fl) Designation: D 3039/D 3039M - 95a Standard Test Method for Tensile Proper “Troll This test method determines the in-plane tensile {properties of polymer matrix composite materials reinforced iby high-modulus fibers. The composite material forms are limited to continuous-fiber or discontinuous-fiber reinforced } @omposites in which the laminate is balanced and symmetric with respect to the test direction. jol.2 This standard does not purport to address all of the fay concerns, if any, associated with its use. It is the wecsponsibility ofthe user of this standard to establish appro diate safety and health practices and determine the applica- ihilty of regulatory limitations prior to use. Jerk3 The values stated in either SI units or inch-pound ‘mits are to be regarded separately as standard. Within the ‘ext the inch-pound units are shown in brackets. The values in each system are not exact equivalents; therefore, “ach system must be used independently of the other. ‘onconformance with the standard a ‘Bi-Referenced Documents 1-2.1 ASTM Standards: siisD 792 Test Methods for Specific Gravity (Relative Den- “te issity) and Density of Plastics by Displacement? 1 D883 Terminology Relating to Plastics? ©2584 Test Method for Ignition Loss of Cured Rein- forced Resins? 12734 Test Methods for Void Content of Reinforced 3171 Test Method for Fiber Content of Resin-Matrix = Composites by Matrix Digestion* »y-D 3878 Terminology of High-Modulus Reinforcing Fibers afy:. and Their Composites ‘ D5229/D 5229M Test Method for Moisture Absorption “i ts. Properties and Equilibrium Conditioning of Polymer P= _ Matrix Composite Materials# ‘80 E 4 Practices for Force Verification of Testing Machines? ° E6 Terminology Relating to Methods of Mechanical Testing’ “Tet Method D3038/D 3039M is under the jersiiction of ASTM. Com ite D30 on High Modulus Fibers and The Composites andthe direct esilty of Subcommittee D30.4 on Lamina and Laminate Test Methods. {Curent eon approved Aug 15, 1993. Published October 1995, Originally sAtbsbed as D 3039-717 Last previous edition D 3039 95, te} Annual ook of ASTM Standards, Vol O80. £2 Anal Book of ASTM Standard, Vol 08.02. Sdn Book of ASTM Standards, Vol 15.03 * annual Book of ASTM Standards, Vol 0301, ombining values from the two systems may result in . 99 s of Polymer Matrix Composite Materials’ ‘This standard is issued ude the ned designation D 3039/0 3039M; the number immediately folowing the designation indicates the year of orignal adoption o, inthe cae of revision, the year of las revision. number in parentheses indtes the year of last reapprval A superscrit ep (indicates an editorial change since the at revision or reapprova, This standard has been approved for use by agencies ofthe Deparment of Defense. Cons the DoD Index of Specifications and ‘Standards forte specie Yar of issue which has Boo adopted bythe Deparment of Defense. E83 Practice for Verification and Classification of Extensometers? E 111 Test Method for Young's Modulus, Tangent Mod- ulus, and Chord Modulus* E 122 Practice for Choice of Sample Size to Estimate a ‘Measure of Quality for a Lot or Process® E132 Test Method for Poisson's Ratio at Room ‘Temperature? E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods® E 251 Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages* E 456 Terminology Relating to Quality and Statistics® E 1012 Practice for Verification of Specimen Alignment Under Tensile Loading’ E 1237 Guide for Installing Bonded Resistance Strain Gages* 3. Terminology 3.1 Definitions —Terminology D 3878 defines terms re- lating to high-modulus fibers and their composites. Termi- nology D 883 defines terms relating to plastics. Terminology E6 defines terms relating to mechanical testing. Termi- nology E456 and Practice E177 define terms relating to statistics. In the event of a conflict between terms, Termi- nology D 3878 shall have precedence over the other stan- dards. 3.2 Descriptions of Terms Specific to This Standard: [Nore 1—If the term represents 2 physical quantity, its analytical ‘dimensions are stated immediately following the term (or letter symbol) in fundamental dimension form, using the following, ASTM standard symbology for fundamental dimensions, shown within square brackets: (441 for mass, (C] for length, [7] for time, [@] for thermodynamic temperature, and [nd] for non-dimensional quantities, Use of these symbols is restricted to analytical dimensions when used with square brackets, asthe symbols may have other definitions when used without the brackets. 3.2.1 nominal value, n—a value, existing in name only, assigned to a measurable property for the purpose of convenient designation. Tolerances may be applied to a ‘nominal value to define an acceptable range for the property. 3.2.2 transition region, n—a strain region of a stress-strain or strain-strain curve over which a significant change in the Annual Book of ASTM Standards, Vol 18.02@b D 3039/D 3039M slope of the curve occurs within a small strain range. 3.2.3 transition strain, <=" [nd], n—the strain value at the mid-range of the’ transition region between the two essentially linear portions of a bilinear stress-strain or strain- strain curve. 3.2.3.1 Discussion—Many filamentary composite mate- rials show essentially bilinear behavior during loading, such as seen in plots of either longitudinal stress versus longitu- inal strain or transverse strain versus longitudinal strain. ‘There are varying physical reasons for the existence of a transition region. Common examples include: matrix cracking under tensile loading and ply delamination. 3.3 Symbols: 3.3.1 4—minimum cross-sectional area of a coupon, 3.3.2 B,—percent bending for a uniaxial coupon of rec- tangular cross-section about y-axis of the specimen (about the narrow direction), 3.3.3 B,—percent bending for a uniaxial coupon of rec- tangular cross-section about the z-axis of the specimen (about the wide direction). 3.3.4 CV—coefficient of variation statistic of a sample population for a given property (in percent). 3.3.5. E—modulus of elasticity in the test direction. 3.36 Fé—ultimate tensile strength in the test direction. 3.3.7 F—uhimate shear strength in the test direction. 3.3:8. coupon thickness. 3.39 L,—extensometer gage length. 3.3.10 L,,i;—minimum required bonded tab length. 3.3.11 n—number of coupons per sample population... 3.3.12 P—load carried by test coupon. 3.3.13 P/—toad carried by test coupon at failure. 3.3.14 P”*—maximum load carried by test. coupon prior to failure. 3.3.15 ,-;—standard deviation statistic of a sample pop- ulation for'a given property. 3.3.16 w—coupon width. 3.3.17 x;—test result for an individual coupon from the sample population for a given property. 3.3.18 3—mean or average (estimate of mean) ofa sample population for a given property. 3.3.19 extensional displacement. 3.320 «general symbol for strain, whether normal strain or shear strain. 3.3.21 e—indicated normal strain from strain transducer or extensometer. 3.3.22 o—normal stress. 3.3.23 »—Poisson’s ratio. 4, Summary of Test Method 4.1 A thin fat strip of material having a constant rectan- gular cross-section is mounted in the grips of a mechanical testing machine and monotonically loaded in tension while recording load. The ultimate strength of the material can be determined from the maximum load carried prior to failure. {If the coupon strain is monitored with strain or displacement ‘transducers then the stress-strain response of the material can be determined, from which the ultimate tensile strain, tensile ‘modulus of elasticity, Poisson's ratio, and transition strain can be derived. 5. Significance and Use 5.1 This test method is designed to produce tensil property data for material specifications, research and devel ‘opment, quality assurance, and structural design and anal ysis. Factors that influence the tensile response and shoul therefore be reported include the following: material ‘methods of material preparation and lay-up, specimet stacking sequence, specimen preparation, specimen condi tioning, environment of testing, specimen alignment anc ‘ripping, speed of testing, time at temperature, void content and volume percent reinforcement. Properties, in the tes direction, which may be obtained from this test methoc include the following: 3.11 Ultimate tensile strength, 5.1.2. Ultimate tensile strain, 5.1.3 Tensile chord modulus of elasticity, 5.14 Poisson's ratio, and 5.1.5 Transition strain, 6. Interferences 6.1 Material and Specimen Preparation—Poor materia fabrication practices, lack of control of fiber alignment, anc ‘damage induced by improper coupon machining are knowr causes of high material data scatter in composites. 6.2 Gripping—A high percentage of grip-induced failures. especially when combined with high material data scatter, an indicator ‘of specimen gripping problems. Specimer gripping methods are’discussed further in 7.2.4, 8.2, anc 115. 6.3 System Alignment—Excessive bending will cause pre mature failure, as well as highly inaccurate modulus 0 elasticity determination. Every effort should be made tc climinate excess bending from the test system. Bending may ‘occur due to misaligned grips, or from specimens themselves if improperly installed in the grips or out-of-tolerance due tc oor specimen preparation. If there is any doubt as to the alignment inherent in a given test machine then the align ‘ment should be checked as discussed in 7.2.5. 7. Apparatus 7.1 Micrometers—A micrometer with a 4- to S-mm [0.16 to 0.20-in] nominal diameter double-ball interface shall be used to measure the thickness of the specimen. A. mi: crometer with a flat anvil interface shall be used to measure the width of the specimen, The accuracy of the instruments shall be suitable for reading to within 1% of the sample ‘width: and thickness. For typical specimen geometries, ap instrument with an accuracy of + 2.5 um [0.0001 in.} adequate for thickness measurement, while an instrument with an accuracy of + 25 ym [40.001 in, is adequate for width measurement. 7.2 Testing Machine—The testing machine shall be in conformance with Practices E4, and shall satisfy the fol owing requirements: 7.2.1 Testing Machine Heads—The testing machine shall have both an essentially stationary head and a movable head. 7.2.2 Drive Mechanism—The testing machine drive mechanism shall be capable of imparting to the movable head a controlled velocity with respect to the stationary head. The velocity of the movable head shall be capable of being regulated as specified in 11.3.[fje023 Load Indicator—The testing machine load-sensing ice shall be capable of indicating the total load being by the test specimen. This device shall be essentially e from inertiaelag atthe specified rate of testing and shall Gfgicate the load with an accuracy over the load range(s) of Sigterest of within +1 % of the indicated value. The load gages) of interest may be fairly low for modulus evaluation, : atch higher for strength evaluation, or both, as required ‘Nore 2—Obtaning precision load data over alae range of intrest SPW Same test, such as when both elastic modulus and ultimate load idetcng determined, place extreme fequrements onthe load cll and iain. For some equipment a special calbration may be ire). For some combinations of material and Toad cel, simul ecion measirement of both elastic modulus ad ulimale ‘ay not be posible and measurement of modulus and sueagth have tobe performed in separate tests using ferent load cel for cach is FAA Grins Each ead ofthe tstng machine hall cary sip for holding the test specimen so thatthe direction of ‘applied to the specimen is coincident with the longitu- axis of the specimen. The grips shall apply sufficient ral pressure to prevent slippage between the grip face and ‘coupon. If tabs are used the grips should be long enough they overhang the beveled portion of the tab by ‘Approximately 10-15 mm [0.5 in], It is highly desirable to “ise. grips that are rotationally sclCaligning to minimize ing stresses in the coupon. 3 Grip surfaces that are lightly serrated, approximately mm (23 serations/in., have bee found stator for us in 38 rips whea kept clean and sharp coarse serations may sdities have been used succésilly with either hydraulic grips or an Giery lth interface, or both. 4.1.2.5 System Alignment—Poot system alignment can be a jor contributor to premature failure, to elastic property scatter, or ‘both. Practice E 1012 describes bending ®aluation guidelines and describes potential ‘sources of ment during tensile testing. In addition to Practice 4012 the degree of bending in a tensile system can also be evaluated using the following related procedure. Specimen ‘ending is considered separately in 11.6.1. {8294 A reotanelar alignment coupon, preferably sim ilar in size and stifness to the test specimen of interest, is instrumented with a minimum of three longitudinal strain ‘ees of similar type, two on the front face across the width sind one on the back face of the specimen, as shown in Fig. |. ‘Any difference in indicated strain between these gages during Ipating provides measure ofthe amount of tending in the ‘ness plane (B,) and width plane (B,) ofthe coupon. The strain gage location should normally be located in the middle of the coupon gage section (if modulus determination is a concer), near a grip (if premature grip failures are a froblem), or any combination of these areas. 7.2.5.2 When evaluating system alignment itis advisable to perform the alignment check with the same coupon inserted in each of the four possible installation permutations escribed relative to the intial position): intial (top-front facing observer), rotated back-to-front only (top-back facing observer), rotated end-forend only (bottom-front facing observer), and rotated both front-to-back and end-to-end (bottom-back facing observer). These four data sets provide 4n indication of whether the bending is due to the system. ‘ripinduced failures in untabbed coupons. Smooth gripping. 101 @) D3039/D 3039M sc || s « | 1G soz | }3 wis tye 2Pt) Front Side FIG. 1. Gage Locations for Systom Alignment Check Coupon itself or to tolerance in the alignment check coupon or aging. 7.2.5.3 The zero strain point may be taken either prior to ripping or after gripping: The strain response of the align- ‘ment coupon is subsequently monitored during the gripping. process, the tensile loading process, or both. Eqs. 1-3 use these indicated strains to calculate the ratio of the percentage of bending strain to average extensional strain for each ‘bending plane of the alignment coupon, and the total percent bending, By. Plotting percent bending versus axial average strain is. useful in understanding trends in the bending behavior of the system. 7.2.5.4 Problems with failures during gripping would be reason to examine bending strains during the gripping process in the location near the grip. Concern over modulus data scatter would be reason to evaluate bending strains over the modulus evaluation load range for the typical transducer location. Excessive failures near the grips would be reason to evaluate bending strains near the grip at high loading levels. While the maximum advisable amount of system mis- alignment is material and location dependent, good testing practice is generally able to limit percent bending to a range of 3 to. 5 % at moderate strain levels (>1000 ie). A system showing excessive bending for the given application should be readjusted or modified. w @ B, = percent bending about system y-axis (about the narrow plane), as calculated by Ea. 1, %, 3) percent bending about system z-axis (about the wide plane), as calculated by Eq. 2, %, = indicated longitudinal strains displayed by gages 1, 2, and 3, respectively, of Fig. 1, we and