About the book - Tribology

1 Design for lifetime performance and reliabilityIIIA bout the book The objective of this book is to provide guidelines for engineers helping them to improve machinelifetime performance and reliability. Many books are written About machine design. Most of these arefocussed on selection and computation of basic machine elements. Those calculations generally relate tothe strength and stiffness of machine elements. In practice, it appears that few machine problems arecaused by these issues thanks to the attention paid to calculation of strength and stiffness. Most machine problems occur with the passage of time, from dynamic loading and interacting surfaces inrelative motion. Friction and wear of interacting surfaces in relative motion may take on anunacceptable form, resulting in play, frictional heat or jams.

2 In rolling contacts surface fatigue isgenerally the predominant failure mode. Cyclically loaded machine elements may suddenly result infatigue fracture after a large number of load cycles. It is estimated that approximately 95% of all machineproblems are related to fatigue fracture and Tribology phenomena as friction and wear. The sciencefocussing on the management of friction, wear and fatigue consequently deserves the necessaryattention. The purpose of this book is to give insight, through case studies and a wide range of illustrations, intohow machine performance deteriorates, how machine elements may fail, how to analyse the cause ofperformance deterioration and failure, and, most importantly, how failures may be prevented andperformance can be improved.

3 The possibilities of pushing the boundaries of load carrying capacity, andmotion control are explored. With newly gained insights the engineer is better equipped to reachinnovative solutions to further optimize machine lifetime performance, improve machine reliability andsimultaneously to minimize the need of maintenance. Many design tools, design charts and guide lines are discussed. User friendly PC calculators of theformulae derived in this book are made available, including calculators for calculating dynamic loadcapacity, friction, frictional heating and wear of machine elements in relative motion. Using thesecalculators design engineers will save much time in determining the outcomes of selecting specific designparameters.

4 The formulae used in the calculators are also available in Mathcad files. With these files thedesigner may in a user friendly way adapt or extend calculations for specific applications. In fact thisbook is a goldmine of information for any engineer who intends to improve machine lifetimeperformance and reliability. The first part of this book concerns the fundamentals of Design for lifetime performance andreliability , including design procedures to estimate and improve machine reliability, failure analysis,fatigue strength, static and dynamic load rating of concentrated contacts, friction phenomena, wearmechanisms, machine lubrication and material selection. The second part concerns Design of highperformance and high reliability applications , including the design of hydrodynamically lubricatedbearings and sliders, viscous dampers, dynamic sealing systems, hydrostatic bearings, pressurised airbearings, flexure mechanisms and many other specialty bearings.

5 Although the designer using this bookis expected to have a good background in mathematics, the objective is that the design tools illustratedby cases will be useful for lifetime performance and reliabilityCONTENTS ADVANCED ENGINEERING DESIGN LIFETIME PERFORMANCE AND RELIABILITYC hapter 1: Reliability DESIGN FOR LIFETIME PERFORMANCE AND Introduction .. Trends in mechanical engineering design .. Innovative RELIABILITY Component System SYSTEMS Precision, accuracy and Errors in How to improve the overall system accuracy .. Running accuracy .. High Tech Systems ..36 Chapter 2: Physics of DESIGN FOR Physics of Failures .. Failure analysis techniques and procedure .. Root Cause Failure CLASSIFICATION OF FAILURE How rolling bearings fail.

6 How gears Fail .. ROOT CAUSE ANALYSIS CASE Failed cam with bucket Failed camshaft with roller Failed railway wheel system .. Failed crane rail .. Failed journal bearings of rocker CORRECTIVE ACTIONS TO PREVENT Dynamic load capacity of plain bearings .. Power transfer of an interference fit ..64 Chapter 3: Fatigue failure prediction and INTERPRETATION OF FRACTURE Shear fracture and tensile fracture .. Fatigue fracture .. Corrosion and corrosion PREDICTION OF THE FATIGUE Stress life Estimating the fatigue strength ..80 Design for lifetime performance and FATIGUE RESISTANT Design of dynamically loaded drive Design of dynamically loaded bolted Design of dynamically loaded welded structures (Eurocode 3 EN 1993 1 9).

7 96 Chapter 4: Rolling contact STATIC AND DYNAMIC LOAD Nominal point Elliptic contact .. Nominal line contact .. Contact conformity .. Geometrical stress Rolling with Permissible contact pressure .. ROLLING Micro slip .. Plastic deformation .. Hysteresis Secondary friction losses and running in conditions .. ELASTOHYDRODYNAMIC EHL line contact .. EHL point contact .. LOAD RATING OF MACHINE Static and dynamic load ratings of rolling bearings .. Static and dynamic load rating of linear rail guides .. Static and dynamic load rating of ball screws .. Surface durability of Dynamic load rating of traction drive mechanisms .. 138 Chapter 5: Friction REAL CONTACT Surface Ratio of real contact area and nominal contact area.

8 Real contact area versus friction .. FUNDAMENTALS OF Adhesion .. CLASSICAL FRICTION Effect of the nominal contact Effect of the normal Effect of sliding Effect of temperature .. Effect of surface STICK SLIP, JAMMING, SIDE SLIP AND JOINT Stick Jamming .. Side slip to eliminate friction .. 162 VIDesign for lifetime performance and Joint Slippage .. Hysteresis .. FRICTIONAL HEATING AND THERMAL Nominal contact temperature .. Flash temperature .. MEASURING Manually .. Motorised .. 178 Chapter 6: Wear TWO BODY WEAR Abrasive Adhesive wear .. Corrosive wear .. Surface fatigue .. SINGLE BODY WEAR Gas Liquid impingement erosion.

9 Cavitation erosion .. Particle Electrical / spark erosion .. CONTACT Contact conformity .. Stationary contact .. Degree of Contact temperature .. WEAR Running Calculation of wear rate .. Classification of the specific wear SELECTING OR CONSTRUCTING TEST Pin on disc / Pin on ring .. Pin on flat / ball on Two disk .. STANDARDS FOR MEASURING FRICTION AND Specimen preparation .. Experiment .. Reporting .. 203 Chapter 7: Material MATERIALS FOR SLIDE Selection criteria for metals .. Selection criteria for polymers .. Selection criteria for technical ceramics .. COATINGS AND SURFACE Where surface treatments are applied .. Classification of surface Surface treatment techniques.

10 228 Design for lifetime performance and reliabilityVIIC hapter 8: Lubricant selection and lubrication LUBRICATION Stribeck Transition Physical Additives .. Oil Trends in engine and industrial lubrication .. TYPES OF LUBRICANTS AND LUBRICANT Base oils .. Food grade lubricants .. Lubricants for thermoplastics, thermosets and elastomers .. Greases .. Solid Lubricant selections for specific applications .. LUBRICATION Grease versus oil Oil lubrication Engine lubrication system .. PROACTIVE MAINTENANCE AND OIL Maintenance engineering .. Proactive maintenance .. Causes of lubricant deterioration and their Chemical and physical oil analysis.