Micro-Contact Models for Metallic Line-Contact Based on Measured Surface Profile

2017 ◽  
Author(s):  
Jian Chen ◽  
Jun Hong ◽  
Jinhua Zhang ◽  
Linbo Zhu ◽  
Zhigang Liu
Keyword(s):  
Surface Profile ◽  
Quadratic Functions ◽  
Line Contact ◽  
Metallic Surfaces ◽  
Metallic Line ◽  
Calculation Results ◽  
Contact Models ◽  
Measured Profile ◽  
Nominal Contact Area ◽  
Contact Mechanism

In order to study the dry rough line-contact mechanism between two longitudinally rough metallic surfaces, the measured profile is mathematically described by quadratic functions for the application of the existing micro-contact models. The mechanical parameters are determined using the different approximating criteria. Next, based on these deterministic parameters, different micro-contact models are employed and extended to predict the characteristics of a line-contact. Comparison of different theoretical calculation results reveals that the greater maximum values of the contact deformation and the ratio of real to nominal contact area are predicted by the Hertz model as compared to the micro-contact models considering the elastoplastic deformation, and that the KE (Kogut and Etsion) and JG (Jackson and Green) models predict closer results. It is also found that when the rough surfaces are described by quadratic functions according to the same area criterion or same root mean square (RMS) criterion, the line-contact responses between them prescribed by any micro-contact models have the same tendency.

RkRk material measure

2019 ◽  
Vol 86 (9) ◽  
pp. 478-486 ◽  
Author(s):  
Jörg Seewig ◽  
Matthias Eifler ◽  
Dorothee Hüser ◽  
Rudolf Meeß
Keyword(s):  
Surface Profile ◽  
Profile Data ◽  
Measuring Process ◽  
Suitable Material ◽  
Precision Turning ◽  
Functional Characterisation ◽  
Ultra Precision ◽  
Measured Profile ◽  
Material Measure ◽  
Comparison Measurements

AbstractThe standard ISO 13565-2 defines the Rk parameters for the functional characterisation of technical surfaces. So far, no particular material measures for the calibration of these parameters have been defined in the international standardization. For the application and the functional behaviour of technical surfaces the Rk parameters however have a critical significance, so there is a demand by the industry to calibrate these parameters as they are increasingly applied for the quality assessment of workpieces. In the present paper, a proposal for suitable material measures is presented. An algorithm is described, which transforms the data of a real measured profile in a way that the exact defined parameters of Rk, Rpk and Rvk are equated. The material measures geometry corresponds to its later application and the target parameters are almost freely selectable. The approach for transforming surface profile data with the aid of the Abbott curve is introduced generically, solves an inverse problem and considers the influences from the manufacturing and measuring process. The designed material measure is manufactured with the aid of ultra-precision turning. In matters of the aspired industrial application, comparison measurements are carried out in order to examine the practical abilities of the material measure and the repeatability of the approach is proven.

scholarly journals Application of profilograph for evaluation of mechanical tillage of slope lands

2020 ◽  
Vol 193 ◽  
pp. 01066
Author(s):  
Mikhail Vasiliev ◽  
Sergey Vasiliev ◽  
Alexey Vasiliev
Keyword(s):  
Surface Roughness ◽  
Average Method ◽  
Soil Cover ◽  
Moving Average ◽  
Surface Profile ◽  
Soil Surface ◽  
Morphological Parameters ◽  
Wide Range ◽  
Data Points ◽  
Measured Profile

In this paper, we analyze a wide range of measurements of the day surface profile of tilled soil in order to substantiate the moving average method for evaluating morphological parameters and studying the influence of the base profile length on the accuracy of the obtained values. The surface roughness of the elementary plot was 4 mm, the surface ridgeness formed by technological furrows was 16 mm, and the slope of the plot was 0.198. The accuracy of the obtained values of roughness and ridgeness of the tilled soil surface depends significantly on the profile length determined by the number of measurements performed. We obtained 5273 data points per one turn of the device on a 6.3 m profile length (1 measurements are made per 1 mm) for the elementary plot. The surface roughness varied from 3, 1 mm to 4, 3 mm, and the ridgeness – 12 ... 21 mm when the number of measurements is from 2000 to 5273. When the measured profile length is about 1.3 m or less (not more 2000 points), the parameters of the tilled soil cover are not considered important. However, they are more critical for ploughed soil than for harrowed soil. On flatter surfaces, the base profile length of 2.5 m may be sufficient to adequately calculate the parameters of the day soil surface.

scholarly journals Numerical Analysis of Sand Bed Degrading and Sediment Transport Rate Under Tailings Dam Break

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhong Tian ◽  
Hao Yang ◽  
Wei Wang ◽  
DeSheng Cao
Keyword(s):  
Sediment Transport ◽  
Surface Profile ◽  
Local Environment ◽  
Dam Break ◽  
Transport Rate ◽  
Tailings Dam ◽  
Sediment Transport Rate ◽  
Outflow Rate ◽  
Calculation Results ◽  
Dam Breaking

Dam-breaking accidents in tailings ponds may result in loss of tailings, damage to the downstream bridges and houses, flooding of farmland and roads, hazards to the local environment, and even loss of property and lives. Therefore, research on dam breaks in tailings reservoirs and prediction of subsequent impacts are of great significance. This paper describes theoretical and numerical analyses of the retrogressive erosion model and calculations of the sand bed surface profile and sediment transport rate following tailings dam break events. The calculation results show that the degrading rate of the bed surface in the reservoir area reaches a maximum when the breach is formed and then rapidly decreases to a stable value. Farther away from the breach, the peak degrading rate of the bed surface is lower. The time of the peak tailings outflow rate is related to the formation of the breach. A larger breach has a shorter formation time and a greater peak flow.

scholarly journals Robot-Assisted Floor Surface Profiling Using Low-Cost Sensors

2019 ◽  
Vol 11 (22) ◽  
pp. 2626
Author(s):  
Scott Wilson ◽  
Johan Potgieter ◽  
Khalid Mahmood Arif
Keyword(s):  
Low Cost ◽  
Laser Scanner ◽  
Surface Profile ◽  
Pavement Condition ◽  
Surface Profiling ◽  
Road Pavement ◽  
Floor Surface ◽  
Industry Applications ◽  
Measured Profile ◽  
Inspection Tasks

Low cost and accurate 3D surface profiling can help in numerous industry applications including inspection tasks, cleaning, minimizing bumps in navigation of non-uniform terrain, aid navigation, and road/pavement condition analysis. However, most of the available systems are costly or inaccessible for widespread use. This research presents investigation into the capability of cheap and accessible sensors to capture the floor surface profile information. A differential drive robotic platform has been developed to perform testing and conduct the research. 2D localization methods are extrapolated into 3D for the floor capturing process. Two different types of sensors, a 2D laser scanner and an RGB-D camera, are used for comparison of the floor profile capture ability. The robotic system is able to successfully capture the floor surface profile of a number of different type floors such as carpet, asphalt, and a coated floor. A key finding is that the surface itself is a significant factor on the measured profile, i.e. dirt or differing materials can cause false height measurements. Overall the methodology has proved a successful real time solution for creating a point cloud of the floor surface.

scholarly journals Bonding xenon and krypton on the surface of uranium dioxide single crystal

Nukleonika ◽  
2014 ◽  
Vol 59 (3) ◽  
pp. 83-89
Author(s):  
Ludwik Dąbrowski ◽  
Marcin Szuta
Keyword(s):  
Single Crystal ◽  
Uranium Dioxide ◽  
Density Functional ◽  
Metallic Surface ◽  
Potential Well ◽  
Metallic Surfaces ◽  
Potential Wells ◽  
Cell Parameters ◽  
Super Cell ◽  
Calculation Results

Abstract We present density functional theory (DFT) calculation results of krypton and xenon atoms interaction on the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalised gradient approximation (GGA) was applied using the ABINIT program package. To compute the unit cell parameters, the 25 atom super-cell was chosen. It has been revealed that close to the surface of a potential well is formed for xenon and krypton atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of ab initio calculations in adiabatic approximation. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown that the potential well for the oxygenic surface is deeper than for the metallic surface. The thermal stability of immobilising the atoms of krypton and xenon in the potential wells were evaluated. The results are shown in graphs.

Dynamic behaviours of piston rings and their practical impact. Part 2: Oil transport, friction and wear of ring/liner interface and the effects of piston and ring dynamics

2002 ◽  
Vol 216 (4) ◽  
pp. 229-248 ◽  
Author(s):  
T Tian
Keyword(s):  
Friction And Wear ◽  
Surface Profile ◽  
Theoretical Models ◽  
Heavy Duty ◽  
Oil Consumption ◽  
Oil Supply ◽  
Oil Transport ◽  
Ring Dynamics ◽  
Calculation Results ◽  
Practical Impact

The paper discusses several important processes that have great impact on the lubrication between the top two rings and the liner. The analysis is conducted on the basis of the calculation results on a heavy-duty (HD) diesel engine using theoretical models. Oil supply mechanisms to different liner regions are analysed, and emphasis is given to the oil transport to the top liner region that is found critical to friction, wear and oil consumption in HD diesel engines. Additionally, the paper discusses the oil supply to the second ring, its uncertainties and the effect on the prediction of the performance of the top two rings. Furthermore, the effects of dynamics of the piston and rings on friction, wear and oil transport are illustrated and the effects of bore distortion on oil transport are discussed. For practical purposes, a formula to describe the second ring running surface profile is given based on simple geometrical constraint. A new truncation method is rendered for plateau surface roughness in order to effectively use the existing mixed lubrication models.

Meshing Theory and Simulation of Noninvolute Beveloid Gears With Crossed Axes

2007 ◽  
Author(s):  
Guangbin Yu ◽  
Yuxiang Shi ◽  
Wei Wang ◽  
Guixian Li
Keyword(s):  
Gear Tooth ◽  
Three Dimensional ◽  
Tooth Profile ◽  
Line Contact ◽  
Cad System ◽  
Engagement Theory ◽  
Beveloid Gears ◽  
Calculation Results ◽  
Tooth Modification ◽  
Crossed Axes

Based on the space engagement theory, a special type of non-involute beveloid gears meshing with line contact between crossed axes has been studied in this paper. The engagement equation and tooth profile equation have been presented by applying the theory of gearing. Meanwhile the tooth profile errors and axial errors have been calculated by means of numerical analysis in this paper. The changes of these errors and the main factors have been studied. As a numerical example, the three-dimensional simulation of beveloid gears between crossed axes has been finished by means of the CAD system, Pro/Engineer. A new way of gear tooth modification is developed based on the space engagement theory for the first time in this paper. By improving the wheel gear grinder of large plane grinding, the paper has provided the tooth modification method of manufacturing noninvolute beveloid gears meshing with line contact between crossed axes. Finally, an example and its calculation results are presented.

scholarly journals A Movie Film Illustrating the Numerical Modelling of Periodically Surging Ice Masses

1976 ◽  
Vol 16 (74) ◽  
pp. 304-305
Author(s):  
W.F. Budd ◽  
B.J. Mcinnes
Keyword(s):  
Steady State ◽  
Flow Line ◽  
Three Dimensional ◽  
Surface Profile ◽  
High Viscosity ◽  
Ice Cap ◽  
Section Shape ◽  
Measured Profile ◽  
Full Temperature ◽  
Line Patterns

AbstractA general two-dimensional numerical model for a typical flow line of a glacier or ice cap has been developed which results in periodical surging for certain ranges of the input parameters. The input includes the bedrock and surface-balance profiles along the flow line, some three-dimensional parameterization depending on the cross-section shape and the flow-line patterns, the flow properties of the ice, and a numerical basal lubrication factor.The movie shows how a number of different ice masses grow from zero thickness to either steady state or a periodically surging state depending on the input. Typical examples of real surging ice masses from the small to the large are closely matched by the model in many effects such as the period, duration, and speed of the surges, as well as the length and thickness changes.A preliminary study for the surging potential of a flow line in east Antarctica is also made even though the full temperature modelling is not included. The results indicate that periodic surging of the ice sheet can develop in spite of the expected high viscosity. The resultant surface profile is very similar to the measured profile. For much lower viscosities steady-state, fast-sliding, ice-stream flow develops.

A Scanning White-Light Interferometric Profilometer for Smooth and Rough Surface

2007 ◽  
Vol 364-366 ◽  
pp. 364-370 ◽  
Author(s):  
Rong Dai ◽  
Tie Bang Xie ◽  
Su Ping Chang
Keyword(s):  
Rough Surface ◽  
White Light ◽  
Surface Profile ◽  
Ccd Camera ◽  
Measuring System ◽  
Profile Measurement ◽  
Integrated Optical ◽  
Optical Grating ◽  
Measured Profile ◽  
Surface Dimension

A profilometer for micro-surface topography measurement is presented. The instrument is based on the scanning white-light microscopic interferometry (SWLMI). A Linnik type interference microscope is used and the interferograms which present changes of surface profile are recorded by a CCD camera. A developed nano-positioning work stage with integrated optical grating displacement measuring system realizes the precise vertical scanning motion during profile measurement. By white-light phase shifting algorism of arbitrary steps, frames of interferograms are processed by computer to rebuild and evaluate the measured profile. Because of the specialty of SWLMI, the profilometer is suitable for both smooth and rough surface measuring. It also can be used for the measurement of curved surface, dimension of MEMS etc. The vertical resolution of the profilometer is 0.5nm, lateral resolution 0.5+m.

scholarly journals Concept Research of a Countermeasure Device for Preventing Scour around the Monopile Foundations of Offshore Wind Turbines

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2593 ◽  
Author(s):  
Wenxian Yang ◽  
Wenye Tian
Keyword(s):  
Shear Stress ◽  
Wind Turbines ◽  
Surface Profile ◽  
Offshore Wind ◽  
Optimal Size ◽  
Offshore Wind Turbines ◽  
Service Period ◽  
Horseshoe Vortices ◽  
Calculation Results ◽  
The Impact

Scouring has long been considered to be a major issue affecting the reliability of the monopile foundations of offshore wind turbines (OWTs) on sandy seabeds. To reduce the impact of scouring, several tons of rock/stone are usually placed around the foundations shortly after the installation of them. Such a measure is costly. Moreover, rock and stone may spread widely on the seabed during the long-term service period of OWTs. It has no doubt that recycling these rock and stone on the seabed is quite difficult in future decommission. For this reason, a new scour-countermeasure device (SEMCD) is proposed and studied in this paper. Considering that the major driver of scouring is horseshoe vortices around the monopile foundation, a hollow horn-like SEMCD with an arc surface profile is designed for weakening the horseshoe vortices. The SEMCD is made of either cement or other kinds of corrosion resistant materials. It is light in weight, and easy to install and decommission. In the paper, the working mechanism of the SEMCD is first explained. Then, its scouring mitigation effect (SME), i.e., its contribution to the reduction of horseshoe vortices and the mitigation of seabed erosion around the foundation, is studied through investigating its influences on down/up-flow and seabed shear stress. Finally, the optimal size of the SEMCD is discussed through investigating the impact of its size on the speeds of up and down flows and the shear stress on seabed surface. The calculation results have shown that the proposed SEMCD has great potential to prevent scouring and seabed erosion, so that it is of significance to improve the reliability of the monopile foundations of OWTs.

Sign in / Sign up

Export Citation Format

Share Document