Development of a device for determining the coefficient of adhesion of a tire simulator with a flat support surface

2021 ◽  
pp. 3-6
Author(s):  
Keyword(s):  
Measurement Accuracy ◽  
Contact Spot ◽  
Support Surface ◽  
Slip Coefficient ◽  
Braking Performance ◽  
The Road ◽  
Physical Essence ◽  
The Coefficient Of Friction ◽  
Braking Distance ◽  
The Stability

To ensure optimal braking performance, i.e. minimum braking distance while maintaining the stability of the car at the limit of controllability, anti-lock systems are currently installed on cars. The relative fraction of the rest friction in the contact spot, which is used to form the longitudinal reaction of the support surface at the appropriate value of the slip coefficient, in relation to the total fraction of the rest friction in the contact spot is a constant value for any type and condition of the road surface. The coefficient of adhesion in physical essence is the coefficient of friction at rest. The proposed device for determining the coefficient of adhesion of a tire simulator with a flat horizontal support surface will simplify the design and increase the measurement accuracy. Keywords: coefficient of adhesion, a device for determining the coefficient of adhesion, a device

scholarly journals Alingment of braking performance for truck and trailer as an important factor in road construction

2021 ◽  
Vol 1203 (3) ◽  
pp. 032085
Author(s):  
Andrej Haring
Keyword(s):  
Traffic Accidents ◽  
Road Construction ◽  
Reference List ◽  
Braking Performance ◽  
The Road ◽  
Start Up ◽  
Braking Distance ◽  
The Stability ◽  
Internal And External Factors

Abstract Alingment of braking performance of truck trailer is an important parameter that affects its braking stability. This shows particular in critical situations or during braking on a surface with reduced adhesion. Alingment of braking performance can be automatic, which is one of quality of electronical brake systems. Further on, can be forcible, which is being executed during service a diagnostic work.This contribution is focused on analysis alingment of braking performance. Describing technical conditions, internal and external factors which affect it. Due to magnitude of this problematics, is in this article evaluated the optimization of braking affects truck trailers in the start-up phase. The analysis of the process – start-up braking effect has justification from the reason, that has primary influence on the stability truck trailer during braking and this can be the cause of collision situations or also traffic accidents. The parameter of alingment of braking performance has a primary influence on the braking stability of the truck trailers, which significantly affects road safety and is also important for the economy of the truck trailers. your abstract here… The abstract should include the purpose of research, principal results and major conclusions. References should be avoided, if it is essential, only cite the author(s) and year(s) without giving reference list. Prepare your abstract in this file and then copy it into the registration web field. Braking distance is an important factor in the road construction. Therefore, it must be taken into account when designing these buildings.

ON THE QUESTION OF BRAKING ARTICULATED BUSES

2021 ◽  
pp. 10-18
Author(s):  
Volodymyr Sakhno ◽  
Volodymyr Poliakov ◽  
Dmytro Yaschenko ◽  
Oleksii Korpach ◽  
Denis Popelysh
Keyword(s):  
Distribution Coefficients ◽  
Force Distribution ◽  
Design Features ◽  
Braking Performance ◽  
The Road ◽  
Braking Distance ◽  
Brake Force ◽  
The Difference ◽  
Brake Force Distribution ◽  
The Stability

The safe movement of a car and a road train is largely determined by its braking properties. The nature of the movement of the road train is fundamentally different from the movement of a single car. The difference can be explained by the presence of additional forces arising in the articulation of the links of the vehicle, as well as forces and moments acting on its individual links and the movement of the vehicle as a whole. Their effect is especially noticeable when braking a road train, which may be accompanied by folding links and loss of stability of the vehicle. As a result of the study, the optimal values of the brake force distribution coefficients for a fully loaded articulated bus are obtained, which provide both high braking efficiency and the stability of the articulated bus (AВ) during braking. The coefficients are determined taking into account the design features of the brake mechanisms and their geometric dimensions, providing the required braking performance. For the selected values of the braking force distribution coefficients along the axes of the AВ and the coefficients that take into account the design features of the braking mechanisms and their geometric dimensions, the braking distance during braking by the main or working braking system and the spare one satisfy the requirements of regulatory documents. With the selected asynchronous response of the brake drives of the bus and trailer, the steady deceleration of the АВ is slightly less than the standard.

scholarly journals RELIABILITY CRITERION AND A MODEL FOR DETERMINING THE OPTIMAL SPEED OF MOVEMENT ON AUTOMOBILE ROADS IN WINTER SLIDING CONDITIONS

2020 ◽  
Vol 6 (444) ◽  
pp. 119-125
Author(s):  
D. E. Yessentay ◽  
◽  
A. K. Kiyalbaev ◽  
S. N. Kiyalbay ◽  
N. V. Borisуuk ◽  
...  
Keyword(s):  
Traffic Accidents ◽  
Road Traffic ◽  
Rolling Resistance ◽  
Main Criterion ◽  
The Road ◽  
Optimal Speed ◽  
Road Surfaces ◽  
Braking Distance ◽  
Effective Decision ◽  
The Stability

The article presents a model for establishing the optimal speed of movement on highways, taking into account the determination of the braking distance in winter slippery conditions. According to the research results, it was established that the main criterion for the formation of road accidents on highways in winter slippery conditions is the drivers' underestimation of the adhesion qualities of road surfaces. The main criterion of the model under consideration is the interaction of the car wheel (braking distance) with the road (adhesion coefficient) and is a complex that characterizes the stability of the car rolling over on slippery surfaces and the driver's actions in making an effective decision and the duration of the reaction time. In the proposed mathematical model, the accident rate on a slippery road is estimated by the coefficient of adhesion of icy road surfaces, the value of the load or the average wheel pressure. Also, the frequency of load application, the amount of deflection of the coating (at an air temperature above +20 ° C), rolling resistance, the coefficient of adhesion of the car wheel to the coating. One of the main characteristics of the model is a subsystem - the average pressure p = Q / S (S is the area of the imprint of the wheel, cm²), etc. Thus, in the process of analyzing the results of the causes of road traffic accidents, the factors of the driver's reliability and the decisions made will be taken into account, which depend on the speed of vehicles in any condition of the road surface.

The Analysis of the Key Problems about Traffic Accident Speed Identification Based on Braking Traces

2013 ◽  
Vol 756-759 ◽  
pp. 4752-4757
Author(s):  
Zhi Wei Guan ◽  
Shao Hua Wang ◽  
Wei Qiang Liang ◽  
Ming Feng Zheng ◽  
Lin Wu ◽  
...  
Keyword(s):  
Traffic Accident ◽  
Performance Test ◽  
National Standard ◽  
Test Report ◽  
Actual Case ◽  
Braking Performance ◽  
Braking Distance ◽  
Braking Process ◽  
Judicial Expertise ◽  
Speed Identification

In order to improve the impartiality and objectivity of judicial expertise, the key problems about traffic accident speed identification are analyzed and the speed of vehicle is calculated by using the braking performance test report with reference to the national standard and automobile theory. The automobile dynamics of driver braking process is analyzed, all kinds of key problems such as the braking distance, braking coordination time, braking speed, longitudinal sliding coefficient of adhesion are combined with the braking performance test report, and the method of determining the longitudinal sliding coefficient of adhesion is proposed, the instantaneous velocity before the collision is calculated. Finally, the method is used to calculate the speed of an actual case, and simulated in the software of PC-Crash, the results are consistent, verifying that the speed identification method is correct.

Design of Monitoring and Controlling Software of Footwear Sole Friction Based on QT

2012 ◽  
Vol 424-425 ◽  
pp. 1347-1351
Author(s):  
Yong Jie Yang ◽  
Xian Xian Lin ◽  
Dong Hua Lv
Keyword(s):  
Real Time ◽  
Coefficient Of Friction ◽  
Measurement Accuracy ◽  
Serial Communication ◽  
Safety Performance ◽  
Development Environment ◽  
Controlling System ◽  
Slip Resistance ◽  
The Coefficient Of Friction

Slip resistance of footwear sole affects the comfort and safety of shoes directly, and slip resistance is mainly expressed by the coefficient of friction. Within a certain range, the greater the coefficient of friction, the better the slip resistance. In order to determine the safety performance of shoes, the system will obtain the coefficient of friction by measuring the tension and pressure put on shoes, so it’s very important to do the measurement precisely. Based on QT development environment and Monitoring-controlling System of footwear sole friction, the software will execute real-time receiving, processing, controlling, displaying, drawing and saving collected data of tension and pressure via serial communication and finally on the basis of the system test to verify the correctness of the software and measurement accuracy

The Stability Control of Soft Soil Foundations of Urban Roads According to the Surface Subsidence Monitoring Data

2013 ◽  
Vol 859 ◽  
pp. 222-227
Author(s):  
Hong Jun Liu ◽  
Jin Hua Tan ◽  
Xue Wen Su ◽  
Hao Wu
Keyword(s):  
Soft Soil ◽  
Stability Control ◽  
Surface Subsidence ◽  
Monitoring Data ◽  
Research Results ◽  
The Road ◽  
Future Design ◽  
Left And Right ◽  
Soil Foundation ◽  
The Stability

Two typical monitoring sections are selected for obtaining the change law of the surface subsidence and the settlement after construction of soft soil foundations, and determining the reasonable unloading time. The research results show that the surface settlement rate is large during the filling stage, the rate decreases after the loading and gradually stabilized. The embankment midline settlement is larger than the settlement of the road shoulder which is concluded from the fact that the subsidence of the middle settlement plate is larger than those of the left and right plate. The surface subsidence rate is less than 5mm per month during the two month before unloading according to the data in the tables. The settlement after construction presumed from the middle plate is more significantly larger than that of left and right sides, hence, as the unloading basis of preloading drainage method in soft soil foundation treatment the settlement after construction which is calculated from the midline monitoring data of the road is appropriate. After 6 months the calculated post-construction settlements of the two sections are in the scope of the design requirement since they decrease with preloading time. The reliable basis is provided for the future design and construction of soft foundation in this area through the research results.

Road Adhesion Coefficient Estimation Based on the Steering Wheel Rebound After Steering

2018 ◽  
Author(s):  
Liangyao Yu ◽  
Sheng Zheng ◽  
Xiaohui Liu ◽  
Jinghu Chang ◽  
Fei Li
Keyword(s):  
Stability Control ◽  
Front Wheel ◽  
Intelligent Vehicles ◽  
Steering Wheel ◽  
Adhesion Coefficient ◽  
The Road ◽  
Whole Process ◽  
Friction Moment ◽  
Stability Control System ◽  
The Coefficient Of Friction

Accurately estimating road adhesion coefficient is very important for vehicle stability control system. In this paper, an innovation method to estimate the road adhesion coefficient is proposed. This method can be used in vehicles without additional sensors. And this method is especially suitable to be used in the intelligent vehicle equipped with steer-by-wire (SBW) system. When vehicle steers, releasing the steering wheel suddenly will result in rebound to a certain angle. When the steer wheel turns the same angle on different road whose adhesion coefficients are different, the front wheel rebound angles are different. The friction moment between the road and tire is the main factor to prevent the tire from turning back, and the coefficient of friction is equal to road adhesion coefficient when the vehicle is stationary. In this paper, the detailed dynamical models describing the whole process of the front wheel and tire rebound are established. Furthermore, the Luenberger reduced-order disturbance observer is established to estimate the friction moment, and then the adhesion coefficient is estimated. The SBW system which is usually equipped in intelligent vehicles can control the steer moment and steer angle accurately. When the steer wheel turns to certain angle, the SBW system is able to stop outputting torque quickly and timely, which is important for improving the experiment accuracy. In this paper, the SBW system is used to conduct an experiment on different roads. The experiment results demonstrate the validity of this method.

The Slabbing Mechanics Analysis of the Tunnel Lining

2011 ◽  
Vol 243-249 ◽  
pp. 3530-3537
Author(s):  
Zu Song Wu ◽  
Guang Qi Chen ◽  
Kou Ki Zen ◽  
Xin Rong Liu
Keyword(s):  
Surrounding Rock ◽  
Tunnel Lining ◽  
The Self ◽  
Road Tunnel ◽  
The Road ◽  
Mechanics Analysis ◽  
The Stability

When the road tunnel is excavated, the multi lining is used to being applied. In order to keep the surrounding rock stabilize and arouse the self-stability of the surrounding rock, building the first support is essential. But the slabbing often occurs near the spring line on the surface of the first lining, and because the slabbling is a common failing and not attracted our most attentions, it will develop to the crack and threaten the stability of the structure finally. This paper uses the line elastic method to analyze the mechanics that causes this slabbing phenomenon via the interaction between the surrounding rock and the first lining, and suggests the measure that escape the slabbing.

scholarly journals The influence of the nature and textural properties of different supports on the thermal behavior of Keggin type heteropolyacids

2006 ◽  
Vol 71 (3) ◽  
pp. 235-249 ◽  
Author(s):  
Alexandru Popa ◽  
Viorel Sasca ◽  
Mircea Stefanescu ◽  
Erne Kis ◽  
Radmila Marinkovic-Neducin
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Solid Phase ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Active Phase ◽  
Support Surface ◽  
Sem Images ◽  
The Stability

In order to obtain highly dispersed heteropolyacids (HPAs) species, H3PMo12O40 and H4PVMo11O40 were supported on various supports: silica (Aerosil - Degussa and Romsil types) and TiO2. The structure and thermal decomposition of supported and unsupported HPAs were followed by different techniques (TGA-DTA, FTIR, XRD, low temperature nitrogen adsorption, scanning electron microscopy). All the supported HPAs were prepared by impregnation using the incipient wetness technique with a 1:1 mixture of water-ethanol. Samples were prepared with different concentrations to examine the effect of loading on the thermal behavior of the supported acid catalysts. The thermal stability was evaluated with reference to the bulk solid acids and mechanical mixtures. After deposition on silica types supports, an important decrease in thermal stability was observed on the Romsil types and a small decrease on the Aerosil type. The stability of the heteropolyacids supported on titania increased due to an anion-support interaction, as the thermal decomposition proceeded in two steps. The structure of the HPAs was not totally destroyed at 450 ?C as some IR bands were still preserved. A relatively uniform distribution of HPAs on the support surface was observed for all compositions of the active phase. No separate crystallites of solid phase HPAs were found in the SEM images.

scholarly journals Effect of Road Profile on Suspension System of Heavy Truck

2019 ◽  
Vol 12 (2) ◽  
pp. 71-75
Author(s):  
Salem F. Salman
Keyword(s):  
Steering System ◽  
Suspension System ◽  
The Road ◽  
Road Profile ◽  
Road Roughness ◽  
Road Type ◽  
Heavy Truck ◽  
Main Factors ◽  
On The Road ◽  
The Stability

All vehicles are affected by the type of the road they are moving on it.  Therefore the stability depends mainly on the amount of vibrations and steering system, which in turn depend on two main factors: the first is on the road type, which specifies the amount of vibrations arising from the movement of the wheels above it, and the second on is the type of the used suspension system, and how the parts connect with each other. As well as the damping factors, the tires type, and the used sprungs. In the current study, we will examine the effect of the road roughness on the performance coefficients (speed, displacement, and acceleration) of the joint points by using a BOGE device.

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