scholarly journals FORMS OF x x   s – DIAGRAMS OF AN AUTOMOBILE TYRE

2017 ◽  
Author(s):  
E.V. Balakina
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Lateral Force ◽  
Road Surface ◽  
Vehicle Stability ◽  
The Road ◽  
The Coefficient Of Friction ◽  
Longitudinal Slip ◽  
The Moment ◽  
Friction Interaction

Vehicle stability, handling and braking properties significantly depends on the friction interaction between a tyre and the road surface. Index of the friction interaction is the coefficient of friction in different coordinates. The friction coefficient is generally calculated as a function of the coefficient of the longitudinal slip of the wheel x  f (sx ) . The lateral force significantly affects the coefficient of friction. In different cases the lateral force can occur either before or after occurrence of the braking moment on the wheel. The purpose of the study is to investigate the effect of different sequence of occurrence of the lateral force and the braking moment on a wheel on the friction properties of the tyre with a solid road surface. The author have developed the methods which allows considering the sequence of occurrence of the lateral force and the moment on the wheel in the calculation of x  sx – diagrams.

scholarly journals Analisa Koefisien Gesek Kinetis Terhadap Struktur Permukaan Jalan Akibat Beban Dinamik Mobil

2018 ◽  
Vol 1 (1) ◽  
pp. 047-051
Author(s):  
Muhammad Nuh Hudawi Pasaribu ◽  
Muhammad Sabri ◽  
Indra Nasution
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Surface Texture ◽  
Road Surface ◽  
Vehicle Speed ◽  
Kinetic Friction ◽  
The Road ◽  
Road Condition ◽  
Asphalt Road ◽  
The Coefficient Of Friction

Tekstur permukaan jalan umumnya terdiri dari aspal dan beton. Kekasaran tekstur permukaan jalan dapat disebabkan oleh struktur perkerasan dan beban kendaraan. Kekasaran tekstur permukaan jalan, bebandan kecepatan kendaraan akan mempengaruhi koefisien gesek. Untuk mengetahui nilai koefisien gesek dilakukan penelitian dengan melakukan variasi beban mobil (Daihatsu Xenia, Toyota Avanza, Toyota Innova dan Toyota Yaris) terhadap kontak permukaan jalan (aspal dan beton) dan kecepatan kendaraan. Hasil penelitian menunjukkan bahwa massa, lebar kontak tapak ban terhadap permukaan jalan dan kecepatan sangat mempengaruhi nilai koefisien gesek kinetis. Koefisien gesek kinetis yang terbesar untuk ketiga kontak permukaan jalan (aspal lama IRI 10,1, Aspal baru IRI 6,4 dan beton IRI 6,7) dengan menggunakan mobil Daihatsu Xenia terjadi pada kondisi jalan beton yaitu 0,495 pada kecepatan 35 Km/Jam. Koefisien kinetis jalan beton > 52 % dibandingkan jalan aspal pada parameter IRI yang sama (6-8).Koefisien gesek kinetis > 0,33 diperoleh di jalan beton pada kecepatan 30 – 40 Km/Jam   The texture of road surface generally consists of asphalt and concrete. The roughness of the road surface texture could be caused by the structure of the pavement and the load of the vehicles. Roughness of road surface texture, load and speed of vehicles would affect to the coefficient of friction. This research was carried out to find out the value of the coefficient of friction by using various load of cars (Daihatsu Xenia, Toyota Avanza, Toyota Innova and Toyota Yaris) on road surface contact (asphalt and concrete) and vehicle speed. The result showed the mass, the width of the tire tread contact to the road surface, and speed very influenced the coefficient value of kinetic friction. The biggest kinetic friction coefficient for all three road surface contacts (IRI 10.1 old asphalt, IRI 6.4 and IRI 6.7) using the Daihatsu Xenia was on the concrete road condition i.e. 0.495 on a speed of 35 km/hour. The concrete road kinetic coefficient was >52% compared to the asphalt road in the same IRI parameter (6-8). The kinetic friction coefficient >0.33 was obtained on the concrete road on a speed of 30 - 40 km/hour.

Friction Characteristics of Porous Rubber Under Wet Conditions

2009 ◽  
Author(s):  
Yutaro Kosugi ◽  
Tomoaki Iwai ◽  
Yutaka Shokaku ◽  
Naoya Amino
Keyword(s):  
Friction Force ◽  
Coefficient Of Friction ◽  
Contact Surface ◽  
Road Surface ◽  
Water Removal ◽  
The Road ◽  
Rubber Specimen ◽  
The Coefficient Of Friction ◽  
The Difference ◽  
Tread Rubber

In recent years, porous rubber has been used as a tread matrix for studless tires. It is said that the pores in the tread rubber remove water between the tire and the wet road surface; however, the water removal is not sufficiently well understood. In this study, a rotating rubber specimen was rubbed against a mating prism to observe the contact surface. The friction force was also measured simultaneously with observation of contact surface. The water entering the pores was distinguished by the continuity method. As the result of these experiments, the coefficient of friction for rubber having pores on the surface was found to be larger than that of rubber without pores. Moreover, the difference in the coefficient of friction for rubber specimens with and without pores tended to be larger at lower sliding speeds. No water entered pores 3mm or less in diameter at any sliding speed in this experiment. An experiment to make the rubber specimen collide with the mating prism was conducted since actual tires seem to be deformed by the vehicle weight, such that the tire surface might contact the road collisionally. In the resulting collision experiment, the water did enter pores 3mm in diameter.

scholarly journals Efficiency of sorbents used to restore the grip of the surface of the oily road

2018 ◽  
Vol 247 ◽  
pp. 00024
Author(s):  
Mirosław Sobolewski ◽  
Dominika Gancarczyk ◽  
Piotr Książek
Keyword(s):  
Coefficient Of Friction ◽  
Static Friction ◽  
Road Surface ◽  
Asphalt Pavements ◽  
Fire Departments ◽  
Initial Coefficient ◽  
The Road ◽  
Road Users ◽  
The Coefficient Of Friction ◽  
High Degree

The use of sorbents is one of the methods most commonly used by the fire departments to remove spilled hydrocarbon liquids. Sorbents approved for use by fire brigades must meet the requirements of the Ministry of Internal Affairs. However, this requirement does not include the assessment of the degree of roughness of the road surface after removal of oily spills. The high degree of restoration of road surface grip is extremely important for the safety of road users. The article presents the results of research on the effectiveness of restoring the coefficient of friction by different sorbents. The tests were carried out for three different asphalt pavements, determining the coefficients of friction for dry, wet and oily surfaces and after applying sorbents. Static friction coefficients were determined by measuring the angle of the inclination of the tested surface specimen, at which the probe imitating the car tire slid. It turned out that none of the used sorbents fully restored the initial coefficient of friction on the asphalt surface. The use of professional sorbents allowed for the restoration of about 80% of the initial coefficient of friction of the dry surface. Significantly poorer results were obtained for the most commonly used sorptive replacement materials, i.e. sand or sawdust.

Physics of the Slipping Wheel. II. Slip under both Tractive and Lateral Forces

1970 ◽  
Vol 43 (2) ◽  
pp. 244-261 ◽  
Author(s):  
D. I. Livingston ◽  
J. E. Brown
Keyword(s):  
Lateral Force ◽  
Tractive Force ◽  
Slip Vector ◽  
Stiffness Modulus ◽  
The Road ◽  
Pressure Distributions ◽  
Longitudinal Stiffness ◽  
The Coefficient Of Friction ◽  
Longitudinal Slip ◽  
Characteristic Relationship

Abstract The mechanics of the slipping wheel has been investigated further with respect to the general problem of slip in any direction under the action of any combination of lateral and tractive force exerted by the road. The tire was considered to have two main directions of anisotropy in the contact surface, and a theory was proposed connecting the resultant force vector with the resultant slip vector regardless of their orientation. The connection was established through the use of a quantity called the slip-modulus which contains the lateral and longitudinal stiffness moduli and the slip components. The behavior of a tire may then be described by a characteristic relationship between the force and the slip-modulus, as has been found for pure lateral or longitudinal slip. Experimental measurements from three literature sources on the effects of tractive on lateral force were used to deduce the characteristic relationships, which represented a considerable condensation of the data. Thus, the theory was confirmed. The pressure distributions underlying these relationships were also calculated by a method given in this work and their distortions attributed to an artifact of variation of the ratio of the coefficient of friction to stiffness modulus with slip.

Experimental study on the relationship between the friction coefficient and interference in locomotive axle press-fitting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Friction Pair ◽  
Rolling Stock ◽  
Content Type ◽  
Press Fitting ◽  
The Press ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Locomotive Wheels

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.

scholarly journals Pavement State Recognition Method Considering Slope

2021 ◽  
Vol 2113 (1) ◽  
pp. 012080
Author(s):  
Xiuhao Xi ◽  
Jun Xiao ◽  
Qiang Zhang ◽  
Yanchao Wang
Keyword(s):  
Surface Condition ◽  
Lateral Force ◽  
Longitudinal Force ◽  
Operating Conditions ◽  
Road Surface ◽  
Tire Model ◽  
State Recognition ◽  
Adhesion Coefficient ◽  
The Road ◽  
Real Time Tracking

Abstract For the problem of road surface condition recognition, this paper proposes a real-time tracking method to estimate road surface slope and adhesion coefficient. Based on the fusion of dynamics and kinematics, the current road slope of the vehicle which correct vertical load is estimated. The effect of the noise from dynamic and kinematic methods on the estimation results is removed by designing a filter. The normalized longitudinal force and lateral force are calculated by Dugoff tire model, and the Jacobian matrix of the vector function of the process equation is obtained by combining the relevant theory of EKF algorithm. The road adhesion coefficient is estimated finally. The effectiveness of the algorithm is demonstrated by analyzing the results under different operating conditions, such as docking road and bisectional road, using a joint simulation of Matlab/Simulink and Carsim.

scholarly journals Anisotropic Vibration Tactile Model and Human Factor Analysis for a Piezoelectric Tactile Feedback Device

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 448 ◽  
Author(s):  
Jichun Xing ◽  
Huajun Li ◽  
Dechun Liu
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Ciliary Body ◽  
Human Factor ◽  
Sliding Friction ◽  
Excitation Frequency ◽  
Tactile Feedback ◽  
Body Structure ◽  
Full Coverage ◽  
The Coefficient Of Friction

Tactile feedback technology has important development prospects in interactive technology. In order to enrich the tactile sense of haptic devices under simple control, a piezoelectric haptic feedback device is proposed. The piezoelectric tactile feedback device can realize tactile changes in different excitation voltage amplitudes, different excitation frequencies, and different directions through the ciliary body structure. The principle of the anisotropic vibration of the ciliary body structure was analyzed here, and a tactile model was established. The equivalent friction coefficient under full-coverage and local-coverage of the skin of the touch beam was deduced and solved. The effect of system parameters on the friction coefficient was analyzed. The results showed that in the full-coverage, the tactile effect is mainly affected by the proportion of the same directional ciliary bodies and the excitation frequency. The larger the proportion of the same direction ciliary body is, the smaller the coefficient of friction is. The larger the excitation frequency is, the greater the coefficient of friction is. In the local-coverage, the tactile effect is mainly affected by the touch position and voltage amplitude. When changing the touch pressure, it has a certain effect on the change of touch, but it is relatively weak. The experiment on the sliding friction of a cantilever touch beam and the experiment of human factor were conducted. The experimental results of the sliding friction experiment are basically consistent with the theoretical calculations. In the human factor experiment, the effects of haptic regulation are mainly affected by voltage or structure of the ciliary bodies.

scholarly journals Identification of Road-Surface Type Using Deep Neural Networks for Friction Coefficient Estimation

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 612 ◽  
Author(s):  
Eldar Šabanovič ◽  
Vidas Žuraulis ◽  
Olegas Prentkovskis ◽  
Viktor Skrickij
Keyword(s):  
Neural Networks ◽  
Friction Coefficient ◽  
Deep Neural Networks ◽  
Image Sensor ◽  
Video Data ◽  
Road Surface ◽  
Driver Assistance Systems ◽  
Surface Type ◽  
Braking Performance ◽  
The Road

Nowadays, vehicles have advanced driver-assistance systems which help to improve vehicle safety and save the lives of drivers, passengers and pedestrians. Identification of the road-surface type and condition in real time using a video image sensor, can increase the effectiveness of such systems significantly, especially when adapting it for braking and stability-related solutions. This paper contributes to the development of the new efficient engineering solution aimed at improving vehicle dynamics control via the anti-lock braking system (ABS) by estimating friction coefficient using video data. The experimental research on three different road surface types in dry and wet conditions has been carried out and braking performance was established with a car mathematical model (MM). Testing of a deep neural networks (DNN)-based road-surface and conditions classification algorithm revealed that this is the most promising approach for this task. The research has shown that the proposed solution increases the performance of ABS with a rule-based control strategy.

The Size of the Friction Coefficient Depending on the Size and Course of Normal Load

2014 ◽  
Vol 474 ◽  
pp. 303-308 ◽  
Author(s):  
Eva Labašová
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Testing Machine ◽  
Constant Load ◽  
Current Component ◽  
Rectangular Shape ◽  
The Coefficient Of Friction ◽  
Ring Method ◽  
Run Up

The coefficient of friction for the bronze material (CuZn25Al6) with inset graphite beds is investigated in the present paper. Friction coefficient was investigated experimentally by the testing machine Tribotestor`89 which uses the principle of the ring on ring method. Tribotestor`89 machine may be classed to the rotary tribometers. The tested sliding pairs were of the same material. The internal bushing performed a rotational movement with constant sliding speed (v = 0.8 m s-1). The external fixed bushing was exposed to the normal load, which was of different sizes and different variations. Process of load was increased from level 50 N to 200 N (400 N, 600 N) during run up 600 s, after the run up the appropriate level of load was held.The forth test had a rectangular shape of loading with direct current component 400 N and the amplitude 200 N period 600 s, the whole test took 1800 s. The obtained results reveal that friction coefficient decreases with the increase of normal load. Further, that the coefficient of friction was found smaller at constant load, as compared to rectangular shape of loading.

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