Scope:

ASTM D6742 test guides for altering open-hole tension and compression test procedures to ascertain filled-hole tensile and compressive strengths. The composite material forms are bound to only continuous-fiber reinforced polymer matrix composites. The laminate used in the test is both symmetric and in equilibrium with respect to the test direction. This test method is analogous to open-hole testing, and the sample is tested only when a fastener is in the hole. The material usually tolerates a higher force during filled hole testing. Different parameters such as fastener selection, material hardness, fastener hole tolerance, torque, and clearance of the hole might affect the strength properties of the material. ASTM D6742 test method is supplementary to ASTM D6484 for compression testing and ASTM D5766 for tension testing. 

Test Procedure:

The testing samples are provided with a close-tolerance fastener, or a pin is inserted in the test hole for the ASTM D6742 test. The sample is loaded in uniaxial tension or compression until fracture. The fastener or pin is not loaded or utilized as a load transfer process between test samples and test fixtures as in a bearing response test. The fastener or pin just fills the hole in the composite laminate material. For validating test data, failure is ensured at or near the hole in the composite sample.

Sample size:

For ASTM D6742, the specimen should have a width thickness up to 2 inches wide or 0.75 inches round up to 0.8 inches thick or 0.75 inches round.

Data:

Filled-hole tensile (FHT) strength

Filled-hole compressive (FHC) strength

Conclusion:

Hence, ASTM D6742 is the standard test method for tensile and compression testing of filled-hole polymer matrix composite laminates.