Working with Honeycomb Material

I think it will be expensive and impractical in terms of repairability for a 'small' project. As you point out panel fixing may well be a problem.
It may sound daft but have you considered plywood?! You could build your own sandwich honeycomb ply panels, it's an easy to use, easy to join, well understood product... it was good enough for some great WWII planes (mosquito)
Del

The project is well funded and we're looking to lighten the vehicle. So we were brainstorming using shear plates instead of diagonals. I haven't put a decision on what the material could be. Seems like kevlar/nomex are going to be expensive but seems to be some of the toughest materials, especially in an off-road racing application (read big rocks).

The idea of building your own plywood sandwich sounds alright if it weren't for the fact that it will require effort to buy high grade plywood, select the appropriate paper honeycomb, pick the wood pieces with the right moisture content, glue the honeycomb, put the pieces together and so on. Would you know anyone who sells ready made structural panels?

Ah, the words 'racing' and 'well funded' have appeared.
The OP gave the impression it was more of a 'home project'.

Del

I work with brazed stainless and alloy honeycomb and honeycomb sandwiches, but for aerospace applications. It is incredibly strong and light, but every new job is a custom job, and for a part big enough for your needs (as I imagine them), we are talking at least six figures. I doubt if you are that well funded.

Dick

Six figures? Are you kidding me? We're looking for a couple of 4X8 panels for the side body work. I can buy a house with that money. See, we're not that well funded!

If the panels are flat, you can do this. Curves complicate things. If you purchase them, all it takes is money. The panels can be drilled, thats how the blind, threaded inserts (or 1/4 turn fasteners) are installed for attachment.

I used to fabricate radomes from honeycomb. (Phenolic, not Kevlar)

I'd check with aerospace job shops, plane and boat builders.

The one airplane job shop I checked sells this stuff as a paper kevlar honeycomb, not as sandwich panels.

Also, I think you can construct curved sandwich panels if you use, for example, lite ply plywood. Its also called "white wood".

For the most part, our application demands flat sections. We're keeping it simple.

Are you sure you can drill into kevlar honeycombs? I wouldn't know. An acquaintance of mine in the Army tells me that once kevlar bulletproof vests are punctured by shrapnel or bullets however small it is, it is regarded as useless and they are told to replace the whole vest.

Bullet proof vests are made from woven Kevlar fabric. In vests, it's flexible, so you can move and breathe. You cannot drill this. It's too tough and it would render it unusable.

Honeycomb is rigid and entirely different from fabric. It would be made from Kevlar impregnated with epoxy resin. You can also get aluminum/paper/phenolic impregnated glass honeycomb.

You can make curved shapes by laying up resin impregnated fabric/HC/fabric, but that's another story.

Sandwich panels with honeycomb core are efficient in resisting moment, where the skins take the tensile / compression forces and the core takes the shear, like an I beam.

I don't see how you want to use the panels to take the shear forces. Please explain.

Vince

The answer is in what you wrote.

"Anyone know of any good companies that deal with this? Has anyone worked with sandwich panels for such an application before? How could the panels be fastened or bonded to the envelope tubular structure and is it bad for the material integrity if it is drilled?"

For one of the company dealing with sandwich panel you may refer to : http://www.corecomposites.com

Most suppliers will also assist you to find best solution to meet your specific needs.

My experience is that assembling sand wich panels require special tools, potting compounds, and special thread inserts and of course good deal of expertise.

While there could little doubt about the fabulous weight to strength properties of the range of honey comb panels, cost could be major constraint.

Best of luck.

Thank you! Looks good. I have to ask them for a quote.

http://www.lakeandbayboats.com/

These people make the worlds best "Flats and Bay" boats out of it. They also use carboan fiber because certain parts that tend to warp will stay flat.

I watched a show once that described balsa wood as an almost perfect reinforcement material for use with polyester resins. As I recall, it was just a matter of saturating the balsa, and letting it set up.

I use Webbcore in Hubbard Oregon. They are one of the leading companies in aluminum honeycomb.

In another life I worked for a major airline. I used to enjoy news letters from the McGill Corp a major suppler of honeycomb panels used by Boeing & the military. Look at the www.mcgillcorp.com website. I never worked with the kevler panels so I can not help you there.

I think a solid, rigid carbon fiber panel would work better for you.

I have to join Vince GEntile in suspecting that honeycomb panels are not the best choice in this application. You are at the mercy of the adhesive bond between the honeycomb core and the outer panels.

Maybe Burt Rutan would help.

Good luck.

Try here

www.aircraftspruce.com/