scholarly journals Experimental and numerical tests of thermo-mechanical processes occurring on brake pad lining surfaces

2011 ◽  
Author(s):  
P. Baranowski ◽  
K. Damziak ◽  
J. Malachowski ◽  
L. Mazurkiewicz ◽  
M. Kastek ◽  
...  
Keyword(s):  
Brake Pad ◽  
Numerical Tests

BaSO4-Friction Dust Filler Improves Friction Characteristic in Non-Asbestos Brake Pad Composite

2019 ◽  
Vol 13 (9) ◽  
pp. 513
Author(s):  
Putri Nawangsari ◽  
Jamasri Jamasri ◽  
Heru Santoso Budi Rochardjo ◽  
Arif Tri Waskito
Keyword(s):  
Brake Pad ◽  
Friction Characteristic

Production of Asbestos-free Brake Pad Using Groundnut Shell as Filler Material

2018 ◽  
Vol 4 (12) ◽  
Author(s):  
W. C. Solomon ◽  
M. T. Lilly ◽  
J. I. Sodiki
Keyword(s):  
Phenolic Resin ◽  
Cost Effective ◽  
Filler Material ◽  
Particle Sizes ◽  
Brake Pad ◽  
Brake Pads ◽  
Environmental Friendly ◽  
Sieve Size ◽  
Groundnut Shell ◽  
The Cost

The development and evaluation of brake pads using groundnut shell (GS) particles as substitute material for asbestos were carried out in this study. This was with a view to harnessing the properties of GS, which is largely deposited as waste, and in replacing asbestos which is carcinogenic in nature despite its good tribological and mechanical properties. Two sets of composite material were developed using varying particle sizes of GS as filler material, with phenolic resin as binder with percentage compositions of 45% and 50% respectively. Results obtained indicate that the compressive strength and density increase as the sieve size of the filler material decreases, while water and oil absorption rates increase with an increase in sieve size of GS particle. This study also indicates that the cost of producing brake pad can be reduced by 19.14 percent if GS is use as filler material in producing brake pad. The results when compared with those of asbestos and industrial waste showed that GS particle can be used as an effective replacement for asbestos in producing automobile brake pad. Unlike asbestos, GS-based brake pads are environmental friendly, biodegradable and cost effective.

Tribological and dynamical analysis of a brake pad with multiple blocks for a high-speed train

2019 ◽  
Vol 234 (11) ◽  
pp. 1771-1788
Author(s):  
YK Wu ◽  
JL Mo ◽  
B Tang ◽  
JW Xu ◽  
B Huang ◽  
...  
Keyword(s):  
High Speed ◽  
Wear Behavior ◽  
Dynamical Analysis ◽  
Brake Disc ◽  
Brake Pad ◽  
High Speed Train ◽  
Brake Squeal ◽  
Element Analysis ◽  
Single Block ◽  
Middle Ring

In this research, the tribological and dynamical characteristics of a brake pad with multiple blocks are investigated using experimental and numerical methods. A dynamometer with a multiblock brake pad configuration on a brake disc is developed and a series of drag-type tests are conducted to study the brake squeal and wear behavior of a high-speed train brake system. Finite element analysis is performed to derive physical explanations for the observed experimental phenomena. The experimental and numerical results show that the rotational speed and braking force have important influences on the brake squeal; the trends of the multiblock and single-block systems are different. In the multiblock brake pad, the different blocks exhibit significantly different magnitudes of contact stresses and vibration accelerations. The blocks located in the inner and outer rings have higher vibration acceleration amplitudes and stronger vibration energies than the blocks located in the middle ring.

scholarly journals Emission Characteristics for Swirl Methane–Air Premixed Flames with Ammonia Addition

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 662
Author(s):  
Joanna Jójka ◽  
Rafał Ślefarski
Keyword(s):  
Equivalence Ratio ◽  
Combustion Process ◽  
Great Influence ◽  
Emission Characteristics ◽  
Firing Rates ◽  
Numerical Tests ◽  
Ammonia Addition ◽  
Swirl Flame ◽  
Reactor Network ◽  
No Emissions

This paper details the experimental and numerical analysis of a combustion process for atmospheric swirl burners using methane with added ammonia as fuel. The research was carried out for lean methane–air mixtures, which were doped with ammonia up to 5% and preheated up to 473 K. A flow with internal recirculation was induced by burners with different outflow angles from swirling blades, 30° and 50°, where tested equivalence ratio was 0.71. The NO and CO distribution profiles on specified axial positions of the combustor and the overall emission levels at the combustor outlet were measured and compared to a modelled outcome. The highest values of the NO emissions were collected for 5% NH3 and 50° (1950 ppmv), while a reduction to 1585 ppmv was observed at 30°. The doubling of the firing rates from 15 kW up to 30 kW did not have any great influence on the overall emissions. The emission trend lines were not proportional to the raising share of the ammonia in the fuel. 3D numerical tests and a kinetic study with a reactor network showed that the NO outlet concentration for swirl flame depended on the recirculation ratio, residence time, wall temperature, and the mechanism used. Those parameters need to be carefully defined in order to get highly accurate NO predictions—both for 3D simulations and simplified reactor-based models.

scholarly journals Some transpose-free CG-like solvers for nonsymmetric ill-posed problems

2020 ◽  
Vol 28 (1) ◽  
pp. 15-32
Author(s):  
Silvia Gazzola ◽  
Paolo Novati
Keyword(s):  
Krylov Subspace ◽  
Main Idea ◽  
System Matrix ◽  
Numerical Tests ◽  
New Methods ◽  
Arnoldi Algorithm ◽  
Ill Posed ◽  
Efficient Alternative ◽  
Original Class ◽  
Theoretical Insight

AbstractThis paper introduces and analyzes an original class of Krylov subspace methods that provide an efficient alternative to many well-known conjugate-gradient-like (CG-like) Krylov solvers for square nonsymmetric linear systems arising from discretizations of inverse ill-posed problems. The main idea underlying the new methods is to consider some rank-deficient approximations of the transpose of the system matrix, obtained by running the (transpose-free) Arnoldi algorithm, and then apply some Krylov solvers to a formally right-preconditioned system of equations. Theoretical insight is given, and many numerical tests show that the new solvers outperform classical Arnoldi-based or CG-like methods in a variety of situations.

scholarly journals PDE limits of stochastic SIS epidemics on networks

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
F Di Lauro ◽  
J-C Croix ◽  
L Berthouze ◽  
I Z Kiss
Keyword(s):  
Network Inference ◽  
Mean Field ◽  
Population Level ◽  
Death Process ◽  
Disease Dynamics ◽  
Epidemic Outbreak ◽  
Numerical Tests ◽  
Mean Field Models ◽  
Stochastic Epidemic ◽  
Fokker Planck Equations

Abstract Stochastic epidemic models on networks are inherently high-dimensional and the resulting exact models are intractable numerically even for modest network sizes. Mean-field models provide an alternative but can only capture average quantities, thus offering little or no information about variability in the outcome of the exact process. In this article, we conjecture and numerically demonstrate that it is possible to construct partial differential equation (PDE)-limits of the exact stochastic susceptible-infected-susceptible epidemics on Regular, Erdős–Rényi, Barabási–Albert networks and lattices. To do this, we first approximate the exact stochastic process at population level by a Birth-and-Death process (BD) (with a state space of $O(N)$ rather than $O(2^N)$) whose coefficients are determined numerically from Gillespie simulations of the exact epidemic on explicit networks. We numerically demonstrate that the coefficients of the resulting BD process are density-dependent, a crucial condition for the existence of a PDE limit. Extensive numerical tests for Regular, Erdős–Rényi, Barabási–Albert networks and lattices show excellent agreement between the outcome of simulations and the numerical solution of the Fokker–Planck equations. Apart from a significant reduction in dimensionality, the PDE also provides the means to derive the epidemic outbreak threshold linking network and disease dynamics parameters, albeit in an implicit way. Perhaps more importantly, it enables the formulation and numerical evaluation of likelihoods for epidemic and network inference as illustrated in a fully worked out example.

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