Framebuilders - Analysis of forces put on frame?

I am an engineering student at the university of Iowa, and I am doing a project on material properties. I have a friend out of Ohio that owns his own bike company and he is in the process of designing a bamboo bicycle. I am doing my project on the material properties of bamboo in order to give him specifications to construct a stronger and more efficient frame.

Now, I am in the process of finding all the forces and stresses put on a bike frame (bumps, peddling, etc) so I can perform the analisys of the material properties and select to optimal diameters and make the frame strong and effiecient.

Dose anyone have any links? I can make the frame in solidworks and run force analisis but, I need to know all the applied forces on the biek, and that is what I am researching now.

Thanks,

Ryan K

P.S. if anyone is doing anything like this private message me, I would love to come into contact with some people with simmilar goals

http://www.calfeedesign.com/bamboo.htm

Calfee makes a beautiful bamboo bike. Im hopeing to use FEA (finite element analysis) to construct the most effiecient frame possible and in order to do that I need to find all the stresses regularly put on a road frame I was just wondering if anyone had links to sites that discussed such topics. I will be doing a static force analysis on the frame in order to determine the optimal sizes of the tubing necisary to build the lightest safest frame with optimal flexing properties.

there is probably more literature about this than you would expect. I just googled for bicycle stress analysis and the second link looked like a thesis. If they did a halfway decent literature review, you will have more literature than you can handle. Also, you can search for papers that cite the papers you find. These will be found on the number of sites, citeseer as just one example.

Calfee makes a beautiful bamboo bike. Im hopeing to use FEA (finite element analysis) to construct the most effiecient frame possible and in order to do that I need to find all the stresses regularly put on a road frame I was just wondering if anyone had links to sites that discussed such topics. I will be doing a static force analysis on the frame in order to determine the optimal sizes of the tubing necisary to build the lightest safest frame with optimal flexing properties.

Having FEA is great for finding the stresses for a specific design. If you want the best design, the "most efficient frame possible" you do indeed need all the stresses. More than that you need to know how to FIND the best design. That can be a sudden flash of insight or a lifetime of trying and testing, or both. Great design engineers start with designing SOMETHING and evaluate their results and process. It's not just being able to analyze.

Plus, what about beauty? Aerodynamics? Customer appeal? Do people really LIKE bamboo as a frame material? Take Calfee for example, how much demand does he have for bamboo? Can it be assembled efficiently, and hence be a cost-effective design? What about dynamic stress? peak pedaling forces? absorption of road shock? These aren't static problems.

Enough engineer talk.

You might want to get a copy of ASTM F2711-08, Standard Test Methods for Bicycle Frames.

http://www.astm.org/Standards/F2711.htm

http://www.sheldonbrown.com/rinard/

http://www.bikethink.com/Frameflex.htm

I just searched "bicycle frame fea" More than you could ever make sense of.

Do people really LIKE bamboo as a frame material? Take Calfee for example, how much demand does he have for bamboo? Can it be assembled efficiently, and hence be a cost-effective design? What about dynamic stress? peak pedaling forces? absorption of road shock? These aren't static problems.

Enough engineer talk.

Calfee has sold about 200 bamboo bikes in 10 years. Demand is so-so.
They are easy to build, search this forum for the word bamboo and you will find a thread where I and ChiapasFixed independently built our bamboo frames.

A bamboo frame is glass like smooth, wood has excellent vibration dampening qualities.

All the fiber in bamboo runs parallel. This is a problem and why my first frame split. To make frames for public consumption the largest hurtle is finding a way to prevent the pipes from splitting when under lateral stresses. I believe Calfee toughens his bamboo chemically. I had thought of using a balloon bladder and some carbon cloth to line the inside of the tubes, but I gave up on the idea.

For personal use a bamboo bike is strong enough, but I would not sell one where the fibers have not been tied together in some fashion, the likelihood of it splitting is too great.

http://www.sheldonbrown.com/rinard/

http://www.bikethink.com/Frameflex.htm

I just searched "bicycle frame fea" More than you could ever make sense of.


Exactly More than I could ever make sense of, I got some good resources already, I was hopeing for some simpler text but, due to the nature of this project I no longer belive simpler text is possible.


Having FEA is great for finding the stresses for a specific design. If you want the best design, the "most efficient frame possible" you do indeed need all the stresses. More than that you need to know how to FIND the best design. That can be a sudden flash of insight or a lifetime of trying and testing, or both. Great design engineers start with designing SOMETHING and evaluate their results and process. It's not just being able to analyze.

Plus, what about beauty? Aerodynamics? Customer appeal? Do people really LIKE bamboo as a frame material? Take Calfee for example, how much demand does he have for bamboo? Can it be assembled efficiently, and hence be a cost-effective design? What about dynamic stress? peak pedaling forces? absorption of road shock? These aren't static problems.

Enough engineer talk.

In regard to that, I have left out a few important details. I am doing project primarily for educational pourposes and secondarily to help out a buddy (i figured if i was going to spend over 100 hours on a project it may as well serve some pourpose) I am serving as a consultant to my friend who is designing the bamboo bicycle, So I am taking his design parameters (exact frame specs) and selecting the tubeing necesary baised off of my material property test results and a generous factor of saftey to make up for the material variance. I don't have the time or resources to completly design this frame so issues such as Aerodynamics, Customer appeal, Jointing, cost-efficeny etc.. will be left up to my friend with the company.

Thanks for all the insight everyone, this is exactly the kind of input I was looking for in terms of treating the bamboo for splitting I am still searching for exactly how to get that done.

Coming from calfee's website, The bamboo has been smoked and heat treated to prevent spliting and the frame is coated with a satin polyurethane to seal it up. Dose anyone think that their is more involed than just that (not looking for anyones trade secrets but, wondering if anyone thaught their was more to it than just that) I am still in the preliminary stages of this project and am still unshure how I will be treating the bamboo to alter its material properties

Wood stabilization with polymers. The process is done under pressure, certain woods are difficult if not virtually impossible, but many woods respond extremely well to the saturation.

Might be something to investigate.

You'll need to take a vector statics course. I'm not exactly sure if community colleges offer it.

the OP is an engineering student at the University of Iowa, so I suspect he's taken a vector statics course or the equivalent.

"Wood stabilization with polymers. The process is done under pressure, certain woods are difficult if not virtually impossible, but many woods respond extremely well to the saturation."

Orvis rods were phenolic impregnated under Wes Jordan's patent for rod reasons, rods don't split, the culms almost always do when treated normally. So bamboo can be impregnated as you suggest.

Craig Calfee also builds a 'boo tandem.
Have ridden one of his 'boo singles . . . rides/handles as nice as one of his c/f bikes.

Coming from calfee's website, The bamboo has been smoked and heat treated to prevent spliting and the frame is coated with a satin polyurethane to seal it up. Dose anyone think that their is more involed than just that (not looking for anyones trade secrets but, wondering if anyone thaught their was more to it than just that) I am still in the preliminary stages of this project and am still unshure how I will be treating the bamboo to alter its material properties

Yes, there is a chemical teatment involved as well.

To the OP please, please, please consider some remedial english courses or implement a spell checker. Your words are painful to read at best.

I'm aware that as an engineering student you probably feel that being able to spell correctly is over-rated but believe me it's not and it could help you in the future.

I am an engineering student at the university of Iowa, and I am doing a project on material properties.


Exactly More than I could ever make sense of, I got some good resources already, I was hopeing for some simpler text but, due to the nature of this project I no longer belive simpler text is possible.


You'll need to take a vector statics course. I'm not exactly sure if community colleges offer it.


the OP is an engineering student at the University of Iowa, so I suspect he's taken a vector statics course or the equivalent.

Out of curiosity, what exactly is your major and what classes have you taken? While radiocontrolhea's response did come off as a bit snarky I was thinking something similar myself. Are you a civil engineer instead of mechanical, or maybe mechanical without physics? I only ask because while programs like Solidworks are very useful tools, if you can't understand the papers you are reading concerning other similar work perhaps your foundation in materials science isn't strong enough. If your goal is just to do something interesting for a project assignment that's understandable. However, if you really want to do fresh and important work in the field you might want to consider brushing up on some of the basics before you "cheat" by jumping straight to software. Statics barely scratches the surface of what you need to understand to do real analytical research, the other option being to just build-test-destroy, which is a perfectly acceptable, if expensive, option. Lastly, if theory really isn't your thing, the easiest way to get hard data (without "borrowing" it) would probably be to throw some rosettes on that puppy and ride it.



To the OP please, please, please consider some remedial english courses or implement a spell checker. Your words are painful to read at best.

I'm aware that as an engineering student you probably feel that being able to spell correctly is over-rated but believe me it's not and it could help you in the future.

That's a gross generalization, an insulting stereotype, and just generally an a**hole thing to say. For what it's worth I'm an engineering physics student with better spelling, grammar, and vocabulary than most language majors. [READ: In the 99th percentile, nationally] So not only are many of us "able to spell correctly" we can do vector calculus much better than the average bear. The image of the snorting lab dork in front of a basement chalkboard is a bit outmoded, to work in the engineering industry today you are expected to be well rounded. Perhaps the OP's spelling issues were rooted in something as simple as typographical errors or maybe, like me, his hands are too large to comfortably fit an average keyboard. Why be hateful?

I’ve got some FMEA analysis performed by an engineering student a few years ago. Provide an email address and I’ll forward it your way.

To everyone who provided me with some insight or constructive criticism, Thanks.

To everyone who felt it necessary to talk some smack, you would be correct in pointing out that my spelling and grammar is about as far from good as you can get. I am horrible at English, to give you a general idea, I will provide you with my act score, I got a 17 on the English, a 34 on the math and, a 32 on the science. I would like you to consider a couple things; first of all you are on a forum talking smack, what does that make you? Smart? Second and probably more important is why are you talking smack? What purpose dose it serve? Does it make you feel better about yourself? If I was a weak-minded individual I could let it get to me and give up on this project. I am working toward becoming a productive member of society and you are discouraging me, which doesn’t make any sense. From a simple economic standpoint the more each member of society is able to produce, the better standard of living everyone within the economy enjoys. I don’t understand non-constructive criticism it doesn’t get anyone anywhere but whatever, to each his own right? I won’t let bogus comments kill my sprit.

To everyone who provided me with some insight or constructive criticism, Thanks.

To everyone who felt it necessary to talk some smack, you would be correct in pointing out that my spelling and grammar is about as far from good as you can get. I am horrible at English, to give you a general idea, I will provide you with my act score, I got a 17 on the English, a 34 on the math and, a 32 on the science. I would like you to consider a couple things; first of all you are on a forum talking smack, what does that make you? Smart? Second and probably more important is why are you talking smack? What purpose dose it serve? Does it make you feel better about yourself? If I was a weak-minded individual I could let it get to me and give up on this project. I am working toward becoming a productive member of society and you are discouraging me, which doesn’t make any sense. From a simple economic standpoint the more each member of society is able to produce, the better standard of living everyone within the economy enjoys. I don’t understand non-constructive criticism it doesn’t get anyone anywhere but whatever, to each his own right? I won’t let bogus comments kill my sprit.
Non-constructive criticism would be calling you a idiot for considering giving up on an engineering project because you can't spell. Suggesting you implement a spell checker when making requests for engineering help when you readily admit that english is your weakest subject is far from that.

The inabilty of prospective fellow engineers to effectively communicate via the written word is one of my pet peeves.

Sorry to harsh your mellow dude. Carry on.





That's a gross generalization, an insulting stereotype, and just generally an a**hole thing to say. For what it's worth I'm an engineering physics student with better spelling, grammar, and vocabulary than most language majors. [READ: In the 99th percentile, nationally] So not only are many of us "able to spell correctly" we can do vector calculus much better than the average bear. The image of the snorting lab dork in front of a basement chalkboard is a bit outmoded, to work in the engineering industry today you are expected to be well rounded. Perhaps the OP's spelling issues were rooted in something as simple as typographical errors or maybe, like me, his hands are too large to comfortably fit an average keyboard. Why be hateful?

FWIW Facts is facts. There was nothing hateful in what I typed.
I have no image of snorting lab dorks in front of a chalkboard and I had very few classmates that gave a **** about the english language. Being well rounded should include having the ability to spell and if you aren't sure perhaps running a spell checker to do it for you rather than throwing up multiple incorrect spelling variations in the hopes of getting one right.

I wonder if you couldn't simply compare the Young's Modulus and yield strength of bamboo to steel, aluminum, or CF and use that comparison to design tubes similar to a high end tubeset. Specifically, Reynolds has already spent a lot of time and money perfecting their 853 tubeset. Why not just use their tubing specifications to size your bamboo after correcting for the modulus and strength?

To Erik B; the OP's spelling was not perfect. However, this is a forum for framebuilding, not grammar improvement. If I were feeling snarky, perhaps I could point out the obnoxious runon sentence with which you ended your last post. I wouldn't typically do that, however, because as long as a person can convey a message without using "u" for "you" or similar trash then I'll read it and help out if I'm able.

It's usually pretty time consuming to get useful information from the literature, mainly because it is not generally assumed that the reader will be starting with an undergraduate student's limited knowledge. I like to read people's thesis, because they are not quite as limited. And a Masters level thesis is good because the criteria for originality is pretty low.

It's actually possible to get aluminium tubing shaped like bamboo. Add realistic paint and you've got the strength of alloy with the look of bamboo.

Not to say it isn't admirable to try to quantify this stuff, but bamboo is a natural material. There is a range of wall thickness and quality in the average bundle. If you used only half of the best of it, you would probably be around an industry average for rods. Rods are highly stressed, and you can't make a good one without Tonkin cane of good quality. But people have made bikes out of any old junk they found at the garden center and the furniture mart. So I don't think they are all using high end stuff. Or grading the good stuff that hard if they are. All that really leaves is the tube size, which is easy to scale from existing bike pictures. Not a complex project.

The Japanese have bikes made from recycled newspaper. I suspect it's all a matter of calculating the necessary thicknesses in the proper locations to deal with the loads.

The most important thing is: know how to do a hand calculation using basic statics principles. A bicycle frame is, relative to to the rider's frame of reference, simply supported, and the traditional 2-D case is statically determinate.

To extend to a 3-dimensional case, which may have various degrees of indeterminacy, use solid mechanics. Depending on what year you're in you may or may not know these yet. You can also choose to go to graduate school, where you can learn elasticity, which can deal with stress concentrations quite nicely. Or Timoshenko theory, which solves short beam problems.

Then, you can understand and criticize matrix/FE approaches. DO NOT start out with matrix/FEA without knowing the basic hand calculations.

Well, this thread has certainly covered a lot of ground. :-)

FEA, materials science, english grammar and composition, computer spell checking software, educational options for future growth, ...

As an engineer in industry for gettin on 25 years, I have some experience to share. First language and communication: it is still a problem for new and seasoned engineers. Some communicate with excellent clarity, and some do not. Sometimes a deficiency is due to skill and sometimes due to attitude. But being capable of more effective communication will make a better engineer.

Analysis and skills basis: One thing I have seen with some newer engineers with some more advanced tool (i.e. FEA) skills, is not being able to answer the question, "does your result make sense?" I have been guilty of this myself, so I'm not setting myself apart here as an embodiment of a standard. It is necessary to judge a complex result, in terms of potential correctness, and to be able to gain credibility by explaining the quality and limitations of your results. It's potential correctness rather than correctness, because an analysis is a prediction of reality, and the only way to absolutely determine if it's correct is to perform physical testing. One can imagine that in say, the space vehicle industry, this is not always possible. So you have to instead be able to judge it on the basis of making sense.

Determining how you want to answer the "make sense?" question is a choice, but what I've found for circuit design and EM field related work is to be able to simplify a system down to a level that facilitates quick hand analysis, and to perform such analyses to find what ballpark a detailed prediction has to lie in. This requires all those undergraduate skills that we may have hated back in school, but it's why those are still necessary, even we have a supercomputer on our desk.

Last, as my earlier comment emphasized, there's a lot more to finding the "optimum" design than maxing out the technical properties. The first major issue is to define "optimum." This involves understanding the needs the end product must fulfill and how those relate to the technical properties of the product and all its parts. This is not or at least in my days was not taught in engineering school.

Good luck to all you young engineers! I hope my industry (automobiles) still has room for all of you when you are in the job market!

Road Fan

Just some thinking about the topics:

Bamboo is one of my absolute favourite things, but I am not sure I would dare to make bikes and sell them to peopel, risking being sued if something goes wrong. If peopel treat theyr bamboo bikes the way they treat theyr "normal" bikes I`d be scared to ride them. I am thinking bamboo bikes is best suited for peopel who know the material well, and best for somebody to pick the bamboo and build it themselves. Just my thinking.

Also what came into my head is that the bicykle has been unchanged for more than one hundred yrs, I suspect the best has been found. For me personally the mixte is the perfect frame. I guess you need to look into if something must be changed since you are building out of baamboo.

Edit: Realised now you do not ask about best geometry but best choice of Bamboo for needed strenght.

Then the spelling. This is happening all the time, and I find it plain cruel what some peopel are doing. This means most peopel should stay away from this forum since English is not theyr native language (like me), or they are dyslectic, or they`we got a disease that affects theyr consentration (like me), or they`we got a crppy keyboard who does not always obey (like me)..

What If I said:" Seriously, Why do`nt you build your own wheels? The world would be so much better for the rest of us (and for you) if you could do that, and you would not bother the rest of us with your crappy wheels". Get a life!

Roadfan,

I believe in testing. I believe in analysis as a tool to support testing. All too often I have seen analyses done which confirm a certain design but when it's tested (properly) it fails,...fails completely. I have seen analyses get re-done which are only then able to explain the failure and guide the resolution.

Without the test failure, the modelling would never have been done with enough fidelity to ever show the problem. The analyses that need to be done are quite detailed and many (most?) engieers cannot do them. This is especially true of composites work, where failure starts at an almost microscopic level but propogate into large scale delams and broken fibers, etc.

I believe in test. Use the analytical tools to help plan your test program.

Just some thinking about the topics:
Then the spelling. This is happening all the time, and I find it plain cruel what some peopel are doing. This means most peopel should stay away from this forum since English is not theyr native language (like me), or they are dyslectic, or they`we got a disease that affects theyr consentration (like me), or they`we got a crppy keyboard who does not always obey (like me)..

What If I said:" Seriously, Why do`nt you build your own wheels? The world would be so much better for the rest of us (and for you) if you could do that, and you would not bother the rest of us with your crappy wheels". Get a life!


If you have a disability (such as dyslexia) or the language is not native to you, I don't think you will get any grief from most people. If you have lived in the US (or other place where English is the language) for several years, you should learn the language. If I lived in Taiwan or Japan or Germany or even France, I would learn the language.

If English is your native language, you should know and use proper spelling, grammar and syntax. It's as simple as that. It is not a "put-down" (insult). It is good advice. Learn to accept good advice gracefully. It is usually given in an attempt to help.



I agree about not selling bamboo bikes, at least not yet. Product liability suits can ruin your life.

I`we seen alot of bullying about spelling in the forums, and most of them is NOT good advice. Also, how can you be sure why somebody is spelling / writing the way they do?

Came here to give you this link http://www.bikeforums.net/showthread.php?t=488635 just found it.

Roadfan,

I believe in testing. I believe in analysis as a tool to support testing. All too often I have seen analyses done which confirm a certain design but when it's tested (properly) it fails,...fails completely. I have seen analyses get re-done which are only then able to explain the failure and guide the resolution.

Without the test failure, the modelling would never have been done with enough fidelity to ever show the problem. The analyses that need to be done are quite detailed and many (most?) engieers cannot do them. This is especially true of composites work, where failure starts at an almost microscopic level but propogate into large scale delams and broken fibers, etc.

I believe in test. Use the analytical tools to help plan your test program.

Mike, basically you're right about testing and I agree with what you say, and where possible it's what I do. However in the three industries where I have extensive experience (automotive, high energy physics, and space flight), I know that not all tests are possible or practical. In the early stages of projects, especially projects to deliver totally new technology such as in space programs, you cannot test the behavior of every space vehicle design configuration IN ORDER TO SELECT one (i.e. in the initial stages of the project), because they are not built. Plus, the customer will not pay you to build every possibility. Many decisions can only be made based on engineering analysis in the early stages of a project. At strategic points you make exploratory and confirmatory tests to better understand the implications of a design that has been chosen, or to confirm the validity and durability of the design.

The OP was talking (IMHO) about finding the requirements for the frame members, so that an adequate set of bamboo frame members could be designed and joined. This is most efficiently done with engineering analysis, not cut and try testing. Validating the design is best done by prototyping and testing.

Road Fan

I understand, the thing is, without a good set of material properties you cannot do the analysis. Materials properties are measured (a test). What I would worry about with bamboo, like wood, is the variability of the material properties associated with growing conditions, internal flaws, "termites", storage conditions, moisture content,... Unless one has nearly control over these things, one cannot control the properties.

Yes, that's all true, I'm glad I'm not the one who's taken on this task. I'd need the energy of a 20 year old undergrad to sort out all those new issues. I'll stick with minor problems like detecting vehicle-vehicle collisions with on-vehicle radar.