_STP_527-1973.pdf

FRACTURE TOUGHNESS EVALUATION BY R-CURVE METHODS A symposium sponsored by Committee E-24 on Fracture Testing of Metals AMERICAN SOCIETY FOR TESTING AND MATERIALS ASTM SPECIAL TECHNICAL PUBLICATION 527 D.E.McCabe,symposium chairman m List price$9.75 04-527000-30%AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race Street,Philadelphia,Pa.19103 ANNIVESSARy Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.by AMERICAN SOCIETY FOR TESTING AND MATERIALS 1973 Library of Congress Catalog Card Number 72-97867 NOTE The Society is not responsible,as a body,for the statements and opinions advanced in this publication.Printed in Tallahassee,Fla.April 1973 Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Foreword This publication is a collection of papers presented at a technical symposium on R-curves held during the regular Committee E-24 meetings in the Fall of 1971.It represents an early effort by a Subcommittee 1 task group to organize the present state of R-curve technology in preparation for a renewed attempt to apply the method to plane-stress fracture toughness evaluation.The symposium was sponsored by Committee E-24 on Fracture Testing of Metals,American Society for Testing and Materials.D.E.McCabe,Armco Steel Corp.,presided as symposium chairman.Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Related ASTM Publications Fracture Toughness,STP 514(1972),$18.75,04-514000-30 Review of Developments in Plane Strain Fracture Toughness Testing,STP 463(1970),$18.25,04-463000-30 Electron Fractography,STP 436(1968),$11.00,04-436000-30 Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Contents Introduction 1 Crack Growth Resistance Curves(R-Curves)-Literature ReviewR.H.HEYER 3 Development of Crack Growth Resistance 3 Major Developments 4 Experimental Determinations 6 Applications of R-Curves 12 Summary 15 R-Curve Determination Using a Crack-Line-Wedge-Loaded(CLWL)Specimen-D.E.MCCABE AND R.H.HEYER 17 Development of Method 18 Instrumentation 24 Fixturing 25 Present Procedures 26 Specimen Dependence of R-Curves 30 Recent AppUcations 32 Strain Measurements of CLWL Specimens 34 Summary 34 Measuring KR-Curves for Thin Sheets-E.J.RIFLING AND ELIEZER FALKENSTEIN 36 Specimen Development 38 Specimen Characteristics 40 Typical Data 43 Conclusions 45 Fracture Extension Resistance(R-Curve)Characteristics for Three High-Strength Steels-R.W.JUDY,JR.,AND R.J,GOODE 48 R-Curve Factors 49 Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Dynamic Tear Test Procedures for Determining R-Curves 52 Materials and Procedures 53 Results 55 Discussion 56 Summary 61 Plane Stress Fracture Testing Using Center-Cracked Panels-C.M.CARMAN 62 Nomenclature 62 Experimental Procedure 64 Characterization of the Fracture Process Zone by Thickness Contraction 71 Experimental Results and Discussion 72 Comparison of R-Curves Determined from Different Specimen Types-A.M.SULLIVAN,C.N.FREED,AND J.STOOP 85 Crack Growth Resistance Curve 86 Materials 86 Experimental Parameters 86 Data Reduction 89 Discussion of R-Curves 90 Discussion of Crack Growth Behavior 96 Conclusions 101 A Note on the Use of a Simple Technique for Failure Prediction Using Resistance Curves-MATTHEW CREAGER 105 Theory of Failure 105 New Prediction Techniques 106 Procedures 107 Copyright by ASTM Intl(all rights reserved);Mon Dec 21 11:12:24 EST 2015Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.STP527-EB/Apr.1973 Introduction The R-curve approach has a basis in fracture mechanics and,when coupled with new hypotheses pertaining to R-curve characteristics,can be used for instability condition predictions.To be sure,some of the hypotheses can be reasonably challenged,and the need for some additional fundamental studies is apparent.It is intended,therefore,that the contents of this publication will serve to stimulate new involvement in R-curve research work.In particular,help is needed in extending the method to lower strength,high toughness materials,and examples are needed to demonstrate the predictive capabilities of the method.In reading these papers,it will be apparent that a variety of specimen types and test techniques are avail