An analytical thermal model of a railway vehicle brake shoe

2021 ◽  
pp. 095440972110221
Author(s):  
SME Ghafelehbashi ◽  
MR Talaee
Keyword(s):  
Cast Iron ◽  
Thermal Model ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Form Solution ◽  
Frictional Heat ◽  
Railway Vehicle ◽  
Brake Shoe ◽  
Good Ability ◽  
Analytical Thermal Model

Estimation of temperature distribution in brake shoes is very important in order to prevent thermal damages such as cracks, fading etc. In this research, the thermal model of brake shoe in a train is introduced considering time-dependent frictional heat load in two modes of emergency and continuous braking. The governing heat conduction equation is solved in polar coordinate by using the method of separation of variables combined with Duhamel integral and a closed-form solution is introduced. Results show the good ability of analytical solution to estimate exact temperature profile in composite and cast iron brake shoes. The ability of the solution for estimation of braking situation to prevent from melting criteria is demonstrated. The composite brake shoe will reach to the melting point of 590 °C in continuous braking at the speed of about 120 km/h and the fading limit in cast iron shoe is occurred after 8 sec in emergency braking mode. The introduced thermal model can be applied as a verification branch of other works and can reduced the huge costs of experimental tests of brake shoes.

scholarly journals An exact solution of linearized flow of an emitting, absorbing and scattering grey gas

1971 ◽  
Vol 45 (4) ◽  
pp. 673-699 ◽  
Author(s):  
Ping Cheng ◽  
A. Leonard
Keyword(s):  
Integral Equation ◽  
Exact Solution ◽  
Transport Theory ◽  
Neutron Transport ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Strong Shock ◽  
Form Solution ◽  
Isotropic Scattering ◽  
Differential Approximation

The governing equations for the problem of linearized flow through a normal shock wave in an emitting, absorbing, and scattering grey gas are reduced to two linear coupled integro-differential equations. By separation of variables, these equations are further reduced to an integral equation similar to that which arises in neutron-transport theory. It is shown that this integral equation admits both regular (associated with discrete eigenfunctions) and singular (associated with continuum eigenfunctions) solutions to form a complete set. The exact closed-form solution is obtained by superposition of these eigen-functions. If the gas downstream of a strong shock is absorption–emission dominated, the discrete mode of the solution disappears downstream. The effects of isotropic scattering are discussed. Quantitative comparison between the numerical results based on the exact solution and on the differential approximation are presented.

Applications of the symplectic method in quasi-static analysis for viscoelastic functionally graded materials

2017 ◽  
Vol 34 (4) ◽  
pp. 1314-1331 ◽  
Author(s):  
W.X. Zhang ◽  
R.G. Liu ◽  
Y. Bai
Keyword(s):  
Functionally Graded Materials ◽  
Correspondence Principle ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Form Solution ◽  
Functionally Graded ◽  
Symplectic Method ◽  
Graded Materials ◽  
Content Type ◽  
Displacement Constraints

Purpose For general quasi-static problems of viscoelastic functionally graded materials (VFGMs), the correspondence principle can be applied only for simple structures with a closed form solution of the corresponding elastic problem exists. In this paper, a new symplectic approach, according to the correspondence principle between linearly elastic and viscoelastic solids, is proposed for quasi-static VFGMs. Design/methodology/approach Firstly, by employing the method of separation of variables, all the fundamental eigenvectors of the governing equations are obtained analytically. Then, the satisfactions of boundary conditions prescribed on the ends and laterals are discussed based on the variable substitution and the eigenvector expansion methods. Findings In the numerical examples, some boundary condition problems are given. The results show the local effects due to the displacement constraints. Originality/value The paper provides an innovative technique for quasi-static problems of VFG Ms. Its correctness and the efficiency are well suported by numerical results.

Exact Analytical Hyperbolic Temperature Profile in a Three-Dimensional Media Under Pulse Surface Heat Flux

2015 ◽  
Vol 32 (3) ◽  
pp. 339-347 ◽  
Author(s):  
M. R. Talaee ◽  
V. Sarafrazi ◽  
S. Bakhshandeh
Keyword(s):  
Heat Flux ◽  
Numerical Solutions ◽  
Rectangular Cross Section ◽  
Separation Of Variables ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Biological Tissues ◽  
Form Solution ◽  
Hyperbolic Heat Conduction ◽  
Duhamel Integral

AbstractIn this paper three-dimensional hyperbolic heat conduction equation in a cubic media with rectangular cross-section under a pulsed heat flux on the upper side has been solved analytically using the method of separation of variables and the Duhamel integral. The closed form solution of both Fourier and non-Fourier profiles are introduced with both modes of steady and pulsed fluxes. The results show the considerable difference between the Fourier and Non-Fourier temperature profiles. Then the answer procedure is used for modeling of interaction of a cubical tissue under a short laser pulse heating. The effects of pulse duration and laser intensity are studied analytically. Furthermore the results can be applied as a verification branch for other numerical solutions or laser treatments of biological tissues.

Closed Form Solutions for Vibration and Sound Radiation of Orthotropic Plates under Thermal Environment

2018 ◽  
Vol 18 (07) ◽  
pp. 1850098 ◽  
Author(s):  
Kai Zhou ◽  
Jinpeng Su ◽  
Hongxing Hua
Keyword(s):  
Closed Form ◽  
Orthotropic Plate ◽  
Acoustic Analysis ◽  
Thermal Environment ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Form Solution ◽  
Thermal Loads ◽  
Orthotropic Plates ◽  
Heated Plates

This paper presents a closed form solution for the vibration and acoustic problem of orthotropic plates under a thermal environment. Hamilton’s principle is utilized to derive the governing equation of motion for the orthotropic plate with thermal loads, which is then solved by the method of separation of variables. The frequency equations and mode functions obtained for the orthotropic heated plates with at least two adjacent edges clamped are much simpler than those by the conventional methods. Several numerical examples are carried out for the modal, dynamic and acoustic analysis of orthotropic heated plates with different combinations of thermal loads and boundary conditions. The results of the parametric study for the orthotropic plate with different thermal loads are discussed in detail. The validity of the present formulation is confirmed by comparing the results obtained with the numerical ones. Due to its accuracy, efficiency and versatility, the present method offers an efficient tool for the structural and acoustic analysis of the orthotropic plate under the thermal environment.

A Closed Form Solution for Wave Propagation in a Rectangular Waveguide Filled with Time-Varying Media

2014 ◽  
Vol 900 ◽  
pp. 110-115
Author(s):  
Bing Kang Chen ◽  
Feng Guo
Keyword(s):  
Closed Form ◽  
Rectangular Waveguide ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Form Solution ◽  
Time Varying ◽  
Propagation Characteristics ◽  
Te Mode ◽  
Accurate Expression ◽  
The Waves

In this paper, the solution and some propagation characteristics of waves inside a rectangular waveguide in the time-varying media are presented. The separation of variables method is used to get a closed form solution i.e. accurate expression for TE mode when the permittivity of media changes with respect to time. It is clearly shown that both the amplitude and frequency of the waves in rectangular waveguide change with respect to time in time-varying permittivity.

On a Closed-Form Solution of Prandtl's System of Equations

2013 ◽  
Vol 40 (2) ◽  
pp. 106-114
Author(s):  
J. Venetis ◽  
Aimilios (Preferred name Emilios) Sideridis
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
System Of Equations

Plane Wave Resonance in the Tire Air Cavity as a Vehicle Interior Noise Source

1995 ◽  
Vol 23 (1) ◽  
pp. 2-10 ◽  
Author(s):  
J. K. Thompson
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Interior Noise ◽  
Cavity Resonance ◽  
Test Results ◽  
Vehicle Interior ◽  
Air Cavity ◽  
Vehicle Interior Noise ◽  
Wave Resonance ◽  
Resonance Frequencies

Abstract Vehicle interior noise is the result of numerous sources of excitation. One source involving tire pavement interaction is the tire air cavity resonance and the forcing it provides to the vehicle spindle: This paper applies fundamental principles combined with experimental verification to describe the tire cavity resonance. A closed form solution is developed to predict the resonance frequencies from geometric data. Tire test results are used to examine the accuracy of predictions of undeflected and deflected tire resonances. Errors in predicted and actual frequencies are shown to be less than 2%. The nature of the forcing this resonance as it applies to the vehicle spindle is also examined.

Capacity Analysis for Correlated Multi-Hop MIMO Channels under Colored Noise

2015 ◽  
Vol 1 ◽  
pp. 41
Author(s):  
Nguyen N. Tran ◽  
Ha X. Nguyen
Keyword(s):  
Computational Complexity ◽  
Mutual Information ◽  
Closed Form Solution ◽  
Optimal Solution ◽  
Form Solution ◽  
Maximization Problem ◽  
Capacity Analysis ◽  
Mimo Channels ◽  
Average Mutual Information ◽  
Channel Output

A capacity analysis for generally correlated wireless multi-hop multi-input multi-output (MIMO) channels is presented in this paper. The channel at each hop is spatially correlated, the source symbols are mutually correlated, and the additive Gaussian noises are colored. First, by invoking Karush-Kuhn-Tucker condition for the optimality of convex programming, we derive the optimal source symbol covariance for the maximum mutual information between the channel input and the channel output when having the full knowledge of channel at the transmitter. Secondly, we formulate the average mutual information maximization problem when having only the channel statistics at the transmitter. Since this problem is almost impossible to be solved analytically, the numerical interior-point-method is employed to obtain the optimal solution. Furthermore, to reduce the computational complexity, an asymptotic closed-form solution is derived by maximizing an upper bound of the objective function. Simulation results show that the average mutual information obtained by the asymptotic design is very closed to that obtained by the optimal design, while saving a huge computational complexity.

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