Second Paper: Studies on the Skidding Resistance of Passenger-Car Tyres on Wet Surfaces

1965 ◽  
Vol 180 (1) ◽  
pp. 122-157 ◽  
Author(s):  
G. Maycock
Keyword(s):  
Road Surface ◽  
Smooth Surfaces ◽  
Passenger Car ◽  
Force Coefficients ◽  
Potential Value ◽  
Lubricating Film ◽  
High Speeds ◽  
Wide Range ◽  
Road Surfaces ◽  
Braking Force

This paper reports investigations into the effect of tread pattern, pattern modifications, tread material and tyre casing construction, on the skidding resistance of passenger-car tyres at speeds between 25 and 80 mile/h on a range of wet road surfaces. The technique used was to brake the front wheels of a car until these wheels locked, and to record the resulting deceleration of the vehicle. From the deceleration record, both the peak and locked-wheel values of the braking force coefficients were obtained. The method is described and an assessment of the errors involved is given. The experiments showed the importance of adequate drainage of the region of contact between tyre and road, particularly at the higher speeds, in order to remove the lubricating film of water. Such drainage can be provided either by a tread pattern or a coarse road surface, and the present results indicate the importance of each and their inter-relation. The results of various modifications to a standard tread pattern are given; these show that on smooth surfaces worth-while increases in wet road adhesion at high speeds can be obtained by suitable design of tyre tread patterns. The magnitude of the increases in friction due to changes in tread material are given for both peak and locked-wheel coefficients. Ratios of peak to locked-wheel coefficients have been calculated over a wide range of surface and tyre combinations, and they show the potential value of devices enabling a vehicle to make use of these high coefficients.

Skid Resistance of Passenger Car Tires on Wet Surfaces

1968 ◽  
Vol 41 (4) ◽  
pp. 780-806 ◽  
Author(s):  
G. Maycock
Keyword(s):  
Road Surface ◽  
Skid Resistance ◽  
Passenger Car ◽  
Force Coefficients ◽  
Potential Value ◽  
Lubricating Film ◽  
High Speeds ◽  
Wide Range ◽  
Road Surfaces ◽  
Braking Force

Abstract This paper reports investigations into the effect of tread pattern, pattern modifications, tread material, and tire casing construction, on skid resistance of passenger-car tires at speeds between 25 and 80 mph on a range of wet road surfaces. The technique was to brake the front wheels of a car until they locked, and to record deceleration of the vehicle. From the deceleration record, both peak and locked-wheel values of braking force coefficients were obtained. The method is described and an assessment of the errors is given. The experiments showed the importance of adequate drainage of the region of contact between tire and road, particularly at higher speeds, in order to remove the lubricating film of water. Such drainage can be provided either by a tread pattern or a coarse road surface. The results indicate the importance of each and their inter-relation. Results of various modifications to a standard tread pattern are given; these show that on smooth surfaces worthwhile increases in wet road adhesion at high speeds can be obtained by suitable design of tire tread patterns. Magnitude of increases in friction due to changes in tread material are given for both peak and locked-wheel coefficients. Ratios of peak to locked-wheel coefficients have been calculated over a wide range of surface and tire combinations. They show the potential value of devices enabling a vehicle to make use of these high coefficients.

Road Texture Influence on Tire Rolling Resistance

2013 ◽  
Vol 597 ◽  
pp. 193-198 ◽  
Author(s):  
Stanislaw Taryma ◽  
Jerzy A. Ejsmont ◽  
Grzegorz Ronowski ◽  
Beata Swieczko-Zurek ◽  
Piotr Mioduszewski ◽  
...  
Keyword(s):  
Surface Texture ◽  
Rolling Resistance ◽  
Surface Characteristics ◽  
Road Surface ◽  
Operating Parameters ◽  
Road Vehicles ◽  
Passenger Car ◽  
Road Surfaces ◽  
Resistive Forces

Tire rolling resistance is one of the most important resistive forces acting on road vehicles. It depends on tire and surface characteristics as well as vehicle operating parameters. This paper deals with the influence of road surface texture on rolling resistance of passenger car tires. Results of road measurements performed on variety of road surfaces are presented.

Wet Skid Resistance of Car and Truck Tires

1974 ◽  
Vol 2 (2) ◽  
pp. 102-116 ◽  
Author(s):  
A. Dijks
Keyword(s):  
Surface Texture ◽  
Road Surface ◽  
Skid Resistance ◽  
Test Results ◽  
Side Force ◽  
Force Coefficients ◽  
Truck Tires ◽  
Braking Force ◽  
Wet Skid Resistance

Abstract Two test trailers for measuring tire characteristics are described. One of the trailers is specially built for testing car tires and can steer, camber, and brake the test tire. This trailer is provided with a five component measuring hub. The second trailer, for testing truck tires, is restricted to braking only. Braking forces are measured with a dynamometer. The determination of peak and locked wheel braking force coefficients is discussed. In addition, for car tires, a method for obtaining side force coefficients is given. Test results are given for both car and truck tires showing the influence of road surface texture, speed, and tread depth on skid resistance, and the results are compared.

Tire-Road Interactions — Harmony or Conflict?

1989 ◽  
Vol 17 (1) ◽  
pp. 66-84
Author(s):  
A. R. Williams
Keyword(s):  
Rolling Resistance ◽  
Major Effect ◽  
Road Surface ◽  
Interactive Effects ◽  
Central Theme ◽  
Water Drainage ◽  
The Road ◽  
Truck Tires ◽  
Road Surfaces ◽  
Tire Wear

Abstract This is a summary of work by the author and his colleagues, as well as by others reported in the literature, that demonstrate a need for considering a vehicle, its tires, and the road surface as a system. The central theme is interaction at the footprint, especially that of truck tires. Individual and interactive effects of road and tires are considered under the major topics of road aggregate (macroscopic and microscopic properties), development of a novel road surface, safety, noise, rolling resistance, riding comfort, water drainage by both road and tire, development of tire tread compounds and a proving ground, and influence of tire wear on wet traction. A general conclusion is that road surfaces have both the major effect and the greater potential for improvement.

scholarly journals Detection of Road-Surface Anomalies Using a Smartphone Camera and Accelerometer

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 561
Author(s):  
Taehee Lee ◽  
Chanjun Chun ◽  
Seung-Ki Ryu
Keyword(s):  
Monitoring System ◽  
Poor Performance ◽  
Road Surface ◽  
Monitoring Systems ◽  
Advantages And Disadvantages ◽  
Acceleration Data ◽  
Road Surfaces ◽  
Road Surface Monitoring ◽  
Surface Monitoring ◽  
Acquisition Method

Road surfaces should be maintained in excellent condition to ensure the safety of motorists. To this end, there exist various road-surface monitoring systems, each of which is known to have specific advantages and disadvantages. In this study, a smartphone-based dual-acquisition method system capable of acquiring images of road-surface anomalies and measuring the acceleration of the vehicle upon their detection was developed to explore the complementarity benefits of the two different methods. A road test was conducted in which 1896 road-surface images and corresponding three-axis acceleration data were acquired. All images were classified based on the presence and type of anomalies, and histograms of the maximum variations in the acceleration in the gravitational direction were comparatively analyzed. When the types of anomalies were not considered, it was difficult to identify their effects using the histograms. The differences among histograms became evident upon consideration of whether the vehicle wheels passed over the anomalies, and when excluding longitudinal anomalies that caused minor changes in acceleration. Although the image-based monitoring system used in this research provided poor performance on its own, the severity of road-surface anomalies was accurately inferred using the specific range of the maximum variation of acceleration in the gravitational direction.

scholarly journals Tire/Road Rolling Resistance Modeling: Discussing the Surface Macrotexture Effect

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 538
Author(s):  
Malal Kane ◽  
Ebrahim Riahi ◽  
Minh-Tan Do
Keyword(s):  
Slip Rate ◽  
Rolling Resistance ◽  
Friction Model ◽  
Slip Rates ◽  
Wide Range ◽  
Road Surfaces ◽  
Profile Depth ◽  
Experimental Rolling ◽  
Resistance Modeling ◽  
Pavement Friction

This paper deals with the modeling of rolling resistance and the analysis of the effect of pavement texture. The Rolling Resistance Model (RRM) is a simplification of the no-slip rate of the Dynamic Friction Model (DFM) based on modeling tire/road contact and is intended to predict the tire/pavement friction at all slip rates. The experimental validation of this approach was performed using a machine simulating tires rolling on road surfaces. The tested pavement surfaces have a wide range of textures from smooth to macro-micro-rough, thus covering all the surfaces likely to be encountered on the roads. A comparison between the experimental rolling resistances and those predicted by the model shows a good correlation, with an R2 exceeding 0.8. A good correlation between the MPD (mean profile depth) of the surfaces and the rolling resistance is also shown. It is also noticed that a random distribution and pointed shape of the summits may also be an inconvenience concerning rolling resistance, thus leading to the conclusion that beyond the macrotexture, the positivity of the texture should also be taken into account. A possible simplification of the model by neglecting the damping part in the constitutive model of the rubber is also noted.

scholarly journals Laboratory experiment on the nano-TiO2 photocatalytic degradation effect of road surface oil pollution

2020 ◽  
Vol 9 (1) ◽  
pp. 922-933
Author(s):  
Qing’e Wang ◽  
Kai Zheng ◽  
Huanan Yu ◽  
Luwei Zhao ◽  
Xuan Zhu ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Oil Pollution ◽  
Road Surface ◽  
Test Method ◽  
Driving Safety ◽  
The Road ◽  
Road Surfaces ◽  
The Many ◽  
The Impact ◽  
Degradation Effect

AbstractOil leak from vehicles is one of the most common pollution types of the road. The spilled oil could be retained on the surface and spread in the air voids of the road, which results in a decrease in the friction coefficient of the road, affects driving safety, and causes damage to pavement materials over time. Photocatalytic degradation through nano-TiO2 is a safe, long-lasting, and sustainable technology among the many methods for treating oil contamination on road surfaces. In this study, the nano-TiO2 photocatalytic degradation effect of road surface oil pollution was evaluated through the lab experiment. First, a glass dish was used as a substrate to determine the basic working condition of the test; then, a test method considering the impact of different oil erosion degrees was proposed to eliminate the effect of oil erosion on asphalt pavement and leakage on cement pavement, which led to the development of a lab test method for the nano-TiO2 photocatalytic degradation effect of oil pollution on different road surfaces.

scholarly journals Angolan vegetable crops have unique genotypes of potential value for future breeding programmes

2016 ◽  
Vol Volume 112 (Number 3/4) ◽  
Author(s):  
José P. Domingos ◽  
Ana M. Fita ◽  
María B. Picó ◽  
Alicia Sifres ◽  
Isabel H. Daniel ◽  
...  
Keyword(s):  
Strong Dependence ◽  
The Other ◽  
Vegetable Crops ◽  
Cucurbita Maxima ◽  
Capsicum Chinense ◽  
Local Markets ◽  
Potential Value ◽  
Wide Range ◽  
Different Types ◽  
Breeding Programmes

Abstract A survey was carried out in Angola with the aim of collecting vegetable crops. Collecting expeditions were conducted in Kwanza-Sul, Benguela, Huíla and Namibe Provinces and a total of 80 accessions belonging to 22 species was collected from farmers and local markets. Species belonging to the Solanaceae (37 accessions) and Cucurbitaceae (36 accessions) families were the most frequently found with pepper and eggplant being the predominant solanaceous crops collected. Peppers were sold in local markets as a mixture of different types, even different species: Capsicum chinense, C. baccatum, C. frutescens and C. pubescens. Most of the eggplant accessions collected belonged to Solanum aethiopicum L. Gilo Group, the so-called ‘scarlet eggplant’. Cucurbita genus was better represented than the other cucurbit crops. A high morphological variation was present in the Cucurbita maxima and C. moschata accessions. A set of 22 Cucurbita accessions from Angola, along with 32 Cucurbita controls from a wide range of origins, was cultivated in Valencia, Spain and characterised based on morphology and molecularity using a set of 15 microsatellite markers. A strong dependence on latitude was found in most of the accessions and as a result, many accessions did not set fruit. The molecular analysis showed high molecular variability and uniqueness in the collected accessions, as shown by their segregation from the set of global controls. In summary, the material collected is quite valuable because of its uniqueness and the potential of the breeding characteristics it possesses.

scholarly journals Hydromechanical Fuel Control for Portable Gas Turbine Generator Sets

1968 ◽  
Author(s):  
G. E. Parker
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Production Cost ◽  
Light Weight ◽  
Turbine Generator ◽  
Design Problems ◽  
Ambient Temperatures ◽  
High Speeds ◽  
Wide Range ◽  
Generator Sets

Controls for small lightweight gas turbines present some unique design problems. The requirements for small size, light weight, ability to rotate at high speeds to save reduction gearing, and low production cost conflict with the requirements for reasonably accurate control of very small fuel flows and the scheduling of a wide range of hydrocarbon fuels over a wide range of ambient temperatures. This paper discusses in some detail the design of such a control and the satisfactory results obtained.

The Measurement and Analysis of Ball Motion in High Speed Deep Groove Ball Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 341-348 ◽  
Author(s):  
R. J. Boness ◽  
J. J. Chapman
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Complete Analysis ◽  
Ball Speed ◽  
Rolling Axis ◽  
High Speeds ◽  
Deep Groove ◽  
Wide Range ◽  
Ring Mode ◽  
Ball Motion

This paper reports on a study of ball motion, including the measurement of ball rolling axis, in deep groove bearings operating at high speeds under thrust load conditions. The technique employed relies on viewing the test bearing, operating in the conventional fixed outer ring mode, through a rotating prism which eliminates optically the gross rotation of the separator. Videotape recordings of a selected ball, distinctively marked and illuminated stroboscopically, allows a complete analysis of ball bearing kinematics. Experimental results of separator speed, ball speed and rolling axis together with separator slip, ball slip and spin velocities at both the inner and outer raceway contacts are presented for a wide range of loads and shaft speeds up to 12,000 rev/min. These results are compared with the existing theory of Jones. Discrepancies between predicted and actual ball motion are due to the assumption made by Jones in neglecting bearing element slip. A further analysis of the experimental results including both gyroscopic torques and slip based on elastohydrodynamic traction values for the test lubricant explains actual ball motion more fully.

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