Composite Half Shafts

[Ryan Parker]

Is there any teams out there that have been successful in getting composite halfshafts made? I have been researching composite shaft makers and have been hitting a brick wall in finding one to work with me, any suggesstions on companies that can do composite shaft manufacturing?

Ryan Parker
joparke3@vt.edu

[Ryan Parker]

Is there any teams out there that have been successful in getting composite halfshafts made? I have been researching composite shaft makers and have been hitting a brick wall in finding one to work with me, any suggesstions on companies that can do composite shaft manufacturing?

Ryan Parker
joparke3@vt.edu

[Igor]

Yes, we asked one of our team members to make them :-)

http://www.dutracing.nl/photogallery/galleries/2003_event/IMG_1108.jpg

Igor
Delft University

[gug]

hey Igor, you guys must have a bit of experience with c-f by now http://fsae.com/groupee_common/emoticons/icon_wink.gif, feel like sharing some hints and tips when it comes to half-shafts? my team is also interested. im curious myself about how you set the cv-joints (or flexplates in your case) into the carbon shaft. how exactly does that work?

any opionions on carbon-kevlar weave? we have the opportunity to use that, but havent looked into it much yet.

- if it isnt coming, you need a bigger tool.

[Angry Joe]

someone on our team tried a few years ago working with an experienced composites professor. They never solved how to bond the carbon to the splines to avoid them separating under torque

The difference between racing and a crack addiction is that racing costs more and has a more adverse affect on your social life

Lehigh Formula SAE Alumni
Team Captain 2002-2003

www.lehigh.edu/~insae/formula (http://www.lehigh.edu/~insae/formula)

[Frank]

Igor,

I was wondering, how many km's (or driving hours) have you put on that car?

regards

Frank

[Gary Norris]

I'm looking into CF halfshafts for the 2004 USC car. Still doing a whole lot of calculations, and there are lots of questions to be answered to see if this is feasible for us. First off is coupling to the flex disc cv's we plan on running. The thought is a flange adhesive bonded to the cf tube. I'm pretty sure this is the process used for aftermarket cf driveshafts for corvettes and the like, and if I'm wrong please correct me. I'm definitely concerned about the bond being strong enough under torsion. But I guess all the calculations in the world don't matter til we build and test/break the thing. If anyone has any suggestions or resources, it'd be greatly appreciated, please let me know.

Gary Norris
SC Racing
gnorris@usc.edu

[Brent Howard]

What is the flange that is going to be bonded on made from? Could the flange just be part of the carbon fiber shaft rather than a seperate piece bonded on? We made carbon fiber flanges for our runners in 2003, although I think the technique would have to be much better to get enough torsional as well as bearing strength.

Brent

www.ucalgary.ca/fsae (http://www.ucalgary.ca/fsae)

[Gary Norris]

My initial thoughts were aluminum. I was also thinking we'd sandwich the CF tube between an inner and outer wall so that we could bond on both surfaces. As far as CF flanges, I thought that initially, but I doubt that'd be sufficient. I have nothing to back this up, just going off of gut feeling. Think it could be made to work in torsion?

Like I said though, this is still all in the conceptual design phase, so until we actually do it, I don't know how it will work. Keep those questions and suggestions comin! We all need some help here. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Gary

[cbarbour]

can the carbon fiber half shafts made by taylor race be used witht eh Torsen (t-1) University Special.

[Gary Norris]

Does taylor make cf halfshafts??? I hadn't heard anything about that...

[Igor]

Gug: The inserts were made from aluminium. They were bonded with some kind of brutal epoxy. To make the shafts in the same way one would need some specialised equipment though. The carbon was laid up by computer.

Frank: After competition everybody ran away on holiday. The team just started up again and is trying to get the car rolling. So no miles and data on the drive shaft yet.... :-(
Destructive testing of the shaft earlier was rather satisfactory though, the shaft itself failed before the bond to the inserts IIRC.

Igor

[Gary Norris]

Hey Igor,

thanks very much for the information. I have just a couple other basic questions if you're willing...

1. I assume that for torsion 45 degree offset weave is optimal. is this what you're running?
2. and is this weave pre-preg material? and would you be willing to say roughly how many layers you ended up with? or did you get fancy and filament wind it?
3. Finally, from the picture it looks like the flange is just bonded to the inside of the CF. Is that right? Like I said before, I want to sandwich the tube and bond on both surfaces, but if the tube failed before the epoxy, maybe this isn't necessary...

Thanks again, I appreciate the help.

Gary
gnorris@usc.edu

[Igor]

Gary,
I am the spark-boy on the team, so I don't have all the c-f info. I know there are other team members lurking, maybe they can be of more help.(hi Wouter :-)
1: that's what it looked like
2: it was wound with uni-directional tape on this thing:
http://www.sml.lr.tudelft.nl/facilities/machines/wikkel.html
Dont' know how many layers, but you will have to calculate and test that anyway.
3: yes, that's correct.

Good luck,
Igor

[Ryan Parker]

There is a compaany named CTG Ltd in the UK that can do composite winding. Also there is a company called performace composites that does prepreg and winding. A few questions to whom ever can asnwer:
1. What exact epoxy is being used?
2. did you outsource the application of the epoxy, and to who if yes?
3. Where have you been getting your flex plates? i have been trying to find a supplier of them that will reply to email. How well do the flex plates perform?

Thanks all to the quick responses to my intial forum posting.

Parker
Virginia Tech Formula
joparke3@vt.edu

[cbarbour]

Gary, if you go to www.Taylor-race.com (http://www.Taylor-race.com) and go to technical documents you can find a cf half shaft set with tripods, but i don't have any drawings on the "universty special so i don't know if they would be able to fit or not. Does anyone have drawings for the Univ. Special?

[cbarbour]

the taylor race shafts are 4340 steel sorry, wat do cf half shafts cost?

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Ryan Parker:
There is a compaany named CTG Ltd in the UK that can do composite winding.
Parker
Virginia Tech Formula
joparke3@vt.edu<HR></BLOCKQUOTE>

At birmingham university last year we were the first racing team of any sort to race CTG composite driveshafts, they were excellent and damn light.

The end fitting has to be an annular cavity to allow two bond surfaces. This means that the splined end was made in two halves (the outer and spline, and an inner sleeve) that were electron beam welded together. The bonding was an oven cured epoxy and rated to 1500Nm, we sheered a splined end and the bond stayed secure.

They were talking about kits being made available, but I haven't heard anything since. They're a great company to work with though so it might be worth giving them a call.

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[Gary Norris]

Basically asking ryan's question again...anyone know what epoxy was used for those of you who have done them before, or anyone else that might know of a suitable epoxy?

and the bonding would have to be a secondary process right? I assume the cf tube is laid up and baked first, then bonded to whatever flange you're using after it's all done?

I know we can secure prepreg sponsorship...wish I could find someone that would donate filament winding services... http://fsae.com/groupee_common/emoticons/icon_smile.gif let's keep this discussion going! it's been helpful so far.

Gary

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Gary Norris:

and the bonding would have to be a secondary process right? I assume the cf tube is laid up and baked first, then bonded to whatever flange you're using after it's all done?

Gary<HR></BLOCKQUOTE>

In our case yes. It's also post cured in an oven.

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[Erik C]

There are some good epoxy based resin systems from Loctite, which work very well for bonding parts to carbon structures. And in a torsion application such as drive shafts, there is going to be very little peal stress on the bond, which is the primary failure mode for most bonded composite parts. As far as the filament winding itself, you might be able to find a manufacturer who is already in production for such a part, who may be willing to give you a "sample" to practice on. The most important aspect of this is going to be the bond gap thickness and finding a way to fixture your splines so that the bond gap is very consistent around the circumference of the shaft. For more info, you can do a quick web search on stresses in bonded joints, or get your hands on a copy of Volume 21 of the ASM Handbook. Some very good information in there.

www.adamaircraft.net (http://www.adamaircraft.net)

[Ryan Parker]

Still in the process of researching C-f structures and bonding. I had just a few q to the group:

1. Can any one reccomend a supplier of C-F prepreg fiber or just fiber? The one we worked with in past to get fiber and fabric for other parts on car is unwilling to cooperate anymore?

2. CTG doesn't like to asnwer email for some reason, has anyone been able to get ahold of CTG?

3. I have started design and analysis of the layer. diameter, wall thickness , etc. Any thoughts makeing the calculations any easier, I think i might shoot myself soon.

parker
VT Formula SAE
joparke3@vt.edu

[Erik C]

1.) There are a lot of carbon manufacturers out there. I suggest contacting Toray (Tokyo Rayon), they makes a lot of prepreg for the aerospace industry, and their products are very consistent.

2.) Nope

3.) Calculating the shear due to torsion should be a fairly straight forward process. (i.e. Ty/J where your y and J vary layer to layer.) What may become more of a concern is shear buckling, so I would start by sizing for this failure mode first. You will want to have a balanced layup, with most (if not all) +/- 45 degree plies. When you are making these parts, watch out for wrinkles, delams, resin dry areas. These will obviously have a detrimental effect on the life of your part.
P.S. Why not use filament winding for a part like this?

[Ryan Parker]

We are looking to using filament winding for this application. I have just found out that on is on campus in some storage facility and am trying to get permission to get it out and use it. I was going to mostly +-45 plies. Eric thanks for the feed back though, it is greatly apprecited.

[Gareth]

Advanced Composites Group - my experience with the Canadian rep has been great. They have a good selection of pre-preg carbon and adhesives. You can get bagging supplies from a variety of places and I wouldn't be nearly as concerned with the quality unless you're using a really nice 'clave and the pressure drops from minor bag leaks make lots of people freak out and run around...

[Erik C]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Gareth:
the pressure drops from minor bag leaks make lots of people freak out and run around...<HR></BLOCKQUOTE>

Is that bad? http://fsae.com/groupee_common/emoticons/icon_wink.gif