scholarly journals Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4766
Author(s):  
Wojciech Sawczuk ◽  
Armando Miguel Rilo Cañás ◽  
Dariusz Ulbrich ◽  
Jakub Kowalczyk
Keyword(s):  
Friction Coefficient ◽  
Regression Models ◽  
Design Parameters ◽  
Railway Vehicle ◽  
Brake Disc ◽  
Operational Parameters ◽  
International Union ◽  
Disc Surface ◽  
Disc Brakes ◽  
Multiple Regression Models

This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The requirements of the International Union of Railways (UIC) regarding the approval of brake linings for use were taken into account. Based on many years of research using a brake bench to test railway disc brakes, the authors developed multiple regression models for the average friction coefficient and fluctuations (tolerances) in the instantaneous friction coefficient and achieved 870 results. The models proposed three types of variables: the input braking parameters (speed, pressure, and mass to be braked), operational parameters (the wear on the friction linings and the brake disc), and design parameters (perforations in the form of holes on the disc surface). The above two models were validated on the basis of 384 brakes, and in subsequent stages a further evaluation was performed. The coefficients were determined to be, respectively, 0.99 for the model of the average friction coefficient and 0.71 for the model of tolerance (fluctuations) of the instantaneous friction coefficient.

scholarly journals The Application of Vibration Accelerations in the Assessment of Average Friction Coefficient of a Railway Brake Disc

2017 ◽  
Vol 17 (3) ◽  
pp. 125-134 ◽  
Author(s):  
Wojciech Sawczuk
Keyword(s):  
Friction Coefficient ◽  
Heat Dissipation ◽  
Brake Disc ◽  
Brake Pads ◽  
Rail Vehicles ◽  
Wide Range ◽  
Disc Brakes ◽  
Vibroacoustic Diagnostics ◽  
Braking Process

AbstractDue to their wide range of friction characteristics resulting from the application of different friction materials and good heat dissipation conditions, railway disc brakes have long replaced block brakes in many rail vehicles. A block brake still remains in use, however, in low speed cargo trains. The paper presents the assessment of the braking process through the analysis of vibrations generated by the components of the brake system during braking. It presents a possibility of a wider application of vibroacoustic diagnostics (VA), which aside from the assessment of technical conditions (wear of brake pads) also enables the determination of the changes of the average friction coefficient as a function of the braking onset speed. Vibration signals of XYZ were measured and analyzed. The analysis of the results has shown that there is a relation between the values of the point measures and the wear of the brake pads.

scholarly journals Rational design for a friction unit of a disc-shoe brake

2021 ◽  
Vol 25 (3) ◽  
pp. 309-319
Author(s):  
A. E. Litvinov ◽  
P. A. Polyakov ◽  
A. A. Golikov ◽  
N. A. Zadayanchuk
Keyword(s):  
Rational Design ◽  
Design Method ◽  
Friction Pair ◽  
Thermal Stabilization ◽  
Design Stage ◽  
Design Parameters ◽  
Friction Unit ◽  
Brake Disc ◽  
Operational Parameters ◽  
Preliminary Calculation

In this study, we develop a rational design for a friction unit provided that restrictions are imposed on the fly-wheel masses of rotating elements and the onset of a thermal stabilization state. The input calculation data were the braking torque, specific pressure in the friction pair, angular velocity and the diameter of the brake disc hub. The geometric programming method was used at the preliminary stage to calculate the design and operational parameters of a discshoe brake. Further, the parameters were refined based on the conditions of mutually exclusive factors (energy intensity and braking time) and the stress-strain state. On the basis of the proposed rational design for a friction unit, a software application for calculating in the DELPHI programming language was developed. The ranges of design parameters were determined at the preliminary design stage: a brake disc diameter from 0.237 to 0.37 m; the width of working surfaces from 0.0335 to 0.1 m; and the thickness of half-discs from 0.012 to 0.026 m. The final result of the rational design method was the specified ranges of design parameters: diameter from 0.31 to 0.324 m; width from 0.041 to 0.0485 m; and thickness from 0.0148 to 0.0151 m. The developed method of rational design reduces the diameter ranges of the designed brake disc in comparison with the preliminary calculation by 9.5 times, while the ranges of the width of the working surfaces are reduced by 8.9 times, and the thickness range – by 46.6 times. At the final stage, the secondary design and operational parameters of the friction unit were determined: the areas of the working and non-working surfaces of the friction pairs and the coefficient of their mutual overlap. The proposed method of rational design reduces the selected range of design parameters, which will provide a more rational choice of compliance with their specified performance characteristics.

scholarly journals 242 Effect of trucking distance on sale price of beef calf and feeder cattle lots sold through video auctions from 2010 through 2018

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 10-11
Author(s):  
Esther D McCabe ◽  
Mike E King ◽  
Karol E Fike ◽  
Maggie J Smith ◽  
Glenn M Rogers ◽  
...  
Keyword(s):  
Multiple Regression ◽  
Regression Models ◽  
Average Weight ◽  
Sale Price ◽  
Feeder Cattle ◽  
A Value ◽  
Multiple Regression Models ◽  
Determine Effect

Abstract The objective was to determine effect of trucking distance on sale price of beef calf and feeder cattle lots sold through Superior Livestock Video Auctions from 2010 through 2018. Data analyzed were collected from 211 livestock video auctions. There were 42,043 beef calf lots and 19,680 feeder cattle lots used in these analyses. Six states (Colorado, Iowa, Kansas, Nebraska, Oklahoma, and Texas) of delivery comprised 70% of calf lots and 83% of feeder cattle lots and were used in these analyses. All lot characteristics that could be accurately quantified or categorized were used to develop multiple regression models that evaluated effects of independent factors using backwards selection. A value of P < 0.05 was used to maintain a factor in the final models. Based upon reported state of origin and state of delivery, lots were categorized into one of the following trucking distance categories: 1) Within-State, 2) Short-Haul, 3) Medium-Haul, and 4) Long-Haul. Average weight and number of calves in lots analyzed was 259.2 ± 38.4 kg BW and 100.6 ± 74.3 head, respectively. Average weight and number of feeder cattle in lots analyzed was 358.4 ± 34.3 kg BW and 110.6 ± 104.1 head, respectively. Beef calf lots hauled Within-State sold for more ($169.24/45.36 kg; P < 0.0001) than other trucking distance categories (Table 1). Long-Haul calf lots sold for the lowest (P < 0.0001) price ($166.70/45.36 kg). Within-State and Short-Haul feeder cattle lots sold for the greatest (P < 0.0001) price ($149.96 and $149.81/45.36 kg, respectively; Table 2). Long-Haul feeder cattle lots sold for the lowest (P < 0.0001) price, $148.43/45.36 kg. These results indicate there is a price advantage for lots expected to be hauled shorter distances, likely because of cost and risk associated with transportation.

scholarly journals Characterization of Ultra-Thin Diamond-Like Carbon Films by SEM/EDX

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 729
Author(s):  
Chanida Puttichaem ◽  
Guilherme P. Souza ◽  
Kurt C. Ruthe ◽  
Kittipong Chainok
Keyword(s):  
Regression Models ◽  
Hard Disk Drives ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Disk Drives ◽  
Cross Sectional ◽  
Protective Films ◽  
High Throughput Method ◽  
Multiple Regression Models

A novel, high throughput method to characterize the chemistry of ultra-thin diamond-like carbon films is discussed. The method uses surface sensitive SEM/EDX to provide substrate-specific, semi-quantitative silicon nitride/DLC stack composition of protective films extensively used in the hard disk drives industry and at Angstrom-level. SEM/EDX output is correlated to TEM to provide direct, gauge-capable film thickness information using multiple regression models that make predictions based on film constituents. The best model uses the N/Si ratio in the films, instead of separate Si and N contributions. Topography of substrate/film after undergoing wear is correlatively and compositionally described based on chemical changes detected via the SEM/EDX method without the need for tedious cross-sectional workflows. Wear track regions of the substrate have a film depleted of carbon, as well as Si and N in the most severe cases, also revealing iron oxide formation. Analysis of film composition variations around industry-level thicknesses reveals a complex interplay between oxygen, silicon and nitrogen, which has been reflected mathematically in the regression models, as well as used to provide valuable insights into the as-deposited physics of the film.

Fatigue life assessment for brake disc of railway vehicle

2009 ◽  
Vol 33 (1) ◽  
pp. 37-42 ◽  
Author(s):  
D.-J. KIM ◽  
C.-S. SEOK ◽  
J.-M. KOO ◽  
W.-T. WE ◽  
B.-C. GOO ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Life Assessment ◽  
Railway Vehicle ◽  
Brake Disc ◽  
Fatigue Life Assessment

Multiple regression models for predicting total daily pollen concentration in Cartagena

Grana ◽  
2005 ◽  
Vol 44 (2) ◽  
pp. 108-114 ◽  
Author(s):  
José Manuel Angosto ◽  
Stella Moreno‐Grau ◽  
Javier Bayo ◽  
Belén Elvira‐Rendueles
Keyword(s):  
Multiple Regression ◽  
Regression Models ◽  
Pollen Concentration ◽  
Multiple Regression Models ◽  
Daily Pollen Concentration

The Effects of Prepaid Metering Systems on Customer Satisfaction in Niger State, Nigeria

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Ayooluwa Femi Aribisala ◽  
Musa Mohammed
Keyword(s):  
Customer Satisfaction ◽  
Regression Models ◽  
Response Rate ◽  
Spearman Correlation ◽  
Electricity Use ◽  
Customer Care ◽  
Level Of Satisfaction ◽  
Multiple Regression Models ◽  
The Relationship ◽  
Structured Questionnaire

Energy consumers in Nigeria have long complained about Distribution Companies' unfair billing practices, exorbitant monthly electricity bills resulting from meter estimation rather than accurate meter reading and calculation based on uninterrupted electricity use. The objectives of the study were to establish the relationship between the prepaid metering system and customer satisfaction; and to evaluate the level of satisfaction with respect to the usage of the prepaid metering system in Niger State, Nigeria. In carrying out the study, the structured questionnaire was administered to 393 randomly chosen respondents drawn from prepaid meter users, out of which 344 responded generating a response rate of 87.5%. The data derived were subjected to spearman correlation and multiple regression models. The major findings from the study showed a significant, moderate and positive relationship between the prepaid metering system and customer satisfaction. Additionally, three significant predictors, Affordability, Availability and Flexibility with p < .01 are statistically significant. Further findings from descriptive statistics revealed that users had the highest level of satisfaction with the privacy they had as a result of no meter readers and no accumulated. The study concluded that there exist a positive and beneficial link between the prepaid metering system and customer satisfaction. The study therefore recommends the provision of a smart metering system, good customer care units and a marketing campaign for better knowledge of the prepaid metering system.

scholarly journals New Algorithms for L1 Norm Regression

2019 ◽  
Vol 1 (1) ◽  
pp. 1-18
Author(s):  
Bijan Bidabad
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Simple Linear Regression ◽  
L1 Norm ◽  
Median Problem ◽  
Regression Parameters ◽  
Multiple Regression Models ◽  
Weighted Median ◽  
Weighted Median Problem ◽  
New Algorithms

In this paper, we propose four algorithms for L1 norm computation of regression parameters, where two of them are more efficient for simple and multiple regression models.  However, we start with restricted simple linear regression and corresponding derivation and computation of the weighted median problem. In this respect, a computing function is coded.  With discussion on the m parameters model, we continue to expand the algorithm to include unrestricted simple linear regression, and two crude and efficient algorithms are proposed. The procedures are then generalized to the m parameters model by presenting two new algorithms, where the algorithm 4 is selected as more efficient. Various properties of these algorithms are discussed.

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