Talk Composites - The Forum for Advanced Composites

Kit Car Floor

http://www.talkcomposites.com/Topic22196.aspx

By OliilO - 11/2/2016 10:08:51 PM

I'm contemplating rebuilding my kit car (Mac#1 seven-alike) over winter and am looking to replace as much as I can with resin infused CF equivalents - davro and  brian2fast's topics have been invaluable so far.

The car currently has a 1.6mm Al floor with a maximum unsupported span of about 500mm. I've a few questions about the feasibility of replacing this with a composite replacement from those with more experience.

Attachment - bond or rivet? I'd instinctively rather rivet in case I need to remove the floor in future but what are likely issues with this? I have some concern about corrosion/different materials reacting and also the proximity of rivet holes to the edge of the composite floor.

Layup - I'd initially look to follow the guide of replacing the original thickness with a similar thickness of composite and want to include some Kevlar for impact/penetration resistance. Would something along the lines of 200gsm CF - 300gsm 45 degree CF - 300gsm Kevlar - 300gsm 45 degree CF - 200gsm CF sound about right?

Or would a Soric cored sheet be a better proposition, with a solid CF perimeter for attachment?

Thanks in advance,

Oli
By Hanaldo - 11/5/2016 11:29:12 AM

I agree with Davro regarding ditching the Kevlar. Remember that Kevlar is only stronger than carbon once the laminate has failed, so if it is in the layup then it's only there to hold things together in the event of failure. Overall impact resilience comes from the stiffness of the laminate, so it's better to make the laminate stiffer to resist impacts which means carbon is the better choice. S-glass fibreglass would actually be the best choice for impact resilience and overall laminate strength. 

 If you are worried about penetration then perhaps a small amount of Kevlar to protect the driver from anything coming through the floor, but keep it localised. 

Davro would know more about these kit cars than me, so his suggestions are probably good. I have built floors for Stohr F1000's, which may be pretty similar. These floors are generally 2 layers of fibreglass with 15mm honeycomb in the middle section and 10mm divinycell in other areas like the rear diffuser section and sides. The areas with no core are 5mm solid fibreglass. I would look closely at that layup and save a bit of weight/thickness by doing it in carbon.