scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

scholarly journals Assessment of the functional functionality of passenger car brake systems by changing the braking distance during operation

2021 ◽  
Vol 13 (1) ◽  
pp. 78-86
Author(s):  
Alexander Nazarov ◽  
◽  
Vitalii Kashkanov ◽  
Ivan Nazarov ◽  
Yevhen Ivanchenko ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Passenger Cars ◽  
Passenger Car ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Distance ◽  
Braking Force ◽  
Braking Process ◽  
Relative Change

The article discusses a methodology for assessing the functional suitability of brake systems to change the braking path of passenger cars, taking into account various operating conditions. The goal is achieved by using the method of mathematical modeling of the emergency braking process, taking into account the possible operating conditions of cars performing emergency braking at certain initial speeds, in particular, exceeding 100 km / h. Based on the analysis of scientific sources, it has been established that the determination of the braking efficiency of a vehicle classically occurs on the verge of blocking all wheels with known methods of distributing braking forces between the axles of the vehicle. In this case, the standards set the maximum value of the minimum deceleration and braking distance. In addition, the jump in the maximum possible value of the braking force between the wheels of each axle makes it possible to compare it with the requirements of DSTU 3649: 2010, and the assessment of the magnitude of this jump for each braking of the car is to establish its functional suitability. As a result, according to the magnitude of the jump in the maximum possible value of the braking distance, the change in the maximum allowable braking force of the car sets, and according to the magnitude of its jump, it is possible to assess the functional suitability of its braking system. As a result, the use of expert information on the value of jumps in the maximum possible value of the braking force of a car, affecting the braking torques and braking coefficient, can reduce the amount of experimental research and significantly reduce the time to reach an objective decision on the functional suitability of the brake systems of operated cars. The paper presents the results of theoretical studies of passenger cars Chevrolet Aveo, Lada Priora and Forza with different loads, performing emergency braking at an initial speed of 40-150 km / h on a road with dry asphalt concrete. The boundaries of the coefficient of the relative change in the braking distance of the tested passenger car, at which it is possible to make a conclusion about the functional suitability of its braking system, have been established.

scholarly journals Comparative assessment of braking properties of operated passenger cars, according to brake wear

2021 ◽  
Vol 12 (2) ◽  
pp. 76-84
Author(s):  
Alexander Nazarov ◽  
◽  
Ivan Nazarov ◽  
Yevhen Shpinda ◽  
Sergiy Shablenko ◽  
...  
Keyword(s):  
Comparative Assessment ◽  
Operating Conditions ◽  
Passenger Cars ◽  
Passenger Car ◽  
Adhesion Properties ◽  
The Road ◽  
Braking System ◽  
Brake Force ◽  
Output Characteristics ◽  
Braking Process

The article proposes a method for assessing the change in the braking properties of passenger cars during operation following a change in the main characteristic of the brake system - the coefficient of distribution of braking forces between the axles of vehicles, both equipped and not equipped with tracking systems for the braking process by installing brake force regulators in the brake circuits, working according to different laws of changing the drive pressure. The aim of the work is a comparative assessment of the braking efficiency of passenger cars using the example of Lanos cars, the braking systems of which are equipped with various devices for changing the coefficient of distribution of braking forces between the axles, under changing operating conditions. It is known that braking efficiency is an indicator characterizing the braking properties and the ability of a car to maintain a given law of motion during braking, which is determined both by the nature of the adhesion properties of the wheels to the road and the capabilities of the braking system itself to implement these properties. Since the operating conditions of passenger cars significantly affect the braking properties, in order to ensure the required braking efficiency, it is necessary to take into account the change in the primary distribution coefficient of the braking forces generated by the braking mechanisms and the change in their implementation during the operation period. In order to assess the change in the braking properties in the general case of the operation of a passenger car, the dependence of the actual coefficient of distribution of braking forces between the axles on the braking coefficient was proposed. Moreover, the value of the coefficient of distribution of braking forces between the axles depends both on the type of laws of regulation of braking forces and on the residual values of the parameters of braking systems that determine these laws. These dependences on the parameters of the braking systems and the parameters of the passenger car in operation are a function of the goal for determining the residual output characteristics of its braking system.

THE USE OF METALLOGRAPHIC ANALYSIS OF FRICTION LININGS IN THE BRAKING SYSTEM TO DETERMINE THE PROCESSES OF TRIBOLOGICAL WEAR

Tribologia ◽  
2018 ◽  
Vol 279 (3) ◽  
pp. 13-18
Author(s):  
Henryk BĄKOWSKI ◽  
Zbigniew STANIK ◽  
Bartosz CHMIELA
Keyword(s):  
Qualitative Analysis ◽  
Diagnostic Criteria ◽  
Wear Mechanisms ◽  
Motor Vehicle ◽  
Friction Pair ◽  
Operating Conditions ◽  
Metallographic Analysis ◽  
Technical Object ◽  
Service Employees ◽  
Braking System

The work presents metallographic examinations of worn brake linings under various operating conditions. The main purpose of this work is to determine the types of friction pair wear of braking systems under specific operating conditions. This is important for car service employees and appraisers who, based on quantitative and qualitative analysis, will determine the dominant mechanisms of wear. This is very important due to the possibility of determining the operating conditions, and thus the assessment of the use not only of the friction pair, but also the entire technical object, which is a motor vehicle. On the basis of the quantitative metallographic analysis of the research, individual wear mechanisms were presented, taking into account the determined diagnostic criteria during the measurement.

scholarly journals Extremum-seeking algorithms for the emergency braking of heavy goods vehicles

2017 ◽  
Vol 231 (14) ◽  
pp. 1961-1977 ◽  
Author(s):  
Graeme Morrison ◽  
David Cebon
Keyword(s):  
Performance Metrics ◽  
Sliding Mode ◽  
Model Fitting ◽  
Operating Conditions ◽  
Extremum Seeking ◽  
Wheel Slip ◽  
Slip Control ◽  
Emergency Braking ◽  
Braking System ◽  
Heavy Goods Vehicles

A pneumatic slip control braking system was demonstrated, which reduces the emergency stopping distances of heavy goods vehicles by up to 19%. Solutions are still required to set the optimal reference wheel slip for this system online, so that it can adapt to changing operating conditions. This paper considers whether the use of extremum-seeking algorithms is a feasible alternative approach to online tyre model fitting, the computational expense of which has, to date, inhibited real-time implementation. The convergence and the stability properties of a first-order sliding-mode extremum-seeking algorithm are discussed, and its tuneable parameters are recast as physically meaningful performance metrics. Computer simulations are conducted using a detailed braking system model, and hardware-in-the-loop simulations are conducted with prototype pneumatic slip control braking hardware for heavy goods vehicles. The extremum-seeking algorithm enables the braking system to achieve at least 95% of the maximum possible braking force for almost the entirety of an emergency stop. The robustness to parameter errors, the road roughness and the changing friction conditions are all explored.

scholarly journals DETERMINATION OF MOST SIGNIFICANT FACTORS FOR ANALYSIS OF HIGHWAY OPERATING CONDITIONS

2017 ◽  
Vol 16 (6) ◽  
pp. 493-497
Author(s):  
M. G. Solodkaya
Keyword(s):  
Real Life ◽  
Operating Conditions ◽  
Dynamic Loads ◽  
Vehicle Speed ◽  
Vehicle Dynamic ◽  
The Road ◽  
Road Pavement ◽  
On The Road ◽  
Significant Factors ◽  
Road System

Traffic circulation on highways is a random process. Therefore automotive damage rate and, respectively, roads on which they are moving is subjected to regularities of random processes. Dynamic processes of vehicle-road interaction are determined to various extents by a host of factors that include road pavement evenness and characteristics of moving vehicles. For this reason the following task has been set: to reveal the most significant factors and mathematically correlate values of vehicle dynamic loads with a quality of road pavement and vehicle speed. Such task statement has not been solved adequately and this situation determines importance and novelty of the investigations in the given direction. While solving the mentioned task the investigations which have been carried out under real-life conditions and with the help of real-life objects are considered as the most reliable ones. However, preparation and execution of such experiments as needed significantly complicates their implementation. In this regard it looks rather expediential to combine a factorial experiment with the tests of a checked model while using ECM with stage-by-stage parameter fixation of working processes passing in “vehicle-road” system, comprehensive assessment pertaining to influence of the selected factors and selection of their optimum combination. Mathematical dependence has been obtained to evaluate influence of several external factors on optimization of vehicle dynamic load on the road. This component makes it possible to attain a simplified and adequate description of element interaction in “vehicle – road” system. While investigating influence of pavement irregularities on maximum dynamic loads on the road influence rate of the selected factors is determined in the following sequence: vehicle weight, pavement evenness and speed of transport facility.

scholarly journals TECHNOLOGICAL MEASURES OF FOREFRONT ROAD IDENTIFICATION FOR VEHICLE COMFORT AND SAFETY IMPROVEMENT

Transport ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Vidas Žuraulis ◽  
Vytenis Surblys ◽  
Eldar Šabanovič
Keyword(s):  
Image Analysis ◽  
Traffic Safety ◽  
Laser Scanning ◽  
Road Surface ◽  
The Road ◽  
Emergency Braking ◽  
Braking System ◽  
Safety Improvement ◽  
Road Friction ◽  
Surface Irregularities

This paper presents the technological measures currently being developed at institutes and vehicle research centres dealing with forefront road identification. In this case, road identification corresponds with the surface irregularities and road surface type, which are evaluated by laser scanning and image analysis. Real-time adaptation, adaptation in advance and system external informing are stated as sequential generations of vehicle suspension and active braking systems where road identification is significantly important. Active and semi-active suspensions with their adaptation technologies for comfort and road holding characteristics are analysed. Also, an active braking system such as Anti-lock Braking System (ABS) and Autonomous Emergency Braking (AEB) have been considered as very sensitive to the road friction state. Artificial intelligence methods of deep learning have been presented as a promising image analysis method for classification of 12 different road surface types. Concluding the achieved benefit of road identification for traffic safety improvement is presented with reference to analysed research reports and assumptions made after the initial evaluation.

Vehicle Impacts in V-Shaped Ditches

2002 ◽  
Vol 1797 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Robert Thomson ◽  
Jarkko Valtonen
Keyword(s):  
Simulation Model ◽  
Experimental Studies ◽  
Ground Contact ◽  
Passenger Cars ◽  
The Road ◽  
Test Conditions ◽  
Vehicle Chassis ◽  
Roadside Environment

V-shaped ditches represent a significant portion of the roadside environment in Sweden and Finland. The consequences of vehicles leaving the road and entering V-shaped ditches are not well documented in simulation or experimental studies. A series of tests were conducted to document the behavior of passenger cars entering V-shaped ditches. Test conditions ranged from 5° to 20° and 80 to 110 km/h. The tests resulted in many vehicles passing over the backslope, and rollovers were observed in four of the tests. Preliminary simulations of the test conditions were not able to fully reconstruct the vehicle motions. Castor steering of the vehicle and ground contact with the vehicle chassis were the two most important features observed in the tests, but they were not incorporated into the simulation model.

scholarly journals ВИЗНАЧЕННЯ ВПЛИВУ МАТЕРІАЛУ ТА ХІМІКО-ТЕРМІЧНОЇ ОБРОБКИ НА ЗНОСОСТІЙКІСТЬ ЕЛЕМЕНТІВ УНІВЕРСАЛЬНО-ЗБІРНИХ ПЕРЕНАЛАГОДЖУВАНИХ ШТАМПІВ

2019 ◽  
pp. 111-124
Author(s):  
Е. А. Фролов ◽  
В. В. Агарков ◽  
С. И. Кравченко ◽  
Н. В. Верещага
Keyword(s):  
Wear Resistance ◽  
Chemical Treatment ◽  
Friction Pair ◽  
Experimental Studies ◽  
Gravimetric Method ◽  
Steel Specimen ◽  
Wear Intensity ◽  
Operating Conditions ◽  
Linear Wear ◽  
Steel 20

The article presents the results of experimental studies of the wear resistance of metals in order to select the most effective for the manufacture of guide elements of prefabricated universal readjusted stamps. To determine the effect of the material and chemical-heat treatment of them on the wear resistance of the guide elements, the optimal friction pair was selected and tested under conditions similar to the operating conditions of the stamps. Specimens for testing were made in the form of cuts of steel 20, 12ХНЗА (12HNZA), 40Х (40Н) and 38ХМЮА (38HMYUA). Laboratory tests were performed on the machine MИ-1M (МI-1M) under a load of 50, 75 and 100 kgf with a contact area of 243 mm2. The amount of wear was determined by the gravimetric method of I. Kragelsky. Before testing for wear resistance, the specimens were subjected to thermal and heat-chemical treatment: Steel 20 (cementation, normalization, quenching, tempering), 12ХНЗА (12HNZA) (cementation, high tempering, quenching, tempering), 40X (40Н) (quenching, tempering, nitriding) and 38ХМЮА (38HMYUA) (quenching, vacation, nitriding). Studies of the microstructure and microhardness of the test specimens have shown that the nitriding of 38ХМЮА (38HMYUA) and 40X (40H) steel specimen reduces its wear by 1...2 µm and 2...3 µm, and the microhardness of both materials decreases by 50...100 Nm. The analysis of the wear intensity graphs on the number of cycles have shown that for all specimens there are two periods of wear (1 – running-in of rubbing surfaces, 2 – steady wear). Also, studies have shown that the surface layer of nitrated specimens on 38ХМЮА (38HMYUA) steel has a higher wear resistance and a slight tendency to seizing and hardening, providing a high resistance of the part to wear in various friction conditions. The results of testing samples under various loads have shown that the linear wear value is proportional to the change in the specific pressure value established on the basis of the conducted studies that the most effective material for the manufacture of guide elements for PURS is 38ХМЮА (38HMYUA) steel with the following thermal and heat-chemical treatment (quenching – 940 ... 950°C, tempering – 650°C and nitriding – 540°C).

scholarly journals Theoretical and experimental study of deep soil compaction with a cone reamer

2021 ◽  
Vol 1 (3) ◽  
pp. 60-70
Author(s):  
Kudratullo Z. Tilloev
Keyword(s):  
Mathematical Modeling ◽  
Dynamic Characteristics ◽  
Soil Compaction ◽  
System Analysis ◽  
Surface Deformation ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Road Surface ◽  
Deep Soil ◽  
The Road

Introduction. The road-building machines and mechanisms are always improved depending on the tasks formed in the specific operating conditions of these machines. One of the problems of road construction in difficult climatic conditions is the lack of ground base strength, which results in road surface deformation during operation and periodic traffic restrictions, increasing the cost of maintenance. The road surface annual repair does not fundamentally solve the problem of the roads’ long-term and reliable performance. This problem can be solved by modernizing, for example, a working body for soil compaction based on a crawler excavator. Research aim is to develop a mathematical model for determining the dynamic characteristics of a cone reamer’s effective design to ensure deep compaction of soil foundations for highways and industrial and civil facilities. Research methodology is based on a system analysis of the basic tracked vehicle, the working body, and the compacted soil. The research methods also include mathematical modeling of the cone working body interaction with the soil. Results reliability is confirmed by comparing the results of numerical modeling and experimental studies. The discrepancy between the obtained results of mathematical modeling and laboratory tests in terms of torque and power does not exceed 7–10%. Conclusions. A method for determining the dynamic characteristics of cone devices is developed, and calculation formulas are derived for determining the tilting moment and torque that are applied to the shaft when compacting soils with different characteristics. Experimental studies have been conducted 70 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 3. 2021 ISSN 0536-1028 that have shown the efficiency of this working body. The developed method for determining the dynamic characteristics of cone devices is experimentally confirmed.

scholarly journals FEATURES OF ADAPTIVE BRAKE CONTROL OF THE SECONDARY BRAKE SYSTEM OF A MULTI-AXLE VEHICLE

2021 ◽  
pp. 27-37
Author(s):  
Viktor Bogomolov ◽  
Valeriy Klimenko ◽  
Dmytro Leontiev ◽  
Oleksandr Kuripka ◽  
Andrii Frolov ◽  
...  
Keyword(s):  
Simulation Model ◽  
Road Safety ◽  
Road Surface ◽  
Brake System ◽  
Technical Literature ◽  
Adhesion Properties ◽  
The Road ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Process

Problem. A malfunction of the service braking system of a wheeled vehicle (CTS) significantly affects road safety, especially when operating multi-axle vehicles with large masses. One of the ways to increase the level of road safety of multi-axle vehicles, when braking them using a spare (emergency) braking system, is the introduction of automated adaptive braking systems into the design of the brake drive of vehicles. The definition of the limits of the use of the adaptive braking system on vehicles with many axles is almost not disclosed in the scientific and technical literature, therefore, the issue of using such a system on vehicles with a large number of axles requires additional research. Purpose. The purpose of this work is to develop a simulation model for adaptive control of the braking process of a multi-axle vehicle using a spare (emergency) braking system, taking into account the simulation of the dynamics of the drive and the variability of the adhesion properties between the tire of the vehicle wheel and the road surface. Methodology. To achieve this goal, it is necessary to develop a simulation model of the brake drive in an adaptive mode, implement a model of the interaction of the tire with the road surface, and implement a model of the braking dynamics of a multi-axle vehicle in the event of a malfunction of its service brake system. Originality. The proposed key criterion (Kr) for changing the throttle section in electro-pneumatic pressure modulators, which provide adaptive air inlet or outlet from the corresponding brake chambers of the drive, during simulation, made it possible to simulate the operation of the drive circuits in the adaptive mode. It has been established that, depending on the potential for the realization of the adhesion between the tires of automobile wheels and the road surface, the pressure in the electro-pneumatic brake drive with its adaptive regulation can be increased by no more than 0.04 MPa.

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