Compressive Strength ASTM C365

Compressive Strength of Sandwich Cores using ASTM C365

The compressive strength of sandwich cores is an important factor in determining the structural integrity of a composite material. The American Society for Testing and Materials (ASTM) has established the ASTM C365 test method to measure the compressive strength of sandwich cores in the direction they would be placed in a structural construction. This test method is applicable to both continuous (foams) and discontinuous bonding surfaces (honeycomb), whether stabilized or unstabilized.

Test Procedure

The test procedure involves installing the conditioned specimens, if required, into the loading platens on the Universal Test Machine and initiating at a specified grip separation significant enough to produce failure within 3 to 6 minutes. The standard speed is 0.50 mm/min [0.020 in/min]. Five specimens are tested at thickness.

Specimen Size

For continuous bonding surfaces, the minimum facing area shall be 625 mm2 (1.0 inch2). For discontinuous cellular bonding surfaces, there must be a minimum of 60 cells per test specimen.

Data

From flatwise compression results, the following calculations can be made:

• Ultimate Strength: The maximum stress sustained by the test specimen during the compressive test

• Failure Type/Mode: The type of failure observed during the compressive test

CONCLUSION

The compressive strength of sandwich cores is a critical factor in designing and manufacturing composite materials. The ASTM C365 test method provides a reliable and accurate means of determining the compressive strength of sandwich cores. With this information, designers and manufacturers can make informed decisions about the suitability of materials for specific applications and ensure the structural integrity of their products.