ASTM D4018 Standard Test Methods for Properties of Continuous Filament Carbon and Graphite Fiber Tows

ASTM D4018 is a test method that covers the preparation and tensile testing of resin-impregnated and consolidated test specimens made from continuous filament carbon and graphite yarns, rovings, and tows to determine their tensile properties. It also cover the determination of the density and mass per unit length of the yarn, roving, or tow to provide supplementary data for tensile property calculation.

The test methods determined by ASTM D4018 are intended for the testing of fibers that have been specifically developed for use as reinforcing agents in advanced composite structures. Fiber tows are used along with resin to create composite materials which will ultimately be used for aerospace, automotive, and industrial applications.

For testing to ASTM D4018 we recommend a low force table model system such as Instron's 6800 Series. Pneumatic side-action grips allow for repeatable gripping pressure and easy specimen insertion. For strain measurement, an automatic video extensometer such as Instron's AUTOX750 or a non-contacting solution such as the AVE2 are recommended.

Instron’s Specimen Protect feature can help protect these delicate specimens from excess force being applied before the test starts. It allows the test operator to set the threshold value at the maximum absolute force that the specimen can experience without damage. If the force exceeds this value, Specimen Protect initiates movement of the crosshead to relieve the force on the specimen.