Appropriate standard of SANDWICH under 4 bend points?

[melixman2016]

In the framework of my work i have to load a SANDWICH under 4 bend points. mode of failure is unknown, for this reason I am testing to know which mode of failure occurs.

There are two standards:

ASTM D7249 Standard Test Method for Facing Properties of Sandwich Constructions by Long Beam Flexure

ASTM C393 Standard Test Method for Core Shear Properties of Sandwich Constructions by Beam Flexure

What should I take for my experiment?

Thank you

 

[SWComposites]

The mode of failure is a function of the span length - which results in different ratos of bending moment to shear force. Thats why there are two standards. What are you really trying to do? And why cant you test both configurations?

 

[melixman2016]

Thank you for your helpful answer.
we are trying a new material as a core for sandwich, and its properties are still under development.
in contrast the skins of Sandwich(flax fibres laminate), the properties of which have been known for a long time
That is why I will choose ASTM C393.

 

[melixman2016]

I have one more question, During the test, should I apply 100% force on trial? or less than 100% force.

Thank you

 

[SWComposites]

Um, not sure I understand the question. Normally one applies force until the specimen fails.

 

[melixman2016]

That's exactly what I meant, applies force until the specimen fails
thank you very much