ASTM_D_5045_-_14.pdf

Designation:D504514Standard Test Methods forPlane-Strain Fracture Toughness and Strain Energy ReleaseRate of Plastic Materials1This standard is issued under the fixed designation D5045;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 These test methods are designed to characterize thetoughness of plastics in terms of the critical-stress-intensityfactor,KIc,and the energy per unit area of crack surface orcritical strain energy release rate,GIc,at fracture initiation.1.2 Two testing geometries are covered by these testmethods,single-edge-notch bending(SENB)and compacttension(CT).1.3 The scheme used assumes linear elastic behavior of thecracked specimen,so certain restrictions on linearity of theload-displacement diagram are imposed.1.4 A state-of-plane strain at the crack tip is required.Specimen thickness must be sufficient to ensure this stressstate.1.5 The crack must be sufficiently sharp to ensure that aminimum value of toughness is obtained.1.6 The significance of these test methods and many con-ditions of testing are identical to those of Test Method E399,and,therefore,in most cases,appear here with many similari-ties to the metals standard.However,certain conditions andspecifications not covered in Test Method E399,but importantfor plastics,are included.1.7 This protocol covers the determination of GIcas well,which is of particular importance for plastics.1.8 These test methods give general information concerningthe requirements for KIcand GIctesting.As with Test MethodE399,two annexes are provided which give the specificrequirements for testing of the SENB and CT geometries.1.9 Test data obtained by these test methods are relevant andappropriate for use in engineering design.1.10 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1This standard and ISO 13586 address the same subject matter,but differ in technical content.2.Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD4000 Classification System for Specifying Plastic Materi-alsE399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 compact tension,nspecimen geometry consisting ofsingle-edge notched plate loaded in tension.See 3.1.5 forreference to additional definition.3.1.2 critical strain energy release rate,GIc,ntoughnessparameter based on energy required to fracture.See 3.1.5 forreference to additional definition.3.1.3 plane-strain fracture toughness,KIc,ntoughnessparameter indicative of the resistance of a material to fracture.See 3.1.5 for reference to additional definition.3.1.4 single-edge notched bend,nspecimen geometryconsisting of center-notched beam loaded in three-point bend-ing.See 3.1.5 for reference to additional definition.3.1.5 Reference is made to Test Method E399 for additionalexplanation of definitions.3.2 Definitions of Terms Specific to This Standard:3.2.1 yield stress,nstress at fracture is used.The slope ofthe stress-strain curve is not required to be zero.See 7.2 forreference to additional definition.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.10 on MechanicalProperties.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved in 1990.Last previous edition approved in 1999 as D5045-99(2007)1.DOI:10.1520/D5045-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Methods4.1 These test methods involve loading a notched specimenthat has been pre-cracked,in either tension or three-pointbending.The load corresponding to a 2.5%apparent incre-ment of crack extension is established by a specified deviationfrom the linear portion of the record.The KIcvalue iscalculated from this load by equations that have been estab-lished on the basis of elastic stress analysis on specimens of thetype described in the test methods.The validity of thedetermination of the KIcvalue by these test methods dependsupon the establishment of a sharp-crack condition at the tip ofthe crack,in a spe