacement of an SMA from the feedback temperature. A novel SMA–Constantan thermocouple records the feedback temperature.

Control of Strain Characteristics of SMA Wires Using Seebeck Voltage

2013 ◽  
Author(s):  
V. V. N. Sriram Malladi ◽  
Pablo A. Tarazaga
Keyword(s):  
Time Delay ◽  
Fuzzy Inference ◽  
Supply Voltage ◽  
Anfis Model ◽  
Inference System ◽  
Control Applications ◽  
Neuro Fuzzy ◽  
Actuator Nonlinearities ◽  
Path Dependent ◽  
The Relationship

Shape Memory Alloys (SMAs), as a branch of smart material actuators, are widely researched in the areas of control applications. These actuators exhibit considerable hysteresis between the supply voltage (conventionally used in resistive heating) and position characteristics of the SMA. Unless a model matches the actuator’s nonlinearities, the control of an SMA would result in an error between the desired and actual strain. An Adaptive Neuro-Fuzzy Inference System (or ANFIS) model is proposed to model the hysteresis of the system. The hysteresis of an SMA is path dependent, thus controlling the SMA in real-time requires a time series forecasting a nonlinear model. The input parameters for such an ANFIS model would be a physical variable at time t and at a time t-n, where n is a time delay. The present work studies the effect of time delay on the actuator nonlinearities for two ANFIS models. One of the models studies the relationship between the desired displacement of an SMA and the supply voltage across the SMA, while the other model predicts the actual displacement of an SMA from the feedback temperature.

Experimental Study on Temperature External-Characteristics of Ni-Mn-Ga Shape Memory Alloy

2011 ◽  
Vol 311-313 ◽  
pp. 1232-1236 ◽  
Author(s):  
Yong Zhi Cai
Keyword(s):  
Experimental Study ◽  
Critical Temperature ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Effect ◽  
Deformation Rate ◽  
Variable Temperature ◽  
Temperature Characteristics ◽  
The Relationship ◽  
External Characteristics

Temperature characteristics are essential to reasonable application of Ni-Mn-Ga alloy. This paper reports an experiment equipment which is used as the research of variable temperature effect. The relationship between deformation rate and temperature is studied. Dynamic and static experiments are done. The results show that critical temperature is around 40°C. It can be predicted that thermo-elasticity and magnetically-controlled characteristics will disappear with the increase of temperature.

A Macromechanical Constitutive Model of Shape Memory Alloys Under Uniaxial Cyclic Loading

2012 ◽  
Vol 28 (3) ◽  
pp. 469-477 ◽  
Author(s):  
H. Lei ◽  
B. Zhou ◽  
Z. Wang ◽  
Y. Wang
Keyword(s):  
Cyclic Loading ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Hysteretic Behavior ◽  
Test Results ◽  
Model Match ◽  
Number Of Cycles ◽  
The Relationship

AbstractIn this paper, the thermomechanical behavior of shape memory alloys (SMAs) subjected to uniaxial cyclic loading is investigated. To obtain experimental data, the strain-controlled cyclic loading-unloading tests are conducted at various strain-rates and temperatures. Dislocations slip and deformation twins are considered to be the main reason that causes the unique cyclic mechanical behavior of SMAs. A new variable of shape memory residual factor was introduced, which will tend to zero with the increasing of the number of cycles. Exponential form equations are established to describe the evolution of shape memory residual factor, elastic modulus and critical stress, in which the influence of strain-rate, number of cycles and temperature are taken into account. The relationship between critical stresses and temperature is modified by considering the cycling effect. A macromechanical constitutive model was constructed to predict the cyclic mechanical behavior at constant temperature. Based on the material parameters obtained from test results, the hysteretic behavior of SMAs subjected to isothermal uniaxial cyclic loading is simulated. It is shown that the numerical results of the modified model match well with the test results.

Experimental characterization and control of a magnetic shape memory alloy actuator using the modified generalized rate-dependent Prandtl–Ishlinskii hysteresis model

2018 ◽  
Vol 232 (5) ◽  
pp. 506-518 ◽  
Author(s):  
Saeid Shakiba ◽  
Mohammad Reza Zakerzadeh ◽  
Moosa Ayati
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Excitation Frequency ◽  
Hysteresis Loops ◽  
Experimental Results ◽  
Hysteretic Behavior ◽  
Magnetic Shape Memory ◽  
Shape Memory Alloy Actuator ◽  
Rate Dependent ◽  
Magnetic Shape Memory Alloy

In this article, two models are used, namely rate-independent and rate-dependent generalized Prandtl–Ishlinskii, to characterize a magnetic shape memory alloy actuator. The results show that the rate-independent model cannot consider the effect of input excitation frequency, while the rate-dependent model omits this drawback by defining a time-dependent operator. For the first time, the effects of excitation frequency on the hysteretic behavior of magnetic shape memory alloy actuator are investigated. In this study, five excitation voltages with different frequencies in the range of 0.05–0.4 Hz are utilized as inputs to the magnetic shape memory alloy actuator and the displacement outputs are measured. Experimental results indicate that, with increasing the excitation frequency, the size of the hysteresis loops changes. Since the generalized rate-dependent Prandtl–Ishlinskii model cannot consider the asymmetric hysteresis loops, in the developed model, a tangent hyperbolic function is applied as an envelope function in order to improve the capability of the model in characterizing the asymmetric behavior of magnetic shape memory alloy actuator. The parameters of both rate-dependent and rate-independent models are identified by genetic algorithm optimization. The results reveal that the rate-independent form is not capable of accurately describing the hysteretic behavior of magnetic shape memory alloy actuator for different input frequencies. Simulation and experimental results also demonstrate the proficiency of the developed model for precise characterization of the saturated rate-dependent hysteresis loops of magnetic shape memory alloy actuator. In addition, the proposed model is utilized for determining a proper range for controller coefficients during controller design.

scholarly journals Adaptive Neurofuzzy Inference System-Based Pollution Severity Prediction of Polymeric Insulators in Power Transmission Lines

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
C. Muniraj ◽  
S. Chandrasekar
Keyword(s):  
Leakage Current ◽  
Transmission Lines ◽  
Power Transmission ◽  
Severity Index ◽  
Power Transmission Lines ◽  
Anfis Model ◽  
Inference System ◽  
Severity Prediction ◽  
Polymeric Insulators ◽  
Adaptive Neurofuzzy Inference System

This paper presents the prediction of pollution severity of the polymeric insulators used in power transmission lines using adaptive neurofuzzy inference system (ANFIS) model. In this work, laboratory-based pollution performance tests were carried out on 11 kV silicone rubber polymeric insulator under AC voltage at different pollution levels with sodium chloride as a contaminant. Leakage current was measured during the laboratory tests. Time domain and frequency domain characteristics of leakage current, such as mean value, maximum value, standard deviation, and total harmonics distortion (THD), have been extracted, which jointly describe the pollution severity of the polymeric insulator surface. Leakage current characteristics are used as the inputs of ANFIS model. The pollution severity index “equivalent salt deposit density” (ESDD) is used as the output of the proposed model. Results of the research can give sufficient prewarning time before pollution flashover and help in the condition based maintenance (CBM) chart preparation.

scholarly journals Modeling and Experimental Research of One Kind of New Planar Vortex Actuator Based on Shape Memory Alloy

Actuators ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Xiangsen Kong ◽  
Yilei Gu ◽  
Jiajun Wu ◽  
Yang Yang ◽  
Xing Shen
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Model ◽  
Angular Displacement ◽  
Complex Structure ◽  
Maximum Error ◽  
Coefficient Of Determination ◽  
Minimum Error ◽  
Output Torque ◽  
The Relationship

In order to alleviate the problems of complex structure and low reliability of traditional Shape Memory Alloy (SMA) rotary actuator, a planar vortex actuator (PVA) based on SMA material was proposed to directly output torque and angular displacement. Based on the calculation method of PVA and the constitutive model of the phase transition equation of SMA, the mechanical model is established, and the pre-tightening torque, temperature, output torque, and rotation angle are obtained. The relationship expression between the tests has verified the mechanical model. The results show that the relationship between the excitation temperature and the output torque, the coefficient of determination between the calculated value and the tested value, is 0.938, the minimum error is 0.46%, and the maximum error is 49.8%. In the relationship between angular displacement and torque, the coefficient of determination between the calculated value and the test value is 0.939, the maximum error is 58.5%, and the minimum error is 28.0%. The test results show that the calculated values of mechanical model and experimental data have similar representation form.

A uniaxial constitutive model for NiTi shape memory alloy bars considering the effect of residual strain

2019 ◽  
Vol 30 (8) ◽  
pp. 1163-1177
Author(s):  
Canjun Li ◽  
Zhen Zhou ◽  
Yazhi Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Residual Strain ◽  
Hysteretic Behavior ◽  
Niti Shape Memory Alloy ◽  
Strain Effect ◽  
Proposed Model ◽  
Residual Strains

Super-elastic shape memory alloys are widely used in structural engineering fields due to their encouraging super-elasticity and energy dissipation capability. Large-size shape memory alloy bars often present significant residual strains after unloading, which emphasizes the necessity of developing a residual strain effect–coupled constitutive model to predict well the performance of shape memory alloy–based structures. First, this article experimentally studies the hysteretic behavior of NiTi shape memory alloy bars under quasi-static loading conditions and investigates the effects of cyclic numbers and strain amplitudes on residual strain. Second, a concept of cumulative transformation strain is preliminarily introduced into a phenomenological Lagoudas model. A uniaxial constitutive model for shape memory alloy bars including the residual strain is proposed. By using OpenSees platform, numerical simulations of shape memory alloy bars are conducted—the results of which indicate that the proposed model can accurately capture the hysteretic behavior of shape memory alloys. The predicted residual strains show a good agreement to experimental results, which demonstrates the desirable efficiency of the proposed model.

NiTi Shape Memory Alloy Wire’s Constitutive Describe at Different Temperatures

2017 ◽  
Vol 729 ◽  
pp. 13-17
Author(s):  
Guang Yong Yang ◽  
Yang Zhong ◽  
Zhi Fei Qiu ◽  
Jun Wang ◽  
Wei Na Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Niti Shape Memory Alloy ◽  
Thermal And Mechanical Properties ◽  
Restoring Force ◽  
Intelligent Material ◽  
Different Temperatures ◽  
Relationship Of ◽  
The Relationship

NiTi shape memory alloy is an intelligent drive and awareness materials which develop very rapidly and is used in many fields in recent years, whose mechanical properties are not only related to chemical composition, but also closely related to the temperature. This article aims to study the NiTi shape memory alloy wire’s constitutive behavior coupled thermal and mechanical properties at different temperatures. By analyzing the results, the relationship of NiTi shape memory alloy between deformation and the restoring force at elevated temperature is obtained, thus providing a basis for the engineering design and simulation process of NiTi intelligent material.

Design of Shape Memory Alloy Damper for Base Isolated Structure

1997 ◽  
Author(s):  
Krzysztof Wilde ◽  
Paolo Gardoni ◽  
Yozo Fujino ◽  
Stefano Besseghini
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Base Isolation ◽  
Hysteretic Behavior ◽  
Isolation System ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
Smart Base Isolation

Abstract Base isolation provides a very effective passive method of protecting the structure from the hazards of earthquakes. The proposed isolation system combines the laminated rubber bearing with the device made of shape memory alloy (SMA). The smart base isolation uses hysteretic behavior of SMA to increase the structural damping of the structure and utilizes the different responses of the SMA at different levels of strain to control the displacements of the base isolation system at various excitation levels. The performance of the smart base isolation is compared with the performance of isolation by laminated rubber bearings to assess the benefits of additional SMA damper for isolation of three story building.

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