Surface Profile and Third-Body Layer Accumulation Measurement Using a 3D Laser Profiler

2020 ◽  
Author(s):  
Ahmad Radmehr ◽  
Arash Hosseinian Ahangarnejad ◽  
Ali Tajaddini ◽  
Mehdi Ahmadian
Keyword(s):  
Surface Finish ◽  
Laser Scanner ◽  
Surface Profile ◽  
Third Body ◽  
Wheel Surface ◽  
Wheel Wear ◽  
Wheel Load ◽  
Traction Forces ◽  
Series Of Experiments ◽  
Roller Rig

Abstract The surface profile wear and the resulting third-body layer accumulation are investigated on the Virginia Tech-Federal Railroad Administration Roller Rig (VT-FRA Roller Rig), using a high-precision 3D laser profiler by Keyence. It is observed that the wheel surface gradually wears and the fine worn material accumulates on the running surfaces. It is further observed that with the progression of the wear and accumulation of a powder-like material at running surface, a preocular change in wheel-rail traction occurs. The first step in exploring the physics of the changes in traction is quantifying, precisely, the micron-sized surface finish changes and wear material accumulation. This paper provides the process of choosing a suitable surface profiler for the VT-FRA roller rig adaptation, and the results of a series of tests under various wheel load and contact configurations. A baseline experiment is conducted to evaluate the wheel wear and the accumulation of the naturally-generated third body layer (the worn material) on the wheel’s running surface. Before each series of experiments, the wheel and roller running surfaces were polished and thoroughly cleaned to make sure that they are perfectly smooth (finished) and free of any debris or dust. The wheel surface profile is measured in the perfectly cleaned condition using the 3D laser scanner. Time controlled experiments are run with different wheel loads, % slippage, and angle of attack (AoA) for 500 seconds. For each run, the change with surface finish and accumulated third body layer build up is measured. It is consistently observed that the traction forces increase gradually with time until they reach a stable level, presented by a plateau in the traction-slippage curves. The time to reach the plateau is directly related to wheel’s dynamic conditions including load, %slippage, and AOA. For some of the conditions, such as wheel load, the relationship is linear and for others (such as AOA) it is nonlinear. Concentrating on the analysis of the baseline results, it is observed that the change in surface finish and the third body layer that naturally accumulates at the running surface — hence, referred to as “natural third body layer” or “NTBL” — is directly correlated and somewhat linearly with NTBL and change in the running surface from smooth to rough. The correlation is most noticeable for the NTBL. With increasing NTBL, traction increases rapidly until the running surface is saturated with the accumulated wear material, presumably a ferrous oxide. There is far weaker correlation between the change in surface finish and traction variations. It is noticed that the surface finish continues to change beyond the time that the traction forces reach their plateau, and its effect remains far more gradual than NTBL.

Evaluating the Effect of Natural Third Body Layers on Friction Using the Virginia Tech Roller Rig

2019 ◽  
Author(s):  
Ahmad Radmehr ◽  
Karan Kothari ◽  
Mehdi Ahmadian
Keyword(s):  
Virginia Tech ◽  
Contact Forces ◽  
Third Body ◽  
Traction Coefficient ◽  
The Coefficient Of Friction ◽  
Creep Force ◽  
Series Of Experiments ◽  
Roller Rig ◽  
Friction Reducer ◽  
Material Wear

In this study, the effect of natural third body layers on the coefficient of friction and contact forces is evaluated using the Virginia Tech-Federal Railroad Administration (VT-FRA) roller rig facility. The test rig allows us to precisely control the contacting surfaces to study its effect on the wheel-rail interface forces and moments. Experiments have shown while running the tests, a slight amount of wear occurs at the running surfaces. The worn material deposits at the surface and behaves like a “natural” third-body layer at the contact, resulting in changes in traction coefficient and creep forces. The material wear and its accumulation on the running surfaces change with wheel longitudinal load and creepage. A series of organized time-based experiments have been conducted with the running surfaces cleaned at the beginning of the test to study the effect of material wear accumulation on selected parameters including traction coefficient and creep forces over time. In order to highlight the effect of the natural third body layer on the wheel-rail contact forces, a series of experiments were conducted, in which the wheel and roller surfaces were cleaned in one case and left uncleaned in another. The results of the experiments are quite revealing. They indicate that when the running surfaces are cleaned after each test, the maximum creep force (or adhesion) is far lower than when the running surfaces are not cleaned, i.e., the natural third-body layer is allowed to accumulate at the surfaces. The results indicate that the wear debris act as a friction enhancer rather than a friction reducer.

An Experimental Study of the Influence of the Amount of Top-Of-Rail Friction Modifiers on Traction

2021 ◽  
Author(s):  
Yu Pan ◽  
Ahmad Radmehr ◽  
Ali Tajaddini ◽  
Mehdi Ahmadian
Keyword(s):  
Experimental Study ◽  
Surface Profile ◽  
Traction Force ◽  
Friction Modifiers ◽  
Wheel Wear ◽  
Rail Wear ◽  
Traction Coefficient ◽  
Added Benefit ◽  
Roller Rig ◽  
Potential Factors

Abstract This study presents an experimental study of the effect of Top-of-Rail Friction Modifiers (TORFM) in quantities ranging from a small to a large amount on the progression of wheel-rail wear, using the Virginia Tech-FRA (VT-FRA) roller rig. TORFM behaves as a third body layer in between the wheel and rail and is applied to reduce wheel and rail wear while preserving a stable traction condition. An added benefit of TORFM is that it is estimated that it can reduce fuel consumption by controlling friction, although we are not aware of any proven data in support of this. Although widely used by the U.S. Class I railroads, there exists no proven method for determining, qualitatively or quantitatively, how the amount of TORFM and rail/wheel wear are related. Simply put, would increasing TORFM amount by a factor of two reduce wheel/rail wear and damage by one-half? How would such doubling effect traction or the longevity of TORFM on the wheel/rail surface? In this study, the VT-FRA roller rig is used to perform a series of tests under highly controlled conditions to shed more light on answering these questions. A series of controlled experiments are designed and performed in order to investigate the potential factors that may influence the traction performance. The wheel surface profile is measured by a high-precision, 3D, laser profiler to measure the progression of wheel wear for the duration of the experiments. The results indicate that it takes as much longer time for the traction force (traction coefficient) to reach a condition that is the same as the unlubricated rail, when compared between lightly-, moderately-, and heavily-lubricated conditions. The results further indicate that wear generation is delayed significantly among all lubrication conditions — even, the lightly-lubricated — when compared with the unlubricated conditions. A further evaluation of the results and additional tests are needed to provide further insight into some of the preliminary results that we have observed thus far.

The Role of Cutter Eccentricity on Surface Finish and Milling Forces

2004 ◽  
Author(s):  
Tony L. Schmitz ◽  
Jeremiah Couey ◽  
Eric Marsh ◽  
Michael F. Tummond
Keyword(s):  
Surface Finish ◽  
Milling Machine ◽  
Time Domain Simulation ◽  
Machined Surface ◽  
Premature Failure ◽  
Series Of Experiments ◽  
Error Motion ◽  
Milling Forces ◽  
Chip Load

In this paper, the role of milling cutter eccentricity, commonly referred to as runout, is explored to determine its effects on surface topography and milling forces. This work is motivated by the observation that commercially-available cutter bodies often exhibit variation in the teeth/insert radial locations as a result of manufacturing issues. Consequently, the chip load on individual cutting teeth varies periodically, which can lead to premature failure of the cutting edges. Additionally, this chip load variation increases the roughness of machined surfaces. This research isolates the effect of runout on cutting forces and the machined surface finish in a series of experiments completed on a precision milling machine with 0.1 μm positioning repeatability and 0.02 μm spindle error motion. The runout is varied in a controlled fashion and results compared between experiment and a comprehensive time-domain simulation.

Computer-Aided Simulation of Dressing Using Diamond Rotary Dresser and Visualization of Dressing Process

2014 ◽  
Vol 1017 ◽  
pp. 592-597 ◽  
Author(s):  
Akihiko Kubo ◽  
A.M.M. Sharif Ullah ◽  
Jun’ichi Tamaki
Keyword(s):  
Solid Body ◽  
Surface Profile ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Wheel Surface ◽  
Contour Map ◽  
Removal Process ◽  
Computer Aided ◽  
Actual Depth

The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.

Experimental Characterization of Electroplated CBN Grinding Wheel Wear: Topology Evolution and Interfacial Toughness

2014 ◽  
Author(s):  
Tianyu Yu ◽  
Ashraf F. Bastawros ◽  
Abhijit Chandra
Keyword(s):  
Grinding Wheel ◽  
Activation Process ◽  
Time To Failure ◽  
Wheel Surface ◽  
Wheel Wear ◽  
Modeling Framework ◽  
Topological Evolution ◽  
Pull Out ◽  
Topological Features ◽  
Cbn Grinding Wheel

The wear rate of a grinding wheel directly affects the workpiece surface integrity and tolerances. This paper summarizes a combined experimental-modeling framework for life cycle prediction of an electroplated Cubic Boron Nitride (CBN) grinding wheel, typically utilized in nickel-based superalloy grinding. The paper presents an experimental framework to facilitate the formulation of a micro-mechanics based modeling framework. The presented work investigates the topological evolution of the grinding wheel surface and mechanisms of grit failure via depth profiling, digital microscopy and scanning electron microscopy. The results are used to elucidate the statistical evolution of the grinding wheel surface. Different modes of grit failure, including grit attritious wear, fracture and pull out haven been identified. The analysis of the surface topological features indicates a unique grit activation process, leading to a non-uniform spatial distribution of the grit wear. Additionally, single grit pull out experiment has been conducted to assess the residual strength of the grit-wheel interface and the associated state of damage percolation. The experimental results can be utilized in developing a life expectancy model for the CBN grinding wheel to assess the grit mean time to failure as well as grit surface topological evolution as a function of the process parameters.

Evaluation of the Working Surface of the Grinding Wheel Using Speckle Image Analysis

2015 ◽  
Author(s):  
Arunachalam Narayanaperumal ◽  
Vijayaraghavan Lakshmanan
Keyword(s):  
Surface Quality ◽  
Surface Condition ◽  
Grinding Wheel ◽  
Optical Parameters ◽  
Wheel Surface ◽  
Wheel Wear ◽  
Speckle Image ◽  
Periodic Monitoring ◽  
Grinding Machine

The surface quality of the ground components mainly depends on the surface condition of the grinding wheel. The surface condition of the grinding wheel changes with grinding time due to wheel wear and loading. The excessive wear and loading increases the cutting force and the temperature. This in turn affects the quality of the produced component. Hence periodic monitoring of the grinding wheel surface is essential to avoid the production of the defective components. In this paper, an attempt is made to study the changes in the grinding wheel surface condition using the laser scattered images. The simple speckle imaging arrangement is fabricated and fitted into the grinding machine to capture the images of the grinding wheel after each 100 passes. The fresh wheel expected to scatter more light due to higher roughness and porosity. On the other hand, the completely glazed and worn-out wheel scatters the light less due to smoother surface. Thus, speckle image intensity distribution captures the changes in the grinding wheel surface condition. The optical parameters evaluated from the speckle images clearly indicating the changes in the grinding wheel condition. This method can be utilized to evaluate the grinding wheel condition to improve the surface quality of the component produced.

An analysis of surface profile for cylindrical osteochondral grafts of the knee quantitative evaluation using a three-dimensional laser scanner

2012 ◽  
Vol 21 (8) ◽  
pp. 1794-1800 ◽  
Author(s):  
Daisuke Araki ◽  
Ryosuke Kuroda ◽  
Tomoyuki Matsumoto ◽  
Kouki Nagamune ◽  
Takehiko Matsushita ◽  
...  
Keyword(s):  
Quantitative Evaluation ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Surface Profile ◽  
Osteochondral Grafts

scholarly journals Experimental Investigation of the Effect of Process Parameters on Material Removal Rate and Surface Finish

2020 ◽  
pp. 46-50
Author(s):  
S. Sudharsan
Keyword(s):  
Experimental Investigation ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Surface Finish ◽  
Material Removal ◽  
Removal Rate ◽  
Optimum Combination ◽  
Taguchi Design Of Experiments ◽  
Finishing Process ◽  
Series Of Experiments

Lapping is a finishing process used especially for removing the material, achieving finer surfaces, correcting minor imperfections and maintaining close tolerances. This process may takes place due to the relative motion between the work material, slurry and lapping plate. This study is done by conducting a series of experiments based on taguchi design of experiments and calculating material removal rate and surface roughness. This study explains about effect of the parameters on material removal rate and surface finish. The final step of this process is to find out the optimum combination of process parameters to determine the material removal rate and the surface finish.

scholarly journals Modelling car motion and the calculation of the wear of wheels with the VNITsTT rolling surface profile

2019 ◽  
Vol 78 (1) ◽  
pp. 41-47
Author(s):  
A. M. Orlova ◽  
Yu. V. Savushkina ◽  
V. I. Fedorova
Keyword(s):  
Mathematical Modeling ◽  
Critical Speed ◽  
Surface Profile ◽  
Operating Conditions ◽  
Wheel Wear ◽  
Large Circle ◽  
Limit Values ◽  
Rolling Surface ◽  
Wheel Profile ◽  
Freight Car

The wear problem of wheels along rolling surface or thin flange is currently involved a large circle of specialists. There are opinions that it is necessary to establish new limit values for wheel wear in operation, put into practice the re-profiling (profile grin ding) of rails, install a larger number of floor-mounted lubricators in places of increased rail wear intensity, but one of the priority direction in this area is the development of a new surface rolling wheel profile for freight cars, the use of which will help to increase the turnaround time and increase the service life of the wheels in operation. Geometry of the rolling surface profile of the wheel should allow to provide a contact form between the wheel and the rail conformal or close to conformal. This solution has already found its application and achieved desired results on foreign railways (North America, South Africa, China, etc.). Authors developed a technique for designing a new wheel profile, which was used to build a profile of the rolling surface made by the Russian Research Center for Transport Technologies (LLC “VNITsTT”). As part of the study, calculations were carried out using the method of mathematical modeling of a freight car motion in the MEDYNA software package and performance indicators were evaluated on the VNITsTT rolling surface profile in comparison with the profile made according to GOST 10791 – 2011, and the wheel wear rate produced on the section of the track close to the average network operating conditions. Additionally, critical speed of the sinuous motion of the car was evaluated, which showed that despite the increased equivalent taper, the critical speed remained almost unchanged (an increase of 6 %). Theoretical calculation of the wheel resource based on the results of mathematical modeling has been made. According to the calculations, it was determined that the resource of the flange before turning for the RDCTT profile is 409.3 thousand km, and for the rolling surface — 663.3 thousand km, for the profile made according to GOST 10791 – 2011, the resource for the flange was 285.6 thousand km, and for the rolling surface 401.2 thousand km. Thus, the use of the VNITsTT profile is more effective than the profile made according to GOST 10791 – 2011 by 30.2 % for the flange and 39.5 % for the rolling surface. The developed VNITsTT profile, in comparison with the profile made by GOST 10791 – 2011, according to the results of calculations, confirmed the provision of standard indicators of the dynamic qualities of a freight car. 

scholarly journals Quantifying the changes of soil surface microroughness due to rainfall-induced erosion on a smooth surface

2017 ◽  
Author(s):  
Benjamin K. B. Abban ◽  
A. N. Thanos Papanicolaou ◽  
Christos P. Giannopoulos ◽  
Dimitrios C. Dermisis ◽  
Kenneth M. Wacha ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Laser Scanner ◽  
Surface Profile ◽  
Soil Surface ◽  
Bare Soil ◽  
Agricultural Landscapes ◽  
Length Scales ◽  
Surface Conditions ◽  
Consistent Increase ◽  
Surface Microroughness

Abstract. This study examines the rainfall induced change in soil microroughness of a bare soil surface in agricultural landscapes. The focus is on the quantification of roughness length under the action of rainfall for initial microroughness length scales of 2 mm or less, defined here as initial smooth surface conditions. These conditions have not been extensively examined in the literature as most studies have focused on initial disturbed surface conditions (bed surface conditions with initial length scales greater than 2 mm and varying between 5–50 mm). Three representative intensities namely 30 mm/h, 60 mm/h and 75 mm/h were applied over a smoothened bed surface at a field plot via a rainfall simulator. Soil surface microroughness measurements were obtained via a surface-profile laser scanner. Two indices were utilized to quantify soil surface microroughness, namely the Random Roughness (RR) index and the crossover length. Findings show a consistent increase in roughness under the action of rainfall for initial microroughness length scales of 2 mm. This contradicts existing literature where a monotonic decay of roughness of soil surfaces with rainfall is recorded for disturbed surfaces. Analysis shows that on an average the RR and the crossover length post run increase by a multiple of 3.15 and 1.9, respectively from their corresponding values apriori the runs.

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