CN101701901B - Method and device for measuring interfacial shearing strength under the connection of disc and flat plate - Google Patents

Abstract

The invention relates to a method and a device for measuring interfacial shearing strength under the connection of a disc and a flat plate. The method comprises the following steps: A, the flat plate slides relative to the static disc at a speed u, with the slide-roll ratio being 2; B, the measured lubricating oil is fed to a line contact area, so as to form the hydrodynamic lubrication in the line contact area, and load is applied between the disc and the flat plate to ensure that the maximum Hertzian contact pressure of the line contact is larger than 0.4GPa; and C, the friction coefficients of the contact surface of the disc or the flat plate under the load are measured twice, and the binary linear equations for the friction coefficients of the contact surface are solved. By using the method and the device, the invention has significant technical effect and has the advantages of larger pressure measurement range of lubricating oil, simple and compact structure, easy implementation, lower manufacturing and servicing cost, easy measurement and higher measurement accuracy; moreover, the device of the invention is capable of measuring the shearing strength parameters of two interfaces at the same time, therefore, the invention is of significant practical value. The device of the invention can substitute for the high-pressure chamber measurement device and other measurement devices.

Description

Under disk and dull and stereotyped Elastic Contact, measure method and the device thereof of interface shear strength

Technical field

The present invention relates to measure the method for interface shear strength, be specifically related to measure under a kind of disk and dull and stereotyped Elastic Contact method and the device thereof of lubricating oil-surface in contact interface shear strength and lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor under atmospheric pressure simultaneously.

Background technology

Shear resistance refers to that material bears the ability of shearing force.A large amount of experiment and engineering practices show, on the interface of mechanical component lubricating oil and part surface in contact when hydrldynamic pressure lubrication, have shear resistance, and this shear resistance is lower than lubricating oil shear resistance.Part lubricating oil-surface in contact interface shear strength when hydrldynamic pressure lubrication plays a role and the lubricated generation material impact to part.Thereby high lubricating oil-surface in contact interface shear strength increases lubrication film thickness to be contributed to lubricate, thereby and low lubricating oil-surface in contact interface shear strength makes lubrication film thickness reduce to be unfavorable for lubricating.Experiment shows, the satisfied relational expression below of lubricating oil-surface in contact interface shear strength under high pressure:

τ _s＝τ _s0+α _sp (1)

Herein, τ _sfor lubricating oil-surface in contact interface shear strength, p is lubricating oil pressure, τ _s0lubricating oil-surface in contact interface shear strength under the atmospheric pressure obtaining for interpolation, α _sfor lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor.From formula (1), can find out τ _s0and α _sfor two characteristic parameters of lubricating oil-surface in contact interface shear strength, known this two characteristic ginseng values, just can calculate the lubricating oil-surface in contact interface shear strength value under setting pressure by formula (1).

Determine before τ _s0and α _smethod be: in high-tension unit, measure the lubricating oil-surface in contact interface shear strength under different oils pressure, lubricating oil is slided along solid surface in contact because pushing in high-voltage connecting contact area, now the shear stress between lubricating oil and solid surface in contact is lubricating oil-solid surface in contact interface shear strength, measures the friction force F on solid surface in contact now _fand calculate the area A of solid surface in contact, F _fbusiness F with A _f/ A is lubricating oil-solid surface in contact interface shear strength τ _s.Measure the τ under each lubricating oil pressure _svalue, to these τ _smeasurement result is carried out linear regression and can be obtained suc as formula the τ shown in (1) _sexpression formula, can obtain τ by this expression formula _s0and α _svalue.

The defect of measuring method before:

1, need to design special high-tension unit (interior pressure can reach 0.5GPa magnitude), need auxiliary hydraulic system that high lubricating oil pressure is provided, the so high fragile device of interior pressure-volume, all proposes very high request to measurement mechanism intensity and structural design.Need in addition to design packoff, prevent that lubricating oil from leaking from high pressure chest.Also have the outer plunger surface of high pressure chest surface and extruding lubricating oil all to need high precision to process and obtain very high surface smoothness.So this measurement mechanism complex structure, cost is high, and lubricating oil pressure is subject to the restriction of auto levelizer intensity and can not reaches very high; On the other hand, use the testing cost of this device also higher.High pressure chest measurement mechanism (referring to list of references 1) just has these defects.

2, in the hertz contact region of the high by-pass contact of two disks, form high pressure, make two disks produce certain relative sliding (general sliding rolling than being 0.1 left and right), make lubricating oil in this higher-pressure region, be squeezed and pass through higher pair contact region, measure the friction force on disk surface in contact and calculate a hertz contact region area, both business are lubricating oil-disk surface in contact interface shear strength.Because approaching a hertz pressure distribution, hertz district pressure distribution presents significant inequality, the interface shear strength recording is hertz lubricating oil-disk surface in contact interface, district average shear intensity, does not have linear relationship in essence and only possess approximate linear relationship between this shear resistance and hertz district mean pressure.On the other hand, on hertz district disk surface in contact, friction stree not all reaches interface shear strength everywhere, and the interface shear strength therefore recording is in fact not accurate hertz of lubricating oil-disk surface in contact interface, district average shear intensity.Average shear intensity-hertz district, interface mean pressure relation curve that measurement result is obtained by linear regression can only be expressed the linear relationship between lubricating oil-disk surface in contact interface shear strength and lubricating oil pressure approx.The τ being obtained by average shear intensity-hertz district, the interface mean pressure linear relation returning out _s0and α _svalue can only be similar to, and is coarse in essence.Therefore this measurement mechanism has the defect that measuring accuracy is not high.Two Disk Machines (referring to list of references 2) just belong to this device.

3, the principle that existing pellet impact testing machine (referring to list of references 3) is measured interface shear strength, with two Disk Machine measuring principles, also has the defect that exists in essence measuring error and measuring accuracy not high.

The list of references the present invention relates to is as follows:

[1]Jacobson，B.O.，High-pressure chamber measurements.Proc.Instn.Mech.Engrs.Part J：J.Eng.Trib.，2006，Vol.220，199-206.

[2]Kleemola，J.and Lehtovaara，A.，An approach for determination oflubricant properties at elliptical elastohydrodynamic contacts using atwin-disc test device and a numerical traction model.Proc.Instn.Mech.Engrs.Part J：J.Eng.Trib.，2008，Vol.222，797-806.

[3]Workel，M.F.，Dowson，D.，Ehret，P.and Taylor，C.M.，Measurements of the coefficients of friction of different lubricants duringimpact under high pressure and shear.Proc.Instn.Mech.Engrs.Part J：J.Eng.Trib.，2003，Vol.217，115-124.

[4] Wen Shizhu, Yang Peiran. elastohydrodynamic lubrication, Beijing: publishing house of Tsing-Hua University, 1990.

[5]Zhang，Y.B.and Wen，S.Z.，An analysis of elastohydrodynamiclubrication with limiting shear stress：Part I-Theory and solutions.TribologyTransactions，2002，Vol.45，135-144.

In view of this, this area inventor seeks to measure under a kind of disk and dull and stereotyped Elastic Contact the method for interface shear strength.

Summary of the invention

The object of this invention is to provide method and the device thereof of under a kind of disk and dull and stereotyped Elastic Contact, measuring interface shear strength, it has solved the existing problem of above-mentioned prior art, can reach the object of simultaneously measuring lubricating oil-surface in contact interface shear strength and lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor under atmospheric pressure.

Technical solution of the present invention is as follows:

A method of measuring interface shear strength under disk and dull and stereotyped Elastic Contact, comprises the following steps:

A, disk are static, dull and stereotypedly with speed u, with respect to disk, slide, and cunning is rolled than being 2, dimensionless rolling speed u η _a/ (2E ' R) should meet 1.0E-11≤u η _a/ (2E ' R)≤1.0E-9, wherein η _abe lubricating oil viscosity under atmospheric pressure, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius;

Tested lubricating oil is supplied in B, past line contact region, make line contact region form hydrldynamic pressure lubrication, imposed load between disk and flat board, makes the maximum hertz contact of line contact be greater than 0.4GPa, and makes dimensionless load w/ (E ' R) < 2.574 (HRD/E ') ², wherein, w is that loaded line density is the load on unit contact length, and E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and HRD is disc surfaces hardness;

C, disk surface in contact or the flat board measured under twice loading respectively contact lip-deep friction co-efficient value, solve two yuan of linear function group (τ about surface in contact friction factor _s0and α _sfor unknown quantity) can obtain τ _s0and α _svalue.

Also comprise that repeated loading measures after described step C, solve some groups of τ _s0and α _sbe worth, try to achieve respectively the τ of these groups _s0and α _smean value, the τ trying to achieve _s0and α _smean value can be got respectively and make τ _s0and α _sfinal measurement.

In described step C, disk surface in contact friction factor and dull and stereotyped surface in contact friction factor are:

$f=\frac{2b{\mathrm{\&tau;}}_s}{w}=\frac{2b({\mathrm{\&tau;}}_{s0}+{\mathrm{\&alpha;}}_s{p}_{\max })}{w}=3.1915\sqrt{\frac{1}{W}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s---\left(6\right)$

Be provided with the loading w meeting the demands for twice ₁and w ₂, its corresponding dimensionless load is respectively W ₁=w ₁/ (E ' R) and W ₂=w ₂/ (E ' R), records and loads lower disc surface in contact friction factor for this twice or dull and stereotyped contact skin-friction coefficient is respectively f ₁and f ₂, can obtain Simultaneous Equations below:

$\left\{\begin{array}{c}3.1915\sqrt{\frac{1}{W_1}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_1\\ 3.1915\sqrt{\frac{1}{W_2}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_2\end{array}\right.---\left(3\right)$

Separate above Simultaneous Equations:

${\mathrm{\&tau;}}_{s0}=\frac{0.3133E^{\&prime;}(f_1-f_2)}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(4\right)$

${\mathrm{\&alpha;}}_s=\frac{f_2\sqrt{\frac{1}{W_1}}-f_1\sqrt{\frac{1}{W_2}}}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(5\right)$

Wherein, τ _s0lubricating oil-surface in contact interface shear strength under the atmospheric pressure obtaining for interpolation, α _sfor lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius.

A device of measuring the method for interface shear strength under disk and dull and stereotyped Elastic Contact, comprises some sensors, also comprises: a disk and a flat board;

Described disk is with dull and stereotyped mutually vertical, and disk is static, forms high by-pass and contact between disk and flat board, and flat board slides with respect to disk with certain speed u, and cunning is rolled than being 2;

The hardness of described disk surface in contact and dull and stereotyped surface in contact is identical with roughness, surface both roughness R _avalue is not more than 0.1 μ m;

Toward line contact region, supply tested lubricating oil, make line contact region form hydrldynamic pressure lubrication.

The material of described disk is identical with plate material.

Described disc radius R should meet 2mm≤R≤50mm.

Described disc shaft should meet to the ratio of thickness h and disc radius R: when 2mm≤R≤5mm, and 1.5≤h/R≤2.0; When 5mm≤R≤15mm, 1.0≤h/R≤1.5; When 15mm≤R≤50mm, 0.5≤h/R≤1.0.

The present invention, owing to having adopted above technical scheme, makes it compared with prior art, has following advantage:

1, method of the present invention can be measured lubricating oil-surface in contact interface shear strength and lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor under atmospheric pressure simultaneously.

2, the apparatus structure of manufacturing by the inventive method is simple, easily manufactures and implements, and manufacturing cost and use cost are all lower.

3, by method of the present invention, can realize under lubricating oil pressure in a big way and measuring.

4, higher by method measuring accuracy of the present invention.

5, by method of the present invention, measure easily.

According to method of the present invention and device, implement to measure, obvious technical effects, there is larger, simple and compact for structure, the easy realization of lubricating oil pressure scope, the manufacturing cost of test and use cost is lower, measure easily and measuring accuracy compared with advantages of higher, and can measure two interface shear strength parameter values simultaneously, there is significant practical value.Device of the present invention can substitute the measurement mechanisms such as high pressure chest measurement mechanism, two Disk Machine and pellet impact testing machine, demonstrates exclusive using value.

Accompanying drawing explanation

Fig. 1 measures the process flow diagram of the method for interface shear strength under a kind of disk of the present invention and dull and stereotyped Elastic Contact.

Fig. 2 is by measuring the device schematic diagram of interface shear strength under a kind of disk of the inventive method enforcement and dull and stereotyped Elastic Contact.

Fig. 3 is hydrodynamic lubrication oil film pressure distribution schematic diagram in the contact of disk peace printed line in embodiments of the invention.

Embodiment

Below in conjunction with drawings and Examples, the present invention is elaborated.

Referring to Fig. 1, according to measuring the method for interface shear strength under a kind of disk of the present invention and dull and stereotyped Elastic Contact, comprise the following steps:

A, disk are static, dull and stereotypedly with certain speed u, with respect to disk, slide, and cunning is rolled than being 2, dimensionless rolling speed u η _a/ (2E ' R) should meet 1.0E-11≤u η _a/ (2E ' R)≤1.0E-9, wherein η _abe lubricating oil viscosity under atmospheric pressure, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius.

Tested lubricating oil is supplied in B, past line contact region, make line contact region form hydrldynamic pressure lubrication, imposed load between disk and flat board, makes the maximum hertz contact of line contact be greater than 0.4GPa, and makes dimensionless load w/ (E ' R) < 2.574 (HRD/E ') ², wherein, w is that loaded line density is the load on unit contact length, and E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and HRD is disc surfaces hardness.

C, disk surface in contact or the flat board measured under twice loading respectively contact lip-deep friction co-efficient value, solve two yuan of linear function group (τ about surface in contact friction factor _s0and α _sfor unknown quantity) can obtain τ _s0and α _svalue.

Described disk surface in contact friction factor and dull and stereotyped surface in contact friction factor are:

$f=\frac{2b{\mathrm{\&tau;}}_s}{w}=\frac{2b({\mathrm{\&tau;}}_{s0}+{\mathrm{\&alpha;}}_s{p}_{\max })}{w}=3.1915\sqrt{\frac{1}{W}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s---\left(6\right)$

Be provided with the loading w meeting the demands for twice ₁and w ₂, its corresponding dimensionless load is respectively W ₁=w ₁/ (E ' R) and W ₂=w ₂/ (E ' R), records under this twice loading disk surface in contact friction factor of the present invention or dull and stereotyped contact skin-friction coefficient is respectively f ₁and f ₂, can obtain Simultaneous Equations below:

$\left\{\begin{array}{c}3.1915\sqrt{\frac{1}{W_1}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_1\\ 3.1915\sqrt{\frac{1}{W_2}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_2\end{array}\right.---\left(3\right)$

Separate above Simultaneous Equations:

${\mathrm{\&tau;}}_{s0}=\frac{0.3133E^{\&prime;}(f_1-f_2)}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(4\right)$

${\mathrm{\&alpha;}}_s=\frac{f_2\sqrt{\frac{1}{W_1}}-f_1\sqrt{\frac{1}{W_2}}}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(5\right)$

Wherein, τ _s0lubricating oil-surface in contact interface shear strength under the atmospheric pressure obtaining for interpolation, α _sfor lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius.

D, repeated loading are measured, and solve some groups of τ _s0and α _sbe worth, try to achieve respectively the τ of these groups _s0and α _smean value, the τ trying to achieve _s0and α _smean value can be got respectively and make τ _s0and α _sfinal measurement.

In actual use, the present invention is steel disc-steel plateform sliding contact measurement mechanism, is used for measuring lubricating oil-steel surface in contact interface shear strength τ under atmospheric pressure _s0and lubricating oil-steel surface in contact interface shear strength-lubricating oil pressure scale-up factor α _s, can measure this two parameter values simultaneously.Disc material is identical with plate material, forms high by-pass and contact between disk and flat board, and disk surface in contact and dull and stereotyped surface in contact all, through fine grinding, reach identical surfaceness, surface both roughness R _avalue is all not more than 0.1 μ m.Disk is static, dull and stereotyped with certain speed u with respect to disk (the dimensionless rolling speed u η that slides _a/ (2E ' R) should meet 1.0E-11≤u η _a/ (2E ' R)≤1.0E-9, herein η _abe lubricating oil viscosity under atmospheric pressure, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius

sliding rolling than being 2, dull and stereotyped contact skin hardness is identical with disk surface in contact hardness.Toward line contact region, supply tested lubricating oil, make line contact region form hydrldynamic pressure lubrication, imposed load between disk and flat board, makes the maximum hertz contact of line contact be greater than 0.4GPa, and makes dimensionless load w/ (E ' R) < 2.574 (HRD/E ') ²thereby, guarantee that disk and dull and stereotyped Contact are Elastic Contact; Herein, w is that loaded line density is the load on unit contact length, and HRD is disc surfaces hardness.

Measure respectively disk surface in contact or the lip-deep friction co-efficient value of dull and stereotyped contact under twice loading, solve two yuan of linear function group (τ about surface in contact friction factor _s0and α _sfor unknown quantity) can obtain τ _s0and α _svalue.For improving measuring accuracy, can measure by repeated loading, solve some groups of τ _s0and α _sbe worth, try to achieve respectively the τ of these groups _s0and α _smean value, the τ trying to achieve _s0and α _smean value can be got respectively and make τ _s0and α _sfinal measurement.

Wherein, 1.0E-11≤u η _a/ (2E ' R)≤1.0E-9, w/ (E ' R) < 2.574 (HRD/E ') ², dull and stereotyped contact skin hardness equals disk surface in contact hardness, and disk surface in contact is identical with dull and stereotyped surface in contact roughness, both roughness R _avalue is not more than 0.1 μ m, and a maximum hertz contact is greater than 0.4GPa.

According to derivation, in Fig. 2, disk surface in contact friction factor of the present invention and dull and stereotyped surface in contact friction factor are:

$f=3.1915\sqrt{\frac{1}{W}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s---\left(2\right)$

Be provided with the loading w meeting the demands for twice ₁and w ₂, its corresponding dimensionless load is respectively W ₁=w ₁/ (E ' R) and W ₂=w ₂/ (E ' R), records under this twice loading disk surface in contact friction factor of the present invention or dull and stereotyped contact skin-friction coefficient is respectively f ₁and f ₂, can obtain Simultaneous Equations below:

$\left\{\begin{array}{c}3.1915\sqrt{\frac{1}{W_1}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_1\\ 3.1915\sqrt{\frac{1}{W_2}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_2\end{array}\right.---\left(3\right)$

Separate above Simultaneous Equations:

${\mathrm{\&tau;}}_{s0}=\frac{0.3133E^{\&prime;}(f_1-f_2)}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(4\right)$

${\mathrm{\&alpha;}}_s=\frac{f_2\sqrt{\frac{1}{W_1}}-f_1\sqrt{\frac{1}{W_2}}}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(5\right)$

The loading repeatedly meeting the demands, measures disk surface in contact friction factor or dull and stereotyped contact skin-friction coefficient under these loadings, obtains some groups suc as formula the Simultaneous Equations shown in (3), separates these Simultaneous Equations and can obtain some groups of τ _s0and α _svalue, obtains respectively these groups τ _s0and α _smean value, the τ obtaining _s0and α _smean value can be respectively as τ _s0and α _sfinal measurement.

Referring to Fig. 2, under a kind of disk of implementing by the inventive method and dull and stereotyped Elastic Contact, measure the device of interface shear strength, comprise some sensors, a disk and a flat board.

Disk is with dull and stereotyped mutually vertical, and disk is static, forms high by-pass and contact between disk and flat board, and flat board slides with respect to disk with certain speed u, and cunning is rolled than being 2.

The hardness of disk surface in contact and dull and stereotyped surface in contact is identical with roughness, surface both roughness R _avalue is not more than 0.1 μ m.

Toward line contact region, supply tested lubricating oil, make line contact region form hydrldynamic pressure lubrication.

The material of described disk is identical with plate material, and disc radius R should meet 2mm≤R≤50mm, and the ratio of disk (axially) thickness h and disc radius R should meet: when 2mm≤R≤5mm, and 1.5≤h/R≤2.0; When 5mm≤R≤15mm, 1.0≤h/R≤1.5; When 15mm≤R≤50mm, 0.5≤h/R≤1.0.

Embodiment:

Disk and flat board are made by No. 45 steel, and surface in contact is all through Quenching Treatment, and skin hardness all reaches HRC50-53, HRD ≈ 2.0GPa.Disk and dull and stereotyped surface in contact are all through fine grinding, surfaceness R _avalue is 0.1 μ m.The comprehensive Young's modulus of elasticity of disk and dull and stereotyped surface in contact is E '=209GPa.The lubricating oil using is paraffin oil LVI260 (the international trade mark), and disc radius is 20mm, disk (axially) thickness h=15mm, dull and stereotyped along disc shaft to width be 25mm, the contact line length along disc shaft to dull and stereotyped and disk is 15mm.The dull and stereotyped sliding speed with respect to disk is u=4.0m/s, and dimensionless rolling speed is u η _a/ (2E ' R)=1.91E-11.

1, the load applying between disk and flat board is w ₁=3.0E+05N/m is that the dimensionless load applying between disk and flat board is w ₁during/(E ' R)=7.16E-05, the friction factor recording on disk surface in contact is f ₁=0.043.The load applying between disk and flat board is w ₂=6.0E+05N/m is that the dimensionless load applying between disk and flat board is w ₂during/(E ' R)=1.432E-04, the friction factor recording on disk surface in contact is f ₂=0.039., by these two measurement results, by formula (4) and (5), obtain τ _s0=7.57MPa, α _s=0.029.

2, the load applying between disk and flat board is w ₃=1.5E+05N/m is that the dimensionless load applying between disk and flat board is w ₃during/(E ' R)=3.58E-05, the friction factor recording on disk surface in contact is f ₃=0.049.The load applying between disk and flat board is w ₄=4.5E+05N/m is that the dimensionless load applying between disk and flat board is w ₄during/(E ' R)=1.074E-04, the friction factor recording on disk surface in contact is f ₄=0.041., by these two measurement results, by formula (4) and (5), obtain τ _s0=7.42MPa, α _s=0.030.

3, the load applying between disk and flat board is w ₅=1.0E+05N/m is that the dimensionless load applying between disk and flat board is w ₅during/(E ' R)=2.39E-05, the friction factor recording on disk surface in contact is f ₅=0.052.The load applying between disk and flat board is w ₆=9.0E+05N/m is that the dimensionless load applying between disk and flat board is w ₆during/(E ' R)=2.148E-04, the friction factor recording on disk surface in contact is f ₆=0.037., by these two measurement results, by formula (4) and (5), obtain τ _s0=7.21MPa, α _s=0.029.

Above-mentioned three groups of τ _s0, α _sthe mean value of measurement result is respectively 7.4MPa and 0.029, final desirable τ _s0, α _smeasured value is respectively 7.4MPa and 0.029.

According to interface sliding elastica contacting with fluid hydrodynamic lubrication result of study before, in Fig. 2, disk is static, dull and stereotyped while sliding (sliding roll than be 2) with respect to disk, within the scope of certain dull and stereotyped sliding speed and certain imposed load (as provided above), the dull and stereotyped line forming with disk contacts under lubricating oil hydrodynamic lubrication, in disk surface in contact place and dull and stereotyped surface in contact place, all there is slippage in the hertz district lubricating oil of online contact, hertz district's disk surface in contact place's shear stress and the dull and stereotyped surface in contact place shear stress of online contact are equal to lubricating oil-disk surface in contact (or dull and stereotyped surface in contact) interface shear strength.Due to hertz district Wei Gao oil pressure district, lubricating oil-surface in contact interface shear strength in hertz district meets formula (1).A large amount of experiment and theoretical researches show, in the line contact shown in Fig. 2, because hertz district oil pressure is high, oil viscosity shearing rate large, oil film is large, the shear stress of hertz district's surface in contact is much larger than the shear stress on the surface in contact of other region (being inlet region and outlet area).Therefore disk surface in contact friction force and friction factor and dull and stereotypedly contact skin-friction force and friction factor depends on hertz district's lubricating oil-surface in contact interface shear strength in Fig. 2.

Result of study shows before, and in the contact of Fig. 2 line, lubricating oil film pressure is normal value p in hertz district _maxand 2p _maxb=w, b is a hertz contact half-breadth herein; In the contact of Fig. 2 line, as shown in Figure 3, Fig. 3 has shown hydrodynamic lubrication oil film pressure distribution situation in the contact of disk peace printed line to lubricating film pressure.

Therefore disk surface in contact or dull and stereotyped contact skin-friction coefficient are in Fig. 2 the present invention:

$f=\frac{2b{\mathrm{\&tau;}}_s}{w}=\frac{2b({\mathrm{\&tau;}}_{s0}+{\mathrm{\&alpha;}}_s{p}_{\max })}{w}=3.1915\sqrt{\frac{1}{W}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s---\left(6\right)$

Herein, τ _sfor hertz district lubricating oil-surface in contact interface shear strength, W=w/ (E ' R).

Be provided with the loading w meeting the demands for twice ₁and w ₂, its corresponding dimensionless load is respectively W ₁=w ₁/ (E ' R) and W ₂=w ₂/ (E ' R), records under this twice loading disk surface in contact friction factor of the present invention or dull and stereotyped contact skin-friction coefficient is respectively f ₁and f ₂, can obtain Simultaneous Equations below:

$\left\{\begin{array}{c}3.1915\sqrt{\frac{1}{W_1}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_1\\ 3.1915\sqrt{\frac{1}{W_2}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_2\end{array}\right.---\left(3\right)$

Separate above Simultaneous Equations:

${\mathrm{\&tau;}}_{s0}=\frac{0.3133E^{\&prime;}(f_1-f_2)}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(4\right)$

${\mathrm{\&alpha;}}_s=\frac{f_2\sqrt{\frac{1}{W_1}}-f_1\sqrt{\frac{1}{W_2}}}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(5\right)$

The loading repeatedly meeting the demands, measures disk surface in contact friction factor or dull and stereotyped contact skin-friction coefficient under these loadings, obtains some groups suc as formula the Simultaneous Equations shown in (3), separates these Simultaneous Equations and can obtain some groups of τ _s0and α _svalue, obtains respectively these groups τ _s0and α _smean value, the τ obtaining _s0and α _smean value can be respectively as τ _s0and α _sfinal measurement.

In summary, adopt method of the present invention and device, obvious technical effects, there is larger, simple and compact for structure, the easy realization of lubricating oil pressure scope, the manufacturing cost of test and use cost is lower, measure easily and measuring accuracy compared with advantages of higher, and can measure two interface shear strength parameter values simultaneously, there is significant practical value.Device of the present invention can substitute the measurement mechanisms such as high pressure chest measurement mechanism, two Disk Machine and pellet impact testing machine, demonstrates exclusive using value.

Certainly, those skilled in the art in the art will be appreciated that, above-described embodiment is only for the present invention is described, and not as limitation of the invention, as long as within the scope of connotation of the present invention, the conversion of above-described embodiment, modification all will be dropped in the scope of the claims in the present invention.

Claims (6)

1. under disk and dull and stereotyped Elastic Contact, measure a method for interface shear strength, it is characterized in that, comprise the following steps:

A, disk are static, dull and stereotypedly with speed u, with respect to disk, slide, and cunning is rolled than being 2, dimensionless rolling speed u η _a/ (2E ' R) should expire 1.0E-11≤u η/(2E ' R)≤1.0E-9, wherein η _abe lubricating oil viscosity under atmospheric pressure, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius;

Tested lubricating oil is supplied in B, past line contact region, make line contact region form hydrldynamic pressure lubrication, imposed load between disk and flat board, makes the maximum hertz contact of line contact be greater than 0.4GPa, and makes dimensionless load ω/(E ' R) < 2.574 (HRD/E ') ², wherein, w is that loaded line density is the load on unit contact length, and E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and HRD is disc surfaces hardness;

C, disk surface in contact or the flat board measured under twice loading respectively contact lip-deep friction co-efficient value;

In D, described step C, disk surface in contact friction factor and dull and stereotyped surface in contact friction factor are:

$f=\frac{2b{\mathrm{\&tau;}}_s}{w}=\frac{2b({\mathrm{\&tau;}}_{s0}+{\mathrm{\&alpha;}}_s{p}_{\max })}{w}=3.1915\sqrt{\frac{1}{W}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s---\left(6\right)$

Be provided with the loading w meeting the demands for twice ₁and w ₂, its corresponding dimensionless load is respectively W ₁=w ₁/ (E ' R) and W ₂=w ₂/ (E ' R), records and loads lower disc surface in contact friction factor for this twice or dull and stereotyped contact skin-friction coefficient is respectively f ₁and f ₂, can obtain Simultaneous Equations below:

$\left\{\begin{array}{c}3.1915\sqrt{\frac{1}{W_1}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_1\\ 3.1915\sqrt{\frac{1}{W_2}}\frac{{\mathrm{\&tau;}}_{s0}}{E^{\&prime;}}+{\mathrm{\&alpha;}}_s=f_2\end{array}\right.---\left(3\right)$

Separate above simultaneous equations:

${\mathrm{\&tau;}}_{s0}=\frac{0.3133E^{\&prime;}(f_1-f_2)}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(4\right)$

${\mathrm{\&alpha;}}_s=\frac{f_2\sqrt{\frac{1}{W_1}}-f_1\sqrt{\frac{1}{W_2}}}{\sqrt{\frac{1}{W_1}}-\sqrt{\frac{1}{W_2}}}---\left(5\right)$

Wherein, wherein, τ _sfor lubricating oil-surface in contact interface shear strength, p _maxmaximum pressure value for lubricating oil; τ _s0lubricating oil-surface in contact interface shear strength under the atmospheric pressure obtaining for interpolation, α _sfor lubricating oil-surface in contact interface shear strength-lubricating oil pressure scale-up factor, E ' is disk and dull and stereotyped comprehensive Young's modulus of elasticity, and R is disc radius, and b is a hertz contact half-breadth.

2. under disk according to claim 1 and dull and stereotyped Elastic Contact, measure the method for interface shear strength, it is characterized in that:

Also comprise that repeated loading measures after described step C, solve some groups of τ _s0and α _sbe worth, try to achieve respectively the τ of these groups _s0and α _smean value, the τ trying to achieve _s0and α _smean value is got respectively and is made τ _s0and α _sfinal measurement.

3. implement the claims a device of measuring the method for interface shear strength under disk described in 1 and dull and stereotyped Elastic Contact, comprise some sensors, it is characterized in that, also comprise: a disk and a flat board;

Described disk is with dull and stereotyped mutually vertical, and disk is static, forms high by-pass and contact between disk and flat board, and flat board slides with respect to disk with certain speed u, and cunning is rolled than being 2;

The hardness of described disk surface in contact and dull and stereotyped surface in contact is identical with roughness, surface both roughness R _avalue is not more than 0.1 μ m;

Toward line contact region, supply tested lubricating oil, make line contact region form hydrldynamic pressure lubrication.

4. device according to claim 3, is characterized in that, the material of described disk is identical with plate material.

5. device according to claim 3, is characterized in that, described disc radius R should meet 2mm≤R≤50mm.

6. device according to claim 3, is characterized in that, described disc shaft should meet to the ratio of thickness h and disc radius R: when 2mm≤R≤5mm, and 1.5≤h/R≤2.0; When 5mm≤R≤15mm, 1.0≤h/R≤1.5; When 15mm≤R≤50mm, 0.5≤h/R≤1.0.

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