1、Designation: D 2291 03Standard Practice forFabrication of Ring Test Specimens for Glass-ResinComposites1This standard is issued under the fixed designation D 2291; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This practice is intended for use in the f
3、abrication 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. Four final ring con
4、figurations 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 systems may result
5、 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 regulatory limi
6、tations prior to use.NOTE 1There is no ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 2290 Test Method for Apparent Hoop Tensile Strength ofPlastic or Reinforced Plastic Pipe by Split Disk MethodD 2344 Test Method for
7、Short-Beam Strength of PolymerMatrix Composite Materials and Their Laminates3. Terminology3.1 For definitions of terms which apply to this practice, seeTerminology D 883.4. Significance and Use4.1 This practice provides a uniform procedure for fabricat-ing glass fiber/thermoset resin ring samples fo
8、r use as testspecimens. Specimens so prepared can be used in Test MethodsD 2290 and in D 2344.5. Apparatus5.1 Winding MachineThe winding machine may consistof any adequate superstructure for mounting impregnatedreinforcement or components for application of resin to thereinforcement, tensioning the
9、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 the tensionaccurately to within 65%.5.3 The
10、 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 to collect the wetted reinforcement. Thesur
11、faces 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 specimen shall be availablefor use. Control o
12、f 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 specified by the glass producer.Prior to use,
13、the rovings shall be conditioned in accordancewith Procedure A of Practice D 618.6.2 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 ex
14、cess of the shelf liferecommended by the supplier. Prior to fabrication of the test1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.18 on Reinforced ThermosettingPlastics.Current edition approved Nov. 1, 2003. Published Jan
15、uary 2004. Originallyapproved in 1964. Last previous edition approved in 1998 as D 2291 - 98.2For 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
16、Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specimen, the resin shall be heated as necessary to providesufficient lowering of the v
17、iscosity to produce good wetting ofthe reinforcement strand.6.3 Preimpregnated materials received for the preparation ofring test specimens shall be stored in a closed container at atemperature as recommended by the supplier. Before winding,they shall be removed from storage and conditioned asrecomm
18、ended by the supplier or in accordance with ProcedureA of Methods D 618.7. Procedure for Dry Reinforcement7.1 Fig. 2 is a schematic diagram of the system for wetting,tensioning, and collecting the reinforcement.7.1.1 Mounting Reinforcement PackagesMount the rein-forcement package in a convenient loc
19、ation within the super-structure of the winding machine. Provide sufficient braking ofthe axle of the package to prevent free-wheeling. This shouldbe a minimum tension.7.1.2 Application of ResinThe reinforcement leaving thepackage shall pass immediately into the resin bath. Heat theresin bath suffic
20、iently 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 breakage of the reinforce-ment.7.1.3 TensioningAfter leaving the resin bath, pass thereinforcement ove
21、r 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 winding operation. Limit thedeviation from the mean tension to 65 % from start to finish ofthe windi
22、ng 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 pulley(s).7.1.4 Level-WindingPass the wetted reinforcementthrough a level-winding guide and onto the m
23、old. 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 amountequivalent to one strand width.7.1.5 Collecting ReinforcementCollect the wetted rein-forcement strand on a
24、 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 the resin. Apply anadequate mold release agent to the mold or mandrel beforewinding is begun to as
25、sure 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, and C specimens in Fig. 3 to athickness beyond that required for finished thickness. Uponcompletion of the win
26、ding 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 an ovenand polymerize the resin in the manner prescribed by themanufacturer.NOTE 2Excess resin on t
27、he 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, resin system and age, operatortechniques, ambient conditions and conditioning, etc. For this reason it isbest to run
28、 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 mandrel in such a mannerthat delamination or other damage to the surfaces does notoccur. An arbor press may be used to a
29、pply force to separatethe mold parts in the single-ring process if required.7.1.8 Preparation of Specimens for Testing:7.1.8.1 WidthMold or machine the width of the Type A,B, C, and D specimens to the correct width.7.1.8.2 ThicknessDo not machine the thickness of theType B specimens. Machine the thi
30、ckness of the Types A, C,and D 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 th
31、esespecimens from the ring, take 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 healt
32、h or safety hazard, or both. Adequateprotection should be afforded operating personnel and equip-ment. This may require adequate ventilation or dust collectingfacilities, or both, at a minimum.FIG. 1 Suggested Single-Ring MoldD 2291 0328. Procedure for Prepregs8.1 The procedure for the preparation o
33、f ring test specimensfrom preimpregnated material shall be identical to that 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
34、 system,reinforcement, or preimpregnated material. It shall also includethe 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 relative hu-midity,9.1.3 Complete desc
35、ription of the impregnation method,9.1.4 Resin wiping 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.10. Keywor
36、ds10.1 composite; glass fiber; prepreg; ring samples; ringtensile testing; shear testing; specimen preparation; thermosetresinFIG. 2 Schematic Diagram of Wet Roving Ring Winding ApparatusType of SpecimenInside Diameter, DIWidth, b Wall Thickness, din. mm in. mm in. mmA 5.750 6 0.002 146.05 6 0.05 0.
37、250 6 0.005 6.35 6 0.127 0.060 6 0.002 1.52 6 0.05B 5.750 6 0.002 146.05 6 0.05 0.250 6 0.005 6.35 6 0.127 0.060 6 0.010 1.52 6 0.25C 5.750 6 0.002 146.05 6 0.05 0.250 6 0.005 6.35 6 0.127 0.125 6 0.002 3.18 6 0.05FIG. 3 Ring Test SpecimenD 2291 033SUMMARY OF CHANGESThis section identifies the locat
38、ion of selected changes to this practice. For the convenience of the user,Committee D20 has highlighted those changes that may impact the use of this practice. This section may alsoinclude descriptions of the changes or reasons for the changes, or both.D 2291 03:(1) Revised paragraph 1.2.D 2291 98:(
39、1) Terminology, Significance and Use, and Keywords sec-tions were added.(2) An ISO equivalency note was added to Section 1.(3) Test Methods D 2290 and D 2344 were added to 2.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item menti
40、onedin 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 technical committee a
41、nd 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 at a meeting
42、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 Drive, PO Bo
43、x 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).FIG. 4 Schematic Diagram of Preimpregnated Roving Winding SystemD 2291 034
