ASTM D3039 Tensile Testing of Polymer Matrix Composite Materials

Scope:

ASTM D3039 tensile testing method measures the in-plane tensile properties of polymer matrix composite materials reinforced by high-modulus fibres. Tensile tests often use a stress-strain diagram to calculate the tensile modulus. The information from such a diagram is used for specifying a material, designing parts for withstanding application force, and also for a quality check of materials. The composite types of the material are limited to continuous fibre or discontinuous fibre-reinforced composites in which the laminate is usually balanced and symmetric.

Test Procedure:

For ASTM D3039 test, the samples are placed in the grips of a Universal Test Machine. Then, the samples are placed at a specified grip separation and pulled until failure. The test speed of material can be measured by the material specification or time to failure (1 to 10 minutes). Typical test speed is 2 mm/min (0.05 in/min) for standard samples. To assess elongation and tensile modulus, an extensometer or strain gauge is used. Testing can be done in more than one direction that may be required depending on the reinforcement type. State-of-the-art equipment includes Align-pro for reduced bending.

Elevated or reduced temperature test procedure:

The Universal Test machine is equipped with a thermal chamber. This chamber allows travelling across the top and bottom of the chamber on the foundation and the crosshead of the Universal Tester. Inside the chamber, standard measurement devices are mounted and the thermal monitored atmosphere is tested in the same way as it is at ambient temperature. The chamber has internal electric heaters to maintain high temperatures and external carbon dioxide is used as the coolant to lower temperatures.

Specimen size:

A constant rectangular cross-section of 25 mm (1 inch) wide and 250 mm (10 inches) in length are the most common samples for ASTM D3039. Optional tabs should be attached to the ends of the specimen to avoid damage caused by gripping.

Data:

Tensile strain (%)
Poisson’s ratio
Tensile strength (MPa or psi)
Tensile chord modulus of elasticity (MPa or psi)
Transition Strain (%)

Conclusion:

ASTM D3039 is a standard test method for tensile testing that is used to measure the force required to break a polymer composite specimen and the extent to which the specimen stretches or elongates to that breaking point.