scholarly journals Characterization of Counter-Surface Substrates for a Laboratory Abrasion Tester (LAT100) Compared with Asphalt and Concrete to Predict Car Tire Performance

Lubricants ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Marzieh Salehi ◽  
Jacques W. M. Noordermeer ◽  
Louis A. E. M. Reuvekamp ◽  
Anke Blume
Keyword(s):  
Driving Safety ◽  
Over The Counter ◽  
Optical Scanning ◽  
The Road ◽  
Power Spectral ◽  
Wet Friction ◽  
Power Spectral Densities ◽  
Tire Friction ◽  
Counter Surface

Tire performance is determined based on the interaction between the tire and the road as a counter-surface, and is of the utmost importance for driving safety. When studying tire friction and abrasion, the characteristics of the roads/counter-surfaces are crucial. The excitations on the tire come from the road asperities. A proper characterization of the counter-surface texture is, therefore, an absolute necessity in order to optimize tire performance. The present study provides the required knowledge over the counter-surfaces employed as common substrates in a Laboratory Abrasion Tester (LAT100), which are typically based on embedded corundum particles for dry/wet friction and abrasion experiments. All surfaces are scanned and characterized by laser microscopy. The surface micro and macro roughness/textures are evaluated and compared with asphalt and concrete as the real roads by power spectral densities (PSD). The reliability of the high-frequency data based on the device type should be considered carefully. The reliable cut-off wavenumber of the PSDs is investigated based on image analyses on the range of tested frequency for micro and macro textures obtained by optical scanning devices. The influence of the texture wavelength range on the rubber−surface interaction is studied on a laboratory scale.

CHARACTERIZATION OF ROAD PROFILES BASED ON FRACTAL PROPERTIES AND CONTACT MECHANICS

2017 ◽  
Vol 90 (2) ◽  
pp. 405-427 ◽  
Author(s):  
Mehran Motamedi ◽  
Saied Taheri ◽  
Corina Sandu ◽  
Pierrick Legrand
Keyword(s):  
Contact Theory ◽  
The Road ◽  
Frictional Properties ◽  
Wet Friction ◽  
Fractal Properties ◽  
Fractal Parameters ◽  
Road Surfaces ◽  
Friction Measurements ◽  
Friction Prediction

ABSTRACT A major challenge in tire and road engineering is to understand the intricate mechanisms of friction. Pavement texture is a feature of the road surface that determines most tire–road interactions, and it can be grouped into two classes of macro-texture and micro-texture. Since the effects of micro-texture and macro-texture dominate the friction measurements at low and high slip speeds, they can help provide sufficient resistance to skidding, if maintained at high levels. A non-contact profilometer is used to measure the macro- and micro-texture of several different road surfaces. The friction number for each surface is measured using the Michigan Department of Transportation's (MDOT) single axle friction trailer. Some fractal parameters of the measured profiles are estimated, and it is proved that all measured profiles display strong fractal behavior. The correlation between texture and fractal parameters and friction is investigated. It is shown that while global fractal quantities fail to classify pavement profiles, the pointwise Hölder exponent as a local fractal parameter, and also the mean square roughness, can discriminate profiles that have different frictional properties. For five road surfaces, two-dimensional (2D) characterization is done using one-dimensional (1D) profile measurements. The hysteretic coefficient of friction is estimated using the contact theory developed by B.N.J. Persson. Good correlation is observed between the wet friction measurements and friction prediction results.

Modal Analysis of a Utility Bicycle From the Perspective of Riding Comfort

2019 ◽  
Author(s):  
Alberto Doria ◽  
Edoardo Marconi ◽  
Pierluca Cialoni
Keyword(s):  
Modal Testing ◽  
Vibration Modes ◽  
Response Functions ◽  
The Road ◽  
Power Spectral ◽  
Vehicle Structure ◽  
Power Spectral Densities ◽  
On The Road ◽  
The Relationship ◽  
Insight Into

Abstract The correlation between the modal properties and the comfort characteristics of a utility, step-through frame bicycle are investigated. In-plane modal testing of the vehicle is carried out both without and with the rider, and the major differences between the results obtained with the two conditions are highlighted. In order to have an insight into the contribution of the various bicycle components to the transmission of vibrations, the frequency response functions (FRFs) between the main interface points in the vehicle structure are measured and studied. Finally, the modal characteristics are compared with road tests data, emphasizing the relationship between the in-plane vibration modes and the main peaks in the acceleration power spectral densities (PSDs) measured on the road.

The Research of Road Profile Estimation Based on Acceleration Measurement

2012 ◽  
Vol 226-228 ◽  
pp. 1614-1617 ◽  
Author(s):  
Ye Chen Qin ◽  
Ji Fu Guan ◽  
Liang Gu
Keyword(s):  
Dynamic Responses ◽  
The Road ◽  
Physical Measurements ◽  
Power Spectral ◽  
Road Profile ◽  
Road Roughness ◽  
Power Spectral Densities ◽  
Profile Estimation ◽  
The Relationship ◽  
Unsprung Mass

To get the certain response of vehicle during the driving process, it’s necessary to measure the road irregularities. Existing method of gauging the roughness is based on physical measurements and the instrument is installed under the vehicle, which is expensive and will affect the vehicle dynamic responses. This paper shows an easier method to estimate the road roughness by measuring and calculating the power spectral density (PSD) of unsprung mass accelerations. This approach is possible due to the relationship between these two via a transfer function. By comparing the power spectral densities of estimated road and the standard classes, we can classify the current road classes easily. Besides, this paper also shows that it’s feasible to estimate the road profile by calculating the PSD of unsprung mass accelerations directly.

scholarly journals The nanomorphology of cell surfaces of adhered osteoblasts

2021 ◽  
Vol 12 ◽  
pp. 242-256
Author(s):  
Christian Voelkner ◽  
Mirco Wendt ◽  
Regina Lange ◽  
Max Ulbrich ◽  
Martina Gruening ◽  
...  
Keyword(s):  
Ion Conductance ◽  
Scanning Ion Conductance Microscopy ◽  
Membrane Fluctuations ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Membrane Protrusions ◽  
Fluctuation Dynamics ◽  
And Migration ◽  
Two Parameters

The functionality of living cells is inherently linked to subunits with dimensions ranging from several micrometers down to the nanometer scale. The cell surface plays a particularly important role. Electric signaling, including information processing, takes place at the membrane, as well as adhesion and contact. For osteoblasts, adhesion and spreading are crucial processes with regard to bone implants. Here we present a comprehensive characterization of the 3D nanomorphology of living, as well as fixed, osteoblastic cells using scanning ion conductance microscopy (SICM), which is a nanoprobing method that largely avoids mechanical perturbations. Dynamic ruffles are observed, manifesting themselves in characteristic membrane protrusions. They contribute to the overall surface corrugation, which we systematically study by introducing the relative 3D excess area as a function of the projected adhesion area. A clear anticorrelation between the two parameters is found upon analysis of ca. 40 different cells on glass and on amine-covered surfaces. At the rim of lamellipodia, characteristic edge heights between 100 and 300 nm are observed. Power spectral densities of membrane fluctuations show frequency-dependent decay exponents with absolute values greater than 2 on living osteoblasts. We discuss the capability of apical membrane features and fluctuation dynamics in aiding the assessment of adhesion and migration properties on a single-cell basis.

scholarly journals Side Branch Interaction with Main Line Standing Waves and Related Signal Handling Approaches

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Arthur Ruggles ◽  
Eric M. Moore ◽  
Michael Shehane
Keyword(s):  
Time History ◽  
Side Branch ◽  
Acoustic Energy ◽  
Main Line ◽  
Test Facility ◽  
Resonance Amplitude ◽  
Resonance Behavior ◽  
Power Spectral ◽  
Power Spectral Densities

Data from a low pressure air test facility are used to quantify the influence of the acoustic field in the main line on side branch resonance behavior. The main line of diameter = 7.6 cm may accumulate acoustic energy broadcast from a resonating branch of diameter = 1.9 cm ( = 0.25). The side branch resonance amplitude is a strong function of branch position along the main line with the normalized pressure rising to 1.2 in the most favorable branch positions with Strouhal number near 0.3. Large time variation of the side branch and main line resonance amplitude is apparent for most branch positions. A moving window is used on the time history to collect an array of power spectral densities (PSDs). Peak amplitude values from the PSD array are represented in a probability density function (PDF) that provides a repeatable characterization of data from the system.

Alternative single-number indicator of longitudinal road unevenness

2009 ◽  
Vol 36 (3) ◽  
pp. 389-401 ◽  
Author(s):  
Oldřich Kropáč ◽  
Peter Múčka
Keyword(s):  
Subjective Rating ◽  
Vehicle Speed ◽  
International Roughness Index ◽  
The Road ◽  
Full Characterization ◽  
Power Spectral ◽  
Roughness Index ◽  
On The Road ◽  
Single Number

For the full characterization of the longitudinal road unevenness based on the road elevation power spectral density (PSD), at least two independent indicators are necessary: the unevenness index and the waviness. Yet, for road management purposes, single-number unevenness indicators are still required and a number of such indicators have been proposed to date. The main problem of this issue consists in an adequate combination of the two mentioned indicators to obtain a single indicator whose application would fulfil the requirements, which are sometimes contradictory. The importance of the interaction coupling between the road and the travelling vehicle, in which the vehicle speed also plays a significant role, is emphasized. An alternative single-number indicator is proposed based on the equivalent vibration response effect, which the uneven road causes on the traversing vehicle. Other approaches to this problem are briefly discussed using comparative examples, including the indirect approach, a proposal for the modification of the international roughness index (IRI), and an assessment of the subjective rating methods.

Investigations of Road Wear Caused by Studded Tires

2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
Test Bench ◽  
Operating Conditions ◽  
Test Method ◽  
Analytical Models ◽  
The Road ◽  
Driving Speed ◽  
Major Factors ◽  
Tire Friction ◽  
Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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

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

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

Characterization of Tissue Microstructure Scatterer Distribution with Spectral Correlation

1993 ◽  
Vol 15 (3) ◽  
pp. 238-254 ◽  
Author(s):  
Tomy Varghese ◽  
Kevin D. Donohue
Keyword(s):  
Formation Process ◽  
Biological Tissue ◽  
Statistical Parameters ◽  
Spectral Correlation ◽  
Tissue Microstructure ◽  
Power Spectral ◽  
Spectral Peaks ◽  
Ultrasound Signal

Characterization of tissue microstructure from the backscattered ultrasound signal using the spectral autocorrelation (SAC) function provides information about the scatterer distribution in biological tissue. This paper demonstrates SAC capabilities in characterizing periodicities in A-scans due to regularity in the scatterer distribution. The A-scan is modelled as a cyclostationary signal, where the statistical parameters of the signal vary in time with single or multiple periodicities. This periodicity manifests itself as spectral peaks both in the power spectral density (PSD) and in the SAC. Periodicity in the PSD will produce a well defined dominant peak in the cepstrum, which has been used to determine the scatterer spacing. The relationship between the scatterer spacing and the spacing of the spectral peaks is established using a stochastic model of the echo-formation process from biological tissue. The distribution of the scatterers within the microstructure is modelled using a Gamma function, which offers a flexible method of simulating parametric regularity in the scatterer spacing. Simulations of the tissue microstructure for lower orders of regularity indicate that the SAC components reveal information about the scatterer spacing that are not seen in the PSD and the cepstrum. The echo-formation process is tested by simulating microstructure of varying regularity and analyzing their effect on the SAC, PSD and cepstrum. Experimental validation of the simulation results are provided using in vivo scans of the breast and liver tissue that show the presence of significant spectral correlation components in the SAC.

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