scholarly journals Roughness-Induced Pavement–Vehicle Interactions

2015 ◽  
Vol 2525 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Arghavan Louhghalam ◽  
Mehdi Akbarian ◽  
Franz-Joseph Ulm
Keyword(s):  
Fuel Consumption ◽  
Mechanistic Model ◽  
Rolling Resistance ◽  
Thermodynamic Quantity ◽  
Surface Characteristics ◽  
Density Parameter ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index ◽  
The Impact

Pavement roughness affects rolling resistance and thus vehicle fuel consumption. When a vehicle travels at constant speed on an uneven road surface, the mechanical work dissipated in the vehicle's suspension system is compensated by vehicle engine power and results in excess fuel consumption. This dissipation depends on both road roughness and vehicle dynamic characteristics. This paper proposes, calibrates, and implements a mechanistic model for roughness-induced dissipation. The distinguishing feature of the model is its combination of a thermodynamic quantity (energy dissipation) with results from random vibration theory to identify the governing parameters that drive the excess fuel consumption caused by pavement roughness, namely, the international roughness index (IRI) and the waviness number, w (a power spectral density parameter). It is shown through sensitivity analysis that the sensitivity of model output, that is, excess fuel consumption, to the waviness number is significant and comparable to that of IRI. Thus, introducing the waviness number as a second roughness index, in addition to IRI, allows a more accurate quantification of the impact of surface characteristics on vehicle fuel consumption and the corresponding greenhouse gas emissions. This aspect is illustrated by application of the roughness–fuel consumption model to two road profiles extracted from FHWA's Long-Term Pavement Performance database.

Analysis on Impact Factor Spectrum for a Continuous Bridge under Normal Traffic Flow

2012 ◽  
Vol 594-597 ◽  
pp. 2792-2796
Author(s):  
Zeng Qian Fei ◽  
Tao Wang
Keyword(s):  
Impact Factor ◽  
Traffic Flow ◽  
Extreme Values ◽  
Dynamic Responses ◽  
Impact Factors ◽  
Dynamic Displacement ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Low Pass ◽  
The Impact

Analysis was carried out for dynamic responses on a continuous bridge under normal traffic flow. The inspection, testing and analysis for the tested bridge mainly consist of the measurement of pavement roughness and analysis on power spectral density, the testing and analysis on natural vibration characteristics, the observation of traffic loads under normal traffic flow and the corresponding measurements of dynamic displacement and acceleration on bridge. To determine impact factors in terms of measured dynamic displacement responses, low pass Butterworth filter is used for filtering the dynamic part of measured dynamic displacement and the static extreme values are reserved. And then，the distribution fit test is performed using K-S methodology for measured impact factors according to Extreme-I type respectively. Finally, the impact factor of this bridge, which is determined based on statistical method, is compared with code-specified impact factors of different countries.

Relationship between International Roughness Index and Power Spectral Density of Asphalt Pavements in China

2013 ◽  
Vol 742 ◽  
pp. 104-108
Author(s):  
Shao Wen Liu ◽  
Xiao Zhang
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Response Function ◽  
Asphalt Pavements ◽  
International Roughness Index ◽  
Quarter Car Model ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index ◽  
Quarter Car

In this paper, pavement roughness is assumed as random stationary variable and used as the exciting force of theoretical analyses of the quarter car model of International Roughness Index (IRI). From the frequency response function of the quarter car, the response function of the displacement difference between sprung and unsprung mass is obtained based on random process theory. Then the relationship between IRI and power spectral density (PSD) is established from statement characteristic of the response function. Finally, the longitudinal road profiles of typical asphalt roads in China are used to validate the proposed model.

scholarly journals International Standards Organization-Compatible Index for Pavement Roughness

1998 ◽  
Vol 1643 (1) ◽  
pp. 110-115 ◽  
Author(s):  
A. T. Papagiannakis ◽  
B. Raveendran
Keyword(s):  
Unit Length ◽  
International Standards ◽  
Whole Body ◽  
User Cost ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Reference Vehicle ◽  
Roughness Index ◽  
Pavement Damage ◽  
International Standards Organization

The development of a new pavement roughness index, which is compatible to the current International Standards Organization (ISO) standard on “exposure to whole-body vibration” is described. The index was intended to be the independent variable in the future development of relationships between user cost (i.e., vehicle depreciation, repairs, discomfort and so on) and pavement roughness; hence it was named RIDE (Roughness Index for Driving Expenditure). RIDE is based on the sprung mass acceleration response of a reference vehicle to the pavement profile. It is calculated in the frequency domain by multiplying the power spectral density (PSD) of the pavement profile by the square of the transfer function of the sprung mass acceleration of the reference vehicle. The resulting sprung mass acceleration PSD is integrated over frequency to yield the root-mean-square of the sprung mass acceleration per unit length of pavement traveled. The sprung mass acceleration is shown to be the main contributor of dynamic axle loads in heavy trucks, which relate to vehicle and cargo damage and also to pavement damage.

Stochastic Analysis of Rolling Resistance Energy Dissipation for a Tractor-Trailer Model

2019 ◽  
Vol 2673 (11) ◽  
pp. 593-603 ◽  
Author(s):  
Seunggu Kang ◽  
Hasan Ozer ◽  
Imad L. Al-Qadi ◽  
Billie F. Spencer
Keyword(s):  
Analytical Solution ◽  
Fuel Consumption ◽  
Aerodynamic Drag ◽  
Rolling Resistance ◽  
Quarter Car Model ◽  
High Speeds ◽  
Road Roughness ◽  
Quantitative Manner ◽  
New Generation ◽  
The Impact

Rolling resistance because of road roughness is often the largest contributor to energy consumption in the environmental assessment of pavement life cycle. Although fuel consumption of passenger vehicles caused by roadway roughness is well studied, further research is needed for truck fuel consumption models utilizing mechanistic approaches. Existing models estimating trucks’ excess fuel consumption because of rolling resistance are based on empirical models or simplified mechanistic models such as the quarter car model. Such approaches may not fully capture the complex dynamic motion of a tractor-trailer. This study suggests a stochastic method utilizing the analytical solution based on a tractor-trailer model to calculate excess truck fuel consumption because of roughness and speed. The illustrative examples show that excess truck fuel consumption tends to increase nonlinearly with roughness; fuel consumption increases with speed but drops after 104 km/h (65 mph) because of a rapid increase in aerodynamic drag at very high speeds. The effect of new generation wide-base tires (NG-WBT) in lieu of the standard dual tire assembly was studied using the introduced model. Results indicate that NG-WBT reduced excess fuel consumption because of roughness by 11% and 8% at 56 km/h and 80 km/h (35 mph and 50 mph), respectively. Finally, Monte Carlo simulation was conducted at two speeds and the simulation results were in agreement with the analytical solution. The results from the developed model and the validation using illustrative examples confirm the impact of roughness and speed on truck fuel consumption in a quantitative manner.

scholarly journals Evaluation of the methodologies used to generate random pavement profiles based on the power spectral density: An approach based on the International Roughness Index

2017 ◽  
Vol 37 (1) ◽  
pp. 49 ◽  
Author(s):  
Boris Jesús Goenaga ◽  
Luis Guillermo Fuentes Pumarejo ◽  
Otto Andrés Mora Lerma
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Pavement Management ◽  
Dynamic Loads ◽  
International Roughness Index ◽  
Vertical Excitation ◽  
Shaping Filter ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index

The pavement roughness is the main variable that produces the vertical excitation in vehicles. Pavement profiles are the main determinant of (i) discomfort perception on users and (ii) dynamic loads generated at the tire-pavement interface, hence its evaluation constitutes an essential step on a Pavement Management System. The present document evaluates two specific techniques used to simulate pavement profiles; these are the shaping filter and the sinusoidal approach, both based on the Power Spectral Density. Pavement roughness was evaluated using the International Roughness Index (IRI), which represents the most used index to characterize longitudinal road profiles. Appropriate parameters were defined in the simulation process to obtain pavement profiles with specific ranges of IRI values using both simulation techniques. The results suggest that using a sinusoidal approach one can generate random profiles with IRI values that are representative of different road types, therefore, one could generate a profile for a paved or an unpaved road, representing all the proposed categories defined by ISO 8608 standard. On the other hand, to obtain similar results using the shaping filter approximation a modification in the simulation parameters is necessary. The new proposed values allow one to generate pavement profiles with high levels of roughness, covering a wider range of surface types. Finally, the results of the current investigation could be used to further improve our understanding on the effect of pavement roughness on tire pavement interaction. The evaluated methodologies could be used to generate random profiles with specific levels of roughness to assess its effect on dynamic loads generated at the tire-pavement interface and user’s perception of road condition.

On-Road Fuel Consumption Testing to Determine the Sensitivity Coefficient Relating Changes in Fuel Consumption to Changes in Tire Rolling Resistance

2013 ◽  
Vol 41 (1) ◽  
pp. 2-20 ◽  
Author(s):  
Calvin R. Bradley ◽  
Arnaud Delaval
Keyword(s):  
Fuel Consumption ◽  
Real World ◽  
Rolling Resistance ◽  
Sensitivity Coefficient ◽  
Fuel Savings ◽  
Passenger Vehicles ◽  
The World ◽  
Label Information ◽  
The Impact ◽  
Measured Sensitivity

ABSTRACT: Tire rolling resistance is one of the primary forces opposing motion on passenger vehicles. New regulations appearing around the world will provide information on tire rolling resistance to consumers. The linear relationship between fuel savings and rolling resistance has been previously demonstrated. Extensive testing in real-world driving conditions has validated previous models. The result is a measured sensitivity coefficient for North American usage, which relates the changes in vehicle fuel consumption of E10 gasoline to changes in rolling resistance. This sensitivity coefficient is shown to not be significantly different between a compact car, a medium-sized sedan, and a full-sized pickup truck. Results provide a simple and robust way for end consumers to predict the impact of tire choice on their fuel consumption and CO2 emissions using tire label information.

Light-Weight Tire Concept

1996 ◽  
Vol 24 (2) ◽  
pp. 119-131
Author(s):  
F. Lux ◽  
H. Stumpf
Keyword(s):  
Fuel Consumption ◽  
Automobile Industry ◽  
Rolling Resistance ◽  
Performance Standards ◽  
Light Weight ◽  
Production Methods ◽  
Lower Fuel Consumption ◽  
Material Resources ◽  
The Past ◽  
Tire Production

Abstract Current demands by the consumer, the automobile industry, and the environment have determined the basis of this investigation. In the past, the requirements—ever faster, ever sportier—were accepted as decisive parameters for the development of our study. In the future, rational and safety-related tire characteristics as well as environmental consciousness will increase, whereas purely performance-related parameters will diminish in their importance. Through our light-weight tire project, we have paved the way for future tire generations. The first priority is the minimal use of material resources; this means a reduction of materials and energy in tire production by using advanced design and production methods without sacrificing performance standards. This benefits the consumer—the final judge of all of our activities—by considerably reducing the rolling resistance, leading to lower fuel consumption. Further design targets include the improvement of rolling behavior and increased comfort by reducing tire weight, and therefore a reduction in unsprung masses on the vehicle.

scholarly journals Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 463
Author(s):  
Gopinathan R. Abhijith ◽  
Leonid Kadinski ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Mechanistic Model ◽  
Water Distribution Systems ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
Growth Rate Constant ◽  
Model Parameters ◽  
Bacterial Regrowth ◽  
The Impact

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

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