To see the other types of publications on this topic, follow the link: Road profile characteristics.
Journal articles on the topic 'Road profile characteristics'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Road profile characteristics.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Luty, Witold, and Marcin Mieteń. "Geometrical analysis of profile of certain heavy terrain sections exerting dynamic loads on the chassis components of off-road vehicles." Journal of KONBiN 41, no. 1 (March 1, 2017): 151–70. http://dx.doi.org/10.1515/jok-2017-0008.
Full textAbstract:
Abstract The paper presents the results of measurements concerned with the changes of profile height observed on selected heavy terrain road sections. Based on the results of direct measurements, primary indicators and amplitude frequency characteristics have been determined. The characteristics of these roads profiles have been presented as a function of path frequency, and also as a function of the vehicle wheels’ excitation frequency observed while driving at a certain, constant speed. The results presented serve as a source of information on specific heavy terrain road sections exerting dynamic loads on the vehicle’s chassis components while driving in off-road conditions.
2
Melcer, Jozef, Eva Merčiaková, and Mária Kúdelčíková. "Statistical characteristics of sources of vehicle kinematic excitation." MATEC Web of Conferences 313 (2020): 00011. http://dx.doi.org/10.1051/matecconf/202031300011.
Full textAbstract:
The longitudinal and transverse road profiles represent the functions of a random variable from a mathematical point of view. It is appropriate to use methods of probability theory and mathematical statistics for their description. The unevenness of the runway surface is the main source of the vehicle's kinematic excitation. This paper describes the statistical properties of the mapped road profiles. It shows a way of categorizing road surface quality based on the power spectral density of unevenness. The interrelationships between the individual points of the profile and the profiles with one another are evaluated by correlation functions.
3
Do, Minh-Tan, Hassan Zahouani, and Roberto Vargiolu. "Angular Parameter for Characterizing Road Surface Microtexture." Transportation Research Record: Journal of the Transportation Research Board 1723, no. 1 (January 2000): 66–72. http://dx.doi.org/10.3141/1723-09.
Full textAbstract:
Development of a device for measuring road surface microtexture and the determination of a microtexture parameter related to wet road/tire friction are discussed. A laser autofocus system was selected from existing devices. The required characteristics were defined from consideration of the contact between wet roads and tires. The autofocus principle is presented briefly, and comparison is made with a tactile system. The microtexture parameter, called the theta parameter, is defined from the useful parts of the texture profiles, that is, those in contact with the tire. It characterizes relative positions of profile peaks. A simple method was proposed to define the peaks. The profile analysis program is presented briefly. Relevance of the theta parameter was validated on surfaces composed of coarse aggregates with planar exposed faces. The specimens were polished using a projection method to emphasize the microtexture contrast between surfaces. Friction was measured using a skid resistance tester (SRT) pendulum. Profiles were measured using both laser and tactile systems. Characteristics of profiles are given. The statistical distribution of theta values obtained on a profile may be described by an exponential function. Close agreement was found between theta values obtained from laser and tactile profiles, values from laser profiles being somewhat lower. The difference is attributed to profile length. Fair correlation was found ( r2 > 0.80) between theta values and SRT friction, and similar tendencies were observed from laser and tactile data.
4
Sayers, Michael W., and Steven M. Karamihas. "Estimation of Rideability by Analyzing Longitudinal Road Profile." Transportation Research Record: Journal of the Transportation Research Board 1536, no. 1 (January 1996): 110–16. http://dx.doi.org/10.1177/0361198196153600116.
Full textAbstract:
A method for estimating pavement rideability by computing a statistic called ride number (RN) from measured longitudinal profiles of the pavement is presented. The computational algorithm was developed with two objectives in mind: (a) relevance, as established by correlation between RN and mean panel ratings obtained for profiled pavements, and (b) portability, as determined by the ability of different profiling systems to obtain comparable RN values for profiles taken on the same pavement. Experimental data show that the new algorithm is comparable to previously developed RN algorithms in terms of its correlation with panel ratings. The new algorithm is much more portable; comparable RN values can be obtained from different profilers and the quasi-static Dipstick device. However, measures from ultrasonic profilers are not as accurate, and in some cases these devices are not acceptable for measuring RN. Although the fundamental relationships between profile characteristics and the human perception of rideability are still not understood, the algorithm is recommended as the best way to apply the results of past research investigating rideability.
5
Lamb, M. J., and V. Rouillard. "Nonstationary coherence characteristics of dual track road profile data." Mechanical Systems and Signal Processing 140 (June 2020): 106721. http://dx.doi.org/10.1016/j.ymssp.2020.106721.
Full text
6
Loprencipe, Giuseppe, Pablo Zoccali, and Giuseppe Cantisani. "Effects of Vehicular Speed on the Assessment of Pavement Road Roughness." Applied Sciences 9, no. 9 (April 29, 2019): 1783. http://dx.doi.org/10.3390/app9091783.
Full textAbstract:
Good ride quality is a fundamental requirement for all road networks in modern countries. For this purpose, it is essential to monitor and evaluate the effect of irregularities on road pavement surfaces. In the last few decades, many roughness indices have been proposed, with the aim to represent shortly the pavement surface characteristics and the relative performances, using a single number and a correspondent scale of values. In this work, a comparison between three different evaluation methods (International Roughness Index, ISO 8608 road profile classification and frequency-weighted vertical acceleration awz according to ISO 2631) was carried out, applying these methods to some real road profiles. The similarities and differences between the obtained results are described, evaluating the effect of the road characteristic speed on the roughness thresholds. In fact, the specific aim of the analyses is to underline the need to use different thresholds depending on the speed at which the vehicular traffic can travel on the road sections. In this way, it will be possible to identify appropriate thresholds for the various types of roads, having for each of them a specific range of design or operating speed.
7
ENDO, Yoshimitsu, Taichi SHIIBA, and Keisuke MORITA. "1306 Estimation of Road Profile based on Vehicle Dynamic Characteristics." Proceedings of the Transportation and Logistics Conference 2009.18 (2009): 117–20. http://dx.doi.org/10.1299/jsmetld.2009.18.117.
Full text
8
Farah, Ashraf. "Digital Road Profile Using Kinematic GPS." Artificial Satellites 44, no. 3 (January 1, 2009): 95–101. http://dx.doi.org/10.2478/v10018-009-0023-6.
Full textAbstract:
Digital Road Profile Using Kinematic GPS A Digital Road Profile (DRP) is a digital representation of road surface topography or terrain in the longitudinal direction. The need for accurate DRP is vital in two stages; before the road construction starts and after the road construction finished where the verification of its geometrical characteristics is essential for engineering safety purposes. Classical surveying techniques are traditionally used for the DRP generation with limitation of high-cost and time-waste. Kinematic DGPS or Real Time Kinematic DGPS positioning can provide accurate enough results for such application. This paper presents an assessment study of using kinematic GPS technique for DRP generation comparing with classical survey in south Egypt. The results shows that, vehicle-GPS system used in combination with post processing kinematic DGPS gave satisfactory accuracy for nearly all points for a distance of nearly 2 km. with max. and min. difference not more than 7.7 cm, a mean value of 0.10 cm and a Root Mean Square RMS value of 4.11 cm.
9
Žuraulis, Vidas, Loreta Levulytė, and Edgar Sokolovskij. "THE IMPACT OF ROAD ROUGHNESS ON THE DURATION OF CONTACT BETWEEN A VEHICLE WHEEL AND ROAD SURFACE." TRANSPORT 29, no. 4 (December 16, 2014): 431–39. http://dx.doi.org/10.3846/16484142.2014.984330.
Full textAbstract:
The paper analyses the impact of the road micro-profile on the duration and the type of the vehicle wheel contact with the road surface driving at different speed. The selected vehicle bicycle model describes vertical displacements of front and rear wheels and their suspension as well as the impact of the vehicle body motion and longitudinal oscillation. International Roughness Index (IRI) and micro-profile irregularities of the road section analysed in the paper were identified using specialized road testing equipment. The experimental investigations measuring the vehicle suspension displacement and the body acceleration were carried out. Frequency characteristics of suspension motion and regularities of vertical movement of the wheel were identified after dividing the investigated road section according to driving modes. The analysis into the wheel contact with the road surface and identified correlations enable to determine the vehicle stability on selected quality roads.
10
Kang, Yong-suk, Troy J. Kim, and John B. Ferris. "Advanced Vehicle Control With an Optimized Speed Profile Using Road Characteristics for Road Departure Prevention." IEEE Transactions on Intelligent Vehicles 5, no. 4 (December 2020): 649–58. http://dx.doi.org/10.1109/tiv.2020.3022974.
Full text
11
Čerškus, Aurimas, Tadas Lenkutis, Nikolaj Šešok, Andrius Dzedzickis, Darius Viržonis, and Vytautas Bučinskas. "Identification of Road Profile Parameters from Vehicle Suspension Dynamics for Control of Damping." Symmetry 13, no. 7 (June 27, 2021): 1149. http://dx.doi.org/10.3390/sym13071149.
Full textAbstract:
Concept of symmetry covers physical link between road profile form, vehicle dynamic characteristics, and speed conjunction. Symmetry frame between these items is asymmetric itself and has no direct expression, but it affects a vibration level on the vehicle and driving comfort. Usually, we can change only the vehicle’s speed to achieve desired vibrations level of the driver and passengers. Recently, vehicle dynamic characteristics can be changed depending on its damping system structure, but these solutions are limited by construction and control possibilities and evidently represented by symmetric dependency between road input and the resulting acceleration of the vehicle. The main limitation of this process is to have a reliable value of the existing road profile that is mainly defined by road category but unpredictable for each road distance. Functional road profile calculations are provided in this article, where power spectral density (further-PSD) and waviness of the road play the main role in delineating road profile parameters. Furthermore, the transfer function system was created using full car dynamic model analysis. Values on vehicle suspension’s effects on acceleration were obtained from vehicle speed and road roughness. Acceleration values and transfer function were used to calculate PSD value quickly and practically. This calculated result can be formed as a control value to the vehicle damping control. In addition, the provided methodology became useful to determine road quality for adjustment of vehicle suspension parameters and set safe driving characteristics, which became part of driver assistant systems or autonomous driving mode.
12
Vaitkus, Audrius, Tadas Andriejauskas, Ovidijus Šernas, Donatas Čygas, and Alfredas Laurinavičius. "DEFINITION OF CONCRETE AND COMPOSITE PRECAST CONCRETE PAVEMENTS TEXTURE." Transport 34, no. 3 (June 11, 2019): 404–14. http://dx.doi.org/10.3846/transport.2019.10411.
Full textAbstract:
In the context of increasing traffic demands and emerging mobility trends road infrastructure has to shift towards the fifth generation of roads, which according to Forever Open Road (FOR) vision are envisioned as adaptable to traffic volumes, resilient to changing weather conditions, quickly built, effectively maintained, suitable for retrofitting, self-monitoring, self-repairing and recyclable. Concrete modular pavements can be defined as an example of such type of road infrastructure. Functional needs are mainly associated with implementation area/location, traffic and mobility demands, environmental constraints and etc. This also has a significant impact on the selection of Precast Concrete Pavements (PCP) texture formation method and materials. Concrete pavement surface texture affects both safety and tyre/road noise characteristics. Exposed Aggregate Concrete (EAC) and porous concrete are the most suitable noise reducing solutions for highways and streets wearing layer even in severe traffic and climate conditions. According to the literature analysis, the algorithm of highways and streets low noise concrete design was created. It is recommended to use the highest quality aggregates with maximum size up to 8 mm, gap-graded gradation, higher amount of cement and lower water/cement ratio. The most important characteristics of EAC are Mean Profile Depth (MPD), Mean Texture Depth (MTD) and profile count, while the most important characteristics of porous concrete are compressive strength, outflow and air void content.
13
Lenkutis, Tadas, Aurimas Čerškus, Nikolaj Šešok, Andrius Dzedzickis, and Vytautas Bučinskas. "Road Surface Profile Synthesis: Assessment of Suitability for Simulation." Symmetry 13, no. 1 (December 31, 2020): 68. http://dx.doi.org/10.3390/sym13010068.
Full textAbstract:
Vibration analysis plays an essential role to enhance the design of the vehicle, related to its comfort and safety level. It is useful to determine the relations between the road profile or its characteristics to the particular properties of vehicles and evaluate the dynamic response to the applied road profile. During the design stage, the simulation of vehicle suspension requires an input of road surface for the initial dynamic load. Therefore, an artificial road profile, created according to a specific methodology, is a key to overall research success. It is possible to generate an artificial road profile using several mathematical methods. This paper is dedicated to analyzing and comparing the usability and ISO-compatibility of three methods: White noise filtration, sinusoidal approximation, and moving average of white noise. Furthermore, we modified the sinusoidal approximation, additionally using a windowing function, thus removing sharp jumps in a generated road profile. Each analyzed method has its advantages and disadvantages, therefore, proper choice in profile generation was a goal of the provided analysis. We defined that the moving average of white noise filtration method has the highest implementation perspectives due to the best compliance to the desired ISO-defined road profile shape and independence from simulation velocity.
14
Yu, Wuhui, Xinjie Zhang, Konghui Guo, Hamid Reza Karimi, Fangwu Ma, and Fumiao Zheng. "Adaptive Real-Time Estimation on Road Disturbances Properties Considering Load Variation via Vehicle Vertical Dynamics." Mathematical Problems in Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/283528.
Full textAbstract:
Vehicle dynamics are directly dependent on tire-road contact forces and torques which are themselves dependent on the wheels’ load and tire-road friction characteristics. An acquisition of the road disturbance property is essential for the enhancement of vehicle suspension control systems. This paper focuses on designing an adaptive real-time road profile estimation observer considering load variation via vehicle vertical dynamics. Firstly, a road profile estimator based on a linear Kalman filter is proposed, which has great advantages on vehicle online control. Secondly, to minimize the estimation errors, an online identification system based on the Recursive Least-Squares Estimation is applied to estimate sprung mass, which is used to refresh the system matrix of the adaptive observer to improve the road estimation efficiency. Last, for mining road category from the estimated various road profile sequencse, a road categorizer considering road frequency and amplitude simultaneously is approached and its efficiency is validated via numerical simulations, in which the road condition is categorized into six special ranges, and this road detection strategy can provide the suspension control system with a better compromise for the vehicle ride comfort, handling, and safety performance.
15
Ramadani, Naser, Valbona Zhjeqi, Merita Berisha, Rina Hoxha, Ilir Begolli, Drita Salihu, and Pranvera Krasniqi. "Public Health Profile of Road Traffic Accidents in Kosovo 2010-2015." Open Access Macedonian Journal of Medical Sciences 5, no. 7 (December 13, 2017): 1036–41. http://dx.doi.org/10.3889/oamjms.2017.214.
Full textAbstract:
AIM: To determine the characteristics of the Socio-medical profile of road traffic accidents in Kosovo, between 2010 and 2015 year.STUDY DESIGN: Retrospective study.METHODS: A descriptive method based on the database of road traffic accidents from the National Police of Kosovo.RESULTS: In Kosovo for the period 2010-2015, on average, the yearly number of road traffic accidents is 18437 with mortality rate 7.4 per 100000 and lethality of 1.5%. The highest number of fatal cases are drivers and above 19 years old with more than 80%. Among injured significantly highest percentage is among passengers for all years and above 19 years old. Road traffic accident with a vehicle occurs most frequently, with approximately over 70%, mostly on dry road 72.9% and clear weather 71.1%. The driver is the contributing factors of road traffic accidents on average 99.3% whereas climatic conditions only 0.5%, with over 50% of crashes occurring in urban road 56.2%, mostly during Monday 16.0% and in the afternoon rush hours between 14.00-18.00 with 31.0%.CONCLUSIONS: There is a slight decrease in the mortality rate of 0.1‰ and lethality rate of 0.1% each year, whereas there is an increase of 21.5‰ for traumatism rate for each year.
16
Song ChangHee, Suk Won Cha, and Wonsik Lim. "A Study on Characteristics of Test Road Excitation PSD Profile for BSR Experiments." Journal of the Korean Society of Mechanical Technology 18, no. 1 (February 2016): 45–51. http://dx.doi.org/10.17958/ksmt.18.1.201602.45.
Full text
17
Kumar, T. Vijay, Drisya Manghat, L. Geetha, and Vivek R. Das. "Performance of Urban Corridor Using Speed Profile Data of Automobile." International Journal of Research in Engineering, Science and Management 3, no. 10 (October 8, 2020): 1–8. http://dx.doi.org/10.47607/ijresm.2020.324.
Full textAbstract:
The level of service on urban roads quality experienced by the drivers will be varying it is difficult to study the variations due to heterogeneous traffic flow conditions of Indian urban roads. As per TRB, 2010 macroscopic traffic flow parameters are found to be deficient in capturing the quality of service on urban roads experienced by users. Hence the objective of the study is to develop new methodology to evaluate the urban roads in heterogeneous traffic conditions considering the microscopic parameters of traffic flow in a four-lane divided urban corridor. The speed profile of the motorised two-wheelers both in free flow and peak flow were collected from the urban corridor of Bangalore Karnataka, India. Using GPS based mobile application. From the speed profile data, the speed variation characteristics were studied. The various speed indices considered in the study are VN (Velocity noise), CV (Co-efficient of variation), AN (Acceleration noise), and MVG (Mean Velocity Gradient). The CV is considered as the measure of effectiveness, higher the CV more will be the variation of quality experienced by the road users.
18
Lilhare, Subham, and Manish Swarnkar. "A study of injury characteristics in road traffic accidents by different road user category." International Surgery Journal 4, no. 1 (December 13, 2016): 395. http://dx.doi.org/10.18203/2349-2902.isj20164477.
Full textAbstract:
Background:Trauma is one of the oldest subjects in medical science because it appeared just as early as human being came to the earth. At the same time trauma is also a novel subject, because trauma has been strikingly increasing with the high-speed development of economical construction, traffic transport and sharp increase of vehicles in number. Therefore, trauma is called the twin brother of the modem civilization. Accidents occur not only due to ignorance but also due to carelessness, thoughtlessness and over confidence. Human, vehicular and environmental factors play role before, during and after a road traffic accidents (RTA). Road traffic injuries are partially predictable and hence preventable.Methods: this was prospective observational study in which all cases of road traffic accident victims admitted to the hospital (AVBRH) between July 2014 to September 2016, were analyzed statistically with respect to their demographic profile, injury characteristics and outcome.Results:This study showed that motorcyclists were predominantly affected (77.3%) in RTA. Males (80.67%) in the working age group 21-40 years (64.66%) were most commonly affected leading to huge economic losses to their families. Majority RTA took place between 4pm to 12am (57.33 %), on Sundays and Saturday (41.66%) and during summer season (52.67%). Extremity injury (67%) was the most common injury followed by craniocerebral injuries (58.33%). Maximum mortality was seen in LMV/HMV occupants (25%).Conclusions:Road traffic accidents are preventable. Strict traffic laws and penalties have to be imposed to curb this ever growing menace.
19
Vaillancourt, Michel, and Daniel Perraton. "Impact of subgrade soils on pavement roughness." Canadian Geotechnical Journal 53, no. 4 (April 2016): 687–95. http://dx.doi.org/10.1139/cgj-2015-0131.
Full textAbstract:
To highlight the impact of subgrade soil variability on the pseudo-profile and roughness at the end of road construction, a research program has been carried out at the Laboratoire sur les chaussées et matériaux bitumineux at École de technologie supérieure (ÉTS). The analysis is intended to highlight the variability of materials’ characteristics according to the longitudinal and vertical axes of the road. The proposed approach aims to calculate potential settlement variations through a global numerical simulation of a road section, in a bid to identify the expected pseudo-profile and to quantify the roughness quality by calculating the international roughness index (IRI). The proposed methodology was tested at a new road construction project in Québec. Here, the results of the simulations are compared to the details of the actual pseudo-profile obtained at the end of road construction for the project under study. It is shown, through the finite difference modeling of the mechanical behavior of the subgrade soil (FLAC calculation code), that the long wavelength pseudo-profile of the road at the end of construction can be determined, and that it is strongly influenced by subgrade soil variability. This article presents a second analysis carried out by Vaillancourt and Perraton in 2015 as part of a study of the impact of subgrade soils on pavement roughness.
20
HOU, BAOLIN, and JIONAG WANG. "EVALUATION OF DYNAMIC PERFORMANCE OF MAGENETO-RHEOLOGICAL DAMPER BY VIRTUAL PROTOTYPE TECHNOLOGY." International Journal of Modern Physics B 19, no. 07n09 (April 10, 2005): 1542–48. http://dx.doi.org/10.1142/s0217979205030566.
Full textAbstract:
Numerical dynamic simulation of a full vehicle incorporating a magneto-rheological damper in the primary suspension is studied using the package ADAMS and SIMULINK. The full vehicle model is built under ADAMS. The interaction between the tire and the road profile is simulated using the ADAMS/TIRE capabilities. The UA tire model is used to model the dynamic characteristics of the tires. A 3-D road profile model is built based on the spatial power spectrum density of a random road profile. In order to model the dynamic characteristics of the primary suspension MR damper, a non-parametric model of an MR damper is proposed which can conveniently be incorporated into the vehicle dynamic model. Two kinds of control policies, a common skyhook and the so-called non-jerk skyhook, are adopted to control the current applied to the MR damper. The simulation results imply that either one of the two skyhook control policies can obtain a good compromise between so-called "soft damping" and "hard damping", and non-jerk skyhook control policy can curb some higher frequency components which are observed in the acceleration response of the chassis. This study demonstrates that virtual prototype technology is an effective approach for investigating the dynamic behavior of MR dampers for complex systems.
21
Irali, F., A. Kivi, S. L. Tighe, and C. Sangiorgi. "Tire–pavement noise and wearing course surface characteristics of experimental Canadian road pavement sections." Canadian Journal of Civil Engineering 42, no. 10 (October 2015): 818–25. http://dx.doi.org/10.1139/cjce-2014-0424.
Full textAbstract:
An evaluation of the acoustic and surface characteristics of different Canadian pavement types was carried out in 2013 at the test track of the Centre for Pavement and Transportation Technology at the University of Waterloo. Noise testing was performed to determine the coefficient of noise absorption on cored samples and noise emissions in the field using the close proximity and the on-board sound intensity methods. Wearing course characteristics were evaluated with field testing, including visual condition surveys, evaluation of frictional properties with the British Pendulum tester, mean texture depth measurements, and surface profile and roughness evaluation with a walking profiler. As of the time of testing, the noise testing results indicate comparable acoustic properties in both flexible and rigid pavement sections, despite differences in the initial pavement materials, mixes, and surface finishing. With increasing pavement age, the amount of noise emissions increases as the pavement surface is worn down. Comparable friction values are also observed in all pavement sections, in line with the noise testing results. However, this is largely based on the initial construction values. Surface distresses are also not uniformly distributed: they are more severe in the oldest sections and more frequent in the loaded lane, which carries the heaviest traffic loads.
22
Abudinen, Daniel, Luis G. Fuentes, and Juan S. Carvajal Muñoz. "Travel Quality Assessment of Urban Roads Based on International Roughness Index: Case Study in Colombia." Transportation Research Record: Journal of the Transportation Research Board 2612, no. 1 (January 2017): 1–10. http://dx.doi.org/10.3141/2612-01.
Full textAbstract:
Roughness is the main feature of the pavement surface that defines user comfort. Pavement roughness is generally defined as irregularities in the pavement surface that adversely affect ride quality, specifically user perception of the road condition. This paper highlights the limitations associated with the evaluation and implementation of the international roughness index (IRI) on urban roads. The paper focuses on ( a) roughness evaluation with full-scale profilers and ( b) conditions particular to urban roads—namely, traffic, intersections, and operating speeds. Given that the speed of urban networks is typically less than the 80 km/h used in the IRI quarter-car model, the implementation of the IRI model on urban roads was evaluated. Even though a given pavement surface reported a unique IRI value, user experience of the profile depended on the travel speed. This result was evidence that user perceptions of road condition are highly influenced by travel speed. The results suggested the need to develop a roughness index that captures the unique characteristics of urban roads and can estimate the road condition as perceived by users. For that reason, this research study focused on establishing thresholds for IRI on the basis of the weighted vertical acceleration parameter as an aid to assessing user perception. The proposed method allows the maximum allowable IRI value for a given road to be established on the basis of the road’s operational speed. The results indicated that IRI thresholds agreed with international and local Colombian standards.
23
You, Qing Long, Nan Xiang Zheng, and Gang Lei Shi. "Study on Temperature Distribution Characteristic of Asphalt Mixtures of Bridge Deck." Advanced Materials Research 163-167 (December 2010): 1829–32. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1829.
Full textAbstract:
Flexible pavements comprise a majority part of highways in china. Many highway bridges are constructed in these highways. These primary highway bridges are subjected to the same heavy loading as the conventional asphalt pavement, but caused much more significant damage than the conventional asphalt pavement. As hot-mix asphalt (HMA) is a visco-elastic material and the all around environment is different between road pavement and bridge deck, the structural or load-carrying capacity of road pavement and bridge deck is different. Thus, to accurately determine in situ strength characteristics of flexible pavement, it is necessary to predict the temperature distribution within the HMA layers and find the difference between road pavement and bridge deck. The majority of previously published research concentrated on pavement temperature prediction. To confirm the bridge deck temperature profile, observing the temperature at bridge deck and road pavement for two months. Compared with the temperature profile of bridge deck and road pavement, find the difference between them. Then some daily temperature prediction models are analyzed and develop a modified double-sine model to simulate the surface temperature variation of bridge deck.
24
Hrůza, Petr, Jaroslav Blahuta, Petr Pelikán, Lucie Olišarová, Jiří Nedorost, Tomáš Mikita, and Zdeněk Patočka. "Recycled Asphalt as an Alternative to Natural Aggregates for Forest Road Reinforcement." Croatian journal of forest engineering 41, no. 1 (November 5, 2019): 149–61. http://dx.doi.org/10.5552/crojfe.2020.571.
Full textAbstract:
The objective of the present paper is to confirm or reject the possible use of recycled asphalt to reinforce forest haul roads regarding the technical requirements set by the standards and directives relevant to the construction of forest road surfaces. The hypothesis is based on the presumption that recycled materials, if correctly used, can reach the same construction properties as standard materials, hence their application does not have a negative effect on reinforcement quality. On a selected stretch of forest road, three test sections were constructed with the use of recycled asphalt, however, each of them with a different technological solution. The first section was reinforced with unbound mixture – Type1 without added water, the second section was constructed using a version of vibrated macadam technology, and recycled asphalt was applied to the third section by the method of basic compacting. In each of the sections, tacheometric cross profile measurement was carried out at monthly intervals to monitor the changes in the cross profile shape, and the number of passages of fully loaded logging trucks was registered; static load tests were performed at pre-defined time intervals to determine the deformation moduli such as deformation characteristics of the road surface structural layers. In all three reinforcement versions, the values of deformation moduli observed during the static load tests were between 68–90 % of the values set by relevant standards for these technologies using natural aggregates. However, the tacheometric measurements did not reveal statistically significant changes in the shape of the reinforcement cross-section. Based on the obtained results, applying recycled asphalt to reinforce forest roads seems to be a suitable alternative to natural quarry aggregate used in unbound structural layers. Recycled material needs to meet the regulatory limits for foreign elements and pass ecotoxicity tests, which is evidenced by a certificate on material compliance issued by the test laboratory.
25
Žuraulis, Vidas. "IMPACT OF THE ROAD PROFILE ON VEHICLE DECELERATION / IŠILGINIO KELIO PROFILIO ĮTAKA AUTOMOBILIO LĖTĖJIMO PAGREIČIUI." Mokslas - Lietuvos ateitis 4, no. 4 (November 28, 2012): 403–7. http://dx.doi.org/10.3846/mla.2012.65.
Full textAbstract:
The article analyzes the impact of the longitudinal road profile on the efficiency of car braking estimated applying deceleration value. Different formulas are used for theoretical calculations, and therefore experimental brakes in different road slopes were performed to obtain the most accurate results. Deceleration, as one of the most important safety parameters, depends on the technical condition of the braking system, road conditions and structural and dynamic properties of the other car. Road alignments can significantly affect car manageability, because of weight transfer and extra track resistance, which may change the overall balance of the car and affect the nature of dynamic characteristics that may vary from certain critical values. The results of corrections to deceleration dependence on the road profile can be used for investigating traffic accidents, optimizing traffic control arrangements and implementing advanced systems for automotive active safety. Santrauka Straipsnyje analizuojama kelio išilginio profilio įtaka automobilio stabdymo efektyvumui, kuris įvertinamas lėtėjimo pagreičio reikšme. Atliekant teorinius skaičiavimus taikomos skirtingos formulės, todėl siekiant gauti kuo tikslesnius rezultatus, buvo atliekami eksperimentiniai stabdymai skirtingo nuolydžio keliuose. Lėtėjimo pagreitis, kaip vienas svarbiausių eismo saugumo parametrų, priklauso nuo stabdžių sistemos techninės būklės, kelio sąlygų ir nuo kitų automobilio konstrukcinių ir dinaminių ypatybių. Išilginis kelio profilis gali gerokai paveikti automobilio valdomumą, nes vyksta svorio persislinkimas, atsiranda papildomos kelio varžos, dėl ko pasikeičia bendras automobilio balansas ir nuo tam tikrų kritinių reikšmių keičiasi dinaminių charakteristikų pobūdis. Patikslinus lėtėjimo pagreičio priklausomybę nuo išilginio kelio profilio, rezultatai gali būti pritaikomi tiriant eismo įvykius, optimizuojant eismo reguliavimo priemonių veikimą, diegiant pažangias automobilių aktyviosios saugos sistemas.
26
Moghadam, Amin, and Rodrigo Sarlo. "Application of Smartphones in Pavement Profile Estimation Using SDOF Model-Based Noisy Deconvolution." Advances in Civil Engineering 2021 (March 24, 2021): 1–13. http://dx.doi.org/10.1155/2021/6654723.
Full textAbstract:
The new generation of smartphones, equipped with various sensors, such as a three-axis accelerometer, has shown potential as an intelligent, low-cost monitoring platform over the past few years. This paper reports the results of an analytical and experimental study on a proposed SDOF model-based noisy deconvolution (SMND) coupled with a deechoing technique to estimate pavement profiles and to modify their geometry using a smartphone inside a vehicle. In the analytical study, the acceleration response of the car was obtained, where the input was a road profile with an arbitrary pattern. Two different methods, classical band-pass filter and wavelet-denoising technique, were used for denoising the acceleration response. In a 2-step deconvolution process coupled with a deechoing technique, the pavement profile was extracted and compared with the original pavement profile, demonstrating good agreement. In the next step, a parametric study was performed to evaluate the effect of vehicle characteristics and speeds. Then, a case study was conducted in Blacksburg, VA, to evaluate the capability of the proposed method in identifying profile types such as potholes and speed bumps. The acceleration-versus-time responses in vertical direction were recorded using smartphone accelerometers located in a moving vehicle. Then, the proposed approach was applied to remove the echo and vehicle dynamics effects to obtain the pavement profiles and to modify their geometry. The results showed that the proposed approach can remove the echo and vehicle dynamics effect from the response to obtain the pavement profile even if the vehicle characteristics and speed are changed.
27
Thuany, Mabliny, Ewa Malchrowicz-Mośko, Zbigniew Waśkiewicz, and Thayse Natacha Gomes. "Individual and Economic Characteristics as Determinants of Brazilian Runners’ Motivation." Sustainability 13, no. 18 (September 11, 2021): 10178. http://dx.doi.org/10.3390/su131810178.
Full textAbstract:
Due to differences in runners’ profiles, which can be related to sociodemographic characteristics, motivations for running can vary. This study aimed to identify Brazilian runners’ motivations for their practice, and the factors associated among runners who point to look for performance improvement as their main motivation. The sample comprised 1097 non-professional road runners. The questionnaire “Profile characterization and associated factors for runner’s performance” was used. The results showed that the oldest athletes and those with the highest income levels presented lower likelihood of reporting performance improvement as their main motivation for taking part in running. In terms of income level, results showed that as this increased, there was a lower chance of getting involved in practice with a focus on incremental improvements in performance. Differences between sexes were also observed, with men more likely to indicate performance improvement as their motivation for running. In Brazil, most runners reported “health” as their main motivation for running. Women, older runners, and those with higher income levels were less likely to point to performance improvements as their main motivation for taking up running.
28
Melo, Matheus, and Suzana Avila. "Comparative analysis of strategies for a semi-active suspension of a ¼ vehicle." MATEC Web of Conferences 211 (2018): 02004. http://dx.doi.org/10.1051/matecconf/201821102004.
Full textAbstract:
The vehicle suspension isolates the chassis from road irregularities, reacting to forces produced by the tires and the braking torques, always keeping the road tire contact, providing stability and safety. Stability and safety are two antagonistic characteristics in suspension design, when improving one the other is impaired and vice versa. The semi-active suspension is a type of vehicle suspension that can change its stiffness and/or damping in real time depending on the vehicle response to the actual road profile. The On-Off semi-active suspension changes its damping coefficient between two fixed limit values. This work proposes an On-Off semi-active suspension model, in which the damping coefficient changes its values considering the road profile function frequency. A control strategy is proposed in a way to improve performance keeping the same simplicity, without any structural change of the semi-active suspension. On the proposed control strategy one of the damping coefficients is obtained through the linear quadratic regulator (LQR) algorithm, with the aim to set the coefficient from the gain matrix associated to the velocity of the suspended mass. This model is compared to anothers found in literature.
29
Han, Wan Shui, Su Jing Yuan, and Bing Wang. "Analysis on Vehicle-Bridge Coupled Vibration of a Rigid-Frame Arch Bridge Based on Measured Road Roughness." Advanced Materials Research 255-260 (May 2011): 1775–80. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1775.
Full textAbstract:
Firstly, synchronous field measurements were carried out for the road roughness of the left and right wheels to obtain the roughness profile using a high speed laser roadway testing vehicle. Secondly, programming idea of multi-girder vehicle-bridge coupled vibration analysis module was presented briefly. Finally, a three-axle heavy truck crossing a rigid-frame arch bridge was taken as an example, detailed comparing and analyzing was carried out for the influence on the dynamic responses and spectrum characteristics of the vehicle-bridge system from three excitation cases which include using measured road roughness corresponding respectively to left and right wheels, using measured road roughness of left wheels and right wheels simultaneously. The analysis shows that when the differences in road roughness between left and right wheels are significant, the responses computed with inconsistent excitation is smaller than that with both of the latter two excitation cases, and there are some differences between the vertical contact forces of wheels and the spectrum characteristics of the vehicle-bridge system.
30
Luty, Witold, and Marcin Mieten. "The analysis of conditions for testing mileage of military vehicles." Scientific Journal of the Military University of Land Forces 189, no. 3 (September 30, 2018): 181–91. http://dx.doi.org/10.5604/01.3001.0012.6236.
Full textAbstract:
The study discusses the issue of determining the conditions for testing the mileage of a vehicle. Lifetime tests are the crucial element of qualification tests. This type of research verifies the resistance of vehicles and elements of their on-board equipment to vibrations and shocks resulting from the interaction of uneven surface during the movement. Certain test conditions can be straightforwardly determined and verified e.g. weather conditions or a type of the road/surface. The problem appears when the tests are to be conducted in field conditions (off-road). At the set driving speed, the level and frequency structure of dynamic loads of elements of a vehicle drive system depend mainly on a surface profile and its viscoelastic conditions. Either the profile or the characteristics of ground foundations change over the time depending on various factors. The paper attempts to assess the interaction of a ground surface of selected field roads on a vehicle. The result of direct measurement of the vertical acceleration captured on a drive axle and on a vehicle’s frame above the axle was addressed. The measurement results were analyzed within the context of possible planning of vehicle test requirements with the application of the method of testing mileage under the field conditions.
31
Saravanan, K. G., and N. Mohanasundara Raju. "Experimental Investigation on Dynamic Characteristics of Magneto-Rheological Fluid Suspension through on Road Comfort Testing." Applied Mechanics and Materials 772 (July 2015): 373–77. http://dx.doi.org/10.4028/www.scientific.net/amm.772.373.
Full textAbstract:
The present study deals with the application of the Magneto-Rheological (MR) fluid assisted semi-active damper as a replacement to the conventional suspension system in Maruti 800 car (source vehicle). MR fluid damper is designed, fabricated and automated with a microcontroller. This experimentation is carried out with real time instrumentation on the selected road profile as a vehicle dynamic approach. Results obtained from the travel imply that MR fluid suspension suppresses the vibrations more effectively than the existing passive damper system. The MR fluid dampens the acceleration and displacement of the piston to a greater extent thereby controlling the ride comfort.
32
López, Griselda, Rosa Arroyo, and Alfredo García. "Structural Equation Approach to Analyze Cyclists Risk Perception and Their Behavior Riding on Two-Lane Rural Roads in Spain." Sustainability 13, no. 15 (July 28, 2021): 8424. http://dx.doi.org/10.3390/su13158424.
Full textAbstract:
The use of bicycles on two-lane rural roads in Spain has been increasing in recent years. However, these roads have no bicycle infrastructure, being cyclists forced to share the road and interact with motorized vehicles. In rural environments, the interaction between road users from the cyclist’s point of view is still not well understood. To analyze it, the relationships between risk perceptions and behavioral factors of rural cyclists according to their demographic characteristics, profile, and self-reported knowledge on traffic rules were obtained. An online survey was used, which collected the opinion of 523 cyclists. Data were analyzed by using structural equation models. The Thurstonian Item Response Theory approach was adopted to include raking responses. Different perceptions among demographic groups were found. Younger cyclists present the lowest risk perception while having a higher risk behavior. The knowledge about traffic rules was correlated with safety behavior, showing the importance of this factor. These results are in line with urban cycling. However important differences under risk elements for rural cyclists, mainly associated with potential hazards on the shoulder, have been drawn. These findings may help policy makers to integrate cycling with vehicular traffic on two-lane rural roads in a safe way.
33
Sadati, S. Hossein, Salar Malekzadeh, and Masood Ghasemi. "Optimal Control of an 8-DOF Vehicle Active Suspension System Using Kalman Observer." Shock and Vibration 15, no. 5 (2008): 493–503. http://dx.doi.org/10.1155/2008/725264.
Full textAbstract:
In this paper, an 8-DOF model including driver seat dynamics, subjected to random road disturbances is used in order to investigate the advantage of active over conventional passive suspension system. Force actuators are mounted parallel to the body suspensions and the driver seat suspension. An optimal control approach is taken in the active suspension used in the vehicle. The performance index for the optimal control design is a quantification of both ride comfort and road handling. To simulate the real road profile condition, stochastic inputs are applied. Due to practical limitations, not all the states of the system required for the state-feedback controller are measurable, and hence must be estimated with an observer. In this paper, to have the best estimation, an optimal Kalman observer is used. The simulation results indicate that an optimal observer-based controller causes both excellent ride comfort and road handling characteristics.
34
Borovlev, Anton, Alexey Skrypnikov, Vyacheslav Kozlov, Tatyana Tyurikova, Oleg Tveritnev, and Vladimir Nikitin. "Mathematical Modeling of the Route of Logging Roads." Lesnoy Zhurnal (Forestry Journal), no. 4 (July 21, 2021): 150–61. http://dx.doi.org/10.37482/0536-1036-2021-4-150-161.
Full textAbstract:
The implementation of tasks related to the development of the transportation network as a whole and logging roads as an integral part of it requires scientifically based theoretical studies of the patterns of formation of spatial curves when combining elements of the plan and the longitudinal profile, since the rational laying of the route for many years determines its most important transport and operational characteristics (speed, traffic safety, traffic capacity). Consideration of the visual perception of the road by the driver will improve the quality of design decisions, which will allow to avoid emergencies in the future after setting the route into service. On the other hand, a decrease in speed before seemingly sharp turns of the road affects the efficiency of logging road transport. Therefore, the view of the road ahead should strongly orient the driver, i.e. be visually clear and clearly changing, ensuring the constancy or smooth reduction of the traffic flow mode. At the same time, the need for a successful spatial solution of the road increases. In the designs of logging roads, straight lines, transition curves, described in recent years most often according to the clotoid, and circular curves are found as elements of the route plan. It is found that the road view in perspective correctly orients the driver of the car, i.e. it is visually clear, provided that the lines describing the edges of the roadway and the edges of the roadway in the perspective image are curved in the same direction as in the road plan. The purpose of the work is to determine a set of quantitative indicators (curvature, radius of the curve in the plan, maximum curvature, maximum rate of change of curvature) for optimization of the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The performed studies allow us to fully characterize the visual smoothness and clarity of the central projections of elementary spatial and plane curves. The above algorithm makes it possible to compile a computer program to determine the mentioned indicators. The indicators determined by this algorithm allow us to evaluate both the visual smoothness and clarity of curves on logging roads.
35
Aliza, Che Amran, Fen Ying Chin, Mariam Md Ghazaly, Shin Horng Chong, and Vasanthan Sakthivelu. "Development of Passive Quarter Car Suspension Prototype." Applied Mechanics and Materials 761 (May 2015): 238–44. http://dx.doi.org/10.4028/www.scientific.net/amm.761.238.
Full textAbstract:
In this paper, a construction of a prototype to represent passive vehicle suspension system for quarter car model is considered. The prototype is represented by two degree-of freedom quarter-car model which are conventionally used by researchers. This laboratory equipment is developed in order to familiarize students with 2 DoF passive suspension system model. It consists of two masses, two springs and a damper. This equipment is easily dismantled and could be assembled with different spring and damper constants which contribute to different characteristics of the suspension system. A number of experiments have been carried out using the experiment setup in order to identify the suspension system characteristics i.e. experiments with different vehicle body mass, different period for one pulse and different pulse width of input pressure of the road excitation have been conducted. The experiment results are evaluated based on the vehicle body displacement and tire displacement of the prototype. Experiment results show that the pulse width of the input pressure or road profile is directly affected the characteristic of this passive suspension system. Lastly, simulations were done in order to compare the simulation and experimental results.
36
Yu, Kaijiang, Xiaozhuo Xu, Qing Liang, Zhiguo Hu, Junqi Yang, Yanan Guo, and Hongwei Zhang. "Model Predictive Control for Connected Hybrid Electric Vehicles." Mathematical Problems in Engineering 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/318025.
Full textAbstract:
This paper presents a new model predictive control system for connected hybrid electric vehicles to improve fuel economy. The new features of this study are as follows. First, the battery charge and discharge profile and the driving velocity profile are simultaneously optimized. One is energy management for HEV forPbatt; the other is for the energy consumption minimizing problem of acc control of two vehicles. Second, a system for connected hybrid electric vehicles has been developed considering varying drag coefficients and the road gradients. Third, the fuel model of a typical hybrid electric vehicle is developed using the maps of the engine efficiency characteristics. Fourth, simulations and analysis (under different parameters, i.e., road conditions, vehicle state of charge, etc.) are conducted to verify the effectiveness of the method to achieve higher fuel efficiency. The model predictive control problem is solved using numerical computation method: continuation and generalized minimum residual method. Computer simulation results reveal improvements in fuel economy using the proposed control method.
37
Verros, G., S. Natsiavas, and C. Papadimitriou. "Design Optimization of Quarter-car Models with Passive and Semi-active Suspensions under Random Road Excitation." Journal of Vibration and Control 11, no. 5 (May 2005): 581–606. http://dx.doi.org/10.1177/1077546305052315.
Full textAbstract:
A methodology is presented for optimizing the suspension damping and stiffness parameters of nonlinear quarter-car models subjected to random road excitation. The investigation starts with car models involving passive damping with constant or dual-rate characteristics. Then, we also examine car models where the damping coefficient of the suspension is selected so that the resulting system approximates the performance of an active suspension system with sky-hook damping. For the models with semi-active or passive dual-rate dampers, the value of the equivalent suspension damping coefficient is a function of the relative velocity of the sprung mass with respect to the wheel subsystem. As a consequence, the resulting equations of motion are strongly nonlinear. For these models, appropriate methodologies are first employed for obtaining the second moment characteristics of motions resulting from roads with a random profile. This information is next utilized in the definition of a vehicle performance index, which is optimized to yield representative numerical results for the most important suspension parameters. Special attention is paid to investigating the effect of road quality as well as on examining effects related to wheel hop. Finally, a critical comparison is performed between the results obtained for vehicles with passive linear or bilinear suspension dampers and those obtained for cars with semi-active shock absorbers.
38
Shui, Yishui, Fang Li, Junyi Yu, Wei Chen, Changzhen Li, Kun Yang, and Fuxing Chang. "Vehicle-to-Vehicle Radio Channel Characteristics for Congestion Scenario in Dense Urban Region at 5.9 GHz." International Journal of Antennas and Propagation 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/1751869.
Full textAbstract:
This paper reports the results of a car-following measurement of the wireless propagation channel at 5.9 GHz on a seriously congested urban road in Wuhan, China. The small-scale amplitude-fading distribution was determined to be a Ricean distribution using the Akaike information criterion. This result shows that this car-following scenario can be regarded as a line-of-sight radio channel. Moreover, the statistical K-factor features follow a Gaussian distribution. According to the power delay profile and average power delay profile, we found that street buildings in this dense urban environment contributed to very strong reflection phenomena. The impact of a powerful reflection is analyzed through path loss, delay, and Doppler spreads in the channel statistical properties. In the frequency domain, we observe a U-shape delay-Doppler spectrum that proved that the dense urban scenario consists of scattering channels. All these results are summarized in tabular form that will be useful in the modeling of vehicle-to-vehicle wireless communication systems.
39
Hassan, Rayya A., and Kerry McManus. "Assessment of Interaction Between Road Roughness and Heavy Vehicles." Transportation Research Record: Journal of the Transportation Research Board 1819, no. 1 (January 2003): 236–43. http://dx.doi.org/10.3141/1819b-30.
Full textAbstract:
Road surface roughness excites low- and high-frequency vibration modes of a heavy articulated vehicle body. These vibrations result in motions in all directions that detract from the driver’s perceived ride and comfort and increase pavement damage due to dynamic wheel loads (DWLs). A subjective assessment survey was conducted to identify surface roughness characteristics that mainly influence the perceptions of heavy-vehicle drivers of pavement rideability and their comfort. The latter was achieved by correlating drivers’ ratings to roughness contents in different roughness wavebands. The results indicated that the drivers mainly object to low-frequency body vibrations excited by roughness wavelengths in the range of 4.88 to 19.5 m. Roughness content in this band was used to establish a new profile-based index called the profile index for truck ( PIt). Drivers consider pavement rideability to be poor when PIt exceeds 2.75 m/km. PIt provides better predictions of heavy vehicle ride than the international roughness index (IRI). The methodology for developing the PIt and assessment of its reliability as a measure of heavy vehicle ride are described. The latter was achieved by testing the statistical significance of the effects of factors other than road roughness that influence the perceived ride of truck drivers. They include factors related to the vehicle, the road, and the driver as well as situational factors. In addition, PIt was found to be a better indicator than IRI of the levels of whole body vibrations transmitted to the driver through the seat and a better predictor of the magnitude of DWL to which the test pavements are subject.
40
Černiauskaitė, Laura, and Kazys Sakalauskas. "TECHNICAL AND ECONOMICAL PROBLEMS OF INTEGRATION OF IX B AND XI D INTERNATIONAL RAILWAY TRANSPORT CORRIDORS INTO EUROPEAN RAILWAY TRANSPORT NETWORK." TRANSPORT 18, no. 4 (June 30, 2003): 143–52. http://dx.doi.org/10.3846/16483840.2003.10414086.
Full textAbstract:
Technical and economical problems of train speed increment up to 160 km/h in existing IX B and IX D international railway transport corridors are analysed. Train speed restriction reasons, values of restrictions and their locations are estimated according to technical parameter characteristics of existing railway line infrastructure and according to the requirements for high-speed trains. The concept railway lines technical shape includes: plan, longitudinal profile, road upper construction and subgrade, besides quantitative and qualitative indices of elements. The most important indicator of railway lines technical shape is the permissible speed of trains. The radius oflying curves is taken as the most important investigation object in the analysis of geometry of railway lines plan. Computer programme „Trauka“ („Traction“) is used for the solution of problems of train speed increase. The programme is intended to calculate train speed and train driving time by evaluating the technical level of existing railway lines infrastructure. Great attention is paid to a complex analysis of road plan, longitudinal profile and upper road structure elements when railway lines infrastructure reconstruction is carried out. The application of these methods in practice allows the exact estimation of train speed increment possibilities when speed restriction reasons are eliminated.
41
Rameau, Hugues Georges, Claude Prepetit, and Jean-Claude Verbrugge. "A suitable methodology for assessing impacts of successive rainfalls infiltration on road slope stability." Bulletin de la Société Géologique de France 184, no. 1-2 (January 1, 2013): 171–81. http://dx.doi.org/10.2113/gssgfbull.184.1-2.171.
Full textAbstract:
Abstract Water precipitation in road slopes, pavements, and shoulders may cause disturbances such as erosion, increase of the water table level, decrease of the carriageway bearing capacity, and so on. Roads are normally equiped with drainage systems that are sized and implemented in accordance with the rules of art. These equipments are used for the collection and quick evacuation of water precipitation estimated on the basis of the return period that is taken into account. Despite that, rainwater can still infiltrate unprotected cut or fill slopes, and pavements for repeated and intense rainfalls, which may cause a raise in pore-water pressure and a decrease of the factor of safety of road slopes. Using laboratory rainfall simulation techniques, infiltration measurements were made on intact samples to determine with respect to soil properties, how cumulative rainfalls cause decrease in apparent cohesion and lead to slope failure. This paper focuses on describing the relationship between the rainfall characteristics, the changes in soil water profile, and the changes in apparent cohesion for sandy clay samples collected on the national road RN3 located in Haiti. For a set of consecutive rainfall events at around an interval of 24 hours, the results prove that when wetting front depth approaches 2 meters or more, the risk of landslide is proportionally high in a soil with apparent cohesion (Ca) initially high and an effective cohesion (c′) relatively low.
42
Contreras-Jara, Manuel, Tomás Echaveguren, José Vargas Baecheler, Alondra Chamorro Giné, and Hernán de Solminihac Tampier. "Reliability-Based Estimation of Traffic Interruption Probability due to Road Waterlogging." Journal of Advanced Transportation 2018 (July 29, 2018): 1–12. http://dx.doi.org/10.1155/2018/2850546.
Full textAbstract:
Floods affect road infrastructure physically and operationally, increase road user costs and road agencies cost, and eventually isolate communities. The research of the effect of floods on vehicular circulation is mainly focused on the stability of vehicles. There are few studies related to the regime of still water in the trafficability. In still water, the speed flow is low and does not compromise the vehicle stability. In this case, the vehicle’s wading height becomes relevant. This article proposes a procedure to estimate the traffic interruption probability caused by floods in roads, considering the still water regime. The procedure uses the first-order reliability method to estimate traffic interruption probabilities, based on the difference between the probability density functions (PDF) of still water depth (or waterlogging depth) and vehicle wading height. A specific procedure to estimate the PDF of wading height based in the geometric characteristics of light and heavy vehicles was developed. The PDF for water depth was estimated using water level profile simulation software. The procedure was applied in the south of Chile. The PDF of wading height was obtained from a record of 166,155 vehicles tagged in open road tolls. The PDF of waterlogging depth was obtained from discharge records of 10 fluviometric stations. 42 probability curves were obtained for six vehicle classes and return periods between 4 and 500 years. The still water depth obtained for traffic interruption probability of 1,0 varied between 70 and 90 cm for light vehicles and between 110 and 150 cm for heavy vehicles.
43
Hearne, Thomas M., Curtis L. Barbee, and Larry N. Helms. "Asphalt Rideability: Construction Control with a Straightedge?" Transportation Research Record: Journal of the Transportation Research Board 1543, no. 1 (January 1996): 81–88. http://dx.doi.org/10.1177/0361198196154300110.
Full textAbstract:
Studies have indicated that the prime factor that influences the user's opinion of a road is longitudinal roughness. California profilographs are widely used for roughness control and are the foundation of many incentive/disincentive specifications. However, there is concern about how well this profilograph responds to the wavelengths of a pavement profile that are felt by highway users. A user's perception of ride quality is influenced by a combination of many factors, including speed, vehicle characteristics, and road profile. All roughness testing devices currently in use have limitations—particularly in providing rapid, meaningful results during construction. Wavelength and amplitude data are included from the roughest-riding sections of two resurfacing projects in North Carolina. Although the California profilograph is widely used for construction roughness control, the response of this device is very poor within the wavelength range found on these projects. If the disturbance wavelengths mainly responsible for causing rough rides fall within a narrow range, then an appropriate length straightedge, when provided with graphical capability, can provide a low-cost, simple, and practical means for controlling roughness during construction.
44
McGehee, Nancy Gard, Yooshik Yoon, and David Cárdenas. "Involvement and Travel for Recreational Runners in North Carolina." Journal of Sport Management 17, no. 3 (July 2003): 305–24. http://dx.doi.org/10.1123/jsm.17.3.305.
Full textAbstract:
This study utilized an adaptation of the uni-dimensional involvement scale developed by Josiam, Smeaton, and Clements (1999) to test Havitz and Dimanche's Proposition XI, which states that “an individual's involvement profile with a recreational activity, tourist destination, or related equipment is positively related to frequency of participation, travel, or purchase” (1990, p. 189). Relationships between recreational runners' involvement in travel to road races and behavioral characteristics, including preparation for and participation in road races, travel behavior and running-related expenditures were examined. Proposition XI was partially supported. The research found statistically significant differences between the high involvement group and medium involvement group in terms of travel behavior and running-related expenditures. There were no significant differences between involvement groups and preparation for or participation in road races. It was concluded that involvement should be considered by sport and tourism agencies when planning, marketing, and managing events targeted at traveling recreational runners.
45
Niculescu, Adrian Ioan. "1⁄4 Car Model for Suspension Trim Corrector Performances Evaluation." Applied Mechanics and Materials 823 (January 2016): 205–10. http://dx.doi.org/10.4028/www.scientific.net/amm.823.205.
Full textAbstract:
The paper presents a complex quarter car model obtained with ADAMS software, View module, useful in the first stage of suspension dimensioning and optimization.The model is equipped with compression and rebound stopper buffer and suspension trim corrector.The proposed quarter car model with two degrees of freedom (wheel and body) performs all these goals allowing changing:Geometrical elementsPosition of equilibrium, depending on vehicle load;Trim correction;Elastic and dissipative characteristics of the suspension and tire;Suspension stroke;Road profile, assessed either by simple or summation of harmonic functions or reproducing real roadsBuffers (for stroke limitation) position and characteristics;The models developed provide information on:Vertical stability assessed by vertical movements of the body and the longitudinal and transversal stability evaluated based on adherence characterized by wheel ground contact force and frequency of soil detachment wheel.Comfort assessed on the basis of body vertical acceleration and collision forces to the stroke ends.The body-road clearanceThe trim corrector efficiencyAll above performances evaluated function the road unevenness, acceleration, deceleration, turning regime.The damping characteristic is defined by damping forces at different speed for each strokes respectively one for rebound and other for compression.The contact force road-wheel is defined based tire rigidity law.The stopper buffer forces on rebound and compression are defined based each specific rigidity characteristics.The road excitation is realized with a function generator.The software allow the model evolution visualisation in real time, also generating the diagrams of displacements, forces, accelerations, speeds, for each elements or for relative evolution between diverse elements.The simulation was realized for unloaded and fully loaded car using a road generated by a sum of harmonic functions presented in equation (8).The excitation covers the specific frequencies area, being under the body frequencies up to the wheel proper frequencies.The realized ¼ car model, have reached the goal to evaluate the suspension trim correction advantages.The simulations confirm the trim corrector increases the suspension performances, thus for the analyzed case the trim corrector increase simultaneous:Body-ground clearance (evaluated by body higher increasing) between 18.5÷55.1 %Body stability (evaluated by maximal body displacement) between 9.8÷11.4 %Body comfort (evaluated by maximal body acceleration) between 3.4÷35.5 %Adherence (evaluated by maximal and RMS wheel-groundcontact force variation) between 7.0÷12.1 %Body and axles protection (evaluated by buffer strike force) between 10.8÷38.2 %
46
Sarach, YE B., YA A. Tkachev, and M. E. Krokhin. "Selection of the characteristics of the suspension system of the high-speed tracked robot." Izvestia MGTU MAMI 1, no. 2 (2021): 63–70. http://dx.doi.org/10.31992/2074-0530-2021-48-2-63-70.
Full textAbstract:
Currently, the field of mechanical engineering is rapidly developing, including the creation of robotic high-speed vehicles. The design of suspension systems for such vehicles must be accompa-nied by the fulfillment of certain requirements, which are currently not formulated. Considering the thing that there is no person in the body of a high-speed robot, the application of the requirements for the suspensions of crew vehicles is not justified. In order to develop recommendations on the choice of characteristics of suspension systems for high-speed tracked robots, the research objects, which mass is in the range from 1000 to 10000 kg are determined. No suspension system is required for objects weighing less than 1000 kg. Objects weighing more than 10,000 kg will be created on the basis of existing serial vehicles. The study is based on the provision that the considered class of vehicles is not subject to re-strictions on the range of natural frequencies of body vibrations. Considering that one of the main requirements remains for high-speed tracked robots - ensuring a high average speed, it is proposed to increase the suspension stiffness in order to exclude resonance from the range of possible travel speeds. Using the accepted provisions, a study of the suspension system of increased stiffness is carried out. The movement along the tracks of a harmonic profile in resonance mode and a broken dirt road is simulated. The results of the study show that the characteristics of the suspension system, selected accord-ing to the proposed method, make it possible to move along the line of the harmonic profile in the resonant mode without suspension breakdowns. The speed of movement on a broken dirt road is limited to a value, which exceeding leads to sig-nificant vibrations of the body and an increase in the load on the elements of the suspension system. The absence of breakdowns leads to a decrease in the loading of the suspension, which makes it possible to reduce the mass of its elements.
47
Motamedi, Mehran, Saied Taheri, and Corina Sandu. "Rubber–Road Contact: Comparison of Physics-Based Theory and Indoor Experiments." Tire Science and Technology 44, no. 3 (July 1, 2016): 150–73. http://dx.doi.org/10.2346/tire.16.440303.
Full textAbstract:
ABSTRACT For tire designers, rubber friction is a topic of pronounced practical importance. Thus, development of a rubber–road contact model is of great interest. In this research, to predict the effectiveness of the tread compound in a tire as it interacts with the pavement, the physics-based multiscale rubber-friction theories developed by B. Persson and M. Klüppel were studied. The strengths of each method were identified and incorporated into a consolidated model that is more comprehensive and proficient than any single, existing, physics-based approach. In the present work, the friction coefficient was estimated for a summer tire tread compound sliding on sandpaper. The inputs to the model were the fractal properties of the rough surface and the dynamic viscoelastic modulus of rubber. The sandpaper-surface profile was measured accurately using an optical profilometer. Two-dimensional parameterization was performed using one-dimensional profile measurements. The tire tread compound was characterized via dynamic mechanical analysis. To validate the friction model, a laboratory-based, rubber-friction test that could measure the friction between a rubber sample and any arbitrary rough surface was designed and built. The apparatus consisted of a turntable, which can have the surface characteristics of choice, and a rubber wheel in contact with the turntable. The wheel speed, as well as the turntable speed, could be controlled precisely to generate the arbitrary values of longitudinal slip at which the dynamic coefficient of friction was measured. The correlation between the simulation and the experimental results was investigated.
48
Hoang, Chi Linh, Hai Minh Vu, Hai Quang Pham, Huong Lan Thi Nguyen, Linh Gia Vu, Bach Xuan Tran, Carl A. Latkin, Roger C. M. Ho, and Cyrus S. H. Ho. "Psychological Distress of Patients Experiencing Different Types of Road Traffic Injuries in Vietnam." International Journal of Environmental Research and Public Health 17, no. 10 (May 14, 2020): 3429. http://dx.doi.org/10.3390/ijerph17103429.
Full textAbstract:
Road-related injuries are often catastrophic, and the eighth leading cause of all-aged mortality. While psychological problems, including anxiety, driving phobia, and post-traumatic stress have been found to be common among injured survivors, the literature in this area is still limited. This study aimed to evaluate the prevalence of distress between different types of road injuries among 413 patients in Thai Binh hospitals from October to December 2018. The Kessler Psychological Distress Scale (K6) was used to assess mental health status. Sociodemographic and clinical characteristics were also collected. The results of Multiple Logistic and Tobit regression models were utilized. Psychological issues were found in 13.8% of the participants. In terms of K6 profile, nervous, restless/fidgety, and “everything was an effort” were the three most frequently endorsed aspects. Having soft-tissue injuries had a 0.32-time lower likelihood of psychological distress compared to those having other injuries. Additionally, patients who were diagnosed with fractures were 4.5-times more likely to report psychological distress. Our finding highlights the need for psychological screening to reduce disabilities associated with non-fatal injury related to road traffic crashes.
49
Liu, Chiu, and Robert Herman. "Roadway-Vehicle Interaction, Physical Indexes, and Human Judgment of Ride Quality." Transportation Research Record: Journal of the Transportation Research Board 1570, no. 1 (January 1997): 55–59. http://dx.doi.org/10.3141/1570-07.
Full textAbstract:
Present serviceability index (PSI) modeling has been an important subject for decades. Other dynamic indexes characterizing a roadway such as the international roughness index (IRI), averaged rectified slope (ARS), and averaged rectified speed (ARV) have been proposed and studied. However, the roles played by these indexes in the interaction between road, vehicle, and human ratings have not been made clear. A unified physical model linking the static profile of a roadway and the dynamic response of a vehicle to the profile to the serviceability index of the roadway is presented here. Analytical expressions for jerk index, acceleration index, ARV, ARS, and IRI are derived from the developed model in terms of the physical parameters for roadways and the dynamic characteristics of a vehicle. Then a linear relation between the PSI and the logarithm of the jerk index is proposed. Using the jerk index computed from field profile data, the linear functional form for the PSI is verified, and regression R2 values higher than 0.94 are obtained for various types of pavements. The same analysis is performed for other dynamic indexes, and the R2 values are found to be approximately in the range from 0.70 to 0.80. These results indicate that the theoretical model correctly predicts and explains the human rating of ride quality and that the jerk experienced by raters in a moving vehicle dictates the ratings. Moreover, the relationship of the static parameters of roadway profiles with human ratings is discussed using the conventional approach.
50
Abdussalam Ali Ahmed. "Quarter car model optimization of active suspension system using fuzzy PID and linear quadratic regulator controllers." Global Journal of Engineering and Technology Advances 6, no. 3 (March 30, 2021): 088–97. http://dx.doi.org/10.30574/gjeta.2021.6.3.0041.
Full textAbstract:
The primary objective of this paper is to improve the performance of a car's active suspension system and control the vibrations that occurred in the car's using two well-known control technologies, namely the Linear Quadratic Regulator (LQR) and fuzzy PID control. When the car suspension is designed, a quarter car model with two degrees of freedom is used. A complete control system is needed to provide the desired suspension performance and characteristics such as passenger comfort, road handling, and suspension deflection, this control system performed using the MATLAB/SIMULINK and includes three parts: input signals (actuator force and road profile), Controller part, and the suspension system model. The simulation results from the implemented Simulink models show a comparison between the uncontrolled suspension system and the suspension system with a fuzzy PID controller and the active suspension system of the car based on the linear-quadratic regulator, and it is explained thoroughly.