ASTM D6484 Open Hole Compressive Strength of Polymer Matrix Composite Laminates

ASTM D6484 is a testing standard that measures the open-hole compressive strength of multidirectional polymer matrix composite laminates. Because mechanical fasteners such as rivets, pins, and bolts are commonly used to connect composite laminates, open-hole compressive testing is required in order to determine the ultimate compressive strength of the laminate, the ratio of the specimen across the hole to the diameter of the hole, and the percent bending. ASTM D6484 is relevant to the aerospace industry for the purposes of material specifications, research and development, quality assurance, and structural design and analysis.

ASTM D6484 should be run on a well-aligned electromechanical test system such as Instron's 6800 Series with grips and fixtures appropriate to which test procedure is being used. Operators also have the option of using edge-mounted extensometers to measure the displacement.

There are two different procedures for testing to ASTM D6484. In procedure A, the laminate face is supported in a bolted test fixture. The ends of the fixture are clamped in hydraulic wedge grips, transmitting the force in shear. In Procedure B, compression platens are required to compress the specimen within the test fixture in end loading.

• During panel fabrication it is critical to have good fiber alignment, since a misalignment could significantly reduce the compressive strength of the laminate.
• When calculating the ultimate compressive strength of the laminate specimen, use the cross-sectional area of the test coupon without taking the hole into account.
• To read the full test procedures for this standard, purchase ASTM D6484.