scholarly journals Calculation of Rail Internal Impedance by Using Finite Elements Methods and Complex Magnetic Permeability

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Alberto Dolara ◽  
Sonia Leva
Keyword(s):  
Finite Elements ◽  
Magnetic Permeability ◽  
Magnetization Curve ◽  
Analytical Models ◽  
Internal Parameter ◽  
Internal Inductance ◽  
Internal Impedance ◽  
Normal Magnetization ◽  
Complex Magnetic Permeability ◽  
Finite Elements Methods

The internal parameter of UNI 60 rail is calculated by using finite elements methods. Steel's characterizations by its normal magnetization curve and by complex magnetic permeability are here considered and included into the proposed FEM models. Rail's resistance and internal inductance in function of current and frequency are calculated using both FEM and analytical models. The results obtained at the frequency of 50 Hz are compared with few measurements available, and then they are extended to other frequencies.

A Discretization Scheme for a Quasi-Hydrodynamic Semiconductor Model

1997 ◽  
Vol 07 (07) ◽  
pp. 935-955 ◽  
Author(s):  
Ansgar Jüngel ◽  
Paola Pietra
Keyword(s):  
Finite Elements ◽  
Mixed Finite Elements ◽  
Exponential Fitting ◽  
Discretization Scheme ◽  
Drift Diffusion Model ◽  
Drift Diffusion ◽  
Current Conservation ◽  
Numerical Tests ◽  
Finite Elements Methods ◽  
Degenerate Type

A discretization scheme based on exponential fitting mixed finite elements is developed for the quasi-hydrodynamic (or nonlinear drift–diffusion) model for semiconductors. The diffusion terms are nonlinear and of degenerate type. The presented two-dimensional scheme maintains the good features already shown by the mixed finite elements methods in the discretization of the standard isothermal drift–diffusion equations (mainly, current conservation and good approximation of sharp shapes). Moreover, it deals with the possible formation of vacuum sets. Several numerical tests show the robustness of the method and illustrate the most important novelties of the model.

scholarly journals Instrumentation for mechanical vibrations analysis in the time domain and frequency domain using the Arduino platform

2016 ◽  
Vol 38 (1) ◽  
Author(s):  
Marcus Varanis ◽  
Anderson Langone Silva ◽  
Pedro Henrique Ayres Brunetto ◽  
Rafael Ferreira Gregolin
Keyword(s):  
Signal Processing ◽  
Finite Elements ◽  
Time Domain ◽  
Good Accuracy ◽  
Low Cost ◽  
Analytical Models ◽  
Experimental Setup ◽  
Mechanical Vibrations ◽  
Python Language ◽  
The Time Domain

In this paper, we use the Arduino platform together with sensors as accelerometer, gyroscope and ultrasound, to measure vibrations in mechanical systems. The main objective is to assemble a signals acquisition system easy to handle, of low cost and good accuracy for teaching purposes. It is also used the Python language and its numerical libraries for signal processing. This paper proposes the study of vibrations of a beam, which is measured by position, velocity and acceleration. An experimental setup was implemented. The results obtained are compared with analytical models and computer simulations using finite elements. The results are in agreement with the literature.

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