_STP_678-1979.pdf

FRACTURE MECHANICS APPLIED TO BRITTLE MATERIALS Proceedings of the Eleventh National Synnposlum on Fracture Mechanics:Part II A synnposium sponsored by ASTM Committee E-24 on Fracture Testing of Metals AMERICAN SOCIETY FOR TESTING AND MATERIALS Virginia Polytechnic Institute and State University Blaclsburg,Va.,12-14 June 1978 ASTM SPECIAL TECHNICAL PUBLICATION 678 S.W.Freiman,National Bureau of Standards,editor#List price$25.00 04-678000-30 AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race Street,Philadelphia,Pa.19103 Copyright by AMERICAN SOCIETY FOR TESTING AND MATERIALS 1979 Library of Congress Catalog Card Number:78-74564 NOTE The Society is not responsible,as a body,for the statements and opinions advanced in this publication.Printed in Baltimore,Md.August 1979 Foreword This publication,Fracture Mechanics Applied to Brittle Materials,con-tains papers presented at the Eleventh National Symposium on Fracture Mechanics which was held 12-14 June 1978 at Virginia Polytechnic Institute and State University,Blacksburg,Va.The American Society for Testing and Materials Committee E-24 on Fracture Testing of Metals sponsored the symposium.S.W.Freiman,National Bureau of Standards,served as editor of this publication.The proceedings have been divided into two volumes:Part IFracture Mechanics and Part IIFracture Mechanics of Brittle Materials.Related ASTM Publications Developments in Fracture Mechanics Test Methods Standardization,STP 632(1977),$24.75,04-632000-30 Properties Related to Fracture Toughness,STP 605(1976),$15.00,04-605000-30 Fracture Analysis,STP 560(1974),$22.75,04-560000-30 A Note of Appreciation to Reviewers This publication is made possible by the authors and,also,the unheralded efforts of the reviewers.This body of technical experts whose dedication,sacrifice of time and effort,and collective wisdom in reviewing the papers must be acknowledged.The quality level of ASTM publications is a direct function of their respected opinions.On behalf of ASTM we acknowledge with appreciation their contribution.ASTM Committee on Publications Editorial Staff Jane B.Wheeler,Managing Editor Helen M.Hoersch,Associate Editor Ellen J.McGlinchey,Senior Assistant Editor Helen Mahy,Assistant Editor Contents Introduction An Evaluation of Double-Torsion TestingAnalysis E.R.FULLER,JR.3 An Evaluation of Double-Torsion TestingExperimental B.J.PLETKA,E.R.FULLER,JR.,AND B.G.KOEPKE 19 Fracture Surface Energy Measurements by the Notch-Beam TechniqueG.K.BANSAL AND W.H.DUCKWORTH 38 Influence of Loading System on Crack Propagation and Arrest Behavior in a Double-Cantilever Beam Specimen W.L.FOURNEY AND T.KOBAYASHI 47 Crack Propagation Measurements on Glass:A Comparison Between Double-Torsion and Double-Cantilever Beam Specimens F.P.CHAMPOMIER 60 Short Bar Specimens for Ki MeasurementsL.M.BARKER 73 Fracture from Controlled Surface Flawsj.j.PETROVIC AND M.G.MENDIRATTA 83 Use of Indentation Fracture to Determine Fracture Toughness R.H.MARION 103 Fracture Toughness:The Role of Indentation Techniques A.G.EVANS 112 Determination of Fracture Mechanics Parameters Through Fractographic Analysis of CeramicsJ.J.MECHOLSKY AND S.W.FREIMAN 136 Fracture Toughness Testing of AluminaF.E.BURESCH 151 Ku and/k of Westerly GraniteEffects of Thickness and In-Plane DimensionsR.A.SCHMIDT AND T.J.LUTZ 166 Fracture and Multiple Cracking of Cementitious Composites A.E.NAAMAN AND S.P.SHAH 183 Application of Fracture Mechanics Concepts to Structural Ceramics S.M.WIEDERHORN AND J.E.RITTER,JR.202 Summary 215 Index 219 STP678-EB/Aug.1979 Introduction The symposium on Fracture Mechanics Applied to Brittle Materials from which this volume was taken was organized to provide a state-of-the-art review of the various test techniques currently being used to obtain fracture mechanics data on a wide variety of brittle materials including ceramics,glasses,rocks,and concrete.This volume is a compilation of papers de-scribing and reviewing most of the commonly used fracture toughness measurement techniques for brittle materials.Particular attention is given to the problems and discrepancies observed in making these measurements.The articles discuss not only critical fracture toughness measurements but also methods for determining crack growth rates in these materials as a func-tion of stress intensity.In the latter case data are used to provide a basis for lifetime predictions for brittle components under stress.The papers in this volume cover a wide variety of test techniques which are now being used.Although the list of techniques discussed is clearly not complete,the papers should describe for the reader the kind of assumptions,problems,and unknown factors involved in making fracture toughness measurements in brittle materials and the reproducibility from one technique to another.One must remember in reading the papers in this volume that there is currently no standard test technique for obtaining fracture mechanics parameters on brittle materials.It is in fact the ob