How expensive is aluminum honeycomb and how is it sold?
I need a 1/4 thick carbon fiber panel with core. Can aluminum honeycomb be purchased in 3/16" thickness?
It is not a structural part, but I do need a core that maintains even thickness even under 1 bar vacuum.
Oh yeah… if it helps in choosing a core material it needs to be very stiff, and it will have a couple holes drilled thru the cf and core so the part can be fastened onto another structure.
These bolts will be very tight… probably around 20ft pounds torque.
Honeycombs should not be processed at full vacuum. We scrap honeycomb sandwich structures that show being subject to over 10" in the record book. Other types of core are to be used for that.
And no, it’s not a good idea to put a localized clamping load (bolt) through a honeycomb panel. Potting usually solves that issue though.
Potting? Filling the honeycomb with epoxy resin just in the bolt hole locations?
Well, not exactly resin but a strong filler of some sort which could be made from thickened epoxy. The potting compound should cover an area larger than the fastener to be put in/through. There are special tools for cleaning out the core inside a panel without drilling too large of a hole. Alternatively a hard fitting can be bonded in.
Cross section looks something like this:
i’m sure a google search will net you tons of core vendors.
as for bolt locations, there are metal inserts you can use, and potting compounds. My experience is with prepreg, where we cured the first skin and core, filled the hole areas with the core fill, and let that cure, then did the second skin. Foam core I would think can be done the same way, and can be done with full infusion. Maybe cut the foam bolt areas away, fill with layers of fabric, or even pre-made panels of the core thickness in shape of the foam cut out.
I’m liking the potting idea + using a metal guide for the bolt.
I thought about foam core, but i am just a little afraid the thickness won’t come out exact to what i need using this core material. I always wanted to try aluminum honeycomb too. But in the end i want what works right.
how about closed cell polyurethane foam sheet? Does anyone know where i can buy it cut to 1/4" sheet thickness?
Would it be wise to do the same with the PU foam: drill out a small area where the bolt will go thru and fill it with potting resin, then drill the bolt hole?
The final part will be a functional side skirt for a race car.