Flatwise Compressive Properties by ASTM C365

Compressive strength is an important parameter for determining the structural integrity of sandwich cores in various applications, such as in aerospace and construction industries. ASTM C365 is a standard test method used to evaluate the compressive strength of sandwich cores, including continuous (foams) and discontinuous bonding surfaces (honeycomb).

Test Procedure

To determine compressive strength, conditioned specimens are installed into the loading platens of the Universal Test Machine and initiated at a specified grip separation. The separation must be significant enough to produce failure within 3 to 6 minutes, with a standard speed of 0.50 mm/min [0.020 in/min].

Specimen size

A minimum facing area of 625 mm2 (1.0 inch2) is required for continuous bonding surfaces. For discontinuous cellular bonding surfaces, a minimum of 60 cells per test specimen is needed. A total of five specimens must be tested at thickness.

Data

From flatwise compression results, various calculations can be made, including the ultimate strength and failure type/mode. The ultimate strength is defined as the maximum load sustained by the specimen before failure. The failure type/mode describes the manner in which the specimen failed, such as by crushing, buckling, or core shear.

The ASTM C365 test method is essential in determining the compressive strength and structural integrity of sandwich cores, allowing for more informed decisions in material selection and design in various industries.