How are seats attached to a Carbon Fibre tub ?

[kittt]

Hello Everyone,

I believe supercars such as the Porsche Carrera GT, Lexus LFA, McLaren MP4, Lambo Aventador, etc... have a carbon fiber tub (central frame).

Do you know how the seats are attached onto the composite floor panel? I figure that these joints are probably the ones that bear the highest loads, so I am wondering how such a joint could be created without locally damaging or creeping the carbon fiber.

Thank you in advance for any shared knowledge about this.

Cheers,
Christopher

[jboggs]

You are right. That is a very touchy connection. Its also one that manufacturers of composite aircraft have been dealing with for years. You could Google "composite bolt connection" and similar phrases and you will get several hits, some magazine articles, academic papers, etc. There are many approaches, but two common themes in all of them. (1) Spread out the concentrated load over as large an area as possible. (2) Consider the strengths and weaknesses of composite materials from the beginning. (Strong in tension, not so much in compression and shear.) They don't just design a tub and then figure out how to attach a seat. The loading from the seats is considered from the very beginning. The actual bolted connection is one thing, but the configuration of the composite shape around it is equally important to properly absorb and distribute the loads.

[sadie]

I have designed and manufactured multiple race cars with carbon tubs. The way that it is done on race cars, and im assuming road cars, is by having an insert inside the carbon/honeycomb sandwhich. The tub consists of an inner and outer skin of multiple carbon layers with usually an aluminum honecomb core. Inserts machined of various materials are placed within the honeycomb layer to allow fastening of anything neccessary (suspensions, seats, etc.) which then spreads the load to the skins of carbon. Hope this helps.

Kevin