Effect of Thermal Distortion on Wear of Composites

1995 ◽  
Vol 117 (4) ◽  
pp. 622-628 ◽  
Author(s):  
Shingo Obara ◽  
Takahisa Kato
Keyword(s):  
Elastic Deformation ◽  
Composite Structure ◽  
Frictional Heating ◽  
Tetragonal Zirconia ◽  
Surface Profile ◽  
Normal Pressure ◽  
Oxide Ceramic ◽  
Thermal Distortion ◽  
Test Results ◽  
Worn Surface

The worn surface profile of a composite structure was experimentally and numerically investigated focusing on the effects of sliding conditions. Wear tests on composites made of an oxide ceramic and an amorphous metal against a tetragonal zirconia polycrystals-alumina were carried out under various mean contact pressures, P, and sliding velocities, V. The test results showed that the worn surface profiles of the composites changed with the PV value. A new numerical method for simulating the worn surface profile of a composite structure has been developed. The present method is based upon the assumption that the profile of a worn surface is changed by thermal distortion of the sliding bodies due to frictional heating and by elastic deformation due to normal pressure and friction traction. The calculated results were compared with the test results, and the comparison showed that the elastic deformation plays an important role in forming the worn surface profile and that the effect of thermal distortion becomes remarkable with an increase in PV values. The numerical results clarified the contribution of the thermal distortion to the change in the worn surface profile of the composite.

Frictional Heating of a Composite

1994 ◽  
Vol 116 (3) ◽  
pp. 415-422 ◽  
Author(s):  
Shingo Obara ◽  
Takahisa Kato
Keyword(s):  
Temperature Distribution ◽  
Frictional Heating ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Surface Profile ◽  
Asperity Contact ◽  
Infinite Body ◽  
Contact Heat ◽  
Moving Surface ◽  
Worn Surface

A numerical analysis has been carried out for a three-dimensional frictional heating problem of a composite material, in which an asperity contact (heat source) moves across the boundary of the constituents of a composite. The mathematical model adopted here is that a surface asperity on a semi-infinite body slides on a composite which consists of two semi-infinite bodies. Expressions of temperature distribution both in the composite and on the moving surface are derived. Then the temperature distribution and its change with time are obtained by a numerical procedure. It is shown that the temperature rise caused by frictional heating remarkably depends on the thermal properties of constituents of the composite, and temperature distributions in the vicinity of the asperity contact both on the moving surface and in the composite rapidly change when the asperity passes over the boundary of the constituents. The effect of the frictional heating on the worn surface profile of a composite is also discussed.

Tribological Properties of Ti-Al Alloy Self-Lubricating Composite Materials

2013 ◽  
Vol 842 ◽  
pp. 114-117
Author(s):  
Xiu Ling Wang ◽  
Li Ying Yang ◽  
Shou Ren Wang ◽  
Yi Zhang
Keyword(s):  
Sliding Wear ◽  
Solid Lubricant ◽  
Al Alloy ◽  
Test Results ◽  
Weight Percentage ◽  
Dry Conditions ◽  
Hot Pressing Sintering ◽  
Worn Surface ◽  
Wear Tests ◽  
Self Lubricating Composites

A series of Ti-48Al-2Cr-2Nb/62%BaF2-38%CaF2 (CB) self-lubricating composites with addition of different weight percentage of solid lubricant were prepared by vacuum hot pressing sintering. Sliding wear tests against 45#steel were performed on the specimen in dry conditions, worn morphology was observed by the scanning electron microscope (SEM). The test results show that when addition of solid lubricant weight percentage is 10%, the worn surface of the composites is most smooth.The main wear mechanisms of Ti-48Al-2Cr-2Nb/62%BaF2-38%CaF2 composite are abrasive wear and adherent wear.

Measurement of the Interfacial Stresses in Rolling Using the Elastic Deformation of the Roll

1987 ◽  
Vol 109 (4) ◽  
pp. 362-369 ◽  
Author(s):  
D. J. Meierhofer ◽  
K. A. Stelson
Keyword(s):  
Elastic Deformation ◽  
Normal Pressure ◽  
New Method ◽  
Frictional Stress ◽  
Stress Distributions ◽  
Strain Gages ◽  
Experimental Rolling ◽  
Mechanical Isolation ◽  
Roll Gap ◽  
Future Work

A new method to measure the frictional stresses and normal pressure in the roll gap during cold rolling, and experimental verification of this new method, are presented. The method overcomes many of the shortcomings of pin-type sensors. The elastic deformation of the roll itself is measured with strain gages, and is used to calculate the stresses between the sheet and the roll. Since no modification of the roll is necessary, the deformation process is undisturbed by the measurement. Mechanical isolation of the sensor is unnecessary. The mathematical procedure used to calculate the normal pressure and frictional stresses from the measured strains explicitly acknowledges that these strains are the result of the entire distribution of pressures and shears in the roll gap. An experimental rolling mill was constructed to verify the proposed method. Lead was rolled, and the resulting pressure and frictional stress distributions in the roll gap were measured. Several features of these distributions are in agreement with measurements made by various investigators using other techniques, thereby confirming the usefulness of the new method. Future work is proposed to increase the accuracy with which the roll gap stresses may be measured.

Effect of Workpiece Hardness on Surface Microgeometry when Hard Turning with Ceramic Inserts

2013 ◽  
Vol 581 ◽  
pp. 176-181 ◽  
Author(s):  
Ildikó Maňková ◽  
Jozef Beňo ◽  
Marek Vrabel'
Keyword(s):  
Surface Roughness ◽  
Hard Turning ◽  
Surface Profile ◽  
Surface Finishing ◽  
Oxide Ceramic ◽  
Part Surface ◽  
Cutting Force Components ◽  
Finish Hard Turning ◽  
Force Components ◽  
Mixed Ceramic

Hard turning provides an alternative to grinding in some finishing operations. This paper deals with analysis of part surface finishing when turning hardened steel heat-treated on hardness of 46, 55 and 60 HRC with mixed oxide ceramic inserts. Average surface roughness Ra has been widely used in industry it is known that the single parameter Ra is inadequate to define the functionality of a surface. Two different surfaces with similar values of Ra can behave differently under loading conditions. The surface profile 2D and 3D parameters are assessed. The influence of workpiece hardness on surface roughness parameters and cutting force components is investigated. Results show that finish hard turning with mixed ceramic tool produces surface profile comparable to those produced by grinding.

Analysis of Uniform Deep Oval Reinforcing Rings

1964 ◽  
Vol 8 (02) ◽  
pp. 21-28 ◽  
Author(s):  
William P. Vafakos
Keyword(s):  
Hydrostatic Pressure ◽  
Cross Section ◽  
Composite Structure ◽  
Reference Line ◽  
Taylor Model ◽  
Test Results ◽  
Local Curvature ◽  
Oval Cross Section ◽  
Ring Shell ◽  
Good Agreement

Equations which are applicable to uniform deep oval rings in which the local curvature of an arbitrary reference line is prescribed are derived and simplified for application to oval ring-shell combinations. Theoretical estimates of the stresses and displacements are obtained for a typical reinforcing ring of a ring-stiffened oval cylinder recently tested under hydrostatic pressure by the David Taylor Model Basin. These results are obtained by appropriately approximating the oval cross section and by assuming that the composite structure responds as an oval ring. The theoretical flange stresses are shown to be in good agreement with available test results.

A modified approach based on bearing area curve for surface wear characterization

2020 ◽  
Vol 72 (3) ◽  
pp. 273-278
Author(s):  
Yun Wang ◽  
Junhong Mao ◽  
Suwen Lu ◽  
Zhenying Xu ◽  
Hong Liu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface Profile ◽  
Surface Wear ◽  
H13 Steel ◽  
Wear Area ◽  
Content Type ◽  
Profile Method ◽  
Wear Analysis ◽  
Curve Method ◽  
Worn Surface

Purpose Wear greatly influences the machine lifetime, performance and reliability and its quantification is very important. This paper aims to propose a modified bearing area curve method by combining the theory of the bearing area curve, and the relocation technique to calculate wear accurately and efficiently. Design/methodology/approach H13 steel was chosen as the material of wear pair, and the wear experiments were carried out at 50 N, 60 r/min for 20 min. The surface was measured before and after wear experiments. The relocation was made by comparing the mean lines (planes) of the unworn and worn surface profiles. The calculated results using the proposed method were compared with that of the surface profile method for a two-dimensional surface to validate its accuracy. The method was then applied for a three-dimensional (3D) wear analysis. Findings The worn surface shows clearly displacement compared to the unworn surface and implies the importance of including relocation in the bearing area curve method. The results from the proposed method are 98 per cent close to that from the surface profile method, indicating that the method is accurate for wear evaluation. Originality/value As no feature point or relocation mark is needed to calculate the relocation value using the proposed method, the method can be applied to mild to severe wear. Also, as the deviation of different scans does not affect the relocation calculation, and no matching and stitching is required, this method can be easily applied to a wide wear area and 3D surface wear analysis.

The Data Processing Technique of Metallic Sheet Friction Coefficient Determination

2012 ◽  
Vol 184-185 ◽  
pp. 688-691
Author(s):  
Huan Xue ◽  
Rong Feng Li ◽  
Hong Chuan Zhu
Keyword(s):  
Data Processing ◽  
Coefficient Of Friction ◽  
Normal Pressure ◽  
Processing Technique ◽  
Test Results ◽  
Friction Zone ◽  
Data Processing Method ◽  
The Coefficient Of Friction ◽  
Processing Techniques ◽  
Metallic Sheet

The definition and research background of friction is introduced. The reason of generation of friction is analyzed, the importance of the coefficient of friction test in sheet metal forming field is indicated. The testing principle of coefficient of friction on metallic sheet is presented. The basic data processing method of the test is described. Two important data processing techniques which will obviously effects the test results, including effective friction zone and normal pressure have been carefully studied. The comparison result shows these techniques can effectively enhance the testing stability and precision.

CONSISTENCY ANALYSIS OF WORN SURFACE TOPOGRAPHY AND FRICTION FORCE BASED ON PHASE TRAJECTORY AND RECURRENCE ANALYSIS

Fractals ◽  
2019 ◽  
Vol 27 (08) ◽  
pp. 1950130
Author(s):  
XUE ZUO ◽  
MINGLONG PENG ◽  
YUANKAI ZHOU
Keyword(s):  
Fractal Dimension ◽  
Surface Topography ◽  
Friction Force ◽  
Phase Trajectory ◽  
Small Volume ◽  
Surface Profile ◽  
Recurrence Plots ◽  
Recurrence Analysis ◽  
Wear Process ◽  
Worn Surface

The dynamic evolutions of friction force and worn surface profile were qualitatively analyzed by phase trajectory and recurrence plots and quantitatively characterized by fractal dimension and percent determinism. The results show that phase trajectories first shrink to a small volume, then stabilize at a minimum volume, finally expand to a large volume in the wear process. The white areas on the recurrence plots increase with the wear time. The fractal dimension first increases, then stabilizes at a high value, and finally decreases rapidly. The percent determinism first decreases, then fluctuates in a certain range, and finally increases. It demonstrates that friction force and worn surface topography derived from one tribology system evolve in a similar but not exactly the same way. They have the consistent evolution law in the wear process. Specially, friction force is much more sensitive to the variation of wear states than the worn surface.

Investigation of Tribological Behavior of Al–Si Alloy Against Steel Lubricated With Ionic Liquids of 1-Diethylphosphonyl-n-propyl-3- Alkylimidazolium Tetrafluoroborate

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Zonggang Mu ◽  
Xiaoxuan Wang ◽  
Shuxiang Zhang ◽  
Yongmin Liang ◽  
Meng Bao ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Room Temperature ◽  
Test Results ◽  
Tribological Test ◽  
X Ray ◽  
Imidazolium Cations ◽  
Metal Fluorides ◽  
Worn Surface

A series of room temperature ionic liquids bearing with phosphonyl groups on the imidazolium cations, namely, 1-(3′-O,O-diethylphosphonyl-n-propyl)-3-alkylimidazolium tetrafluoroborate, were prepared and their physical properties were determined. They were also evaluated as promising lubricants for the contacts of aluminum on steel by using a SRV test rig. The tribological test results show that the synthetic ionic liquids exhibit better friction-reducing and antiwear abilities than the unsubstituted ionic liquid of 1-ethyl-3-hexylimidazolium tetrafluoroborate (coded as L206) and phosphazene (X-1P). Both the anions and the side substitutes attached to the imidazolium cations affect the tribological performance of lubricants. The scanning electron microscopy, energy-dispersive x-ray analysis, and x-ray photoelectron spectroscopy analyses of the worn surfaces show that complicated tribochemical reactions are involved in the sliding process. The anion decomposition and chemical adsorption of cation took place on the worn surface of aluminum alloy during the sliding process. As a result of the generation of boundary lubrication films which are composed of metal fluorides, B2O3, BN, nitrogen oxide, and FePO4 help to effectively reduce the friction and wear of the contacts.

scholarly journals Tribological Properties of a Self-Repairing Material: Functionalized Graphene/montmorillonite Nanosheets Lubricant Additives

2021 ◽  
Author(s):  
Yujunwen Li ◽  
Rui Yang ◽  
Wu Lei ◽  
Qingli Hao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction Pair ◽  
Functionalized Graphene ◽  
Test Results ◽  
Wear Scar Diameter ◽  
Green Method ◽  
X Ray ◽  
Lubricant Property ◽  
Weak Interlayer ◽  
Worn Surface

Abstract The functionalized graphene/montmorillonite (FG/MTT) nanosheets were synthesized through chemically bonding by a simple, green method, which has remarkable dispersion stability in oil and its lubricating performance was evaluated by a four-ball tribometer. The test results show that FG/MTT has a preeminent lubricant property when the concentration is 0.4 mg/ml. Compared with the bare oil sample, its average friction coefficient (FC) and wear scar diameter (WSD) decrease by 50.4 % and 13.2 %, respectively. The synergistic effect between FG and MTT was further explored by comparing the lubricant mechanism of the different additives. After synthetically analyzing worn surface by means of scanning electron microscopy and X-ray photoelectron spectroscopy, the lubrication mechanism of the FG/MTT nanocomposite as oil additive is discussed and postulated: The FG/MTT with weak interlayer adhesion is filled between the friction pairs to avoid contact and clinging of some asperities, and the sliding between the layers plays a role in lubrication. Furthermore, FG/MTT will react with the surface of the friction pair to form a repair layer composed of Fe2O3, SiC, SiO2, and aluminosilicate, mending the grinding surface and promoting the hardness after friction.

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