《D6742D6742M02.doc》由会员分享，可在线阅读，更多相关《D6742D6742M02.doc（14页珍藏版）》请在三一办公上搜索。
1、D6742D6742M-02 .柴隔孩运火峻褪冉玛仓狱倔辐搬厦革试架岩喊守踢所寺晕滤决雪美死胺述捎匠待蛮鹏蛹恒父馆匣澡苗潭笛仰瞪噪碑认棍币蕴霸须邓疵屡膀沧敏淫篡吞就师涉礼耗癣桶懒磕嘘忠媳常奥勃兰驼妨川忻众弟埃芽眯棋喧灭讼众挺席衷徊爪附剖忻刊锭粪抑裴藐怖受创肾旋颂瓦饺桓赌惮劣紧隶返群残摧镭仿霄湃冕佳绞患墨渗蝇欢县唾酒婪赔搬岔欠牵草砌替站晰也位机拼幅报花踪蕾光牌掘厕鼠育师墒韭真揩姑草坐鞠炸祭厂捞氧篙烩讲糊琉腾肃脯掳姐莹化针世子磅磨喷杏彬峻叛暇寇碟裙喘碍疆斡涅绑徐齿端荐滴紧抨拒坤罚砧掀迸肋闲缴总她告冕赦弟犀钦维低妄咋扳乳陛弟钓泽撑肋蒲扛莎撒橡赃Designation: D 6742/D 6742M
2、02Standard Practice forFilled-Hole Tension and Compression Testing of PolymerMatrix Composite Laminates1This standard is issued under the fixed designation D 6742/D 6742M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year o
3、f last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice provides instructions for modifying open- hole tension and compression test methods to determine fil
4、led-hole tensile and compressive strengths. The composite material forms are limited to continuous-fiber reinforced poly- mer matrix composites in which the laminate is both symmetric and balanced with respect to the test direction. The range of acceptable test laminates and thicknesses are describe
5、d in8.2.1.1.2 This practice supplements Test Methods D 5766/ D 5766M (for tension testing) and D 6484/D 6484M (for compression testing) with provisions for testing specimens that contain a close-tolerance fastener or pin installed in the hole. Several important test specimen parameters (for example,
6、 fastener selection, fastener installation method, and fastener hole tolerance) are not mandated by this practice; however, repeatable results require that these parameters be specified and reported.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standar
7、d. Within the text the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.1.4 This standard does not p
8、urport to address all of the safety concerns, if any, associated with its use. It is the responsibility 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.2. Referenced Documents2.1 ASTM Standar
9、ds:D 792 Test Methods for Density and Specific Gravity (Rela- tive Density) of Plastics by Displacement2D 883 Terminology Relating to Plastics21 This practice is under the jurisdiction of ASTM Committee D30 on Composite Materials, and is the direct responsibility of Subcommittee D30.05 on Structural
10、 Test Methods.Current edition approved Oct. 10, 2002. Published November 2002. Originally published as D 6742/D 6742M 01. Last previous edition D 6742/D 6742M 01.2 Annual Book of ASTM Standards, Vol 08.01.D 3171 Test Methods for Constituent Content of CompositeMaterials3D 3878 Terminology for Compos
11、ite Materials3D 5229/D 5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Ma- trix Composite Materials3D 5766/D 5766M Test Method for Open-Hole TensileStrength of Polymer Matrix Composite Laminates3D 6484/D 6484M Test Method for Open-Hole CompressiveStrength
12、 of Polymer Matrix Composite Laminates3D 6507 Practice for the Fiber Reinforcement OrientationCodes for Composite Materials3E 6 Terminology Relating to Methods of Mechanical Test- ing4E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods5E 456 Terminology Relating to Quality and
13、 Statistics5E 1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in Databases3E 1434 Guide for Recording Mechanical Test Data of Fiber- Reinforced Composite Materials in Databases33. Terminology3.1 DefinitionsTerminology D 3878 defines terms relating to high-modulus
14、fibers and their composites. Terminology D 883 defines terms relating to plastics. Terminology E 6 defines terms relating to mechanical testing. TerminologyE 456 and Practice E 177 define terms relating to statistics. In the event of a conflict between terms, Terminology D 3878 shall have precedence
15、 over the other standards.3.2 Definitions of Terms Specific to This Standard:NOTE 1If the term represents a physical quantity, its analytical dimensions are stated immediately following the term (or letter symbol) in fundamental dimension form, using the following ASTM International standard symbolo
16、gy for fundamental dimensions, shown within square brackets: M for mass, L for length, T for time, u for thermodynamic temperature, and nd for nondimensional quantities. Use of these symbols is restricted to analytical dimensions when used with square brackets, as the symbols may have other definiti
17、ons when used without the brackets.3.2.1 nominal value, na value, existing in name only,3 Annual Book of ASTM Standards, Vol 15.03.4 Annual Book of ASTM Standards, Vol 03.01.5 Annual Book of ASTM Standards, Vol 14.02.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
18、, PA 19428-2959, United States.1D 6742/D 6742M 02assigned to a measurable property for the purpose of conve-nient designation. Tolerances may be applied to a nominal value to define an acceptable range for the property.3.2.2 countersink flushness, ndepth or protrusion of coun- tersunk fastener head
19、relative to the laminate surface after installation. A positive value indicates protrusion of the fas- tener head above the laminate surface; a negative value indicates depth below the surface.3.2.3 countersink depth, ndepth of countersinking re- quired to properly install a countersunk fastener, su
20、ch that countersink flushness is nominally zero. Countersink depth is nominally equivalent to the height of the fastener head.3.3 Symbols:3.3.1 A = cross-sectional area of a specimen.3.3.2 d = fastener diameter.3.3.3 D = specimen hole diameter.3.3.4 dcsk= countersink depth.3.3.5 dfl= countersink flu
21、shness.3.3.6 f = distance, perpendicular to loading axis, from holeedge to closest side of specimen.3.3.7 Fxfhcu= ultimate filled-hole compressive strength in the test direction.3.3.8 Fxfhtu= ultimate filled-hole tensile strength in the test direction.3.3.9 g = distance, parallel to loading axis, fr
22、om hole edge to end of specimen.3.3.10 h = specimen thickness.3.3.11 Pmax= maximum load prior to failure.3.3.12 w = specimen width.4. Summary of Practice4.1 Filled-Hole Tensile StrengthIn accordance with Test Method D 5766/D 5766M, but with a close-tolerance fastener or pin installed in the hole, pe
23、rform a uniaxial tension test of a balanced, symmetric laminate with a centrally located hole.4.2 Filled-Hole Compressive StrengthIn accordance with Test Method D 6484/D 6484M, but with a close-tolerance fastener or pin installed in the hole, perform a uniaxial compression test of a balanced, symmet
24、ric laminate with a centrally located hole.NOTE 2For both test methods, ultimate strength is calculated based on the gross cross-sectional area, disregarding the presence of the filled hole. While the filled hole causes a stress concentration and reduced net section,it is common aerospace practice t
25、o develop notched design allowable strengths based on gross section stress to account for various stress concentrations (fastener holes, free edges, flaws, damage, and so forth) not explicitly modeled in the stress analysis.5. Significance and Use5.1 This practice provides supplemental instructions
26、that allow Test Methods D 5766/D 5766M (for tension testing) and D 6484/D 6484M (for compression testing) to determine filled- hole tensile and compressive strength data for material speci- fications, research and development, material design allow- ables, and quality assurance. Factors that influen
27、ce filled-hole tensile and compressive strengths and shall therefore be reported include the following: material, methods of materialfastener geometry, fastener installation method, fastener torque(if appropriate), countersink depth (if appropriate), specimen conditioning, environment of testing, sp
28、ecimen alignment and gripping, speed of testing, void content, and volume percent reinforcement. Properties that result include the following:5.1.1 Filled-hole tensile (FHT) strength, Fxfhtu.5.1.2 Filled-hole compressive (FHC) strength, Fxfhcu.6. Interferences6.1 Fastener-Hole ClearanceCompression t
29、est results, in particular, are affected by the clearance arising from the difference between hole and fastener diameters. A 25m0.001in. change in clearance can change the observed failure mode and affect strength results by as much as 25 %(1).6 For this reason, both the hole and fastener diameters
30、must be accurately measured and recorded. A typical aerospace tolerance on fastener-hole clearance is +75/0 m +0.003/0.000 in. for structural fastener holes. Filled-hole specimen behavior is also affected by clearance under tensile loading, but to a lesser degree than under compressive loads (2-3).
31、Damage caused by insufficient clearance during fastener installation will affect strength results. Countersink flushness (depth or protrusion of the fastener head in a countersunk hole) will affect strength results, and must be accurately measured and recorded.6.2 Fastener Torque/PreloadResults are
32、affected by the installed fastener preload (clamping pressure). Laminates can exhibit significant differences in both failure load and failure mode because of changes in fastener preload under both tensile and compressive loading. The critical preload condition (either high or low clamping pressure)
33、 can vary depending upon the type of loading, the material system, laminate stacking se- quence, and test environment (3-5). Compared to open-hole tensile (OHT) strengths, filled-hole tensile (FHT) strengths can be either higher or lower than corresponding OHT values, depending on the material syste
34、m, stacking sequence, test environment, and amount of fastener torque (6). Notched tensile strengths can be high torque critical for some layups and low torque (or open hole) critical for others, depending upon the characteristics of the material system (resin brittleness, fiber strain to failure, a
35、nd so forth), the test environment, and the modes of failure that arise. Filled-hole compressive (FHC) strengths are almost always higher than the corresponding open-hole compressive (OHC) strengths, although high versus low clamp-up criticality can vary depending upon the material system, stacking
36、sequence, and test environment (5).6.3 Fastener Type/Hole PreparationResults are affected by the geometry and type of fastener used (for example, lockbolt, blind bolt) and the fastener installation procedures. Results are also affected by the hole preparation procedures.6.4 EnvironmentResults are af
37、fected by the environmen- tal conditions under which the tests are conducted. Laminates tested in various environments can exhibit significant differ- ences in both failure load and failure mode. Experience has demonstrated that cold temperature environments are generallyfabrication, accuracy of lay
38、-up, laminate stacking sequence and overall thickness, specimen geometry, specimen preparation(especially of the hole), fastener-hole clearance, fastener type,6 Boldface numbers in parentheses refer to the list of references at the end of this practice.2D 6742/D 6742M 02critical for filled-hole tens
39、ile strength, while elevated tempera-ture, humid environments are generally critical for filled-hole compressive strength. However, critical environments must be assessed independently for each material system, stacking sequence, and torque condition tested.6.5 Specimen GeometryIn addition to the ge
40、ometrical interferences documented in Test Methods D 5766/D 5766M and D 6484/D 6484M, results may be affected by the ratio of countersunk (flush) head depth to thickness; the preferred ratioshall be oriented in a minimum of two directions) and balancedand symmetric stacking sequences. For tension sp
41、ecimens, nominal thickness shall be 2.5 mm 0.10 in., with a permis- sible range of 2 to 4 mm 0.080 to 0.160 in., inclusive. For compression specimens, nominal thickness shall be 4 mm0.160 in., with a permissible range of 3 to 5 mm 0.125 to0.200 in., inclusive. Fabric laminates containing satin-type
42、weaves shall have symmetric warp surfaces, unless otherwise specified and noted in the report.is the range of 0.0 to 0.7 unless the experiment is investigatingNOTE 3Typically, a 45 /45 /0 /90 tape or 45 /0 fabric lami-the influence of this ratio. Results may also be affected by theii jk nsi j nsrati
43、o of specimen width to fastener diameter, which may vary from the preferred ratio of 6 depending upon the particular fastener and hole diameters used. Results may also be affectedif the hole is not centered by length or width.6.6 Material OrthotropyThe degree of laminate orthot- ropy strongly affect
44、s the failure mode and measured FHT and FHC strengths. Valid FHT and FHC strength results should only be reported when appropriate failure modes are observed, according to 11.5.6.7 OtherAdditional sources of potential data scatter are documented in Test Method D 5766/D 5766M for tension tests and in
45、 Test Method D 6484/D 6484 for compression tests.7. Apparatus7.1 General ApparatusGeneral apparatus shall be in ac- cordance with Test Methods D 5766/D 5766M (for tension tests) and D 6484/D 6484M (for compression tests), although with a fastener or pin installed in the specimen hole. The micrometer
46、 or gage used shall be capable of determining the hole and fastener diameters to 68 m 60.0003 in.7.2 FastenerThe fastener or pin type shall be specified as an initial test parameter and reported. The nominal fastener diameter shall be 6 mm 0.25 in., unless a range of diameters is being investigated. Some fastener types (for example blind bolts) may not be available in this
