Field Determination of Cargo-Deck Friction Coefficients

Author(s):  
Jos A. Romero ◽  
Miguel Marti´nez ◽  
Alejandro Lozano

Friction between cargo and vehicle’s deck has been considered among the supplemental means for securing cargo. Although friction coefficients have been determined as a function of different influencing factors, such measurements have been performed under laboratory controlled conditions that simplify vehicle vibration and cargo-deck stiffness and contact characteristics. In this paper a methodology is proposed to quantify cargo-deck friction coefficients under realistic field conditions throughout the kinematical analysis of the stopping of the cargo-carrying vehicle by effects of dragging the cargo on the vehicle’s platform. The vehicle is located on an inclined road segment while the cargo is lashed to a fixed point on the road, in such a manner that the vehicle can travel a certain distance before the lashing becomes tensioned and the cargo starts stopping the vehicle. While average values for friction coefficients correlated well with those reported in the literature, standard deviations represented up to 33% of such average values.

1949 ◽  
Vol 22 (1) ◽  
pp. 259-262
Author(s):  
J. F. Morley

Abstract These experiments indicate that softeners can influence abrasion resistance, as measured by laboratory machines, in some manner other than by altering the stress-strain properties of the rubber. One possible explanation is that the softener acts as a lubricant to the abrasive surface. Since this surface, in laboratory abrasion-testing machines, is relatively small, and comes repeatedly into contact with the rubber under test, it seems possible that it may become coated with a thin layer of softener that reduces its abrasive power. It would be interesting in this connection to try an abrasive machine in which a long continuous strip of abrasive material was used, no part of it being used more than once, so as to eliminate or minimize this lubricating effect. The fact that the effect of the softener is more pronounced on the du Pont than on the Akron-Croydon machine lends support to the lubrication hypothesis, because on the former machine the rate of wear per unit area of abrasive is much greater. Thus in the present tests the volume of rubber abraded per hr. per sq. cm. of abrasive surface ranges from 0.03 to 0.11 cc. on the du Pont machine and from 0.0035 to 0.0045 cc. on the Akron-Croydon machine. On the other hand, if the softener acts as a lubricant, it would be expected to reduce considerably the friction between the abrasive and the rubber and hence the energy used in dragging the rubber over the abrasive surface. The energy figures given in the right-hand columns of Tables 1 and 3, however, show that there is relatively little variation between the different rubbers. As a test of the lubrication hypothesis, it would be of interest to vary the conditions of test so that approximately the same amount of rubber per unit area of abrasive is abraded in a given time on both machines; this should show whether the phenomena observed under the present test conditions are due solely to the difference in rate of wear or to an inherent difference in the type of wear on the two machines. This could most conveniently be done by considerably reducing the load on the du Pont machine. In the original work on this machine the load was standardized at 8 pounds, but no figures are quoted to show how abrasion loss varies with the load. As an addition to the present investigation, it is proposed to examine the effect of this variation with special reference to rubbers containing various amounts and types of softener. Published data on the influence of softeners on the road wear of tire rubbers do not indicate anything like such large effects as are shown by the du Pont machine. This throws some doubt on the value of this machine for testing tire tread rubbers, a conclusion which is confirmed by information obtained from other workers.


Author(s):  
Daniil A. Loktev ◽  
Alexey A. Loktev ◽  
Alexandra V. Salnikova ◽  
Anna A. Shaforostova

This study is devoted to determining the geometric, kinematic and dynamic characteristics of a vehicle. To this purpose, it is proposed to use a complex approach applying the models of deformable body mechanics for describing the oscillatory movements of a vehicle and the computer vision algorithms for processing a series of object images to determine the state parameters of a vehicle on the road. The model of the vehicle vertical oscillations is produced by means of the viscoelastic elements and the dry friction element that fully enough represent the behavior of the sprung masses. The introduced algorithms and models can be used as a part of a complex system for monitoring and controlling the road traffic. In addition, they can determine both the speed of the car and its dynamic parameters and the driving behavior of the individual drivers.


1985 ◽  
Vol 13 (1) ◽  
pp. 41-64
Author(s):  
W. R. Garrott ◽  
D. A. Guenther

Abstract An experimental study was made to compare the validities of methods currently used by accident reconstructionists to determine the coefficient of friction between the road and the vehicle tires at the time of an incident. This value could then be used in conjunction with skid mark length and vehicle weight to calculate the prebraking speed of the vehicle. Three automobiles and three trucks with a variety of tires and loadings were used on a variety of pavements. The accuracy and area of applicability of each of four methods for obtaining friction coefficients were determined by relating the prebraking speed calculated from each to the actual speed at the time of brake application. All four methods were satisfactory for automobiles and the pickup truck used, but only two were acceptable for heavy trucks. The most valid coefficients are obtained from skid mark lengths obtained under conditions duplicating those in an incident.


Author(s):  
Чирков ◽  
E. Chirkov ◽  
Дорохин ◽  
S. Dorokhin ◽  
Скрыпников ◽  
...  

This article describes the relevance of road transport under current conditions in the region of a transport hub. Established transit factor, let-conductive to determine the optimal value of the extra-urban transit from the total intensity-sti movement. Submitted economic calculations of the cost of work on transportation, taking into account speed limits. Recommended cost performance of all modes of transport that are formed on the main roads


1883 ◽  
Vol 10 (5) ◽  
pp. 199-205 ◽  
Author(s):  
T. G. Bonney

In my brief paper published in this Magazine for 1880 (Decade II. Vol. VII. p. 404), I mentioned that pebbles of felstone were not uncommon in the Bunter conglomerate on the northern part of Cannock Chase. Since that time, as opportunity has occurred, I have been making a more special study of these pebbles, and think it may be worth while publishing a description of some of the commoner varieties, as a contribution to the lithology of this interesting deposit and a help to the determination of the question of the origin of its material. I believe that I have observed most of the varieties, which commonly occur in the district, but do not pretend (for circumstances have not allowed of this) to have made anything like a complete collection. Many of my specimens have been derived from the broken materials spread upon some roads newly made over the portion of the Chase in the vicinity of Rugeley, but several of them were obtained in a large pit in the Bunter itself, by the side of the railway on the road to Hednesford, and I was able by a careful search in it to identify most of the varieties that I had collected elsewhere. I cannot say that erratics are absolutely unknown in this district, but they are extremely rare, and there is practically no danger of making a mistake as to the source of the pebbles. These pebbles of felstone (to use an inclusive term) appear to be by no means rare. I think one could hardly search a couple of square yards of a newly “metalled” road without picking up a fragment. Now and then specimens are found with a dark ground-mass, and occasionally one which seems to be an indurated felspathic breccia; but in the majority there is a certain common character, though there are many varietal differences. These have a compact ground-mass, varying from a pale brick-red (the commonest) to some tint of pinkish-grey.


2014 ◽  
Vol 41 (2) ◽  
pp. 97-105
Author(s):  
L. Beaulieu ◽  
R. Pleau ◽  
P. Pierre ◽  
P. Poulin ◽  
S. Juneau

The main objective of this article is to propose a methodology to evaluate and to study the mechanical performance of various hygroscopic, organic and synthetic dust suppressants and stabilization agents through field tests. Different road sections were treated for several years and many tests have been conducted. The impact on the mechanical performance of the treated granular material has been studied under field conditions by evaluating the deterioration of the road following the spreading of the product on the road. Field tests were conducted over three years in summers 2007, 2008, and 2009. The deterioration of the road is evaluated in terms of improper cross section, inadequate roadside drainage, corrugations, dust, potholes, ruts, and loose aggregates. To evaluate the influence of stabilization agents on the bearing capacity of the granular material on the road, falling weight deflectometer (FWD) tests have also been performed.


1986 ◽  
Vol 30 (3) ◽  
pp. 256-260 ◽  
Author(s):  
Helmut T. Zwahlen ◽  
David P. DeBald

Two groups of six young and healthy subjects were used in this study to investigate the lateral path deviations when driving in a straight path with the eyes fixated on the road ahead, when driving while reading information inside of the automobile, and when driving with the eyes closed. Each group of subjects drove a typical large car and a typical small car at a fixed speed of 30 mph. An unused 2000 foot long and 75 foot wide, level, concrete airport runway was used to conduct the experiment. Each subject made three runs under each of the three conditions with the large car and with the small car (18 runs total). The lateral path deviations from the longitudinal centerline of the car to the centerline of the runway were measured every 15 feet for a distance of 705 feet. A device which dripped liquid dye was attached to the center of the rear bumper of the automobiles to indicate their paths. The results of this study show that the average lateral standard deviations for driving with the eyes fixated upon the road ahead were between 5.5″ and 11.3″. The difference in the lateral standard deviations for large and small automobiles was statistically not significant for distances between 100 and 500 feet from the starting point for the three conditions tested. The lateral standard deviation was smaller for reading text within the automobile than for driving with the eyes closed, and was statistically significant after an occlusion distance of 225 feet or an occlusion time of about 5 seconds. Using a constant of 0.041, the fundamental relationship between the lateral standard deviation, the speed, and the occlusion distance developed by Zwahlen and Balasubramanian (1974) fits the data for reading text inside of the automobile while driving fairly well. This constant is approximately one half of that which has been used for driving with the eyes closed (0.076) in this study. Based upon the results of this study, the development and introduction of sophisticated in-vehicle displays and/or touch panels should be halted and their safety aspects with regard to information aquisition, information processing, and driver control actions should be critically evaluated.


2014 ◽  
Vol 13 (1) ◽  
pp. 339-347
Author(s):  
Vitalii Naumov ◽  
Natalia Vnukova ◽  
Ganna Zhelnovach

The analysis of problems and of approaches for ensuring the environmental safety of roads in Ukraine has been performed. The proposed mathematical model on the basis of neural networks allows numerical evaluation of quality of road area in the conditions of incomplete and fuzzy information. The proposed approach allows the determination of roads’ environmental safety level, the indica­tion of necessity for arrangement of environmental monitoring stations, and allows the development of a number of activities for environmental protection on the road sections as well.


2018 ◽  
Vol 18 (2) ◽  
pp. 55-64
Author(s):  
Arie Setyawan ◽  
Anas Puri ◽  
Harmiyati Harmiyati

[ID] Perkembangan kota yang diikuti dengan meningkatnya jumlah penduduk di Kota Pekanbaru menyebabkan terjadi alih fungsi lahan menjadi areal pemukiman ataupun perkantoran. Adanya perubahan fungsi lahan dari areal hijau menjadi areal pemukiman atau perkantoran mengakibatkan terganggunya daya resap tanah sehingga aliran permukaan (run off) menjadi semakin besar. Tujuan dari penelitian ini adalah unutuk mengetahui kemampuan saluran drainase Jalan Arifin Ahmad dalam menampung debit aliran dengan pengaruh perubahan tataguna lahan dalam 10 tahun yang akan dating dan mengetahui penyebab dari tergenangnya air pada salah satu ruas Jalan Arifin Ahmad tepat nya pada ruas antara Jalan Rambutan dengan Jalan Paus Ujung. Pada penelitian ini dilakukan perhitungan frekuensi curah hujan menggunakan jenis uji distribusi Log-Pearson III. Intensitas curah hujan dihitung menggunakan metode rasional. Debit rencana (Qr) berdasarkan jumlah debit hujan (Qh), debit air kotor (Qk) dan debit kiriman (QKiriman). Perubahan tata guna lahan mengacu kepada RTRW kota pekanbaru, kapasitas saluran drinase dihitung menggunakan persamaan manning, dan selanjutnya di analisa apakah saluran tersebut masih mampu menampung debit rencana 10 tahun mendatang dengan perubahan tata guna lahan yang ada. Dari hasil analisa debit rencana 10 tahun mendatang adalah 2,74 m3/detik dengan debit saluran (Qs) sebesar = 0,97 m3/detik untuk saluran tanah dan 2,34 m3/detik untuk saluran permanen, maka dapat disimpulkan bahwa saluran eksisting drainase Jalan Arifin Ahmad pada ruas antara Jalan Rambutan dengan Jalan Puas Kota Pekanbaru tidak aman. Adapun dimensi saluran drainase rencana 10 tahun mendatang adalah lebar dasar saluran (B) = 3,5 m, tinggi permukaan air (h) = 1,75 m, tinggi jagaan air (w) = 0,25 m, dan tinggi saluran (H) = 2 m. Faktor-faktor penyebab terjadinya genangan air pada salah satu ruas Jalan Arifin Ahmad tepatnya pada ruas antara Jalan Rambutan dengan Jalan Paus Ujung adalah tidak mengalirnya air dari badan jalan ke saluran drainase akibat kurang berfungsinya tali air sebagai tempat mengalirnya air hujan dari badan jalan ke saluran drainase, banyaknya sampah dan lumpur yang menyebabkan penyumbatan aliran air pada saluran drainase. Adapun faktor utama nya adalah debit rencana aliran lebih besar dari pada debit saluran eksisting, dimana debit rencana aliran (Qr) = 2,32 m3/detik, debit saluran tanah eksisitng (Qs) = 0,97 m3/detik, dan debit saluran permanen eksisting (Qs) = 2,34 m3/detik. [EN] The development of the city followed by the increasing number of residents in the city of Pekanbaru causing the conversion of land into residential areas or offices. The change of land function from green area to residential area or offices resulted in disturbance of soil absorption so that runoff becomes bigger.The purpose of this research is to know the ability of drainage channel Arifin Ahmad Road in accommodating flow discharge with the effect of land use change in 10 years that will come and know the cause of the water flooding on one of Arifin Ahmad Road segment right on the road between Jalan Rambutan with Jalan Pope Edge. In this research is calculated the frequency of rainfall using the type of Log-Pearson III distribution test. Rainfall intensity is calculated using rational methods. The plan debit (Qr) is based on the amount of rainfall (Qh), gross discharge (Qk) and debit of mail (QKiriman). Land use change refers to RTRW kotabaru, drainage channel capacity is calculated using the manning equation, and then analyzed whether the channel is still able to accommodate the discharge of the next 10 years plan with changes in existing land use.From the results of the next 10 years plan debit analysis is 2.74 m3 / second with the channel discharge (Qs) of 0.97 m3 / sec for the ground channel and 2.34 m3 / sec for the permanent channel, it can be concluded that the drainage existing channel Arifin Ahmad Road on the segment between Jalan Rambutan and Jalan Puas Pekanbaru is not safe. The dimensions of the drainage channel of the plan for the next 10 years are the bottom width of the channel (B) = 3.5 m, the water level (h) = 1.75 m, the water velocity (w) = 0.25 m, and the channel height (H ) = 2 m. The factors causing water puddle on one of Arifin Ahmad Road segment precisely on the road between Rambutan Street and Ujung Pope Road is not the flow of water from the road to the drainage channel due to the lack of functioning of the water line as a place of rain water flow from the road to the drainage channel , the amount of garbage and mud that causes blockage of water flow in the drainage channel. The main factor is the flow of the flow plan is greater than the existing channel discharge, where the flow of the flow plan (Qr) = 2.32 m3 / sec, the discharge of the exisiting ground channel (Qs) = 0.97 m3 / sec, and the permanent channel discharge Existing (Qs) = 2.34 m3 / sec.


Author(s):  
Jozef Gnap ◽  
Jana Kupculjakova ◽  
Stefania Semanova

The paper deals with the issue of delays of public transport vehicles at the signal controlled junctions. Based on the road traffic survey results, the average values of vehicle delays were determined. By using those values, it is possible to define time savings for the vehicles and mainly for passengers that are transported. The time savings were determined based on the relationships and coefficients defined in this paper.


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