scholarly journals A New Model for Characterizing Nonlinear Hysteresis of Magnetorheological Fluid Damper

2019 ◽  
Vol 24 (4) ◽  
pp. 784-791 ◽  
Author(s):  
Xianju Yuan ◽  
Tianyu Tian ◽  
Hongtao Ling ◽  
Tianyu Qiu
Keyword(s):  
Algebraic Model ◽  
Parametric Models ◽  
Control Algorithms ◽  
Hyperbolic Tangent ◽  
Mr Dampers ◽  
Shock Absorbers ◽  
Nonlinear Hysteresis ◽  
Proposed Model ◽  
Fluid Damper ◽  
Tangent Function

Magnetorheological (MR) dampers whose nonlinear hysteresis is a rather complicated phenomenon have been widespread in mechanical systems, automobile shock absorbers, the civil engineering, etc. The understanding of such a behaviour is helpful to control effectively and utilize maximum advantages of MR dampers. It is vitally important to construct parametric models used to develop control algorithms. Hence, the current study aims at developing a parametric model which exhibits considerably better predictions than that of more complicated models. In addition to achieving such a target, a simple algebraic model including only an exponential function, a hyperbolic tangent function, and other algebraic expressions can be able to capture the non-linear hysteresis adequately. Compared to an existing algebraic model and the experimental dataset, the proposed model is a reliable one.

Experimental Identification of a Shear-Mode MR Damper and Numerical Evaluation of Hysteretic Models

2007 ◽  
Author(s):  
Mauricio Zapateiro ◽  
Ningsu Luo ◽  
Ellen Taylor ◽  
Shirley J. Dyke
Keyword(s):  
Effective Means ◽  
Mr Damper ◽  
Good Control ◽  
Parametric Models ◽  
Shear Mode ◽  
Control Performance ◽  
Hyperbolic Tangent ◽  
Civil Structures ◽  
Mr Dampers

Magnetorheological (MR) dampers have become an effective means for the semiactive vibration control of civil structures. For achieving good control performance, it is necessary to make the accurate characterization of the civil structures to be controlled, the sensors, the actuators and some other systems integrated. Nowadays, the modeling and identification of the dynamics of an MR damper is still a challenging task due to its highly hysteretic nonlinearities. This paper presents experimental results on the modeling and identification of a type of MR damper prototype whose MR fluid is contained in a foam. A comparative study is made among three parametric models (Bingham, Bouc-Wen and Hyperbolic tangent).

A new hysteresis model for magneto–rheological dampers based on Magic Formula

2020 ◽  
pp. 095440622095488
Author(s):  
Quoc–Duy Bui ◽  
Quoc Hung Nguyen ◽  
Xian–Xu ‘Frank’ Bai ◽  
Duc–Dai Mai
Keyword(s):  
Excitation Frequency ◽  
Model Parameters ◽  
Magic Formula ◽  
Hysteresis Behavior ◽  
Hysteresis Curves ◽  
Mr Dampers ◽  
Nonlinear Hysteresis ◽  
Proposed Model ◽  
Wide Range ◽  
Magneto Rheological

This paper investigates a novel model based on the Magic Formula and the Pan’s model to effectively predict the inherent nonlinear hysteresis behavior of magneto–rheological (MR) dampers. In the proposed model, the hysteresis element is employed from the Magic Formula and Pan’s model, and two new independent horizontal shift parameters, which are separated from one original parameter of the Pan’s model, are added. Each of them characterizes an offset with respect to the origin for each branch of hysteresis curves, providing more flexibility and effectiveness for simulating curves with high asymmetry. In addition, a parameter to further control the sharpness of hysteresis curves in the backward region of damping force–velocity is proposed, which is useful to simulate the behavior of MR dampers in rather extreme operating cases. A case study is performed on a prototype MR damper for washing machines, in which the model incorporates applied current and excitation frequency as variables to make it more adaptable to a wide range of working conditions. For comparison, performance of three hysteresis models, including the Spencer’s model, the Pan’s model and the proposed model, are analyzed and evaluated. The research results show that, as compared with the others, the proposed model can not only predict the nonlinear hysteresis behavior of MR dampers more precisely, but is also more compatible with different operating excitations, and the clearer meanings of the model parameters make them easier to study and identify.

Study on Shock Response of Cushion Packaging System Based on Combined Model Using Hyperbolic Tangent and Tangent Functions with Consideration of Rotation Effect

2011 ◽  
Vol 101-102 ◽  
pp. 1161-1166 ◽  
Author(s):  
De Gao ◽  
Fu De Lu
Keyword(s):  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Rotation Effect ◽  
Hyperbolic Tangent ◽  
Combined Model ◽  
Packaging System ◽  
Acceleration Pulse ◽  
Proposed Model ◽  
Tangent Function ◽  
Packaging Structure

This paper proposes to model cushioning materials by combining hyperbolic tangent function and tangent function together. Based on the proposed model, the kinetics equations for cushion packaging system under excitation of half-sine acceleration pulse shock have been derived, where the rotation due to product’s eccentricity in center of mass has been taken into account. The law for coupling between rotation and translation is discussed. Numerical analysis shows that it may lead to a certain degree’s excessive packaging and thus causes waste if the rotation effect is not considered in design. The proposed model and the established kinetics equations with consideration of coupling between translation and rotation provide much better description regarding the characteristics of practical cushion packaging systems, and thus can be taken as reference in design optimization for packaging structure. The proposed approach can also be directly applied in analyzing the shock responses of packaging systems with multiple degrees of freedom.

A Non Parametric Model for Magneto Rheological Dampers

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
Xubin Song
Keyword(s):  
Test Data ◽  
Mr Damper ◽  
Parametric Model ◽  
Parametric Models ◽  
Magnetic Saturation ◽  
Mr Dampers ◽  
Electro Magnetic ◽  
Magneto Rheological ◽  
Force Characteristics ◽  
Non Parametric

Abstract A non-parametric model for magneto-rheological (MR) dampers is presented. After discussing the merits of parametric and non-parametric models for MR dampers, the test data for a MR damper is used to develop a non-parametric model. The results of the model are compared with the test data to illustrate the accuracy of the model. The comparison shows that the non-parametric model is able to accurately predict the damper force characteristics, including the damper non-linearity and electro-magnetic saturation. It is further shown that the parametric model can be numerically solved more efficiently than the parametric models.

scholarly journals Real-Time Prediction of the COVID-19 Epidemic in Thailand using Simple Model-Free Method and Time Series Regression Model

2021 ◽  
Vol 18 (14) ◽  
Author(s):  
Rati WONGSATHAN
Keyword(s):  
Genetic Algorithm ◽  
Time Series ◽  
Regression Model ◽  
Regression Models ◽  
Gaussian Function ◽  
Logistic Function ◽  
Hyperbolic Tangent ◽  
Time Series Regression ◽  
Model Free ◽  
Tangent Function

The novel coronavirus 2019 (COVID-19) pandemic was declared a global health crisis. The real-time accurate and predictive model of the number of infected cases could help inform the government of providing medical assistance and public health decision-making. This work is to model the ongoing COVID-19 spread in Thailand during the 1st and 2nd phases of the pandemic using the simple but powerful method based on the model-free and time series regression models. By employing the curve fitting, the model-free method using the logistic function, hyperbolic tangent function, and Gaussian function was applied to predict the number of newly infected patients and accumulate the total number of cases, including peak and viral cessation (ending) date. Alternatively, with a significant time-lag of historical data input, the regression model predicts those parameters from 1-day-ahead to 1-month-ahead. To obtain optimal prediction models, the parameters of the model-free method are fine-tuned through the genetic algorithm, whereas the generalized least squares update the parameters of the regression model. Assuming the future trend continues to follow the past pattern, the expected total number of patients is approximately 2,689 - 3,000 cases. The estimated viral cessation dates are May 2, 2020 (using Gaussian function), May 4, 2020 (using a hyperbolic function), and June 5, 2020 (using a logistic function), whereas the peak time occurred on April 5, 2020. Moreover, the model-free method performs well for long-term prediction, whereas the regression model is suitable for short-term prediction. Furthermore, the performances of the regression models yield a highly accurate forecast with lower RMSE and higher R2 up to 1-week-ahead. HIGHLIGHTS COVID-19 model for Thailand during the first and second phases of the epidemic The model-free method using the logistic function, hyperbolic tangent function, and Gaussian function  applied to predict the basic measures of the outbreak Regression model predicts those measures from one-day-ahead to one-month-ahead The parameters of the model-free method are fine-tuned through the genetic algorithm  GRAPHICAL ABSTRACT

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