Combined loading compression test fixture

ASTM D6641 – This test method determines the compressive strength and stiffness properties of polymer matrix composite materials using a combined loading

compression (CLC) (1) 2 test fixture.

This test method is applicable to general composites that are balanced and symmetric.

The specimen may be untabbed (Procedure A) or tabbed (Procedure B), as required.

One requirement for a successful test is that the specimen ends do not crush during the test.

Untabbed specimens are usually suitable for use with materials of low orthotropy, for example, fabrics, chopped fiber composites, and laminates with a maximum

of 50 % 0° plies, or equivalent

Materials of higher orthotropy, including unidirectional composites, typically require tabs.

The compressive force is introduced into the specimen by combined end- and shear-loading. In comparison,

Test Method D3410/D3410M is a pure shear-loading compression test method and Test Method D695 is a pure end-loading test method.

***Unidirectional (0° ply orientation) composites as well as multi-directional composite laminates, fabric composites, chopped fiber composites, and similar

materials can be tested.

*** Before conducting ASTM D6641 , it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.