Scope:

Core Shear Properties by ASTM C393 test determines the flexural strength, core shear strength, and facing compressive and tensile strengths in the direction the core is positioned in structural construction. The core content types that are evaluated include continuous bonding surfaces (such as balsa wood and foams) and discontinuous bonding surfaces (such as honeycomb).

Test Procedure:

Conditioned samples, for the ASTM C393 test, are installed into a 3-point loading fixture on a Universal Test Machine. Then, the samples are initiated, at a specified grip separation significant enough to produce failure within 3 to 6 minutes. The standard speed of the ASTM C393 test is 6 mm/min (0.25 inch/min). The standard loading setup is a 3-point configuration with a 150 mm (6.0 inches) support span. 

Specimen size:

Five rectangular samples, 75 mm (3.0 inches) 200 mm (8.0 inches) are tested at thickness during the determination of Core Shear Properties of Sandwich Constructions by ASTM C393.

Data:

From the 3-point loading ASTM C393 test, the following calculations are done

Core Shear Ultimate Stress
Core Shear Yield Stress
Facing Stress
Failure type/mode

Conclusion:

Hence, ASTM C393 test method covers determination of the core shear properties of flat sandwich constructions subjected to flexure in such a manner that the applied moments produce curvature of the sandwich facing plane.