1、Designation: D695 10Standard Test Method forCompressive Properties of Rigid Plastics1This standard is issued under the fixed designation D695; 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 p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () 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 test method covers the determination of the me-chanical pro
3、perties of unreinforced and reinforced rigid plas-tics, including high-modulus composites, when loaded incompression at relatively low uniform rates of straining orloading. Test specimens of standard shape are employed. Thisprocedure is applicable for a composite modulus up to andincluding 41,370 MP
4、a (6,000,000 psi).1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.NOTE 1For compressive properties of resin-matrix composites rein-forced with oriented continuous, discontinuous, or cross-ply reinforce-ments, tests may be made i
5、n accordance with Test Method D3410/D3410M.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 regulato
6、ry limitations prior to use. A specific precau-tionary statement is given in 13.1.NOTE 2This test method is technically equivalent to ISO 604.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD883 Terminol
7、ogy Relating to PlasticsD3410/D3410M Test Method for Compressive Propertiesof Polymer Matrix Composite Materials with UnsupportedGage Section by Shear LoadingD4000 Classification System for Specifying Plastic Materi-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE4 Practices
8、 for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:3ISO 604 PlasticsDetermination of Compressive Proper-ties3. Terminology
9、3.1 General The definitions of plastics used in this testmethod are in accordance with Terminology D883 unlessotherwise indicated.3.2 Definitions:3.2.1 compressive deformationthe decrease in length pro-duced in the gage length of the test specimen by a compressiveload. It is expressed in units of le
10、ngth.3.2.2 compressive strainthe ratio of compressive defor-mation to the gage length of the test specimen, that is, thechange in length per unit of original length along the longitu-dinal axis. It is expressed as a dimensionless ratio.3.2.3 compressive strengththe maximum compressivestress (nominal
11、) carried by a test specimen during a compres-sion test. It may or may not be the compressive stress(nominal) carried by the specimen at the moment of rupture.3.2.4 compressive strength at failure (nominal)the com-pressive stress (nominal) sustained at the moment of failure ofthe test specimen if sh
12、attering occurs.3.2.5 compressive stress (nominal)the compressive loadper unit area of minimum original cross section within the gageboundaries, carried by the test specimen at any given moment.It is expressed in force per unit area.1This test method is under the jurisdiction of ASTM Committee D20 o
13、n Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved April 1, 2010. Published April 2010. Originallyapproved in 1942. Last previous edition approved in 2008 as D695 - 08. DOI:10.1520/D0695-10.2For referenced ASTM standards, visit the AST
14、M 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036
15、, http:/www.ansi.org.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.3.2.5.1 DiscussionThe expression of compressive proper-ties in terms of the minimum original cross
16、 section is almostuniversally used. Under some circumstances the compressiveproperties have been expressed per unit of prevailing crosssection. These properties are called “true” compressive prop-erties.3.2.6 compressive stress-strain diagrama diagram inwhich values of compressive stress are plotted
17、 as ordinatesagainst corresponding values of compressive strain as abscis-sas.3.2.7 compressive yield pointthe first point on the stress-strain diagram at which an increase in strain occurs without anincrease in stress.3.2.8 compressive yield strengthnormally the stress at theyield point (see also s
18、ection 3.2.11).3.2.9 crushing loadthe maximum compressive force ap-plied to the specimen, under the conditions of testing, thatproduces a designated degree of failure.3.2.10 modulus of elasticitythe ratio of stress (nominal) tocorresponding strain below the proportional limit of a material.It is exp
19、ressed in force per unit area based on the average initialcross-sectional area.3.2.11 offset compressive yield strengththe stress at whichthe stress-strain curve departs from linearity by a specifiedpercent of deformation (offset).3.2.12 percent compressive strainthe compressive defor-mation of a te
20、st specimen expressed as a percent of the originalgage length.3.2.13 proportional limitthe greatest stress that a materialis capable of sustaining without any deviation from propor-tionality of stress to strain (Hookes law). It is expressed inforce per unit area.3.2.14 slenderness ratiothe ratio of
21、the length of a col-umn of uniform cross section to its least radius of gyration. Forspecimens of uniform rectangular cross section, the radius ofgyration is 0.289 times the smaller cross-sectional dimension.For specimens of uniform circular cross section, the radius ofgyration is 0.250 times the di
22、ameter.4. Significance and Use4.1 Compression tests provide information about the com-pressive properties of plastics when employed under conditionsapproximating those under which the tests are made.4.2 Compressive properties include modulus of elasticity,yield stress, deformation beyond yield point
23、, and compressivestrength (unless the material merely flattens but does notfracture). Materials possessing a low order of ductility may notexhibit a yield point. In the case of a material that fails incompression by a shattering fracture, the compressive strengthhas a very definite value. In the cas
24、e of a material that does notfail in compression by a shattering fracture, the compressivestrength is an arbitrary one depending upon the degree ofdistortion that is regarded as indicating complete failure of thematerial. Many plastic materials will continue to deform incompression until a flat disk
25、 is produced, the compressivestress (nominal) rising steadily in the process, without anywell-defined fracture occurring. Compressive strength canhave no real meaning in such cases.4.3 Compression tests provide a standard method of obtain-ing data for research and development, quality control, accep
26、-tance or rejection under specifications, and special purposes.The tests cannot be considered significant for engineeringdesign in applications differing widely from the load-time scaleof the standard test. Such applications require additional testssuch as impact, creep, and fatigue.4.4 Before proce
27、eding with this test method, referenceshould be made to the ASTM specification for the materialbeing tested. Any test specimen preparation, conditioning,dimensions, and testing parameters covered in the materialsspecification shall take precedence over those mentioned in thistest method. If there is
28、 no material specification, then thedefault conditions apply. Table 1 in Classification D4000 liststhe ASTM materials standards that currently exist.5. Apparatus5.1 Testing MachineAny suitable testing machine capableof control of constant-rate-of-crosshead movement and com-prising essentially the fo
29、llowing:5.1.1 Drive MechanismA drive mechanism for impartingto the movable cross-head member, a uniform, controlledvelocity with respect to the base (fixed member), with thisvelocity to be regulated as specified in Section 9.5.1.2 Load IndicatorA load-indicating mechanism ca-pable of showing the tot
30、al compressive load carried by the testspecimen. The mechanism shall be essentially free frominertia-lag at the specified rate of testing and shall indicate theload with an accuracy of 61 % of the maximum indicatedvalue of the test (load). The accuracy of the testing machineshall be verified at leas
31、t once a year in accordance withPractices E4.5.2 CompressometerA suitable instrument for determin-ing the distance between two fixed points on the test specimenat any time during the test. It is desirable that this instrumentautomatically record this distance (or any change in it) as afunction of th
32、e load on the test specimen. The instrument shallbe essentially free of inertia-lag at the specified rate of loadingand shall conform to the requirements for a Class B-2extensometer as defined in Practice E83.NOTE 3The requirements for extensometers cited herein apply tocompressometers as well.5.3 C
33、ompression ToolAcompression tool for applying theload to the test specimen. This tool shall be so constructed thatloading is axial within 1:1000 and applied through surfaces thatare flat within 0.025 mm (0.001 in.) and parallel to each otherin a plane normal to the vertical loading axis. Examples of
34、suitable compression tools are shown in Fig. 1 and Fig. 2.5.4 Supporting JigA supporting jig for thin specimens isshown in Fig. 3 and Fig. 4.5.5 MicrometersSuitable micrometers, reading to 0.01mm or 0.001 in. for measuring the width, thickness, and lengthof the specimens.6. Test Specimens6.1 Unless
35、otherwise specified in the materials specifica-tions, the specimens described in 6.2 and 6.7 shall be used.These specimens may be prepared by machining operationsD695 102from materials in sheet, plate, rod, tube, or similar form, orthey may be prepared by compression or injection molding ofthe mater
36、ial to be tested. All machining operations shall bedone carefully so that smooth surfaces result. Great care shallbe taken in machining the ends so that smooth, flat parallelsurfaces and sharp, clean edges, to within 0.025 mm (0.001 in.)perpendicular to the long axis of the specimen, result.6.2 The
37、standard test specimen, except as indicated in6.3-6.7, shall be in the form of a right cylinder or prism whoselength is twice its principal width or diameter. Preferredspecimen sizes are 12.7 by 12.7 by 25.4 mm (0.50 by 0.50 by1 in.) (prism), or 12.7 mm in diameter by 25.4 mm (cylinder).Where elasti
38、c modulus and offset yield-stress data are desired,the test specimen shall be of such dimensions that the slender-ness ratio is in the range from 11 to 16:1. In this case, preferredspecimen sizes are 12.7 by 12.7 by 50.8 mm (0.50 by 0.50 by2 in.) (prism), or 12.7 mm in diameter by 50.8 mm (cylinder)
39、.6.3 For rod material, the test specimen shall have a diameterequal to the diameter of the rod and a sufficient length to allowa specimen slenderness ratio in the range from 11 to 16:1.6.4 When testing tubes, the test specimen shall have adiameter equal to the diameter of the tube and a length of 25
40、.4mm (1 in.) (Note 4). For crushing-load determinations (at rightangles to the longitudinal axis), the specimen size shall be thesame, with the diameter becoming the height.NOTE 4This specimen can be used for tubes with a wall thickness of1 mm (0.039 in.) or over, to inside diameters of 6.4 mm (0.25
41、 in.) or over,and to outside diameters of 50.8 mm (2.0 in.) or less.6.5 Where it is desired to test conventional high-pressurelaminates in the form of sheets, the thickness of which is lessthan 25.4 mm (1 in.), a pile-up of sheets 25.4 mm square, witha sufficient number of layers to produce a height
42、 of at least 25.4mm, may be used.6.6 When testing material that may be suspected of anisot-ropy, duplicate sets of test specimens shall be prepared havingtheir long axis respectively parallel with and normal to thesuspected direction of anisotropy.6.7 Reinforced Plastics, Including High-Strength Com
43、pos-ites and High-Strength Composites and Highly OrthotropicLaminatesThe following specimens shall be used for rein-forced materials, or for other materials when necessary tocomply with the slenderness ratio requirements or to permitattachment of a deformation-measuring device.6.7.1 For materials 3.
44、2 mm (18 in.) and over in thickness, aspecimen shall consist of a prism having a cross section of 12.7mm (12 in.) by the thickness of the material and a length suchthat the slenderness ratio is in the range from 11 to 16:1 (Note5).6.7.2 For materials under 3.2 mm (18 in.) thick, or whereelastic modu
45、lus testing is required and the slenderness ratiodoes not provide for enough length for attachment of acompressometer or similar device, a specimen conforming toNOTE 1Devices similar to the one illustrated have been successfullyused in a number of different laboratories. Details of the device develo
46、pedat the National Institute for Standards and Technology are given in thepaper byAitchinson, C. S., and Miller, J.A., “ASubpress for CompressiveTests,” NationalAdvisory Committee forAeronautics, Technical Note No.912, 1943.FIG. 1 Subpress for Compression TestsFIG. 2 Compression ToolFIG. 3 Support J
47、ig for Thin SpecimenD695 103that shown in Fig. 5 shall be used. The supporting jig shown inFig. 3 and Fig. 4 shall be used to support the specimen duringtesting (Note 6).NOTE 5If failure for materials in the thickness range of 3.2 mm (18in.) is by delamination rather than by the desirable shear plan
48、e fracture, thematerial may be tested in accordance with 6.7.2.NOTE 6Round-robin tests have established that relatively satisfactorymeasurements of modulus of elasticity may be obtained by applying acompressometer to the edges of the jig-supported specimen.6.8 When testing syntactic foam, the standa
49、rd test specimenshall be in the form of a right cylinder 25.4 mm (1 in.) indiameter by 50.8 mm (2 in.) in length.7. Conditioning7.1 ConditioningCondition the test specimens in accor-dance with Procedure A of Practice D618 unless otherwisespecified by contract or relevant ASTM material specification.Conditioning time is specified as a minimum. Temperature andhumidity tolerances shall be in accordance with Section 7 ofPractice D618 unless specified differently by contract ormaterial specification.7.2 Test ConditionsConduct the tests at the same
