Experimental Testing and Validation of a Magnetorheological (MR) Damper Model

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Weng Wai Chooi ◽  
S. Olutunde Oyadiji
Keyword(s):  
Mathematical Model ◽  
Experimental Testing ◽  
Mr Damper ◽  
Parallel Plates ◽  
Mr Fluids ◽  
Annular Gap ◽  
The University ◽  
University Of Manchester ◽  
The Mathematical Model ◽  
Theoretical Simulations

The focus of this paper is on the experimental validation of a mathematical model that was developed for the flow of magnetorheological (MR) fluids through the annular gap in a MR damper. Unlike previous work by other researchers, which approximate the flow of the MR fluid through this annulus as a flow of fluid through two infinitely wide parallel plates, the model presented represents accurately the annular flow. In this paper, the mathematical model is validated via experimental testing and analysis of a double-tube MR damper fabricated at the University of Manchester, UK. The experimental setup and the procedures for executing the tests on the MR damper according to established standards for the testing of conventional automotive dampers are given. This involved sets of many isofrequency sinusoidal tests of various displacement amplitudes. Predictions from theoretical simulations based on the mathematical model are validated using the data collected from the experiments. It was found that the modeling procedure represents the MR damper very satisfactorily.

THE DEVELOPMENT OF THE MATHEMATICAL MODEL OF PREDICTING THE INDICATORS OF ACCREDITATION OF TECHNICAL UNIVERSITIES IN THE RUSSIAN FEDERATION

2017 ◽  
pp. 27-38
Author(s):  
Olga Mikhaylovna Tikhonova ◽  
Alexander Fedorovich Rezchikov ◽  
Vladimir Andreevich Ivashchenko ◽  
Vadim Alekseevich Kushnikov
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Regression Model ◽  
Oriented Graph ◽  
Real Data ◽  
Educational Process ◽  
Proposed Model ◽  
Linear Differential ◽  
The University ◽  
The Mathematical Model

The paper presents the system of predicting the indicators of accreditation of technical universities based on J. Forrester mechanism of system dynamics. According to analysis of cause-and-effect relationships between selected variables of the system (indicators of accreditation of the university) there was built the oriented graph. The complex of mathematical models developed to control the quality of training engineers in Russian higher educational institutions is based on this graph. The article presents an algorithm for constructing a model using one of the simulated variables as an example. The model is a system of non-linear differential equations, the modelling characteristics of the educational process being determined according to the solution of this system. The proposed algorithm for calculating these indicators is based on the system dynamics model and the regression model. The mathematical model is constructed on the basis of the model of system dynamics, which is further tested for compliance with real data using the regression model. The regression model is built on the available statistical data accumulated during the period of the university's work. The proposed approach is aimed at solving complex problems of managing the educational process in universities. The structure of the proposed model repeats the structure of cause-effect relationships in the system, and also provides the person responsible for managing quality control with the ability to quickly and adequately assess the performance of the system.

Deep and Shallow Water Low-Speed Maneuvering Tests: Comparison Between Experimental and Simulation Results

2016 ◽  
Author(s):  
Felipe Ribolla Masetti ◽  
Pedro Cardozo de Mello ◽  
Guilherme F. Rosetti ◽  
Eduardo A. Tannuri
Keyword(s):  
Mathematical Model ◽  
Small Scale ◽  
Shallow Waters ◽  
Hydrodynamic Coefficients ◽  
Low Speed ◽  
Tunnel Model ◽  
Oceanographic Research ◽  
Simulation Results ◽  
The University ◽  
The Mathematical Model

This paper presents small-scale low-speed maneuvering tests with an oceanographic research vessel and the comparison with mathematical model using the real time maneuvering simulator developed by the University of São Paulo (USP). The tests are intended to verify the behavior of the vessel and the mathematical model under transient and low speed tests. The small-scale tests were conducted in deep and shallow waters, with a depth-draft ratio equal to 1.28, in order to verify the simulator ability to represent the vessel maneuverability on both depth conditions. The hydrodynamic coefficients used in the simulator model were obtained by CFD calculations and wind tunnel model tests carried out for this vessel. Standard turning circle and accelerating turn maneuvers were used to compare the experimental and numerical results. A fair agreement was achieved for shallow and deep water. Some differences were observed mainly in the initial phase of the accelerating turn test.

A Musculoskeletal Model of the Equine Forelimb for Determining Surface Stresses and Strains in the Humerus—Part II. Experimental Testing and Model Validation

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Sarah Pollock ◽  
Susan M. Stover ◽  
M. L. Hull ◽  
Larry D. Galuppo
Keyword(s):  
Mathematical Model ◽  
Stress Fracture ◽  
Biceps Brachii ◽  
Experimental Testing ◽  
Longitudinal Axis ◽  
Principal Strain ◽  
Longitudinal Strains ◽  
The Mathematical Model ◽  
Experimental Strains

The first objective of this study was to experimentally determine surface bone strain magnitudes and directions at the donor site for bone grafts, the site predisposed to stress fracture, the medial and cranial aspects of the transverse cross section corresponding to the stress fracture site, and the middle of the diaphysis of the humerus of a simplified in vitro laboratory preparation. The second objective was to determine whether computing strains solely in the direction of the longitudinal axis of the humerus in the mathematical model was inherently limited by comparing the strains measured along the longitudinal axis of the bone to the principal strain magnitudes and directions. The final objective was to determine whether the mathematical model formulated in Part I [Pollock et al., 2008, ASME J. Biomech. Eng., 130, p. 041006] is valid for determining the bone surface strains at the various locations on the humerus where experimentally measured longitudinal strains are comparable to principal strains. Triple rosette strain gauges were applied at four locations circumferentially on each of two cross sections of interest using a simplified in vitro laboratory preparation. The muscles included the biceps brachii muscle in addition to loaded shoulder muscles that were predicted active by the mathematical model. Strains from the middle grid of each rosette, aligned along the longitudinal axis of the humerus, were compared with calculated principal strain magnitudes and directions. The results indicated that calculating strains solely in the direction of the longitudinal axis is appropriate at six of eight locations. At the cranial and medial aspects of the middle of the diaphysis, the average minimum principal strain was not comparable to the average experimental longitudinal strain. Further analysis at the remaining six locations indicated that the mathematical model formulated in Part I predicts strains within ±2 standard deviations of experimental strains at four of these locations and predicts negligible strains at the remaining two locations, which is consistent with experimental strains. Experimentally determined longitudinal strains at the middle of the diaphysis of the humerus indicate that tensile strains occur at the cranial aspect and compressive strains occur at the caudal aspect while the horse is standing, which is useful for fracture fixation.

scholarly journals A General Modeling Approach for Shock Absorbers: 2 DoF MR Damper Case Study

2021 ◽  
Vol 7 ◽  
Author(s):  
Jorge de-J. Lozoya-Santos ◽  
Juan C. Tudon-Martinez ◽  
Ruben Morales-Menendez ◽  
Olivier Sename ◽  
Andrea Spaggiari ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Linear Models ◽  
Mr Damper ◽  
Shock Absorbers ◽  
Magneto Rheological ◽  
The Mathematical Model ◽  
Force Displacement ◽  
Standard Tests

A methodology is proposed for designing a mathematical model for shock absorbers; the proposal is guided by characteristic diagrams of the shock absorbers. These characteristic diagrams (Force-Displacement, Velocity-Acceleration) are easily constructed from experimental data generated by standard tests. By analyzing the diagrams at different frequencies of interest, they can be classified into one of seven patterns, to guide the design of a model. Finally, the identification of the mathematical model can be obtained using conventional algorithms. This methodology has generated highly non-linear models for 2 degrees of freedom magneto-rheological dampers with high precision (2–10% errors).

scholarly journals WAVE ATTENUATION AND WAVE SET-UP ON A COASTAL REEF

1980 ◽  
Vol 1 (17) ◽  
pp. 27 ◽  
Author(s):  
Franciscus Gerritsen
Keyword(s):  
Mathematical Model ◽  
Wave Attenuation ◽  
Scale Effects ◽  
Shallow Reef ◽  
Laboratory Investigations ◽  
Deep Water Wave ◽  
Set Up ◽  
The University ◽  
Incident Waves ◽  
The Mathematical Model

In attempting to specify criteria for the design of structures on coastal reefs, it was found that no adequate method existed to derive those criteria from the deep water wave conditions. In order to fill the gap, a program of measurements and analysis was initiated at the University of Hawaii. The program consisted of prototype and laboratory measurements. Great emphasis was placed on reliable field data, which were collected on Ala Moana Reef, in Honolulu. Laboratory investigations on the behavior of waves on shallow reefs are subject to scale effects; verification from field observations is required to obtain reliable results. As a result of this study, a mathematical model was developed for the calculation of wave attenuation and wave set-up on a shallow reef, using the incident waves in the ocean as boundary conditions. This paper discusses the general behavior of waves approaching a shallow reef and presents some essential characteristics of the mathematical model. The study is limited to waves approaching the shoreline at right angles. The results of this study can be extended to breakwaters with wide, submerged berms.

scholarly journals Research on Indentation Rolling Resistance Based on Viscoelasticity of Cover Rubber under a Conveyor Belt

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaoxia Zhao ◽  
Wenjun Meng ◽  
Lidong Zhou
Keyword(s):  
Mathematical Model ◽  
Normal Force ◽  
Experimental Testing ◽  
Rolling Resistance ◽  
Maxwell Model ◽  
Conveyor Belt ◽  
Belt Conveyor ◽  
Belt Speed ◽  
Indentation Rolling Resistance ◽  
The Mathematical Model

Minimizing the power consumption of the belt conveyor is the common wish of all enterprises and even countries. Among all the resistances generated by the belt conveyor during the operation, the indentation rolling resistance accounts for the largest proportion and the power consumed is the largest. Therefore, accurately predicting and reducing the rolling resistance of indentation is the focus of current research. Firstly, based on the three-element Maxwell solid model, the dynamic loading experiments of cylindrical rubber made of conveyor belt cover material were carried out at different temperatures. The identification models of elastic moduli E2 and E3 and viscosity coefficient η2 in the three-element Maxwell model were obtained, and then the fitting functions of the three parameters were gotten, which can intuitively reflect the influence of temperature. Secondly, the mathematical model of the indentation rolling resistance was derived. The mathematical model is characterized by the direct parameters such as belt speed v, thickness of backing material h, the idler radius R, and the rubber viscoelastic parameters E2, E3, and η2 and the indirect parameters such as normal force P and temperature T. Afterwards, the effects of belt speed, normal force, temperature, idler radius, and thickness of underlay on the indentation rolling resistance were studied under different working conditions. After that, experimental testing and analysis were fulfilled using test equipment and compared with theoretical analysis results. The results prove that the theoretical results are basically consistent with the experimental results, in line with the actual engineering rules. Finally, the application of the results in practical engineering was analyzed superficially.

Curriculum Schedule Arrangement Solved by an Improved Immune Optimization Algorithm

2013 ◽  
Vol 756-759 ◽  
pp. 3556-3561
Author(s):  
Xiao Feng Li ◽  
An Shi ◽  
Jian Guo Luo
Keyword(s):  
Mathematical Model ◽  
Optimization Algorithm ◽  
Immune Algorithm ◽  
Experimental Result ◽  
Simulation Experiments ◽  
Immune Optimization ◽  
University Timetabling ◽  
Immune Optimization Algorithm ◽  
The University ◽  
The Mathematical Model

To solve the university timetabling problem (UTP) effectively, a immune algorithm-based solution for UTP was proposed. The mathematical model of UTP was expounded, a framework of immune algorithm was given, and simulation experiments were done to validate algorithm. Experimental result shows that proposed algorithm can solve the UTP effectively, and has the advantage of good application value.

scholarly journals Experimental Testing of a Cross-Entropy Algorithm to Detect Damage

2013 ◽  
Vol 569-570 ◽  
pp. 1170-1177 ◽  
Author(s):  
Arturo González ◽  
Enrique Covián ◽  
Miguel Casero ◽  
John Cooper
Keyword(s):  
Finite Element ◽  
Experimental Testing ◽  
Optimization Procedure ◽  
Element Model ◽  
Cross Entropy ◽  
Stiffness Properties ◽  
The Mathematical Model ◽  
Theoretical Simulations ◽  
True Structure ◽  
The Finite Element Model

Cross-entropy optimization has recently been applied to the damage detection in structures subject to static loading. The optimization procedure minimizes the error between the measured deflection data and theoretical deflection data obtained from artificially generated finite element models based on assumed statistical distributions of stiffness for each discretized element. Following a number of iterations, the finite element model with stiffness properties producing deflections closer to reality is established as the mathematical model closest to the true structure. However, while previous testing of the algorithm has been relatively successful, it has been limited to theoretical simulations. Therefore, this paper conducts lab experiments on a beam loaded statically to test the accuracy of the algorithm. Deflections are measured for beam scenarios under different loading levels. The accuracy of the results is discussed and recommendations are made to improve the performance of the algorithm when implemented in practice.

scholarly journals Modelling and Analysis of a Magnetorheological Damper with Nonmagnetized Passages in Piston and Minor Losses

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Guojie Li ◽  
Ze-Biao Yang
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Damping Force ◽  
Mr Fluid ◽  
Pressure Drops ◽  
Viscous Loss ◽  
Minor Losses ◽  
The Mathematical Model

This work aims to establish the mathematical model with the high effectiveness in predicting the damping force of an MR damper with nonmagnetized passages in piston. The pressure drops due to viscous loss, MR effect, and the minor losses at the inlet and outlet of passages are considered in the mathematical model. The widely reported Bingham model is adopted to describe the mechanical property of MR fluid. The mechanical behaviours of the MR damper are experimentally evaluated under different excitations and current. The yield stress of MR fluid with respect to the current applied to piston coil is obtained by finite element analysis in Ansoft Maxwell 14.0. The proposed model is validated by comparing the simulated damping characteristics with the measured data under various currents applied to the piston coil. The simulated results are also compared with those obtained from the mathematical model without the pressure drop due to the minor losses at the inlet and outlet of passages. The comparisons show that the proposed mathematical model can yield more accurate predictions of damping force. This indicates that the pressure drop due to the minor losses is significant and nonnegligible. The nonlinearity of force-velocity characteristics is discussed. In order to quantitatively explain the necessity of taking the minor losses into account for modelling the MR damper, the proportion of pressure drop due to the minor losses to the total pressure drop is investigated and discussed. Pressure drops due to the minor losses and viscous loss are also investigated and discussed. At last, the proposed mathematical model is used to analyse the working principle of nonmagnetized passages.

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