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#162255 - 12/08/08 04:58 PM Carbon Fiber Braces  
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“an island in the Pacific....
One of my kids was born with a lot of physical problems. A few require that he wear plastic braces. They usually last about two years. Shriner's Hospital has an excellent program that takes care of the kids needs until they're 21.

Now that he's 21, he faced with insurance companies that want to play 20 questions before even considering replacements. Part of the process was to be seen by a podiatrist. This doc says he's been working on some carbon fiber braces that he thinks will last a life time. Reading through other threads here I kinda doubt it but they have to be better than what's currently available.

Here's my question. Is there anything I can offer the doc on materials, weaves, etc. that would make them stronger? Any other advice that may be helpful is greatly appreciated.

TIA



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#162258 - 12/08/08 05:11 PM Re: Carbon Fiber Braces [Re: hobie1616]  

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Can you post a photo of the current braces.

If you're really looking to improve things for both your son and other's with similar requirements sponsor an undergraduate thesis at your local uni and encourage your Son's doctor to be involved as an adviser. Sponsoring an UG thesis will be relatively cheap (materials etc only) and if the student comes up with something with potential it can be taken to the "market" to get commercial sponsorship for a PHD thesis/commercial development.

#162259 - 12/08/08 05:12 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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From what I understand aramid fibers (kevlar) have higher abrasion resistance than carbon, meaning it could be used on the outside of the laminate/part to make it more wearproof.
Hope people with more knowledge about this would step in. And Spectra(hight strenght polyethilene) fibers have even higher abrasion resistance than aramid.

regards,

Last edited by isvflorin; 12/08/08 05:16 PM.

Florin
#162265 - 12/08/08 07:39 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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Originally Posted by hobie1616
One of my kids was born with a lot of physical problems. A few require that he wear plastic braces. They usually last about two years. Shriner's Hospital has an excellent program that takes care of the kids needs until they're 21.

Now that he's 21, he faced with insurance companies that want to play 20 questions before even considering replacements. Part of the process was to be seen by a podiatrist. This doc says he's been working on some carbon fiber braces that he thinks will last a life time. Reading through other threads here I kinda doubt it but they have to be better than what's currently available.

Here's my question. Is there anything I can offer the doc on materials, weaves, etc. that would make them stronger? Any other advice that may be helpful is greatly appreciated.

TIA



What wears out on the plastic braces? Do they wear out from abrasion or fatigue from flexing?

Carbon isn't very abrasion resistant but it is strong and lightweight (I know...duh). Lightweight strength means that you can build something stronger while maintaining the same weight as other materials. If cycle stresses are the leading cause of failure in the other plastic versions then the carbon can probably help...some. If the problem is abrasion, then kevlar would definitely be the way to go. Actually, Kevlar is probably the way to go anyway. It is not as strong as carbon but it is less brittle and handles abrasion and flex much better. Note: use epoxy resins with Kevlar...Kevlar (aramids) aren't naturally clingy and their strength properties are only truly realized when used with epoxy based resins.

I thought spectra and the like had adhesion problems with epoxy or polyester resins?

However


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#162266 - 12/08/08 07:42 PM Re: Carbon Fiber Braces [Re: isvflorin]  
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Go to your local surfshop, and find a kid board shaper. One of them surely will find it a challenge to build leg braces from thin plastic foam panel, fiberglass and epoxy that will last for 5 years or more. Cost $50. If this works, the kid could do the same thing in carbon fiber cloth and epoxy: result would be lighter and maybe a bit stronger- and last for more years. Cost $100. Seriously. Kid could do this as a science fair project. Do you still have science in Maui high schools? Or I could do it in my garage if I lived there. (DAC- Ph.D. chemistry, U. Hawaii, Mano'a)


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#162271 - 12/08/08 08:49 PM Re: Carbon Fiber Braces [Re: dacarls]  
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“an island in the Pacific....
Wow! Great responses.

Jake, the failures are caused by flexing. It's usually at the bend between the horizontal foot and vertical leg sections.

dacarls, I know some surf guys who may be able to hook me up with a shaper. Science is still taught in the Maui schools. Our closest is Lahainaluna. I'll nose around and see what I can turn up. I'll also pass your suggestions on materials to the doc.


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#162274 - 12/08/08 09:44 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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They have been using carbon in bracing for many years now... Infact one of the big debates for the future will be whether amputees should be allowed to compete in the olympics on an even playing field due to the biomechanical advantages they are able to achieve with their prosthesis. Check out a quick search for AFO (ankle foot orthosis) and carbon for a huge variety of options. Not sure what kind of specific bracing your son needs, but a good protetist should be able to give you some ideas and with some hints here you could likely make somethng... I can promise medical devices pay much better than boat parts for the manufacturer!

Attached Files
carbon AFO.jpg (458 downloads)
#162306 - 12/09/08 07:42 AM Re: Carbon Fiber Braces [Re: acceleratedchaos]  
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I stumbled on the parametric 100m world championship race this weekend on TV, its amazing how fast these guys are, the guy that won is missing both of his legs from the knee down.

#162321 - 12/09/08 10:13 AM Re: Carbon Fiber Braces [Re: hobie1616]  
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There are a couple of things I would look at for materials.

1) I would look at a mixture of carbon and kevlar. Kevlar has poor compression strength and carbon has poor resistance to sharp impacts. Alternating layers of kevlar and carbon, seem to work better that a single fabric that has carbon and kevlar in the weave (TWAIN). My favorite layup is 2 layers carbon/ 1 layer kevlar 49.

2) I would look at using phenolic rather than epoxy. Phenolic is heavy but very durable. I would not use it to build a boat out of it but I would use it for the trailer cradles or something to drag around on the beach. Autoclaved Phenolic fiberglass is very tough stuff


I also have a question, are the braces intended to flex ? If the braces need to flex, you might have a hard time building something better. If they don't need to flex or don't need to flex as much, carbon might be a better answer.

#162329 - 12/09/08 12:22 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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There might be something more to add on. If you want to make a part that will last a lifetime it would probably be too heavy and actually hurt other parts of the body because of its rigidity. Considering that the part will be interfacing with human body it should be allowed to flex to a certain extent, and flexing will always destroy a part gradually.

We are just speculating since we don't know how it looks like.
Instead of making a bulletproof, ultra tough, ultra high strenght thing I would rather investigate the possibility of making a very very easy to use mould which you could use to make the braces at different intervals (2 years or 5 or 10, don't know). Just layup let it cure and you can have another one in a few hours.

Parts that need to interface with human body should not be rigid, even our bones flex, so the brace should flex too, which will destroy it in time. Better to have an easy to use mould so you can be independant of insurance companies.

I don't think the doc can make a perfect brace the first time - it will either be too rigid or too soft, if you have the mould you can make trials at home with different layups untill satisfied.

Regards,


Florin
#162331 - 12/09/08 01:21 PM Re: Carbon Fiber Braces [Re: isvflorin]  
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“an island in the Pacific....
[Linked Image]
My wife has some additional detail on the AFOs or braces. The podiatrist they saw yesterday said he could get the above carbon fiber AFOs that are already on the market for his cost of $700. OR, if the old plastic ones can be repaired and we can hang on until January, his new product will be available and he'll fit my son for free.

Thank you all again for your excellent responses. I'm going to pass all of them on the the doc to see if it will help his development.


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#167191 - 02/03/09 06:58 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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“an island in the Pacific....
We just got back from the podiatrist's office. His product is delayed due to paperwork issues so he fitted my son with some Trulife AFOs. http://trulife.com/product.html?product_id=1012

The kid felt an immediate difference in feel and comfort. His feet no longer roll over as he walks which means less wear on his knees. It also means the sides of his shoes don't wear so we won't have to buy new ones every three weeks.

I'll post more after the doc gets his product out.

[Linked Image]


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#167194 - 02/03/09 07:59 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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very cool! That's good news!


Jake Kohl
#167197 - 02/03/09 08:13 PM Re: Carbon Fiber Braces [Re: Jake]  
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What about metal? Something light and semi exotic like Titanium? Probably horribly expensive, but last a very long time.

#167201 - 02/03/09 09:19 PM Re: Carbon Fiber Braces [Re: Karl_Brogger]  
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“an island in the Pacific....
Originally Posted by Karl_Brogger
What about metal? Something light and semi exotic like Titanium? Probably horribly expensive, but last a very long time.

It's always an option but the vendors are all going with carbon. That's what good press will do.

The doc that's developing them says he'll use my kid in developing his product. The payoff for us is he'll give us the AFOs for free for life. That's a huge amount of money.


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#185757 - 07/21/09 05:37 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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“an island in the Pacific....
Like everything carbon, stuff breaks. My kid apparently has lots of low end torque which resulted in:
[Linked Image] [Linked Image] [Linked Image]
The piece with the kink in it is a rubber covering over the carbon.

The doctor recommended taking them to the Ding King for repair.
[Linked Image]

It's a ratty old building but they have a huge operation in building and repairing surfboards, outrigger canoes, etc. Richard, their carbon guy, took one look and determined the vertical piece was undersized and the footplate weave was in the wrong direction.

He repaired the vertical piece with carbon and laid a piece of fiberglass over that. The footplates were strengthened with additional layers of carbon.
[Linked Image] [img]http://farm3.static.flickr.com/2497/3743726051_2c01fd048c.jpg[/img]
[img]http://farm3.static.flickr.com/2663/3743731801_bb51469faa.jpg[/img] [img]http://farm3.static.flickr.com/2629/3743730025_620a53d9f3.jpg[/img]


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#185765 - 07/21/09 09:16 PM Re: Carbon Fiber Braces [Re: hobie1616]  
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“an island in the Pacific....
Richard is the guy who repaired the braces.

Cat Boarding


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#185787 - 07/22/09 06:20 AM Re: Carbon Fiber Braces [Re: hobie1616]  
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The link didn't work, but no matter. It's great to see your son is getting the braces he needs.


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#185801 - 07/22/09 08:14 AM Re: Carbon Fiber Braces [Re: pgp]  
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“an island in the Pacific....
Originally Posted by pgp
The link didn't work, but no matter.

Try naish.tv, click Windsurfing, slide to the bottom and click Q's Quest.


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