ASTM D7565 D7565M-2009 1875 Standard Test Method for Determining Tensile Properties of Fiber Reinforced Polymer Matrix Composites Used for Strengthening of Civil Structures.pdf

1、Designation: D7565/D7565M 09Standard Test Method forDetermining Tensile Properties of Fiber Reinforced PolymerMatrix Composites Used for Strengthening of CivilStructures1This standard is issued under the fixed designation D7565/D7565M; the number immediately following the designation indicates theye

2、ar of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes the requirements for sampl

3、epreparation, tensile testing, and results calculation of flat fiberreinforced polymer (FRP) composite materials used for thestrengthening of structures made of materials such as metals,timber, masonry, and reinforced concrete. The method may beused to determine the tensile properties of wet lay-up

4、andpre-impregnated FRP composites fabricated on site or manu-factured in a factory setting. The FRP composite may be ofeither unidirectional (0-degrees) or cross-ply (0/90 type) rein-forcement. For cross-ply laminates, the construction may beachieved using multiple-layers of unidirectional fibers at

5、 either0 or 90 degrees, or one or more layers of stitched or woven0/90 fabrics. The composite material forms are limited tocontinuous fiber or discontinuous fiber-reinforced compositesin which the laminate is balanced and symmetric with respectto the test direction. The method only covers the determ

6、inationof the tensile properties of the FRP composite material. Othercomponents used to attach the FRP material to the substrate,such as the primer, putty, and adhesive in externally bondedstrengthening systems, are excluded from the sample prepara-tion and testing detailed in this document. This te

7、st methodrefers to Test Method D3039/D3039M for conduct of the tests.1.2 The values stated in either SI units or inch-pound unitsare to be regarded as standard. Within the text, the inch-poundunits are shown in brackets. The values stated in each systemare not exact equivalents; therefore, each syst

8、em must be usedindependently of the other. Combining values from the twosystems may result in nonconformance with the standard.1.3 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 a

9、ppro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD3039/D3039M Test Method for Tensile Properties ofPolymer Matrix Composite MaterialsD3878 Terminology for Co

10、mposite MaterialsD5229/D5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composite MaterialsD5687/D5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionE6 Terminology Relating to Methods of Mechanic

11、al TestingE122 Practice for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics3. Terminology3.1 DefinitionsTermin

12、ology D3878 defines terms relatingto high-modulus fibers and their composites. TerminologyD883 defines terms relating to plastics.Terminology E6 definesterms relating to mechanical testing. Terminology E456 andE177 define terms relating to statistics. In the event of aconflict between terms, Termino

13、logy D3878 shall have prece-dence over the other standards.3.2 Definitions of Terms Specific to This Standard:3.2.1 screed, vto move a flat rule along the top of asaturated laminate to level the top of the laminate andsimultaneously remove excess resin.3.2.2 shop-manufactured FRP composite, nan FRP

14、com-posite material manufactured under controlled conditions usingan automated process in a factory, typically with tight control1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.05 onStructural Test Methods.C

15、urrent edition approved Nov. 1, 2009. Published January 2010. DOI: 10.1520/D7565_D7565M-09.2For 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 Su

16、mmary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.over the volume fractions and alignment of fibers, matrix, andvoids in the material as well as the cross-sectional geometry.For strengthening applications,

17、 shop-manufactured FRP com-posites are typically bonded to the substrate subsequent to thefabrication of the composite reinforcement3.2.3 wet lay-up FRP composite, nan FRP compositematerial fabricated by manually impregnating dry fibers with amatrix of polymeric resin. Semi-automated processes such

18、asmachine-aided wetting of fabrics before placement or vacuum-aided impregnation of laminates after placement are consideredpart of wet lay-up FRP. For civil infrastructure strengtheningapplications, the degree of control over the volume fractions offibers, matrix, and voids as well as the overall c

19、ross-sectionalgeometry in wet lay-up FRP composites may be less than thatfor shop-manufactured composites on account of the manualprocess. For strengthening applications, wet lay-up FRP com-posites are typically applied to the substrate at the same timethe dry fiber is impregnated. The impregnating

20、resin acts as thesaturant for the FRP composite and as the bonding agentbetween the composite reinforcement and the substrate. Wetlay-up specimens may be fabricated in either a field or alaboratory setting.3.3 Symbols:3.3.1 CVsample coefficient of variation.3.3.2 F*force carrying capacity of FRP lam

21、inate per unitwidth.3.3.3 K*stiffness of FRP laminate per unit width.3.3.4 Lgextensometer gage length.3.3.5 nnumber of specimens.3.3.6 Pforce carried by test coupon.3.3.7 Pmaxmaximum tensile force.3.3.8 sn1sample standard deviation.3.3.9 wcoupon width.3.3.10 xItest result for an individual coupon fr

22、om thesample population for a given property.3.3.11 xmean or average (estimate of mean) of a samplepopulation for a given property.3.3.12 snormal stress.4. Summary of Test Method4.1 Flat FRP specimens are prepared using a wet lay-upfabrication procedure or cut from a shop-manufactured lami-nate. For

23、 testing purposes, wet lay-up material may be preparedin a laboratory or field setting, as the testing objectives dictate.The testing of the specimens is carried out according to theprovisions of Test Method D3039/D3039M. The ultimate forceper unit width of the material is determined from the maximu

24、mforce carried before failure. If the load-strain response of thematerial is monitored with strain gages or extensometers, thenthe stiffness of the material per unit width and the ultimatetensile strain of the material may be determined.5. Significance and Use5.1 This test method can be used to obta

25、in the tensile forcecapacity and ultimate tensile strain of FRPmaterial used for thestrengthening of other structural materials such as, metals,timber, and reinforced concrete. The principal test variablescould be the FRP constituents and fabrication method or thesize or type of FRP laminate. The ob

26、tained tensile propertiescan be used for material specifications, quality control andassurance, structural design and analysis, and research anddevelopment. The stress, strength, and modulus of elasticitycan be calculated using either the gross composite area methodor the effective fiber area method

27、.5.2 This test method focuses on the FRP material itself,irrespective of the gripping method.Therefore, maximum forceand strain data associated with failure or pullout at either gripare disregarded. The force capacity and maximum strainmeasurements are based solely on test specimens that fail in the

28、gauge section.6. Interferences6.1 A summary of the interferences, specifically materialand specimen preparation, gripping, system alignment, andedge effects are presented in D3039/D3039M.6.2 Additional interferences may arise from lack of controlin wet lay-up specimen preparation procedures outlined

29、 in8.3.1. Specimen variations in resin content, ply thickness, voidcontent and degree of cure may contribute to variability in testresults.7. Apparatus7.1 Requirements for testing machines and instrumentationare the same as those given in D3039/D3039M, Section 7.8. Sampling and Test Specimens8.1 Sam

30、plingTest at least five specimens per test condi-tion unless valid results can be gained through the use of fewerspecimens, such as in the case of a designed experiment. Forstatistically significant data, the procedures outlined in PracticeE122 should be consulted. Report the method of sampling.NOTE

31、 1If specimens are to undergo environmental conditioning toequilibrium, and are of such type or geometry that the weight change ofthe material cannot be properly measured by weighing the specimen itself(such as a tabbed mechanical coupon), then use another traveler coupon ofthe size (but without tab

32、s) to determine when equilibrium has beenreached for the specimens being conditioned.8.2 GeometryVariation in specimen width should be nogreater than 61%. Specimens width should be determined perTest Method D3039/D3039M, Section 7.1. Other dimensionsshall conform to Test Method D3039/D3039M Section

33、8.2.1with the exception of thickness, which is not required to bemeasured. Specimen thickness may however be measured aspart of the general characterization of the specimen, and shouldbe reported if measured.NOTE 2Calculations according to this method are based on force perunit coupon width and stif

34、fness per unit coupon width. Specimenthickness is not required for these calculations.8.2.1 Specimen WidthMinimum specimen width for uni-directional shop-manufactured and wet lay-up FRP specimensshall be 25 mm 1.0 in. Minimum width for cross-plyspecimens shall be 25 mm 1.0 in. for shop-manufacturedc

35、omposites and 38 mm 1.5 in. for wet lay-up composites.NOTE 3For both unidirectional and cross-ply laminates, where fibersare used in large bundles (i.e, rovings, tows) that will be wider than 3 mm0.12 in. when laid into the laminate, it is recommended that a specimenwidth of 38 mm 1.5 in. or higher

36、be used.D7565/D7565M 0928.3 Specimen Preparation:8.3.1 Wet Lay-up FRPA polymer release film, typically600 x 600 mm 24 x 24 in. is placed on a smooth, flathorizontal surface. The release film should be at least 0.076mm 0.003 in. thick and made of a polymer that will notadhere to the resin used to imp

37、regnate the fibers. Usually,acetate and nylon are acceptable. Resin is first applied to therelease film. The first ply of dry fiber preform with a minimumdimension of 300 x 300 mm 12 x 12 in. is saturated or coatedwith the specified amount of resin and placed on the releasefilm. This can be done usi

38、ng a properly calibrated saturatormachine or using a manufacturer-specified fiber to resin weightratio. The specified number of plies at the specified angles (0 or90 degrees) are sequentially impregnated with resin andstacked onto the release film using the specified amount ofresin per ply per unit

39、area as in the actual installation. Using theflat edge of a small hand tool or a grooved roller, air bubblesare worked out of the material. The bubbles should be workedout in the direction of the primary fibers to ensure that nodamage is caused to the fibers. A second release film is thenplaced over

40、 the material to provide protection. An alternativemethod to eliminate air bubbles is to use the flat edge of a smallpaddle on the outer side of the upper release film to force theentrapped air out of the material with a screeding action in theprimary fiber direction. In order to ensure a smooth top

41、 surfaceof the FRP material, a rigid flat plate should be placed on topof the top layer of release film while the resin cures. Thelaminate should be placed in an area of the jobsite so as to notinterfere with the installation and allowed to cure according tothe manufacturers recommendation. After th

42、e specified curingprocedure is complete, the release films are removed from thepanel. Specimens may be cut and tabbed after the curingprocedure.NOTE 4The final fiber, resin, and void content of the material willdepend on the method of rolling or screeding the material duringfabrication. If the aim o

43、f testing is to evaluate FRP material representativeof the installed strengthening material, rolling and screeding proceduresused to prepare specimens should resemble those used for the installedstrengthening material.NOTE 5Guide D5687/D5687M provides guidelines for strictly con-trolling the prepara

44、tion of composite test specimens in the laboratory.Preparation of wet lay-up FRPshould follow these guidelines to the extentthat they are compatible with the intended cure and laminate consolidationregimes specified for the wet-laid FRP composite system. The lay-up andlaminate consolidation steps pr

45、esented in Guide D5687/D5687M are ofparticular relevance to this standard.8.3.2 Shop-Manufactured FRPThe thickness of shop-manufactured FRP is predetermined and should not be altered.Specimen width may be altered by the agreement of therequestor and material manufacturer. Care should be taken toensu

46、re that the specimen is flat. Testing of non-flat specimensmay result in lower tensile strength due to induced moments.8.3.3 Machining MethodsSpecimen preparation is ex-tremely important for this test method. If specimens are cutfrom plates, take precautions to avoid notches, undercuts,rough or unev

47、en surfaces, or delaminations caused by inappro-priate machining methods. Obtain final dimensions by water-lubricated precision sawing, milling, or grinding. The use ofdiamond tooling has been found to be extremely effective formany material systems. Edges should be flat and parallelwithin the toler

48、ances specified in 8.2. See Appendix X3 ofGuide D5687/D5687M for specific recommendations on speci-men machining methods.8.3.4 LabelingLabel the specimens so that they will bedistinct from each other and traceable back to the raw material.Labeling must be unaffected by the test and must not affect t

49、heoutcome of the test.9. Calibration9.1 The accuracy of all measuring equipment shall havecertified calibrations that are current at the time of use of theequipment.10. Conditioning10.1 The recommended pre-test condition is effective mois-ture equilibrium at a specific relative humidity as establishedby Test Method D5229/D5229M; however, if the test requestordoes not explicitly specify a pre-test conditioning environment,no conditioning is required and the specimens may be tested asprepared.10.2 The pre-test specimen conditioning process