ASTM D3039 Tensile Testing of Polymer Composites | UnitedTest Composites Testing Machine & Fixtures

Information on the most widely used ASTM standards within the materials testing industry

Descriptions of the most prominent lSO standards within the materials testing industry

Standards including EN, DIN, JlS, and more

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ASTM D3039 Tensile Test Machine | Polymer Matrix Composite Tensile Properties | UnitedTest

ASTM D3039 standard governs in-plane tensile property testing for high-modulus fiber-reinforced polymer matrix composites. UnitedTest manufactures ASTM D3039 compliant tensile testing machines for balanced symmetric laminate quality control and structural design verification.

ASTM D3039 is the authoritative industry standard dedicated to measuring in-plane tensile properties of high-modulus fiber-reinforced polymer matrix composite materials (PMC). It provides a unified, repeatable laboratory test procedure specifically designed for continuous fiber and discontinuous fiber-reinforced composite laminates that feature balanced and symmetric layup structures relative to the tensile test direction.

This standardized test method accurately captures critical mechanical performance indicators including tensile strength, tensile modulus, and failure strain for advanced composite laminates. Widely recognized for material specification validation, R&D optimization, batch quality assurance, and structural engineering analysis, ASTM D3039 delivers reliable baseline data for qualifying composite materials used in high-performance industrial applications. It serves as a fundamental testing benchmark for symmetric composite laminate mechanical characterization across advanced manufacturing sectors.

UnitedTest designs and manufactures high-precision ASTM D3039 tensile testing machines fully compliant with standard test protocols. Our professional composite tensile test equipment ensures precise load control, stable specimen gripping, and accurate displacement measurement, perfectly suited for aerospace, automotive, wind energy and advanced polymer composite laboratories to conduct standardized laminate tensile performance testing and material certification.

Test Principles:

A thin flat strip of constant rectangular cross-section ("coupon") is mounted in the grips of a mechanical testing machine and monotonically loaded in tension to failure while force is recorded.

Ultimate strength comes from the maximum force carried before failure.

If strain or displacement transducers are attached, the full stress–strain response is obtained, from which are derived: ultimate tensile strain, tensile chord modulus of elasticity, Poisson's ratio, and transition strain.

Physically it is a uniaxial force-introduction test: the grips must transfer load into the specimen (through tabs or friction) without causing premature failure, and the gage section must see a nearly pure, uniform tensile stress field with minimal bending.

Properties obtained

Property	Symbol	Notes
Ultimate tensile strength	Fᵗᵘ	Max force / average cross-sectional area
Ultimate tensile strain	εᵗᵘ	Strain at or near rupture
Tensile chord modulus of elasticity	Eᶜʰ	Slope over a defined strain range (1000–3000 µε)
Poisson's ratio	ν	Requires longitudinal + transverse strain
Transition strain	—	Strain at midpoint of the "knee" of a bilinear curve (matrix cracking / ply delamination onset)

Test Specimen information

1, Minimum 5 specimens per test condition.

2, Constant rectangular cross-section along the gage length;

Minimum overall length = gripping length + 2×specimen width + gage length.

3, Recommended Dimensions

Fiber Orientation	Width	Overall Length	Thickness	Tab Length	Tab Bevel Angle
0° unidirectional	15 mm	250 mm	1.0 mm	56 mm	7° or 90°
90° unidirectional	25 mm	250 mm	2.5 mm	25 mm	90°
Balanced/symmetric laminate	25 mm	175 mm	2.0 mm	25 mm	90°
Random discontinuous fiber	25 mm	250 mm	2.5 mm	— (emery cloth interface)	—

4, Bonded tabs: Most commonly made of [0/90] E-glass/epoxy laminates, bonded with a tough, high-elongation adhesive.

Friction tabs: Non-bonded tabs held by grip pressure, often used with an emery cloth interface.

ASTM D3039 Tensile Testing of Polymer Composites

Test Equipment required of ASTM D3039 Tensile Testing of Polymer Composites:

Tensile Tester	Conforms to ASTM E4 practices for force calibration and verification Configuration: one stationary head + one movable head with controlled velocity Force indicator: ±1% accuracy over the test force range, free of inertia lag at specified test speeds Grips: rotationally self-aligning grips are recommended to minimize bending stresses. Wedge-action grips (with ~1 serration/mm lightly serrated surfaces) or hydraulic grips are standard; grips must extend 10–15 mm past the tapered portion of specimen tabs.
Dimensional Measurement Tools	Ball-anvil micrometers (4–7 mm nominal diameter) for specimens with irregular surfaces (e.g., bag-side laminates); flat-anvil micrometers for smooth tooled surfaces Flat-anvil calipers for width measurement
Strain Measurement Devices	Bonded resistance strain gages: Comply with ASTM E251; minimum 3 mm active gage length (6 mm recommended for most materials). Surface preparation must not expose or damage reinforcing fibers. Temperature compensation and transverse sensitivity correction are required for accurate Poisson’s ratio measurement. Extensometers: Comply with ASTM E83 Class B-1 minimum requirements; gage length 10–50 mm. Class A extensometers are recommended for very stiff materials or transverse strain measurement.
Temperature chamber	Maintains controlled temperature/humidity during testing for non-ambient test conditions.

Test parameters and stipulations

Speed (strain control)	Standard strain rate 0.01 min⁻¹
Speed (head displacement)	Standard 2 mm/min [0.05 in/min]
Time to failure	1 to 10 minutes (run trials if ultimate strain unknown)
Specimen insertion	Long axis aligned with test direction; grip pressure recorded; wedge grip ends even to avoid bending moment; tabbed coupon inserted so jaws extend 10–15 mm past the taper start
Transducer installation	Symmetrical about mid-span/mid-width; back-to-back axial transducers for modulus unless bending ≤3 %

Step-by-Step Test Procedure of ASTM D3039 Tensile Testing of Polymer Composites:

Pre-test measurement: Measure specimen width and thickness at 3 locations in the gage section; calculate average cross-sectional area A = w x h. Verify all equipment has current calibration certification.
Specimen installation: Align the specimen’s longitudinal axis with the load direction. Tighten grips and record grip pressure (for hydraulic/pneumatic grips).
Transducer mounting: Attach strain sensors symmetrically at the mid-span, mid-width location. For modulus testing, mount back-to-back axial transducers to quantify bending.
Tensile loading: Apply axial load at the specified rate until specimen failure. Continuously record force, displacement, and strain data.
Failure documentation: Record failure mode and location using the standard 3-character coding system:

1st character = failure type (e.g., angled, delamination, grip/tab, splitting)
2nd character = failure area (e.g., at grip/tab, gage section, multiple areas)
3rd character = failure location (e.g., top, bottom, middle, various)

Data reduction: Calculate tensile properties using defined equations, and compute statistical values (mean, standard deviation, coefficient of variation) for the specimen set.

ASTM D3039 Tensile Testing of Polymer Composites

Industry applications

Sector	Use of D3039 data
Aerospace	Material qualification and allowables (A-/B-basis), CMH-17 / NCAMP datasets, prepreg specification, batch acceptance, FEA input (E₁, E₂, ν₁₂, F₁ᵗᵘ, F₂ᵗᵘ, εᵗᵘ)
Defense	DoD-approved material and process control, structures and armor
Wind energy	Blade spar-cap and shell laminate strength/modulus verification
Automotive	Lightweight structural laminates, crash and stiffness design data
Marine / pressure vessels	Hull laminates, filament-wound and COPV overwrap characterization
Civil infrastructure	FRP strengthening laminates, rebar/grid qualification
Sports / consumer / rail	Carbon frames, panels, interior structural parts
R&D and manufacturing	Comparing fiber/resin systems, cure cycles, fiber alignment, void content, moisture and temperature effects — the test is sensitive to all of them (§6 interferences)

Related Standard:

ISO 527‑4 / ISO 527‑5	tensile properties of isotropic and orthotropic fiber-reinforced plastic composites. tensile properties of unidirectional fiber-reinforced composites. These are the nearest ISO counterparts; a formal ASTM/ISO harmonization study exists, but specimen dimensions, grip recommendations and the modulus chord differ.
ASTM D3039	Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials
GB/T 3354	Test method for tensile properties of orientation fiber reinforced polymer matrix composite materials
EN 2561 / EN 2597	European aerospace series CFRP unidirectional laminate tensile test parallel (and transverse) to the fiber direction.
SACMA SRM 4R-94	Legacy industry method, historically used alongside early D3039 editions
ASTM D3479	tension–tension fatigue; explicitly uses the D3039 specimen geometry.
ASTM D5766	open-hole (notched) tensile strength.
ASTM D7291	through-thickness ("flatwise") tensile strength and modulus.
ASTM D3518	in-plane shear response by tensile test of a ±45° laminate; same straight-sided coupon, no fixture.

Why the test is important for the material

It produces the primary design allowables. Fiber-direction tensile strength and stiffness (F₁ᵗᵘ, E₁) are the first numbers in any composite design handbook and the first entries in any FEA material card. Without them a laminate cannot be sized.

It captures matrix-dominated behavior too. The 90° (transverse) coupon gives F₂ᵗᵘ, E₂ and the transition strain — the strain at which matrix cracking and ply delamination begin, which drives damage-tolerant design and leak-before-burst criteria.

It is a manufacturing-quality mirror. The result is highly sensitive to fiber alignment, void content, cure state, ply orientation, machining damage, moisture and temperature — so it doubles as a diagnostic for process control (§6 lists these as interferences precisely because they move the number).

It enforces that you measure the material, not the fixture. Gripping, alignment and bending limits (3–5 % system, 3 % specimen), the ≥5-specimen rule, mandatory failure coding and the retest rule exist to keep grip-induced, low-biased failures out of the dataset.

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WDW Series Computer Control Electronic Universal Testing Machine made by UNITEDTEST range from 100N to 600KN load capacity with various models like single columns, table type, door frame type etc., is used to perform tension, compression, flexure/bending, shearing, peeling etc., test for metal and nonmetal specimens.

Hydraulic wedge test grips are a robust and versatile solution for tensile testing of high-strength materials. It can be used in both static and dynamic materials testing applications – from 20KN to 500 kN force capacity for dynamic tests, and up to 600 kN for static tests.

Temperature furnace chamber for tensile testing machine, furnace have a columnar split structure, three stage control function. Mainly consists of furnace, temperature controller, high temperature pull rod, high temperature clamp, high temperature extensometer and supporting device.

Video extensometer, is a non-contact real-time high-precision strain measurement system, which is based on a separate camera and real-time image processing algorithm, by taking images of the experimental process, analyzing image characteristic changes, dynamically measuring the strain changes.

Q1. What is ASTM D3039?

A: ASTM D3039/D3039M is the ASTM International standard test method for determining the in-plane tensile properties of polymer matrix composite materials reinforced by high-modulus fibers. The current edition is D3039/D3039M-17, reapproved in 2025. It is issued by ASTM Committee D30 on Composite Materials, Subcommittee D30.04, and is approved for use by U.S.Department of Defense agencies.

Q2. Which materials can be tested by ASTM D3039?

A: Continuous fiber or discontinuous fiber reinforced polymer matrix composites — carbon/epoxy, glass/epoxy, aramid/epoxy and similar systems — provided the laminate is balanced and symmetric with respect to the test direction. Unidirectional tapes, woven fabric laminates, multidirectional laminates and randomly reinforced sheet-molding compounds are all covered, each with its own recommended coupon geometry.

Q3. What properties does the test produce?

A: Five properties: (1) ultimate tensile strength, (2) ultimate tensile strain, (3) tensile chord modulus of elasticity, (4) Poisson's ratio, and (5) transition strain. Strength alone can be obtained from force and specimen area; the other four require strain measurement with an extensometer or bonded strain gages.

Q4. Why is ASTM D3039 important for composite materials?

A: Because it generates the primary design allowables that a composite structure cannot be sized without. Fiber-direction strength and modulus (F1tu, E1) are the first entries in any FEA material card and in any composite design handbook. The 90-degree (transverse) coupon adds the matrix-dominated properties and the transition strain — the strain at which matrix cracking and ply delamination begin, which drives damage-tolerant design. The result is also sensitive to fiber alignment, void content, cure state, moisture and temperature, so it doubles as a manufacturing quality check. Finally, its defined geometry, speed, strain range and failure coding make the data defensible across laboratories, which is what aerospace and defense qualification requires.

Q5: Is ASTM D3039 the same as ISO 527-5?

A: ASTM D3039 and ISO 527-5 are similar in purpose (both measure tensile properties of fiber-reinforced plastic composites) and have been formally harmonized under WTO TBT principles for international standardization. However, they have differences in specimen geometry recommendations, strain ranges for modulus calculation, and reporting requirements. They are not identical, but many testing systems — including UnitedTest composite tensile testers — can be configured to meet both standards.

Q6: What is the difference between ASTM D3039 and ASTM D638?

A: ASTM D638 is the tensile test standard for unreinforced plastics, while ASTM D3039 is specifically designed for high-modulus fiber-reinforced polymer matrix composites. D3039 addresses composite-specific challenges such as fiber alignment, tab design, edge effects, bending correction, and bilinear stress-strain behavior that are not relevant to unreinforced plastics. Using D638 for composites will produce inaccurate and unreproducible results.

Q7. Are end tabs required?

A: Not required by rule, but strongly recommended for unidirectional (fiber-direction) specimens and usually necessary for 90-degree matrix-direction coupons, to prevent grip damage and premature failure. Tabs are commonly continuous E-glass fabric/epoxy, bonded with a tough high-elongation adhesive. Wedge grips work best with a low 7 to 10 degree feathered bevel; hydraulic or pressure-operated grips work with squared 90 degree tabs. Friction tabs (non-bonded, with emery cloth between tab and coupon) are also permitted.

Q8. How many specimens are needed?

A: At least five specimens per test condition, unless valid results can be obtained with fewer, for example in a designed experiment. Practice E122 should be consulted when statistically significant data is required.

Q9. What test speed should be used?

A: Two standard options: a strain-controlled rate of 0.01 min-1, or a constant head displacement rate of 2 mm/min [0.05 in./min]. In either case the rate must be selected so that failure occurs between 1 and 10 minutes. Note that a fixed head speed on a compliant system with wedge grips can produce a real strain rate 10 to 50 times lower than intended.

Q10. Which strain range is used for the chord modulus?

A: The standard chord is 1000 to 3000 microstrain, with the percent-bending check taken at the 2000 microstrain mid-point. For materials that fail below 6000 microstrain, a range of 25% to 50% of the ultimate strain is recommended. If a transition region (a knee in the curve) falls inside the range, a different range must be selected and reported.

Q11. Which grips are best for composite coupons?

A: Hydraulic or pneumatic wedge grips with constant, recorded grip pressure are the most common choice, because composite coupons are sensitive to both crushing and slip. Lightly serrated faces of about 1 serration/mm (25 serrations/inch) work well in wedge-action grips when kept clean and sharp; coarse serrations cause grip-induced failures in untabbed coupons. Smooth faces with hydraulic grips, or an emery cloth interface (80 to 180 grit, grit side toward the specimen), are also accepted. The jaws should overhang the tab taper by about 10 to 15 mm.

Q12. Should I use an extensometer or strain gages?

A: Either is allowed. Extensometers are faster to apply and reusable, and a gage length of 10 to 50mm is typical; they must be light enough not to bend the coupon. Bonded gages (6 mm active length recommended, never below 3 mm, 350 ohm or higher, 1 to 2 V excitation) suit Poisson's ratio work and non-ambient testing, but surface preparation must not damage the fibers and transverse-sensitivity correction is needed on the transverse gage.

Q13. How much bending is acceptable?

A: Good practice limits system percent bending to 3% to 5% at moderate strain levels above 1000 microstrain. For a single specimen, one transducer may be used if measured bending is no more than 3%; above that, back-to-back axial transducers should be averaged. Excessive bending causes premature failure and inaccurate modulus, so alignment should be verified per Practice E1012 and the machine readjusted if bending is high.

Q14. What should a buyer look for in an ASTM D3039 testing machine?

A: Force accuracy at or better than ±1% of indicated value across both the low-force modulus range and the high-force strength range (multiple load cells in one frame is a real advantage here); a speed range that comfortably covers 2 mm/min and holds it stable; a stiff, well-aligned load frame with self-aligning or hydraulic grips and controllable, recorded grip pressure; enough crosshead travel and test space for 250 mm coupons plus tabs and extensometer; strain measurement to Practice E83 Class B-1 or better; a data acquisition rate of at least 2 to 3 samples per second with a minimum of 100 data points per test; and software that can compute chord

modulus over a user-defined strain range, Poisson's ratio, transition strain, percent bending and the full statistics package (mean, standard deviation, coefficient of variation).

Q15. Which UnitedTest machines are suitable for ASTM D3039?

A: UnitedTest (Beijing United Test Co., Ltd., founded 2012) supplies electromechanical universal testing machines in the ranges used for composite coupon work: the WDT series bench-top systems from 10 kN to 600 kN for lower-force coupons such as 0-degree unidirectional, and the WDW series floor-type systems at 100 kN, 200 kN and 300 kN for higher-force multidirectional and fabric laminates. Load measurement accuracy is Class 0.5 or Class 1 to ISO 7500-1 and meets the requirements of ASTM E4; speed range is 0.001 to 500 mm/min, which covers the 2 mm/min standard head speed. UnitedTest also supplies the wedge and pneumatic grips, manual and hydraulic grip options, extensometers, and fixtures for composites, plus FastTest software for control, curve display, chord modulus calculation and reporting. Configurations can be matched to the coupon geometry, expected failure load and test standard.

We offer customization to meet your specific needs. Our expert team will collaborate with you to develop the perfect product for you