Relationships between the decoupled and coupled transfer functions: Theoretical studies and experimental validation

2018 ◽  
Vol 98 ◽  
pp. 936-950 ◽  
Author(s):  
Zengwei Wang ◽  
Ping Zhu ◽  
Zhao Liu
2017 ◽  
Vol 139 (5) ◽  
Author(s):  
David Kostal ◽  
Petr Sperka ◽  
Petr Svoboda ◽  
Ivan Krupka ◽  
Martin Hartl

The paper deals with an experimental study of an elastohydrodynamic contact under insufficient lubricant supply. Theoretical studies published in this research area focus mainly on the development of theoretical models, and there is a lack of experimental validation of the theoretical models. This paper presents original experimental results and aims to describe the starvation severity level as a function of the inlet film thickness and contact geometry. Experimental data are compared with an analytical model for point contacts published by Chevalier. The study was also extended to elliptical contacts to achieve a comparison with the different parameters of the side-flow resistance used by Damiens. Both models agree well with the experiments.


2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Dorian Vigoureux ◽  
Nicolas Totaro ◽  
Jonathan Lagneaux ◽  
Jean-Louis Guyader

Many methods to detect, quantify, or reconstruct acoustic sources exist in the literature and are widely used in industry (near-field acoustic holography, inverse boundary element method, etc.). However, the source identification in a reverberant or nonanechoic environment on an irregularly shaped structure is still an open issue. In this context, the inverse patch transfer functions (iPTF) method first introduced by Aucejo et al. (2010, “Identification of Source Velocities on 3D Structures in Non-Anechoic Environments: Theoretical Background and Experimental Validation of the Inverse Patch Transfer Functions Method,” J. Sound Vib., 329(18), pp. 3691–3708) can be a suitable method. Indeed, the iPTF method has been developed to identify source velocity on complex geometries and in a nonanechoic environment. However, to obtain good results, the application of the method must follow rigorous criteria that were not fully investigated yet. In addition, as it was first defined, the iPTF method only provides source velocity while wall pressure or intensity should also give useful information to engineers. In the present article, a procedure to identify wall pressure and intensity of the source without any additional measurement is proposed. This procedure only needs simple numerical postprocessing. Using this new intensity identification, the influence of background noise, evanescent waves, and mesh discretization are illustrated on numerical examples. Finally, an experiment on a vibrating plate is shown to illustrate the iPTF procedure.


2004 ◽  
Vol 16 (3) ◽  
pp. 477-489 ◽  
Author(s):  
Petr Lánský ◽  
Roger Rodriguez ◽  
Laura Sacerdote

Frequency coding is considered one of the most common coding strategies employed by neural systems. This fact leads, in experiments as well as in theoretical studies, to construction of so-called transfer functions, where the output firing frequency is plotted against the input intensity. The term firing frequency can be understood differently in different contexts. Basically, it means that the number of spikes over an interval of preselected length is counted and then divided by the length of the interval, but due to the obvious limitations, the length of observation cannot be arbitrarily long. Then firing frequency is defined as reciprocal to the mean interspike interval. In parallel, an instantaneous firing frequency can be defined as reciprocal to the length of current interspike interval, and by taking a mean of these, the definition can be extended to introduce the mean instantaneous firing frequency. All of these definitions of firing frequency are compared in an effort to contribute to a better understanding of the input-output properties of a neuron.


Author(s):  
Veysel Erel ◽  
Mingliang Jiang ◽  
Michael R. Moreno ◽  
Alan D. Freed

There have been various theoretical studies done on anisotropic neo-Hookean models; however, there have been limited experimental validations of these theories. In this study, a silicone/silicone laminate with a fiber volume fraction of 18% has been parameterized. Conventional neo-Hookean models have been modified for compressible in-plane deformations. Two-dimensional deformation limitations and a compressible constraint have been discussed. Material parameters have been calculated for three different anisotropic, neo-Hookean models from the literature.


Author(s):  
M. Hamed ◽  
B. Tesfa ◽  
F. Gu ◽  
A.D. Ball

Incorrect inflation pressures in tyres affects the vehicle handling, passenger comfort and braking conditions in addition to causing a reduction in fuel efficiency and tyre life. To address this problem, mathematical models have been produced and an experimental validation has been carried out. The models were developed with 7-DOF, for a full car system, using MATLAB programs. In the simulation study, the suspension faults have been considered by running the models with a range of inflation pressures at four conditions i.e. at standard pressure (2.3bar) and 1.5bar on the passenger wheel, driver wheel and front wheels. In each case, an analysis was carried out on the performances of the suspension in terms of ride comfort, road handling and stability of the vehicle followed by the presentation of the results obtained. In addition, the influence of parameter variations on transfer functions as a fault detection of suspension has been introduced. This approach has been used when detecting faults of vehicle tyres being under-inflated 35% and also to detect other suspension faults in the future.


2017 ◽  
Vol 50 (1) ◽  
pp. 4528-4533 ◽  
Author(s):  
Gustavo A. de Andrade ◽  
Rafael Vazquez ◽  
Daniel J. Pagano

Author(s):  
F P Wardle

Experimental vibration measurements of a system containing a single ball bearing are compared with theoretical predictions based upon the model described in Part 1 and measurements of system transfer functions. Agreement between theory and experiment is reasonable.


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