1、Designation: D2291/D2291M 16Standard Practice forFabrication of Ring Test Specimens for Glass-ResinComposites1This standard is issued under the fixed designation D2291/D2291M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the yea
2、r 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This practice is intended
3、for use in the fabrication ofring-type test specimens to be used in the evaluation of themechanical properties of reinforcement and resins in a com-posite structure. The practice outlines the steps in the prepara-tion of the test specimens, including the final specimenmachining where applicable. Fou
4、r final ring configurations areincluded.1.2 The values stated in either SI units of inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two sy
5、stems may result in nonconformancewith 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 appro-priate safety and health practices and determine the applica-bility of
6、 regulatory limitations prior to use.NOTE 1There is no known ISO equivalent to this practice.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD2290 Test Method for Apparent Hoop Tensile Strength ofPlastic or Reinforced
7、 Plastic PipeD2344/D2344M Test Method for Short-Beam Strength ofPolymer Matrix Composite Materials and Their Laminates3. Terminology3.1 For definitions of terms which apply to this practice, seeTerminology D883.4. Significance and Use4.1 This practice provides a uniform procedure for fabricat-ing gl
8、ass fiber/thermoset resin ring samples for use as testspecimens. Specimens so prepared can be used in Test MethodsD2290 and D2344/D2344M.5. Apparatus5.1 Winding MachineThe winding machine may consistof any adequate superstructure for mounting impregnatedreinforcement or components for application of
9、 resin to thereinforcement, tensioning the reinforcement, and collecting thewetted, tensioned material on a mold or mandrel of the desiredsize.5.2 Tension Measuring SystemAny device suitable formeasurement of the tension applied to the wetted reinforce-ment. The device shall be capable of measuring
10、the tensionaccurately to within 65%.5.3 The single-ring fabrication mold on which the wettedreinforcement is collected shall be constructed as shown in Fig.1. For cylinder fabrication from which rings are to be cut, amandrel with the proper diameter fitted to a suitable windingmachine shall be used
11、to collect the wetted reinforcement. Thesurfaces of the mold or mandrel that contact the ring specimensshall be coated or otherwise treated to prevent sticking of thering or cylinder in the mold or on the mandrel.5.4 Curing OvensOvens having adequate range in tem-perature to produce a fully cured sp
12、ecimen shall be availablefor use. Control of the curing-postcuring temperatures towithin 69F (65C) is required.6. Storage and Conditioning of Components6.1 Glass rovings and yarns for use in fabrication of ring testspecimens shall be stored in a dry place, not subject totemperature extremes, or as s
13、pecified by the glass producer.Prior to use, the rovings shall be conditioned in accordance1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.18 on Reinforced ThermosettingPlastics.Current edition approved Sept. 1, 2016. Publ
14、ished September 2016. Originallyapproved in 1964. Last previous edition approved in 2009 as D2291 - 09. DOI:10.1520/D2291_D2291M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume inform
15、ation, 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 States1with Procedure A of Practice D618, which requires
16、40 hours at23C 6 2C and a 50 % relative humidity 610 %.6.2 Resins to be used in the fabrication of ring test speci-mens shall be stored in closed containers at a temperaturespecified by the supplier. In addition, no resin shall be used thathas been stored for a period in excess of the shelf lifereco
17、mmended by the supplier. Prior to fabrication of the testspecimen, the resin shall be heated as necessary to providesufficient lowering of the viscosity to produce good wetting ofthe reinforcement strand.6.3 Preimpregnated materials received for the preparation ofring test specimens shall be stored
18、in a closed container at atemperature as recommended by the supplier. Before winding,they shall be removed from storage and conditioned asrecommended by the supplier or in accordance with ProcedureA of Methods D618.7. Procedure for Dry Reinforcement7.1 Fig. 2 is a schematic diagram of the system for
19、 wetting,tensioning, and collecting the reinforcement.7.1.1 Mounting Reinforcement Packages:7.1.1.1 Outside Pull PackagesMount the reinforcementpackage in a convenient location within the superstructure ofthe winding machine. Provide sufficient braking of the axle ofthe package to prevent free-wheel
20、ing. This should be aminimum tension.7.1.1.2 Inside Pull PackagesMount the reinforcementpackage so that the roving is pulled from the inside of thepackage and passes through a guide eye such that the rovingdoes not rub against the package edge or any sharp edges.7.1.2 Application of ResinThe reinfor
21、cement leaving thepackage shall pass immediately into the resin bath. Heat theresin bath sufficiently to lower the resin viscosity to a workablerange. As the reinforcement is pulled from the resin bath,remove excess resin by any convenient method that results ina minimum amount of fraying or breakag
22、e of the reinforce-ment.7.1.3 TensioningAfter leaving the resin bath, pass thereinforcement over a pulley or a series of pulleys, adequatelybraked to impart the desired tension to the fibers. The tensionmay be monitored, by any convenient method, either periodi-cally or continuously during the windi
23、ng operation. Limit thedeviation from the mean tension to 65 % from start to finish ofthe winding of a test specimen. The diameter of the tensionpulley(s) shall be a minimum of 3.0 in. (76.2 mm). Larger sizesshould be used when available. Take care that no slippage ofthe strand occurs over the pulle
24、y(s).7.1.4 Level-WindingPass the wetted reinforcementthrough a level-winding guide and onto the mold. The guideshall be geared to the mold or mandrel or shall follow a cam insuch a manner that each revolution of the mold or mandrel willbe accompanied by a precision of the guide by an amountequivalen
25、t to one strand width.7.1.5 Collecting ReinforcementCollect the wetted rein-forcement strand on a mold or mandrel that is mounted on theaxle of a variable-speed drive. The strand velocity through theresin bath shall be constant and shall be slow enough to givegood wetting of the reinforcement with t
26、he resin. Apply anadequate mold release agent to the mold or mandrel beforewinding is begun to assure easy removal of the specimen afterfabrication. Wind specimens to be tested without machiningthe surface to a thickness as indicated for the Type B specimen,Fig. 3. Build up Types A, B, C, and D spec
27、imens in Fig. 3 toa thickness beyond that required for finished thickness. Uponcompletion of the winding process, secure the strand in such amanner as to retain the tension before cutting the strand andremoving the mold or mandrel from the winding machine.7.1.6 CuringTransfer the molds or mandrel to
28、 an oven andpolymerize the resin in the manner prescribed in the resinmanufacturers data sheet.NOTE 2Excess resin on the surface of the Type B specimen should beremoved if possible during cure.NOTE 3Many fabricating factors influence the mechanical propertiesof the rings such as the equipment system
29、, resin system and age, operatortechniques, ambient conditions and conditioning, etc. For this reason it isbest to run a control material with each set of samples and to randomizethe fabrication order of the rings.7.1.7 Removing Rings from Mold or MandrelRemove thering specimens from the molds or ma
30、ndrel in such a mannerthat delamination or other damage to the surfaces does notoccur. An arbor press or rubber hammer may be used to applyforce to separate the mold parts in the single-ring process ifrequired. Use gloves when handling rings to prevent reinforce-ment splinters from entering hands.7.
31、1.8 Preparation of Specimens for Testing:7.1.8.1 WidthMold or machine the width of the TypeA, B,C, and D specimens to the correct width.FIG. 1 Suggested Single-Ring MoldD2291/D2291M 1627.1.8.2 ThicknessDo not machine the thickness of theType B specimens. Machine the thickness of the Types A, C,and D
32、 specimens to the correct wall thickness.7.1.8.3 The dimensions of the finished test specimen aregiven in Fig. 3. Following the machining operation, thespecimen may be submitted to test or may be cut into flexuralor horizontal shear specimens as desired. When cutting thesespecimens from the ring, ta
33、ke care that all cut surfaces areparallel to the radius of the ring.7.1.8.4 When fabricating composite specimens by machin-ing operations, a fine dust consisting of particles of fibers or thematrix material, or both, may be formed. These fine dusts canbe a serious health or safety hazard, or both. A
34、dequateprotection should be afforded operating personnel and equip-ment. This may require adequate ventilation or dust collectingfacilities, or both, at a minimum.8. Procedure for Prepregs8.1 The procedure for the preparation of ring test specimensfrom preimpregnated material shall be identical to t
35、hat de-scribed for dry roving, except omit 7.1.2 (see Fig. 4).9. Report9.1 The report shall include the following:9.1.1 Complete identification of all components in the ringsfabricated; including type, source, form of the resin system,reinforcement, or preimpregnated material. It shall also includet
36、he history of the material including, but not limited to, age andstorage conditions,9.1.2 Complete description of conditions under which therings were fabricated, including temperature and relativehumidity,9.1.3 Complete description of the impregnation method andresin temperature,9.1.4 Resin wiping
37、technique,9.1.5 Tension,9.1.6 Rate of winding,9.1.7 Any special equipment or methods utilized,9.1.8 Type of specimen fabricated, single or cylinder,9.1.9 Mold materials used,9.1.10 Complete cure procedure, and9.1.11 Date of fabrication.FIG. 2 Schematic Diagram of Wet Roving Ring Winding ApparatusTyp
38、e ofSpecimenInside Diameter, DIWidth, b Wall Thickness, din. mm in. mm in. mmA 5.750 0.002 146.05 0.05 0.250 0.005 6.35 0.127 0.060 0.002 1.52 0.05B 5.750 0.002 146.05 0.05 0.250 0.005 6.35 0.127 0.060 0.010 1.52 0.25C 5.750 0.002 146.05 0.05 0.250 0.005 6.35 0.127 0.125 0.002 3.18 0.05D 5.750 0.002
39、 146.05 0.05 0.250 0.005 6.35 0.127 0.250 0.005 6.35 0.127FIG. 3 Ring Test SpecimenD2291/D2291M 16310. Keywords10.1 composite; glass fiber; prepreg; ring samples; ringtensile testing; shear testing; specimen preparation; thermosetresinSUMMARY OF CHANGESCommittee D20 has identified the location of se
40、lected changes to this standard since the last issue (D2991 - 09)that may impact the use of this standard. (September 1, 2016)(1) Revised 7.1.1, 7.1.6, 7.1.7, and 9.1.3. (2) Revised Fig. 3.ASTM International takes no position respecting the validity of any patent rights asserted in connection with a
41、ny item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technica
42、l committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration
43、at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor
44、 Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 4 Schematic Diagram of Preimpregnated Roving Winding SystemD2291/D2291M 164
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