Hi all,
i´m trying to do a race seat for my car buy i have no idea of how many layers i should apply to make a good compromise between cost/weight/rigidity. It´s to use at trackdays mostly not competitions.
I was thinking in carbon/glass/soric/glass/carbon but no idea of how many layers and grams of each one.
Anyone can help?
Thanks in advance!
David
Anyone please? 
That’s not a simple question… I think it’s even proprietary info for anyone who’s building seats. From the lack of response here, it’s such an open ended question I don’t think anyone want to wast time re-explaining things.
Also seats are regulated and need approval in order to be used on a race track. There is a some liability involved in creating these sorts of products. Maybe that doesn’t matter.
You speak of cost as a factor, which it most definitely is but, you shouldn’t be going cheap on such an important component. Just making the molds alone is going to be some what expensive. Making the seat itself should be more so.
Usually the best place to start is by looking at something similar to what you plan on making. Maybe figure out what they weigh and do some math and get a rough estimate of how much carbon is involved. Then start by making test panels in various configurations. Though without any sort of testing the panels might not yield too much info. You could also model a seat and run some CFD to figure out where the stress points are and where the seat needs to be the strongest.
I probably should have started with this, but have you searched the forum?
http://www.compositescentral.com/search.php?searchid=18129
I found several threads on exactly this topic.
Sounds like you’re fairly new to this so there are many things you can learn to avoid making mistakes before you invest time and money in a design. If budget is a concern and you still want to do a project, maybe start smaller first and learn then work up to your goal.
I did a lot of searching but those topics you posted donºt have a suggesting name so i just didn´t find them.
I´m not new on making carbon fiber parts, but the parts i´ve been doing are mostly cosmetic and not structural so I feel a bit lost when calculating aspects like stiffness.
I don´t want to go cheap! Not at all. I just asked for a good compromise between cost/weigh/rigidity. Maybe the order is wrong because it starts with the least important for me.
I will do some testing but If i could have a starting point I would get the result faster and with less cost.
And I do understand that if you are in the industry of making Seats you won´t share the knowledge. But if everybody is from the industry there is no point on having a forum about composites if you don´t want to share some knowledge. But again, I respect who thinks like that.
Thanks for your answer
Your question is a little difficult. I would do some test panels of the laminate you spoke of. A lot depends on the bracing and or mounting of the seat. Your schedule sounds good but again it’s dependant on the weight of the carbon, fiberglass and soric. Also what resin matrix? But again I agree with making a few test panels.
Hope this helps.
what do you mean with resin matrix? type of resin? If yes i will use Epoxy and will do it by infusion.
The mounting is four screws on the side(two each side). I have one seat here that came with other car I bought and it fits perfect on my actual car (Honda S2000). But it´s fiberglass with a cosmetic layer of kevlar on the outside and it doesn´t feel very stiff. It seems to bend when doing corners.
You can go two ways :
1st - apply thick laminate
2nd - apply thinner check after demould wheter it meets your criteria
1st way - in my opinion carbon 200g + carbonkevlar/diolen 240g( for safety reasons) + light glass fabric like 80-100g ( for good support and bonding with soric) + soric 3-4mm + light fabric + 290g glass + carbon 200g
2nd way - as you wish , after demoulding simply try yourself if it is enough , if not just add extra material on the back side of seat with hand layup
It sounds about right. This kind of part has a lot of shape so this means you can get away with a reasonably thin laminate. Use and extra layer or two around the edges so the edges are strong.
You could start by knowing the weight of other seats and then do some calculations on your own laminate to see if you are in the ball park.
CFD WTF!
The one I have here is 7,2KG but i think the kevlar layer was added later so lots of resin to make in glossy.
luxury:
Wouldn´t ir be better to have the kevlar layer as the last layer inside? So in case of failure of the seat The inner carbon layer won´t cause problems to the driver?
And if only for safety reasons can I apply diolen? For two reasons. It´s a lot cheaper than kevlar and looks like carbon and for cosmetic i like it most.
So:
carbon 200 + diolen 240gr + glass 100gr + soric 3mm + glass 100gr + glass290+diolen 240 seems right?
Thanks a lot!
Yes Wochi, I do mean resin type. Epoxy will be great. I also agree with the Kevlar in the laminate. I’ve never used diolin so I don’t know anything about it. I like your last post #9 but I think I might remove the fiberglass. But there again I would make a test panel. Maybe off the seat itself in a curved area and flat.
Is it a adjustable seat or race seat?
Is a race seat. No ajustments. Looking at some photos on the internet it´s very similar to Recaro Pole Position
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Wouldn´t ir be better to have the kevlar layer as the last layer inside? So in case of failure of the seat The inner carbon layer won´t cause problems to the driver?
And if only for safety reasons can I apply diolen? For two reasons. It´s a lot cheaper than kevlar and looks like carbon and for cosmetic i like it most.
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Diolen is also good , I have made some tests whith Diolen in the past ( trying to punch it with sharp stuff and I failed) - for me it is quiet good material which is very similar to kevlar. In my opinion Ciolen should be placed just right behind carbon as second layer, and the closest possibly to drivers back. It will help to keep carbon laminate - in case of accident- as whole layer, not letting it split to sharp edges.
I suggested carbon/kevlar mix cause it will give extra rigidity with “bulletproof” , where diolen gives only “bulletproof” and no additional stiffness
also be prepared that soric will leave some marks/prints of its octagonal cells on the surface of the seat
Thanks a lot for all the help!
So with the materials I have with me i think i will try:
200Carbon-200Diolen-500biaxial glass (45º)-soric 2mm-500unidireccional glass-200glass-200diolen.
I can have a good cosmetic finish on the outside with the carbon and in the inside the diolen is also good looking
The weight of the materials is also balanced and i have covered all the fiber orientations (0,90 and ±45) keeping the cost acceptable (only the carbon fiber is expensive in these materials)
Sounds good?