scholarly journals A Rational Theory of Tire-Pavement Friction

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Robert H. Smith ◽  
Waheed Uddin
Keyword(s):  
Coefficient Of Friction ◽  
Surface Deformation ◽  
Field Testing ◽  
Rational Theory ◽  
Pavement Friction ◽  
Deformation Hysteresis

The present study involves field testing of a tire-loading-based theory of pavement traction in place of the traditional coefficient of friction. An associated hypothesis concerns the indicated existence of a fourth rubber force, surface deformation hysteresis, which is theorized to be independent of tire loading during tire sliding.

Curvilinear Behavior of Base Layer Moduli from Deflection and Seismic Methods

2000 ◽  
Vol 1716 (1) ◽  
pp. 55-63
Author(s):  
Kamal Tawfiq ◽  
John Sobanjo ◽  
Jamshid Armaghani
Keyword(s):  
Surface Deformation ◽  
Low Frequency ◽  
Field Testing ◽  
Base Layer ◽  
Falling Weight Deflectometer ◽  
Seismic Methods ◽  
Extensive Field ◽  
Curvilinear Relationships ◽  
Falling Weight ◽  
Surface Deflections

The reality of curvilinear relationships of stiffness versus deformation is usually neglected when moduli values from seismic methods are compared with those of deflection methods. On the basis of extensive field testing, results showed that moduli values for the base layers from deflection methods did not conform to those of seismic methods. Deflection testing techniques were signified by the falling weight deflectometer (FWD) and the Dynaflect methods. Seismic testing was carried out by use of the seismic pavement analyzer (SPA) method. The SPA test results yielded moduli values higher than those obtained from the deflection methods. Utilizing pavement parameters obtained from the SPA data, researchers determined surface deflections by use of frequency response functions of signals from the two groups of sensors used in the testing setup. Because of the types of hammers in the SPA testing, two different deflection basins were obtained at each testing point. Comparison of surface deflections from these methods indicated that deflection amplitudes from the FWD method were about 100 times higher than those obtained from the high-frequency hammer of the SPA. At certain pavement sections, deflections from the Dynaflect method were comparable to those obtained with the SPA low-frequency hammer. Accordingly, curvilinear relationships between surface deformation versus stiffness values were derived. These relationships can be used to determine moduli values at all surface deflections, including those from service loads.

Determining the Coefficient of Friction for Rolling Disks

1978 ◽  
Vol 100 (1) ◽  
pp. 25-30
Author(s):  
D. H. Offner ◽  
N. Tomita
Keyword(s):  
Potential Energy ◽  
Coefficient Of Friction ◽  
Surface Deformation ◽  
Empirical Relationship ◽  
Rolling Resistance ◽  
Experimental Results ◽  
Testing Device ◽  
The Coefficient Of Friction ◽  
Static Coefficient Of Friction ◽  
Static Coefficient

A method and testing device for determining a coefficient of friction for rolling disks is described. The method equates the energy of rolling resistance to the change in potential energy of a moving system. The experimental results of applying this method to steel, aluminum, and plexiglass disks of 3.8, 2.5, and 1.7 cm radii and 1 cm width rolling on steel and aluminum bases are summarized. An empirical relationship between the coefficient of friction and energy of surface deformation is presented. Use of device for determining the static coefficient of friction for impending rolling and sliding of disks is discussed.

Effect of surface roughness and deformation on Rayleigh step bearing under thin film lubrication

2017 ◽  
Vol 69 (6) ◽  
pp. 1016-1032 ◽  
Author(s):  
Rahul Kumar ◽  
Mohammad Sikandar Azam ◽  
Subrata Kumar Ghosh ◽  
Hasim Khan
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Coefficient Of Friction ◽  
Surface Deformation ◽  
Load Capacity ◽  
Performance Parameters ◽  
Thin Film Lubrication ◽  
Small Surface ◽  
Content Type ◽  
Film Lubrication

Purpose The aim of this paper is to study the effect of deterministic roughness and small elastic deformation of surface on flow rates, load capacity and coefficient of friction in Rayleigh step bearing under thin film lubrication. Design/methodology/approach Reynolds equation, pressure-density relationship, pressure-viscosity relationship and film thickness equation are discretized using finite difference method. Progressive mesh densification (PMD) method is applied to solve the related equations iteratively. Findings The nature and shape of roughness play a significant role in pressure generation. It has been observed that square roughness dominates the pressure generation for all values of minimum film thickness. Deformation more than 100 nm in bounding surfaces influences the film formation and pressure distribution greatly. Divergent shapes of film thickness in step zone causes a delay of pressure growth and reduces the load capacity with decreasing film thickness. The optimum value of film thickness ratio and step ratios have been found out for the maximum load capacity and minimum coefficient of friction, which are notably influenced by elastic deformation of the surface. Practical implications It is expected that these findings will help in analysing the performance parameters of a Rayleigh step bearing under thin film lubrication more accurately. It will also help the designers, researchers and manufacturers of bearings. Originality/value Most of the previous studies have been limited to sinusoidal roughness and thick film lubrication in Rayleigh step bearing. Effect of small surface deformation due to generated pressure in thin film lubrication is significant, as it influences the performance parameters of the bearing. Different wave forms such as triangular, sawtooth, sinusoidal and square formed during finishing operations behaves differently in pressure generation. The analysis of combined effect of roughness and small surface deformation has been performed under thin film lubrication for Rayleigh step bearing using PMD as improved methods for direct iterative approach.

Field testing the AMIT Job Performance Aid: Methods, results, and implications for the Air Force maintenance community

2007 ◽  
Author(s):  
David E. Kancler ◽  
Christopher C. Curtis ◽  
Darryl S. Stimson ◽  
Johnnie Jernigan
Keyword(s):  
Job Performance ◽  
Air Force ◽  
Field Testing ◽  
Force Maintenance

Leadership Effectiveness Assessment Profile (LEAP): Officer Instrument Field Testing and Refinement

1992 ◽  
Author(s):  
Victor H. Appel ◽  
Carol Murray Quintana ◽  
Richard W. Cole ◽  
Mark D. Shermis ◽  
Paul D. Grubb ◽  
...  
Keyword(s):  
Leadership Effectiveness ◽  
Field Testing ◽  
Effectiveness Assessment

Sexuality-related conditions: A multistakeholder approach to explore feasibility of field-testing ICD-11 revisions in developing countries.

2016 ◽  
Vol 5 (3) ◽  
pp. 184-191 ◽  
Author(s):  
Megan M. Campbell ◽  
Rebeca Robles ◽  
Denise L. Vieira ◽  
Brigitte Khoury ◽  
Saria Daouk ◽  
...  
Keyword(s):  
Developing Countries ◽  
Field Testing

Optimizing, validating, and field testing a multiplex qPCR for the detection of amphibian pathogens

2018 ◽  
Vol 129 (1) ◽  
pp. 1-13 ◽  
Author(s):  
I Standish ◽  
E Leis ◽  
N Schmitz ◽  
J Credico ◽  
S Erickson ◽  
...  
Keyword(s):  
Field Testing ◽  
Multiplex Qpcr ◽  
Amphibian Pathogens
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