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In Reply to: RE: How to lower the resonant frequency of a structure? posted by andyr on May 12, 2022 at 21:39:29
Using steel is asing for a resonant frequency buzz.
Try a non-resonant material. I suspect Alluminum is better.....if not perfcct.
Wood might be better, with a distributed mode.
If you can 'short' the vibration to ground? That may help, too.
Various damping materials may also be employed........
You have many more choices than 2 to help your problem. Some design ingeniuty will help here.
Too much is never enough
Follow Ups:
The stiffness of a metal depends on the modulus of elasticity, also known as Young's Modulus, which is constant for a given metal. Since Young's Modulus for steel is three times that of aluminum, an aluminum part under load will deflect three times as much as a similarly loaded steel part. Hope that helps.
Yet.....NO Aluminum bells...
Too much is never enough
Ringing has nothing to do with stiffness. Go figure. Brass is a relatively soft metal and makes good bells. It's more musical. Carbon fiber makes a good viola.
Edits: 08/10/22
Didn't say it did.....
All I noted was that for a non-resonant structure.....you could do worse than Aluminum.
It's other properties of no fatigue strength have little to do with a reframe.....
Personally? I'd start with a 7000 series alloy......one of the bondable ones, so I could glue it together. Most of the 6000 series are OK for bicylce frames after broght to T6 treatment....but still and all? That's no better than mild steel tubing.....
I've alwasys felt that INGENIOUS design trumps sheer mass or the bridge style frames I see so much of.
Too much is never enough
I'll take My steel road bike over ANY aluminum bike. Much better better physical characteristics. End of story. Good luck with your aluminum bike. In fact steel is preferred fir building large structures like uh, bridges and skyscrapers.
Edits: 08/10/22
You jump to conclusions ONCE AGAIN.
For a bike? I think Titanium may be the best metal. And than only a few select alloys....Like 6/4 which is good for dropouts OR 6/2.5 which finds use as aircraft hydraulic tubing. Among the first successful framesets, Gary Helfrich used surplus or not quite-to-spec tubing.
For STEEL? The Unavailable tubing made by EXCELL which is the ONLY steel alloy I know in bicycle use (ago) that used NICKEL in the alloy. The remainder are mainly Chrome / Moly with a few minor alloying agents addes. VERY high tensile strenght and fatigue limits. Tensile over 200,000lb and yield of 171,000. Good elongation, too which may mean a more 'compliant' ride?
This is better than your 4130 Huffy......by far.
Most people do not know that......just for example.....The very famous Reynolds 531 is exactly the same composition as the highly regarded 753r.......the difference being cold working and such.
You needed a special certification from Reyonlds to be sold this material.
Within its limits, (not to exceed fatigue limit) steel should last nearly forever. However, for Aluminum, EACH stress cycle eats into ultimate lifespan.
As an aside? I've seen the NEW Carbon Wheels. OUCH! They are VERY expensive and also massively durable. Spoke counts are now approaching Egyptian Chariot levels.....
I had this chat with my brother. He was a long haul trucker where NET WEIGHT of cargo carried is the rule. He showed me Aluminium trailers. Ravens, I think? Check LINK.
They ARE lighter, but not in proportion of the weights of the same amount of Steel V Aluminum.
Strength and longevity are the reason. Most of the trailers at the link are about 20 years old and I suspect near the end of a useful life......i'd inpsect CAREFULLY for cracks, stress risers and other career limiting defects. The extra capacity made more money for the hauler, but took years. Big Rigs even use aluminum wheels which are also much heavier than the ratio of Fe / Al weights would imply.
The first Aluminum frame I rode? VITUS. And it was awful. LIke riding a screen door. Next up was Klein / Cannondale. Both used thicker wall 'big' diameter tubing of 6061 alloy which were post treated to T6 hardness. VERY brutal ride, as you may have noticed. Big dimeter / thick wall was very rigid and necessary to avoid 'soda straw' breakage. this is when a tube 'folds' in half at a dent. Try it WITH a straw for a demo...
i'd own steel if I could afford it. Or Ti or even Beryllium......But Aluminim is abundent and cheap. As long as ridden properly, it'll last me a long time......
Look at the NEW Pinarello bikes. Like carbon graphite space ships. And priced like one!
Enjoy the ride.
Too much is never enough
Nope, wrong again. Steel is the best metal for a road bike, at least in terms of comfort, flexibility and overall enjoyment. It's you who are jumping to conclusions.Steel provides the best ride, other metals like titanium are obviously lighter, and even stronger, which certainly deserves some consideration, but still even though the heaviest metal used in road bike construction is the best ride, you can make up for the weight penalty other ways. That's why very high grade steel bikes like my All City Mach Man are so damn expensive. The roads around here are all downhill, which helps considerably.
Titanium, measures better, rides worse. Sound familiar?
Edits: 08/11/22 08/11/22
there is so much to 'best' ride as to render your answer as just another opinion / datapoint.
Comfort / Ride is to a large extent design driven. Aero or non-round tubes are more compliant in one direction than at 90 degrees.
Aluminim, for example, NEEDS more material than the simple weight ratio with steel would imply, because of its metalurgical characeristics. And big tubes require thicker walls.....I can't off-hand rmember the 'rule' but go too thin on the wall and you are setting yourself up for a soda straw failure.
Steel tubes are frequently 'butted' where wall thickness varies from thick at the joins.....better for brazing.....to thinner in the middle where stresses may be less.
Don't forget that OTHER characteristics / treatments matter a lot, too. The Reynolds 531 which was used in many regular bikes of the era ws identical in composition to the high-end 753r, differening only in cold working post tube fabrication.....
And you can NOT make a bike from Al or Fe using one set of plans. You should take into considertaion the material to be used in fabrication. I've even seen BAMBOO bikes. As a matter of fact? You can buy a bike KIT and make your OWN bamboo bike. A real conversation piece.
And don't forget the Fork. this is a big part of the ride equation. Different design. different materials. Even Chrome plating of steel.......ALL make a difference in ultimate ride.
so while you may like your steel bike, it is unfair to make such a blanket statement. Even those pesky carbon graphite bike have a place in all this, though $$$.
Your bike is apparently a regular...though with 'shaped' tube version of a traditional steel bike. Nothing exotic BUT is executed very well. A 4130 front fork is also quite traditional. I've lost track of the prices of this stuff, but know that 4000$ and UP are not uncommon for the very high end.
Sounds like you live in an Escher.......
Too much is never enough
I've opened up a hornets nest. I nominate your post for the longest logical fallacy of the week. When you ass-u-me something you make an ass out of me and Uma Thurman.
Edits: 08/12/22 08/12/22
Yes somebody that knows materials and design. Please do a LITTLE better than a general
statement about 'logical fallacy' or whatever.....
But one thing for SURE? Enjoy your bike. No matter.
And for the Record? I think steel is great stuff for a bike. I just can't afford it. Gone from the
entry market and replaced by Mass Produced frames from who knows WHERE? Of Aluminum.
I see many Litespeed Titanium on the market. This would be a good USED move since new goodies
and wheels are easy. Handlebar tape is CHEAP and fun.
Too much is never enough
I have much deeper and broader background in materials than you do. And my education too. This conversation can serve no purpose any more. Ta, ta
I'm sorry to be so.....judgmental......but you did not get your monies worth.....
You never address any questions or comments, but just pontificate....
Tell me why steel is 'the best'?
Too much is never enough
Never is a very long time. Mr. Smarty Pants.
Edits: 08/15/22 08/15/22
Agree with THAT.
I figure the entire universe will be down about about 2 above absolute Zero by the time you are in the mood to'share'.......You are abrogating your duty to educate, if you can.....
Too much is never enough
No one is more sharing and generous than your humble scribe. Or more knowledgable. Did you forget to take your Xanax? This is all probably a simple case of technician versus real engineer.
Edits: 08/16/22
I've read your 'pontifications' on a number of subjects. And speaking of 'subjects'.....that's how you tend to treat people.
You should spend some serious 'introspection' time and try to contact your inner self. Sounds like you skipped a few doses of your Ritalin.....Or Lithium? Contact your medical professional.....
When I need to have such time? A couple days ALONE in the mountains / camping has always worked wonders. Keep it basic.
I about choked on the misuse of the word 'humble'.......than I laughed.....
Too much is never enough
How much do I owe you for the physiological analysis? How about ten cents?
I'm VERY glad you asked.
My advice, as is yours, is generally worth what is paid for it.
I'm under no illusions that you will listen or act on any advice, no matter how well intended.
That being said? I believe in 'pay it forward'. One of these days, you'll have an opportunity to take a deep breath and be more civil than you ever though you had IN YOU.....
Take that chance and be better for it....
Too much is never enough
This conversation can have no porpoise any more.
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