DOCSLIB.ORG

Fatigue Effects in the Wear of Polymers Vinod Kumar Jain Iowa State University

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fatigue Effects in the Wear of Polymers Vinod Kumar Jain Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1980 Fatigue effects in the wear of polymers Vinod Kumar Jain Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Mechanical Engineering Commons Recommended Citation Jain, Vinod Kumar, "Fatigue effects in the wear of polymers " (1980). Retrospective Theses and Dissertations. 7380. https://lib.dr.iastate.edu/rtd/7380 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This was produced from a copy of a document sent to us for microfilming. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help you understand markings or notations which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure you of complete continuity. 2. When an image on the film is obliterated with a round black mark it is an indication that the film inspector noticed either blurred copy because of movement during exposure, or duplicate copy. Unless we meant to delete copyrighted materials that should not have been filmed, you will find a good image of the page in the adjacent frame. 3. When a map, drawing or chart, etc., is part of the material being photo­ graphed the photographer has followed a definite method in "sectioning" the material. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete. 4. For any illustrations that cannot be reproduced satisfactorily by xerography, photographic prints can be purchased at additional cost and tipped into your xerographic copy. Requests can be made to our Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases we have filmed the best available copy. University Microfilms International 300 N. ZEEB ROAD, ANN ARBOR, Ml 48106 18 BEDFORD ROW, LONDON WCIR 4EJ, ENGLAND 8019638 JAIN, VINOD KUMAR FATIGUE EFFECTS IN THE WEAR OF POLYMERS Iowa State University PH.D. 1980 University Microfilms I nt©rn 3ti on&l 300 N. Zeeb Road, Ann Arbor, MI 48106 18 Bedford Row, London WCIR 4EJ, England PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark . 1. Glossy photographs 2. Colored illustrations 3. Photographs with dark background "4. Illustrations are poor copy 5. °rint shows through as there is text on both sides of page 6. Indistinct, broken or small print on several pages throughout 7. Tightly bound copy with print lost in spine 8. Computer printout pages with indistinct print ^ 9. Page(s) lacking when material received, and not available from school or author 10. Page(s) seem to be missing in numbering only as text follows 11. Poor carbon copy 12. Not original copy, several pages with blurred type 13. Appendix pages are poor copy 14. Original copy with light type 15. Curling and wrinkled pages 16. Other Universi^ Micrdriims Internarloncil 300 N -=== =0. ANN ASaOn Mi JS106 '313) 751-1700 Fatigue effects in the wear of polymers by Vinod Kumar Jain A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Major: Mechanical Engineering Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. For the Major Department Signature was redacted for privacy. Iowa State University Ames, Iowa 1980 ii TABLE OF CONTENTS Page ABSTRACT xv NOMENCLATURE xvii 1. INTRODUCTION 1 1.1. Literature Review 1 1.1.1. Wear of polymers 1 1.1.1.1. Adhesive wear 2 1.1.1.2. Abrasive wear 4 1.1.1.3. Fatigue wear 5 1.1.1.4. Other mechanisms of wear 7 1.1.2. Surface topography and wear 8 1.1.2.1. Topographical analysis 9 1.1.2.2. Surface parameters 10 1.1.2.3. Effect of surface topography on wear 12 1.1.3. Fatigue of polymers and its effect on wear 14 2. EXPERIMENTAL PROCEDURE 18 2.1. Test Equipment IB 2.1.1. Wear test set-up 18 2.1.2. System for surface analysis 20 2.2. Material Selection 20 2.3. Test Procedures 22 2.3.1. Specimen preparation for sliding experiments 22 2.3.2. Wear test 23 2.3.3. Surface topography evaluation 23 iii I Page 2.3.4. Fatigue tests 24 2.4. Surface Examination 25 3. ANALYTICAL METHODS 28 3.1. Development of the Fatigue Wear Equation 28 3.2. Contact Parameters 31 3.3. Stresses in a Contact Zone 35 3.4. Criterion for Asperity Fracture 37 3.5. Wear Equation 38 3.6. Computation of Surface Parameters 40 4. RESULTS AND DISCUSSIONS 47 4.1. Mechanism of Fracture in Wear 47 4.1.1. Markings on fracture surfaces 47 4.1.2. Fracture markings on a plane surface loaded by a sliding hemispherical indentor 52 4.1.3. Microscopic examination of fatigue fracture surfaces 54 4.1:4= Microscopic examination of wear surfaces 63 4.2. Polymer Wear 75 4.3. Microscopic Examination of Metal Disk Surfaces 81 4.4. Surface Topography 89 4.4.1. Arithmetic average of surface roughness, 89 4.4.2. Radius of curvature of asperity tips, 6 95 4.4.3. Average slope of asperities 108b 4.4.4. Distribution of surface parameters 113 4.4.5. Asperity density 119 4.5. Polymer Fatigue 125 iv Page 4.5. Computation of Wear from Fatigue Wear Equation 128 4.6.1. Evaluation of integral F^(h) 128 4.6.2. Asperity density and standard deviation for Gaussian distribution of asperity heights 130 4.6.3. Volume of a wear particle 130 4.6.4. Computation of wear rates 132 5. CONCLUSIONS AND SUGGESTIONS 137 5.1. Conclusions 137 5.2. Suggestions for Future Work 139 6. ACKNOWLEDGMENTS 140 7. REFERENCES 141 a. APPENDIX A: ASSEMBLY LANGUAGE PROGRAM FOR THE KIM MICROCOMPUTER 148 9. APPENDIX B: COMPUTER PROGRAM FOR THE COMPUTATION OF SURFACE TOPOGRAPHICAL PARAMETERS 153 10. APPENDIX C: COMPUTER PROGRAM FOR THE REDUCTION OF A POPULATION OF RANDOM VARIABLES TO A GAUSSIAN DISTRIBUTION 157 oo 2 11. APPENDIX D: TABLE OF INTEGRAL F (h) = (s-h)" ^ds 160 12. APPENDIX E: ERROR ANALYSIS 162 V LIST OF FIGURES Page Fig- 2.1. Schematic diagram of a pin-on-disk wear machine. 19 Fig. 2.2. Line diagram of data acquisition system for surface analysis. 21 Fig. 2.3. Geometry of a notched fatigue specimen. 26 Fig. 3.1. Schematic representation of sliding contact between two rough surfaces. 29 Fig. 3.2. Contact between a moving hemispherical indentor and a plane surface: (i) Schematic view of circular contact. (ii) Variation of stress S (in sliding direction) around the center of contact for varying values of coefficient of friction, f. Here (3P ^/2TTa ^ ^) is the maximum pressure at the center of contact under a static load (65). 30 Fig. 3.3. Contact between a smooth and a rough surface. The load is supported by the asperities (shaded) whose heights are greater than the separation between the reference planes (33). 33 Fig. 3.4. Two-dimensional representation of a surface profile. 42 Fig. 3.5. Effect of Weibull shape parameter b on the variation of probability density function (75). 45 Fig. 4.1. Chevron (also called "herringbone") markings on the fracture surface of a cellulose acetate plate: (a) regular (b) reversed. The crack propagated from left to right (77). 48 Fig. 4.2. Optical micrograph of the fracture surface of an AISI 1050 steel shaft showing beach and ratchet marks (78), 49 Fig, 4.3. Optical micrograph of 7076-T6 aluminum alloy showing fatigue striations (78). 49 Fig. 4.4. Scanning electron micrograph showing dimples on the fracture surface of AISI 1020 steel failed in uniaxial tension (78). 51 VI Page Fig. 4.5. Parabolic markings on the fracture surface of an acrylic (Trade name "Lucite") plate. The fracture progressed from left to right (77). 51 Fig. 4.5. Development of surface cracks on a plane surface due to the sliding of a hemispherical indentor on it. 53 Fig. 4.7. Optical micrograph showing cracks on a glass surface due to the sliding of a hemispherical indentor on it. Sliding direction is shown by the arrow (80). 55 Fig. 4.8. Scanning electron micrograph showing the region of crack initiation and growth on a fatigue fracture surface of poly(methyl methacrylate). Crack propagation is from left to right. Tilt angle 30°. 55 Fig. 4.9. Scanning electron micrograph of the same surface as in Fig. 4.8, showing the fatigue striation. Tilt angle 30°. 56 Fig. 4.10. Scanning electron micrograph of the same surface as in Fig. 4.8, but from a different location well ahead in the direction of crack propagation.
Load more

Recommended publications
  • Tech Spotlight
    impact.qxd 3/12/04 11:25 AM Page 1 TECH SPOTLIGHT Impact Testing notched side by the moving striker by the metrology of the parts that are Wayne Hayward pendulum, and the energy needed to subject to the most wear and tear, and Tinius Olsen Testing Machine Co. break off the free end is the measure some machines were manufactured Horsham, Pennsylvania of the impact strength. This article before strict adherence to the specifi- discusses the equipment, calibration, cations in ASTM E23 was deemed to and procedures for Charpy testing. be critical. Accurate results are not pos- he purpose of impact testing is to sible if the equipment is not operating Tdetermine the toughness of a ma- Impact testing equipment according to the specification; there- terial by measuring the amount of en- Instruments for impact testing of fore, it is strongly recommended that ergy absorbed by a specimen as it frac- metals have been manufactured com- the impact tester be calibrated and/or tures while being struck by a striker mercially since the 1900’s, and several verified by an accredited calibration pendulum moving at high speed. The manufacturers of testing equipment service at regular intervals. impact strength is defined as the max- meet the requirements of ASTM E23, imum amount of energy that can be “Standard Test Methods for Notched Instrument calibration absorbed by the specimen without Bar Impact Testing of Metallic Mate- A calibration swing is performed to fracture. rials.” The standard provides dimen- ensure that energy losses due to In the Charpy impact test, a notch sion and tolerance requirements for windage and friction in the bearings is placed in the specimen.
    [Show full text]
  • Galling and Galling Resistance of Stainless Steels
    Stainless Steel Advisory Service Tel: 0114 267 1265 Fax 0114 266 1252 A service provided by the SSAS Information Sheet No.5.60 th British Stainless Steel Association Issue 02 12 March 2001 Page 1 of 1 Galling and Galling Resistance of Stainless Steels Introduction Galling, or cold welding as it is sometimes referred to as, is a form of severe adhesive wear. Adhesive wear occurs between two metal surfaces that are in relative motion to each other and under sufficient load to permit the transfers of material between themselves. This is a solid-phase welding process. The load must be sufficient, during relative motion, to disrupt the protective oxide layer covering surface asperities of the metal and permit metal to metal contact. Under high stress and poor lubrication conditions, stronger bonds may form over a larger surface area. Large fragments or surface protrusions may be formed and the result is galling of the surfaces. Severe galling can result in the seizure of metal components. Materials which are highly ductile or which possess low work-hardening rates tend to be prone to galling. Austenitic stainless steels show a tendency to gall under certain conditions. Factors Affecting Wear and Galling The factors affecting wear and galling are related to design, lubrication, environment, and steel properties. The material properties relevant to the issue of galling of stainless steels include: - • design tolerances and surface finish of the steel • surface properties (hardness) and structure of the steel • applied load • contact area and degree of movement. Design tolerances should provide sufficient clearance. The contact load on sliding components should be kept to a minimum, while the contact area should be maximised.
    [Show full text]
  • Vertical Turbine Pumps Models VIT, VIC & VIS
    An ITT Brand Vertical Turbine Pumps Models VIT, VIC & VIS Flexibility by Design: This bulletin is designed to assist the user in selecting Three Pump Models, One Common Bowl Assembly the best pump for the conditions required; however, any The three different pump models in the vertical turbine line questions will be answered promptly by calling the Goulds have one thing in common – the hydraulic design of the sales office or representative in your area. pump bowl assembly. Using state-of-the-art techniques in turbine pump design, Goulds vertical turbine line covers a wide range of hydraulic conditions to meet virtually every pumping service in the industry with optimum efficiency. Goulds flexibility of design allows the use of a wide range of materials and design features to meet the custom requirements of the user. No matter what the requirements, Goulds can design and manufacture the pump to best satisfy them, specifically and thoroughly. Driver Discharge Driver Adapter Fabricated Fabricated Discharge Discharge Head Head Bowl Assembly Flanged Flanged Column Column Suction Can Adapter Bowl BoBowlwl Assembly Submersible Assembly Assembly Motor 2 Vertical Turbine Pumps Vertical Turbine Pumps Goulds Vertical Turbine Pumps Pump Bowl Assembly The bowl assembly is the heart of the vertical turbine pump. The impeller and diffuser type casing are designed to deliver the head and capacity that your system requires in the most efficient way possible. The fact that the vertical turbine pump can be multi-staged allows maximum flexibility both in the initial pump selection and in the event that future system modifications require a change in the pump rating.
    [Show full text]
  • Analysis of Fatigue and Wear Behaviour in Ultrafine Grained Connecting Rods
    metals Article Analysis of Fatigue and Wear Behaviour in Ultrafine Grained Connecting Rods Rodrigo Luri, Carmelo J. Luis, Javier León, Juan P. Fuertes, Daniel Salcedo and Ignacio Puertas * Mechanical, Energetics and Materials Engineering Department, Public University of Navarre, Campus Arrosadía s/n, Pamplona 31006, Spain; [email protected] (R.L.); [email protected] (C.J.L.); [email protected] (J.L.); [email protected] (J.P.F.); [email protected] (D.S.) * Correspondence: [email protected]; Tel.: +34-948-169-305 Received: 3 July 2017; Accepted: 20 July 2017; Published: 29 July 2017 Abstract: Over the last few years there has been an increasing interest in the study and development of processes that make it possible to obtain ultra-fine grained materials. Although there exists a large number of published works related to the improvement of the mechanical properties in these materials, there are only a few studies that analyse their in-service behaviour (fatigue and wear). In order to bridge the gap, in this present work, the fatigue and wear results obtained for connecting rods manufactured by using two different aluminium alloys (AA5754 and AA5083) previously deformed by severe plastic deformation (SPD), using Equal Channel Angular Pressing (ECAP), in order to obtain the ultrafine grain size in the processed materials are shown. For both aluminium alloys, two initial states were studied: annealed and ECAPed. The connecting rods were manufactured from the previously processed materials by using isothermal forging. Fatigue and wear experiments were carried out in order to characterize the in-service behaviour of the components.
    [Show full text]
  • Low Alloy Steel Susceptibility to Stress Corrosion Cracking in Hydraulic
    LOW ALLOY STEEL SUSCEPTIBILITY TO STRESS CORROSION CRACKING IN HYDRAULIC FRACTURING ENVIRONMENT Thesis Submitted to The School of Engineering of the UNIVERSITY OF DAYTON In Partial Fulfillment of the Requirements for The Degree of Master of Science in Chemical Engineering By Ezechukwu J. Anyanwu Dayton, OH May, 2014 LOW ALLOY STEEL SUSCEPTIBILITY TO STRESS CORROSION CRACKING IN HYDRAULIC FRACTURING ENVIRONMENT Name: Anyanwu, Ezechukwu John APPROVED BY: ______________________ ________________________ Douglas C. Hansen, Ph.D. Sean C. Brossia, Ph.D. Advisory Committee Chairman Research Advisor Research Advisor and Professor Senior Vice President and Chemical and Materials Engineering Senior Principal Engineer DYCE USA ________________________ Robert J. Wilkens, Ph.D., P.E. Committee Member Professor Chemical and Materials Engineering _______________________ ________________________ John G. Weber, Ph.D. Tony E. Saliba, Ph.D. Associate Dean Dean, School of Engineering School of Engineering and Wilke Distinguished Professor ii ABSTRACT LOW ALLOY STEEL SUSCEPTIBILITY TO STRESS CORROSION CRACKING IN HYDRAULIC FRACTURING ENVIRONMENT Name: Anyanwu, Ezechukwu John University of Dayton Research Advisors: Dr. Douglas C. Hansen Dr. Sean C. Brossia The pipelines used for hydraulic fracturing (aka. “fracking”) are often operating at a pressure above 10000psi and thus are highly susceptible to Stress Corrosion Cracking (SCC). This is primarily due to the process of carrying out fracturing at a shale gas site, where the hydraulic fracturing fluid is pumped through these pipes at very high pressure in order to initiate fracture in the shale formation. While the fracturing fluid is typically more than 99% water, other components are used to perform various functions during the fracturing process. Research into the occurrence of SCC reveals that SCC is engendered by a number of factors, of which two main contributors are stress in iii the pipe steel and a particular type of corrosive environment in contact with the pipeline in the service setting.
    [Show full text]
  • 3Rd Edition A.R
    WEAR – MATERIALS, MECHANISMS AND PRACTICE Editors: M.J. Neale, T.A. Polak and M. Priest Guide to Wear Problems and Testing for Industry M.J. Neale and M. Gee Handbook of Surface Treatment and Coatings M. Neale, T.A. Polak, and M. Priest (Eds) Lubrication and Lubricant Selection – A Practical Guide, 3rd Edition A.R. Lansdown Rolling Contacts T.A. Stolarski and S. Tobe Total Tribology – Towards an integrated approach I. Sherrington, B. Rowe and R. Wood (Eds) Tribology – Lubrication, Friction and Wear I.V. Kragelsky, V.V. Alisin, N.K. Myshkin and M.I. Petrokovets Wear – Materials, Mechanisms and Practice G. Stachowiak (Ed.) WEAR – MATERIALS, MECHANISMS AND PRACTICE Edited by Gwidon W. Stachowiak Copyright © 2005 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (+44) 1243 779777 Chapter 1 Copyright © I.M. Hutchings Email (for orders and customer service enquiries): [email protected] Visit our Home Page on www.wiley.com Reprinted with corrections May 2006 All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or emailed to [email protected], or faxed to (+44) 1243 770620.
    [Show full text]
  • Study on Wear and Fatigue Performance of Two Types of High-Speed Railway Wheel Materials at Different Ambient Temperatures
    materials Article Study on Wear and Fatigue Performance of Two Types of High-Speed Railway Wheel Materials at Different Ambient Temperatures Lei MA 1,* , Wenjian WANG 2, Jun GUO 2 and Qiyue LIU 2 1 School of Mechanical Engineering, Xihua University, Chengdu 610039, China 2 Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiao Tong University, Chengdu 610031, China; [email protected] (W.W.); [email protected] (J.G.); [email protected] (Q.L.) * Correspondence: [email protected] Received: 14 January 2020; Accepted: 2 March 2020; Published: 5 March 2020 Abstract: The wear and fatigue behaviors of two newly developed types of high-speed railway wheel materials (named D1 and D2) were studied using the WR-1 wheel/rail rolling–sliding wear simulation device at high temperature (50 C), room temperature (20 C), and low temperature ( 30 C). The ◦ ◦ − ◦ results showed that wear loss, surface hardening, and fatigue damage of the wheel and rail materials at high temperature (50 C) and low temperature ( 30 C) were greater than at room temperature, ◦ − ◦ showing the highest values at low temperature. With high Si and V content refining the pearlite lamellar spacing, D2 presented better resistance to wear and fatigue than D1. Generally, D2 wheel material appears more suitable for high-speed railway wheels. Keywords: alpine region; high-speed wheel and rail materials; temperature; wear; fatigue damage 1. Introduction Railways play a vital role in the development of rail transportation. The environmental climate has a certain impact on wheel/rail systems exposed to the open air. Especially in China, wheel and rail materials may serve under extreme temperature conditions due to torridity and severe cold.
    [Show full text]
  • Friction, Wear and Corrosion: Learning from Nature
    V. Stoilov & D. O. Northwood, Int. J. of Design & Nature and Ecodynamics. Vol. 9, No. 4 (2014) 276–284 FRICTION, WEAR AND CORROSION: LEARNING FROM NATURE V. STOILOV & D. O. NORTHWOOD Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Canada. ABSTRACT Friction, wear and corrosion play a central role in diverse systems and phenomena that at fi rst sight may seem unrelated. On closer scrutiny, however, bio-system phenomena such as the lotus leaf effect (hydrophobicity) and surface passivation are found to display common features that are shared by many tribological processes in technological (manufacturing and automotive) and geological (drilling and mining) applications. Through the process of natural selection, nature has produced surface textures and water-based lubricant systems that far outclass the best oil-based lubricants of most man-made devices. To emulate these systems is one of today’s great challenges. Keywords: Corrosion resistance, hydrophobicity, surface patterning, ultralow friction. 1 INTRODUCTION Many terrestrial plants and animals are water-repellent due to hydrophobic surface components with microscopic roughness. These surfaces provide a very effective anti-adhesive property against par- ticulate contamination. This self-cleaning mechanism, called the ‘Lotus-Effect’, is an important function of many micro-structured biological surfaces [1]. It is now recognized that the fascinating fl uid behaviors observed for the lotus plant, like the rolling and bouncing of liquid droplets and self- cleaning of particle contaminants, arise from a combination of the low interfacial energy and the rough surface topography of waxy deposits covering their leaves [2]. 2 NATURE’S SOLUTIONS TO CONTROL FRICTION, WEAR AND CORROSION 2.1 Hydrophobic surfaces As shown in Fig.
    [Show full text]
  • Stress Corrosion Cracking Control Measures
    : 4 BurssD of Standarci f^OV Z 8 1977 QcloG Stress Corrosion Cracking ^^f^^^Control Measures ^c ^ ' B. F. Brown Chemistry Department The American University Washington, D.C. 20016 Sponsored by the Advanced Research Projects Agency under ARPA Order No. 2616, through contract No. N00014-68-A-0245-0007 of the Office of Naval Research. U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary Dr. Sidney Harman, Under Secretary , NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director (J , ^ Issued June 1977 Library of Congress Cataloging in Publication Data Brown, Benjamin Floyd, 1920- Stress corrosion cracking control measures. (NBS monograph ; 156) Bibliography, p. Includes index. Supt. of Docs, no.: C 13.44; 156 1. Stress corrosion. I. Title. II. Series: United States. National Bureau of Standards. Monograph ; 156. QC100.U556 no. 156 [TA462] 602Ms [620.r6'23] 76-608306 National Bureau of Standards Monograph 156 Nat. Bur. Stand. (U.S.), Mono. 156, 81 pages (June 1977) CODEN: NBSMA6 U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1977 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. C13.44:156). Stock No. 003-003-01674-8 Price $4.50 cents. (Add 25 percent additional for other than U.S. mailing.) Truth will sooner come out from error than from confusion. Francis Bacon, 16th century Were I to await perfection, my book would never be finished. Tai K'ung, 13th century SI Conversion Units In view of present accepted practice in this technological area, U. S. customary units of measurement have been used throughout this report.
    [Show full text]
  • Introduction and Aims Reducing Fatigue Failure Methods Material
    Poster Exhibit October 2006 “Within Any Important Issue, There Are Always Aspects No One Wishes To Discuss”- G. Orwell – Femoral Component Failure Keggi, K.1, Keggi, J.1, Kennon, R.1, Tkach, T.2, Low, W.2, Froehlich, J.3, McTighe, T.4, Cheal, E.5, Cipolletti, G.5 Introduction And Aims Reducing Fatigue Failure • Modular design allows for large Stem Removal Complications still occur in THA. One The most effective method of reducing selection of necks, to achieve Components are of these complications continues to be fatigue failure is to make improvements proper combination of designed with an femoral component failure. in design: lateral offset, leg length, and axial extraction anteversion This subject needs more open discussion. • Eliminate or reduce stress raisers by feature that The literature documents examples that streamlining the part; • Dual Press™ connection is facilitates simple, robust, and stable removal. This Retrieved stem. unsupported stems will fail regardless • Avoid sharp surface tears resulting from of fixation, material, and design but has • Indexing pin permits allows preservation of proximal bone punching, stamping, shearing, or other stock for re-implantation. not recently addressed the risk due to processes; selection of neutral, and 16º increased patient activity. anteversion position • Prevent the development of surface Apex Neck Retrievals Metal fatigue is caused discontinuities during processing; Dual Press™ by repeated cycling of the All retrieved stems that we have been load. It is a progressive • Reduce or eliminate tensile residual The Dual Press modular examined suggest quasi-static shear localized damage due to stresses caused by manufacturing; junction employs two failure of the alignment pin – a single • Improve the details of fabrication and areas of cylindrical high load (high torsion) event.
    [Show full text]
  • Tribology Wear Analysis
    Tribology Prof. Harish Hirani Department of Mechanical Engineering Indian Institute of Technology, Delhi Module No. #03 Lecture No. #10 Wear analysis (Refer Slide Time: 00:32) TRIBOLOGY LECTURE 10: WEAR ANALYSIS Welcome to tenth lecture of video courses on Tribology. The title of this lecture is wear analysis. In my previous four lectures, we discussed various mechanisms related to wear. Now, today’s lecture is related to how to analyze some failure related to wear. Can we go ahead systematically point by point? Can we pin point what kind of wear mechanism is taking place and how we can get remedy for that? How can we reduce that kind of wear mechanism? In true sense there will never be a single wear mechanism which will cause a failure. It will be generally related to one wear mechanism, which will promote another wear mechanism. So, generally they are integrated one way or other. Thinking only one wear mechanism may not give a 100 percentage solution. In addition to that, we need to know that there are too many system parameters which affect the wear mechanism. So, we need to think out of box whenever we attack this kind of problem. We need to find alternative solution from the load point of view, from system point of view, from materials point of view, from lubrication point of view. Quite possible one solution may be better solution compared to other solution otherwise every solution will provide some results some results comparative results but, we should choose the best solution. So, first question comes in our mind can one estimate the wear rate? I believe yes.
    [Show full text]
  • Tribology Module3: Wear
    Tribology Module3: Wear Q.1. What is wear constant and how it is related to coefficient of friction? Ans: As per Archard’s wear equation, wear volume rate (m3/s) is proportional to normal load (N), relative speed (m/s) and inversely proportional to hardness (N/m2). Wear constant (non-dimensional) is constant of proportionality relating wear volume rate with load, relative speed and hardness. There is no established relation between friction-coefficient and wear rate, but reduction in friction-coefficient means lesser resistant to relatively moving surface and as a result lesser wear rate. Q.2. What are the main criteria for classification of wear and what are various types of wear? Ans: Failure mechanisms causing wear are used to classify wear. For example wear caused by formation and rupture of adhesive junctions is known as “adhesive wear”. Wear caused by abrasion of hard surface on soft surface is termed as “abrasive wear”. Formation of brittle layer due to chemical action and removal of that layer by mechanical action is called “corrosive wear”. Similarly formation of subsurface cracks and rapid propagation of those cracks to surface due to friction is named as “fatigue wear”. There are more than 2000 wear equations to describe the wear behavior. There are more than 35 mechanisms detailed as wear sources. This means there are more than 35 types of wear. Q.3. In a tribological system where two tribo-surfaces are moving at relatively high speed, should the design of such system involve the use of similar metals or dissimilar metals to prevent adhesive wear and seizure? Ans: Whether low or high speed, molecular attraction, between similar materials will be higher so resultant friction shall be higher.
    [Show full text]