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ASTM C393
ASTM C393
ASTM C393 is an ASTM International standard that is designed to determine the core shear properties of sandwich constructions, with shear properties determined via a bend test in a 3- or 4-point loading condition. It is widely used across aerospace, marine, automotive, and composite panel manufacturing industries where accurate measurement of core shear performance is critical to structural design and quality assurance. Presto's precision flexural testing instruments support manufacturers in conducting ASTM C393 compliant core shear property evaluations under controlled laboratory conditions for production validation and material qualification.
Significance
ASTM C393 provides information on core-to-face bonding stability, load transfer, and flatwise tensile strength of sandwich core material, with the data often used to specify a material, to design parts to withstand application force, and as a quality control check of materials. By generating quantitative core shear ultimate strength and facing stress values, manufacturers can optimize sandwich panel fabrication parameters, validate core material selection, and ensure structural panels reliably withstand service-level shear loading conditions throughout their operational life. Scope ASTM C393 requires a uniquely articulating bend fixture with pressure pads to provide the most accurate and consistent core shear results possible, with calculations yielding core shear ultimate strength, core shear yield stress, and facing bending stress. The standard is applicable for continuous bonded surfaces such as foams and discontinuous bonded surfaces such as honeycomb materials. It applies to sandwich panel manufacturers, composite material suppliers, aerospace and marine component producers, and quality inspection laboratories requiring standardized core shear property testing for structural design, material specification, and production compliance verification.