Standard Test Method for Shear Properties of Sandwich Core Materials

Importancia y uso:

5.1 The core shear properties are fundamental properties that are used in the design of sandwich panels. This test method provides information on the force-deflection behavior of sandwich constructions or cores when loaded in shear parallel to the plane of the facings. From a complete force-deflection curve, it is possible to compute core shear stress at any force (such as the shear stress at proportional limit, at yield, or at maximum force) and to compute an effective core shear modulus.

5.2 The test does not produce pure shear, but the specimen length is prescribed so that secondary stresses have a minimum effect. Approximate shear properties can also be obtained from a sandwich flexure test (see Test Method C393).

5.3 This test method provides a standard method of obtaining sandwich core shear data for material specifications, sandwich panel design, research and development applications, and quality assurance.

5.4 Factors that influence core shear strength and shall therefore be reported include the following: facing material, core material, adhesive material, methods of material fabrication, core geometry (density, cell size, orientation, and so forth), adhesive thickness, specimen geometry and associated measurement accuracy, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, speed of testing, and adhesive void content. Further, core-to-facing strength may be different between precured/bonded and co-cured facings in sandwich panels with the same core and facing material.

Subcomité:

D30.09

Referida por:

E1749-18, E1974-19, D7446-09R17, D7249_D7249M-20, E1730-19, E1975-22, C0394_C0394M-16R24, D4762-23

Volúmen:

15.03

Número ICS:

83.120 (Reinforced plastics)

Palabras clave:

A micrometer with a 4 to 8 mm [0.16 to 0.32 in.] nominal diameter ball-interface or a flat anvil interface shall be used to measure the specimen thickness. A ball interface is recommended for thickness measurements when facings are bonded to the core and at least one surface is irregular (for example, the bag-side of a thin facing laminate that is neither smooth nor flat). A micrometer or caliper with a flat anvil interface is recommended for thickness measurements when facings are bonded to the core and both surfaces are smooth (for example, tooled surfaces). A micrometer or caliper with a flat anvil interface shall be used for measuring length and width, as well as the specimen thickness when no facings are present. The use of alternative measurement devices is permitted if specified (or agreed to) by the test requestor and reported by the testing laboratory. The accuracy of the instruments shall be suitable for reading to within 1 % of the sample dimensions. For typical specimen geometries, an instrument with an accuracy of ±0.025 mm [±0.001 in.] is adequate for the length, width, and thickness measurements.; core; honeycomb; sandwich; sandwich construction; shear modulus; shear strength ;