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bigga
May 20, 2004, 7:35 PM
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I know this post isn't gonna stay up for long but I'll give a try...
Is there any Materials Engineer here? I need some advice.
Thanks
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noshoesnoshirt
May 20, 2004, 9:04 PM
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I'm a mechanical, but I share my office with a material guy. What's your question?
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enanubis
May 20, 2004, 9:27 PM
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Metallurgist by trade,
Chemical Engineer by Education.
Although it depends on you question. What do you want to know
.
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dhoyne
May 20, 2004, 9:56 PM
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I'm a Materials Engineer. What's up?
BTW: I lurk here alot, but barely ever post.
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tech_dog
May 20, 2004, 10:44 PM
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I'm a computer engineer. I'm ready to help if this is a digital climbing question.
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freezerfrost
May 20, 2004, 10:46 PM
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I'm a theoretical chemist. My advice to you is to give up now: entropy will only increase.
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r6driver
May 20, 2004, 11:00 PM
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As a Mechanical Engineer, I assure you that I can break any material that you can come up with.
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bigga
May 20, 2004, 11:38 PM
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Wow. Never believed I would get any replies...who'd o' Thunk?
I'll try explain....Is it possible to make a transition between a flexable rubber (somehow re-inforced with a strong flexible mettle mesh to make it strong) to a strong metal ( like a stem starting as rubber and ending as metal) and still have that area of transition/join strong enough to withstand a large force (like a factor 2 fall)?
thanks alot...
if its hard to follow what I'm talking about, its cos of me not you, I know nothing about the subject....just hope you follow what I'm getting at
thanks
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philbox
Moderator
May 21, 2004, 12:51 AM
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I`m a sanitary engineer and stand ready with the shovel.
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enanubis
May 21, 2004, 1:38 AM
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Not to sound like a professor, but...
You are using a relative term, Strong. There are many materials that are strong against a translational force but weak against a shearing force or a torque. So I have to make an assumption, a factor two fall is mostly translational force (up and down). So to answer your question, most likely (it is usual cost and time that derime whether or not it is possible not ability), but I would not put my life on the line (literally) without extensive testing. Products have teams of engineers working on one product line doing extensive testing to insure you don't die. Since you are in Rock climbing.com and talking about factor two falls I just felt I need a disclaimer on any advise. I don't know you application so I don't know what is best, but I was thinking of a composite material. If you mold the metal and the rubber around carbon fiber or a flexible metal fiber, this creates a material usual stronger then either material individually. You have to realize that the weakest part of the product will be the joint between the two different materials (rubber to metal), if you find a fiber that rubber can adhere well to and on that can either be welded or molded into the metal then that will strengthen the joint. If you don't have access to equipment to mold rubber and metal, you could try machining some device to attach them, like the toothed part of a Mini-Traxion, where the end of the metal has a wedging device, where the more force applied downward pulls the wedge tighter.
I haven't taken to many composite courses so I haven't heard of any chemical adhesion to directly and strongly adhere rubber to metal.
Don't know if this helps
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hippie_dreams
May 21, 2004, 3:10 AM
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I'm a Mechanical Engineer...
Can you give anymore details about what you're doing so we can get a better idea of what you're trying to accomplish? - I understand if you want to try to keep it under wraps though...
I assume what you want is one end stiff (metal) and one end flexible (rubber), and you want to join the two with a metal mesh core?
Again, it's already been said, but your joint is the weakest point. But, if your core is continuous from end to end, you could look into using that to determine your strength. Maybe think about wire (like the kind used for nuts, hexes, etc..) - should still give you the flexibility and the strength.
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phineas
May 21, 2004, 4:09 AM
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Made and destroyed automotive parts using injection molding around metal blanks. As the real engineers said if you use a core material to help achieve the overall strength it may be possible, note that the core will probably have to be treated with a primer of some sort (depends on metal and plastic/vinyl/rubber used) to keep a good bond.
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dhoyne
May 21, 2004, 6:08 PM
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Your transition area will give you the most problems once you test your device, especially for thermal expansion. There's plenty of ways to go from a metal to a hard rubber, but I can't think of any really STRONG ways off the top of my head. The first thought that comes into my head is to make the entire thing out of the rubber composite -- you want a composity for strength -- then core out the rubber on one end and insert your metal shaft for the rigidity you desire. This eliminates the interface for the most part.
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bigga
May 23, 2004, 2:20 PM
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Thanks alot....
I really didn't expect to get so many answers. Seems this place has got an inordinately high amount of people who know what they are talking about...
I might have to talk more in depth with someone a bit later on, if one of you doesn't mind...
thanks again
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rrrADAM
May 23, 2004, 2:30 PM
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I'm a Materials Inspecter/Evaluator at Nuclear Power Plants in the US.
From what you are describing, I envision a step made from hollow stainless steel braid (similar to what is around an Alien stem), empregnated with rubber to make it more rigid. Think Chineese Finger Puzzle for the stainless braid. Will be strong, but would more than likely delaminate between the rubber and stainless in a fall as the braid lengthens at a different rate than the rubber, unless a rubber was used that had the same elongation rates.
The above is similar to rebar reinforced concrete, but instead of rigid, as the stainless braid and rubber would be flexible in all directions including tensionally.
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nolan14
May 23, 2004, 2:49 PM
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Wow since theres so many of you guys I guess now would be a good time to ask, Can you make passive pro? Found a guy in California once who made some and wouldent sell them for money. wondering if you could make some cheap? Or something?
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rrrADAM
May 23, 2004, 3:04 PM
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Simple answer... Yes.
Know why they are called "nuts" ???
Back in the day, climbers took machinist's nuts and filed out the threads inside and strung them with chord to make the first "nuts". :wink:
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collegekid
May 23, 2004, 4:42 PM
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Have you thought of using a kevlar composite? I'm sure kevlar threads are much more flexible than steel (and probably carbon).
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allan_thomson
May 30, 2004, 7:59 PM
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In reply to: Simple answer... Yes. Know why they are called "nuts" ??? Back in the day, climbers took machinist's nuts and filed out the threads inside and strung them with chord to make the first "nuts". :wink:
In Wales, they used nuts taken off railway lines. In classical climbing, you can also use slings rapped around actual rocks etc. But I won't carry on too much here, incase I give this crazy kid too many ideas. Let's all hope he finds someone to mentor him before he either kills himself, or totally loses heart.
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