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LiLi--Ming Ming ChuChu2009.03.022009.03.02

TribologyTribology

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OUTLINEOUTLINE

•• WhatWhat’’s s TribologyTribology??•• History of History of TribologyTribology

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TribologyTribology is the science and technology ofis the science and technology ofinteracting surfaces in relative motioninteracting surfaces in relative motion

WhatWhat’’s s TribologyTribology??• The term tribologytribology is derived from the

Greek word "tribotribo" meaning rubbingrubbing and "logylogy" meaning knowledgeknowledge.

Body ABody A

Body BBody B

Interacting surfaceInteracting surface

Body ABody A

Body BBody B

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The Scope in The Scope in TribologyTribology•• TribologyTribology has grown to include the

methodical study of frictionfriction, lubricationlubrication, and wearwear.

WearWear

TribologyTribology

FrictionFrictionLubricationLubrication

摩擦摩擦潤滑潤滑 磨耗

磨耗

磨潤學磨潤學

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History of History of TribologyTribology

SledgeSledge

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Calculating COF of ColossusCalculating COF of Colossus

COF=(172*800)/600000=0.23COF=(172*800)/600000=0.23

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60公噸重80公斤重

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Calculating COF of ColossusCalculating COF of ColossusThe "law" of friction : F= F= µµNN

F : the frictional force,N: the normal force,µ : the coefficient of friction (COF)

N=600000N

F(friction force)

172*800N

µµ = F /N= = F /N= (172*800)/600000=(172*800)/600000=0.230.23

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TribologicalTribological Applications of Applications of Manufacturing processesManufacturing processes

Cuttinggrinding

rolling

extrusion

Open die forging Impression die forging Deep drawing

drawing

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TribologicalTribological Applications of Applications of Automobile EngineAutomobile Engine

The development of The development of lubricants in the lubricants in the

automobile industry automobile industry depends on the depends on the

adhesion of nanometer adhesion of nanometer layers (mono layers) to layers (mono layers) to

a material surface.a material surface.

引擎汽缸壁需抗磨耗

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TribologicalTribological Applications ofApplications ofBiologyBiology

Ref: Wear-Material,Mechanisms and Practice

人工關節人工關節 人體關節組織人體關節組織

心臟瓣膜心臟瓣膜

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TribologicalTribological Applications ofApplications ofMEMSMEMS

Motor diameter is 120umMotor diameter is 120um

Variable capacitance sideVariable capacitance side--drive drive micromotormicromotor

–– up to 100000 RPMup to 100000 RPM

Surface Force EffectSurface Force Effect

Ref: Wear-Material,Mechanisms and Practice

微馬達微馬達

表面力效應表面力效應

每分鐘每分鐘1010萬轉萬轉

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Scales of Scales of TribologyTribology

MarcoMarco--TribologyTribology

Micro/Nano-Tribology

Tera-Tribology

巨觀磨潤巨觀磨潤

微奈米磨潤微奈米磨潤

天體宇宙磨潤天體宇宙磨潤

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Scales of Scales of TribologyTribologyfrom from NanotribologyNanotribology to to TeratribologyTeratribology

Ref: Wear-Material,Mechanisms and Practice

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Surface TopographySurface Topography

MacroMacro--roughness (mm)roughness (mm)

MicroMicro--roughness (um)roughness (um)

MolecularMolecular--roughness (roughness (ÅÅ))

(Contact)(Contact)

(Micro(Micro--Contact)Contact)

((NanoNano--Contact)Contact)

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Engineering Contacts - Tribology

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So What Do We Want to Know?• Size of the Area of Contact• Real Area of Contact• Contact Pressure• Thickness of any Lubricant Films

• Contact Stresses• Friction• Wear• Contact Fatigue

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• contact area = Sicily• oil film = height of a person• surface roughness = rolling hills• lubricant molecules = blades of grass

If the world werethe size of a

ball bearing ...

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The Units of a Tribologist

• Pressures in GPa

• Areas in mm2

• Film thickness in μm or nm

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Molecular DynamicsMolecular Dynamics

分子動力學模擬壓痕器作壓痕的動作分子動力學模擬壓痕器作壓痕的動作

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Molecular DynamicsMolecular Dynamics

分子動力學分子動力學3D3D模擬銅的正交切削模擬銅的正交切削

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NanoNano/Micro Wear/Micro Wear

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Surface TopographySurface Topography

MacroMacro--roughness (mm)roughness (mm)

MicroMicro--roughness (um)roughness (um)

MolecularMolecular--roughness (roughness (ÅÅ))

(Contact)(Contact)

(Micro(Micro--Contact)Contact)

((NanoNano--Contact)Contact)

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Surface TopographySurface Topography

AnisotropyAnisotropyisotropyisotropy

Surface Roughness VS. Surface MicroSurface Roughness VS. Surface Micro--geometrygeometry

Surface RoughnessSurface Roughness

Surface MicroSurface Micro--geometrygeometry

isotropyisotropy AnisotropyAnisotropy

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MicroMicro--ContactContact

事實上事實上, , 再平滑光亮的表面經過高倍的放大再平滑光亮的表面經過高倍的放大, , 仍然會是有凹凸起伏仍然會是有凹凸起伏

單粗糙度單粗糙度峰接觸峰接觸

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Basic Basic nanonano/micro/micro--Wear ConceptWear ConceptMacroMacro--ViewView

MicroMicro--ViewView

Static ContactStatic Contact

真實接觸真實接觸面積面積

巨觀接觸巨觀接觸面積面積

靜態接觸靜態接觸

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Basic Basic nanonano/micro/micro--Wear ConceptWear Concept

Asperity contact

Induced friction forceInduced friction force

Real contact areaReal contact areaSurface Asperities are removed or deformed

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Basic Basic nanonano/micro/micro--Wear ConceptWear ConceptMicroMicro--ContactContact

Increasing wear depth, the microIncreasing wear depth, the micro--contacts are differentcontacts are different

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Single Asperity WearSingle Asperity WearRigid indenter (single asperity)Rigid indenter (single asperity)

Sliding directionSliding direction

Softer deforming surfaceSofter deforming surface

ElastoplasticElastoplasticdeformationdeformation

Fully plastic Fully plastic deformationdeformation

Depending on the scratched material, the dimensions of Depending on the scratched material, the dimensions of the asperity and the indentation depththe asperity and the indentation depth

Sliding ContactSliding Contact

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Wear Behavior of SurfaceWear Behavior of SurfaceApplied Normal ForceApplied Normal Force

Sliding ContactSliding Contact施加垂直力施加垂直力

滑動接觸滑動接觸拉伸裂紋拉伸裂紋

磨屑產生磨屑產生

新的組織相新的組織相

熱傳導熱傳導

結構變化結構變化

擠壓變形擠壓變形

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Influencing factors of wearInfluencing factors of wear

刮痕器性質

刮痕器尺寸 刮痕器形狀硬度 降伏強度破裂性質 應力集中

接觸情況

力/衝擊標準 速度衝擊角度 滑動/滾動溫度 濕/乾 酸鹼值

磨耗材料性質

硬度 降伏強度 彈性模數延性 韌性 加工硬化性 破裂韌性 微結構抗腐蝕性

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Wear Deformation modeWear Deformation mode

elastic elastoplastic plastic

Sliding ContactSliding Contact

Normal ForceNormal ForceSliding directionSliding direction

Normal ForceNormal ForceSliding directionSliding direction

Normal ForceNormal ForceSliding directionSliding direction

Rigid indenter vs. different material properties

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Analysis of a wear scarAnalysis of a wear scar

Rigid indenterRigid indenter

Sliding directionSliding direction

ShoulderShoulder

Groove(AGroove(Agroovegroove))

A wear scar A wear scar is formed in is formed in

the softer surfacethe softer surface

The wear scar consists of a groove The wear scar consists of a groove flanked by two shouldersflanked by two shoulders

((AAshouldershoulder))

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The degree of wear parameterThe degree of wear parameter

AAgroovegroove =2*=2*AAshouldershoulder + wear debris+ wear debris

No wear debris = No wear debris = ploughingploughing

have wear debris = cuttinghave wear debris = cutting

The degree of wear parameterThe degree of wear parameter((ξξ) = (A) = (Agroovegroove--AAshouldershoulder)/A)/Agroovegroove

Groove(AGroove(Agroovegroove))

ShoulderShoulder((AAshouldershoulder))

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Wear mode mapWear mode mapSliding contact between a rigid indenter and softer perfectly plSliding contact between a rigid indenter and softer perfectly plastic astic deforming surface:( three different situation can occur)deforming surface:( three different situation can occur)

(1) (1) rubbing(3D), ploughing(2D)rubbing(3D), ploughing(2D) –– The hard indenter slides or The hard indenter slides or rubs over the softer material (no volumetric wear occurs)rubs over the softer material (no volumetric wear occurs)(2) (2) wearing(3D), wedge formation(2D)wearing(3D), wedge formation(2D) –– a wave is formed in a wave is formed in front of the wedge (like a prow)front of the wedge (like a prow)(3) (3) cutting(2D,3D)cutting(2D,3D) –– the hard indenter cuts through the the hard indenter cuts through the material and a chip is formedmaterial and a chip is formed

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Wear mode mapWear mode map

contact interface shear strengthwear material shear strength

ftr=Dp=Indentation depth

contact radius

Dp↓

ftr ↓

Dp↑

ftr ↑

Ref: Wear-Material,Mechanisms and Practice

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Plough犁割現象

Material: Al

Wear Debris

Groove(VGroove(Vgroovegroove))

ShoulderShoulder((VVshouldershoulder))

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(200μm)

Wear parameter : 10mN, 1rpm, 60secmaterial: Al

(400μm) (600μm)

(800μm) (1000μm)

1400014000倍倍

Stick SlipStick Slip

輕負荷時，磨輕負荷時，磨痕出現滯滑痕出現滯滑(Stick slip)(Stick slip)現象現象

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Cam/Follower Contact• Direct acting cam/follower (1.8l

diesel)• Cam nose contact• Scanned at 2.5, 5 and 7.5kN

WaterCouplant

UltrasonicTransducer

UltrasonicSignalFocusedon Interface

Cam Nose

Load fromHydraulic Piston

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Pressure Maps

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Tripode Joint

• Plunging tripode type universal joint

• Three rollers contact on the inside of an outer raceway shell

• Loading rig built• Applied torques: 0-1.5kNm

2006-01-1622

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Contact Maps(a) (b)

(d) (e) (f)

(c)

1kNm

0kNm 0.3kNm 0.5kNm

1.5kNm1.2kNm

3.5mm

Predicted Hertziancontact widths

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Piston Skirt Oil Film - Test Engine• Based at Loughborough University• Perfect Bore development engine• liquid-cooled, single cylinder engine (41 kW at 9,000 rpm)

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Liner and Instrumentation• Wet liner• transducer bonded onto liner outside• Capture the reflected pulse as a segment (with 1000 data points)• Stored on the scope (onboard memory of 250k points per channel)• Store 250 pulses per capture cycle• Measurement rate 100kHz

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Motored Test 850rpm

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

0 0.0001 0.0002 0.0003 0.0004 0.0005

Time (Seconds)

Ref

lect

ion

Coe

ffici

ent

A A'B'CB

• A - piston wall area above the ring zone• B - passage of the piston rings• C - piston skirt passing the transducer

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What is Happening to Engine Valves

• Recent developments in the automotive industry– Emissions and economy - improved engine performance - increase in the wear of

components

• New valve materials and manufacturing techniques developed – Unable to keep pace with the new demands

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• Regardless of design/configuration the valves move quickly

• When closed the valve seals against the valve seat insert

• Materials

– Inlet valves – low alloy steel– Exhaust valves – stainless steel– Valve seat inserts – tool steels, increasing use of special coatings

Automotive Engine Valve Systems

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永久磁鐵的發展

磁浮驅動傳動系統之設計與性能量測 (1)

磁傳系統測試檯設計圖驅動盤設計圖

一、具過負載保護特性，當最大扭矩超過聯軸 器之傳輸扭矩時，只會造成聯軸器磁極間之滑移，對於結構無不良影響；二、可獲完全之密封特性，適合應用於高真空、或高腐蝕性之半導體製程設備及化工設備中；三、無磨耗及摩擦阻力之損失，可使用於高速運轉中，無機件之磨 耗與能源之損失；四、可吸收一定程度的軸向或角向位移誤差；五、較為安靜，因為沒有接觸及碰撞，故無噪音存在。

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磁浮驅動傳動系統之設計與性能量測 (3)

0.0 5.0 10.0 15.0 20.0 25.0

Angle (degree)

0.0

10.0

20.0

30.0

Tq (N

-m)

d=5mm experiment

d=9mm experiment

d=19mm experiment

d=23mm experiment

A : d=5mm simulationB : d=9mm simulationC : d=19mm simulationD : d=23mm simulation

AB

C

D

扭矩與滑差角實驗值與模擬值的比較圖

4.0 8.0 12.0 16.0 20.0 24.0Distance (mm)

4.0

8.0

12.0

16.0

20.0

24.0

Max

. Tor

que

(N-m

)

20.0

22.0

24.0

26.0

28.0

30.0

Max. A

ngle (degree)

max. angle (simulation)

max. angle (experiment)

max. torque (simulation)

max. torque (experiment)

最大扭矩、最大磁力與磁極間隙大小實驗值與模擬值的比較圖

4.0 8.0 12.0 16.0 20.0 24.0Torque (N-m)

85.0

90.0

95.0

100.0

Effic

ienc

y (%

)

d=5mm

d=9mm

d=13mm

d=17mm

d=23mm

在不同磁極間隙條件下外加扭矩與傳輸效率之關係圖

磁性聯軸器扭矩分析磁通密度粒子分佈圖與向量分佈圖

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汽缸溫度及熱變形量測技術之研究 (1)

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聯髖全人工髖關節之零組件

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在球窩關節模型中，以代表人類天然和人工髖關節的軟襯墊預測潤滑膜的厚度

φθωη

φφθθ

θθ

∂∂

=∂∂

∂∂

+∂∂

∂∂ hRphpph 222

33 sin6)()sin(sin

Reynolds equation :

pEd )

121(

2

ννδ−

−=

)sinsincossin1( φθεφθε yxg ch −−=

δ+= ghhElasticity equation:

Force balance equations:

0sincossin21

2

1

22 == ∫∫

θ

θ

φ

φφθθφθ ddpRFx

wddpRFy == ∫∫2

1

2

1

sinsinsin22θ

θ

φ

φφθθφθ

0sincos21

2

1

22 == ∫∫

θ

θ

φ

φφθθθ ddpRFz

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人工關節磨耗試驗機

正常的膝關節

人工關節

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磨耗試驗機

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金合金、鈀銀合金

鎳鉻合金

內層金屬,外燒瓷粉(左：金合金；右：鈀銀合金)

牙齒磨耗試驗機

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皮膚摩擦特性量測試驗機

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Thank you for your Thank you for your attention!attention!