Mechanical Testing Options for Sandwich Panels

[jonnyjhh]

TL;DR Summary

I am looking to mechanically test different variations of the same sandwich panel. The sandwich panel will consist of a honeycomb core made from recycled PP, with skins made from Flax tape combined with resin. I need help in deciding what tests I should perform. Thank you!

Hello,

I am looking to mechanically test different variations of the same sandwich panel. The sandwich panel will consist of a honeycomb core made from recycled PP, with skins made from Flax tape combined with resin.

The end goal of these tests is to investigate how the material property changes with different core thicknesses, and orientations of the layered flax tape.

I will be inputting the findings of these results into Simens NX to perform static tests on a designed structure.The main variations will revolve around a change of core thickness (10mm vs 15mm) and several orientations of the flax tape. The specimens will also use two different types of resin.

My question is what mechanical properties should I be most interested in, and which tests should I perform to acquire the desired values?

My initial idea was to perform tensile testing, combined with a three-point bend test. I believe this will give me certain values like UTS, and youngs. However, I've started having doubts as the thickness of material (up to 20-23mm) will be to thick for most tensile testing machines.

Would compressive testing be a much better option, and if so, how should I perform it for the honeycomb composite?

It seems like things get very complicated when it comes to honeycombs due to their orthotropic nature.

Many thanks for any advice you can provide.

 

[jrmichler]

Be aware of the various failure modes - face bucking, face tensile failure, core bucking, core adhesion, etc. And which of those modes apply to the intended use of the panels. Before you choose a test or tests, you need to know what you are looking for. Some examples:

If edge compression is important, then an edge crush test such as that used for corrugated cardboard boxes.
If an exterior wall panel subject to wind loading, then three point bending with a long sample.
If a floor, then point loading (local crushing), and three point bending with both long and short (to measure shear strength) samples.
If for a pallet, crush load while laying flat.

After you decide on a test or tests, you need to find designs for test fixtures and sample preparation.