given what you think you've learned from this:
this is open book. provide references if used.
don't worry brent, i'll get around to helping you with your homework some time this weekend. [you'll still have to find your own "drawings" though.]
Mr. Beam, I didn't read this drivel from you the first time. When you learn to read an engineering paper, when you learn the proper terms and their proper use so you can understand then maybe just maybe you'll be worth the time explaining this to you. Your attempt to divert the discussion into yet another back and forth regarding your incorrect use of engineering terms is noted. If I chose to explain it to you, that's where it would end up, because you don't understand the language. The fact is that you do not understand the article or perhaps you're just a despicable troll. In either case your misinformation should not be left to stand.
Now re-read the article:
"Generally, there are two ways to coil a spring: hot coiling and cold-coiling. Hot coiling implies that the spring is wound from stock at or above the recrystallization temperature. The strength and fatigue resistance are controlled afterwards by an appropriate heat treatment. Cold-coiling means that the helical winding takes place at a low temperature after the spring has been hardened and tempered. Cold-coiling allows the high temperature heat treatments to take place on the bar stock, which is easier to handle than the coiled end-product. The resulting residual stresses can be essentially eliminated by a relatively low temperature tempering treatment fol- lowing the cold coiling.
The idea is to measure the residual stress field in a number of specimens that represent various stages of the production process. Using neutron diffraction one can determine the effect of the prior processing on the residual stress state of that particular stage in the process. Of equal importance, these measurements can serve to verify well established elasto-plastic models that are being used to predict the formation of residual stress. Finally one can look for a way to correlate the residual stress at the surface to the stress field as a whole.
We have looked at three cold-coiled springs. The first spring is an as-cold coiled spring. The second one is cold-coiled followed by a relatively low temper. The third one is identical to the second one, but in addition to being tempered the spring has been com- pressed to the point where the length of the spring is equal to the number of windings times the wire thickness. After this the spring was allowed to relax. A small part of this torsion strain is in the plastic region, so this spring is slightly shorter than all the others. In the automotive industry this process is known as .bulldozing."
"FIGURE 2. Contour map of the residual stress in the direction of the length of the coiled bar stock, plotted on the bar stock cross-section. With reference to Fig. 1, this is the tangential direction. This map represents the as-cold- coiled spring. The left and right side of the map represent the convex and concave sides respectively"
"FIGURE 3. Same as Fig. 2, these data representing the as-tempered spring. The data for the as-bulldozed spring, though not given here, look essentially the same"
When you can understand the plain language of this article then I can attempt to take you to the next level of understanding. Until then such action would be a waste of time.
it's funny - yet another opportunity to prove you know what you think you're talking about, simply goes "WHOOOOSH".
but, moving on to something of actual technical interest, residual stress is an issue for fatigue because it can reduce the effective cycle load. in a nutshell, if a component will take a cyclic load of +300lbs for 10^8 cycles, but it has a residual stress of +100lbs, that means its fatigue load is only +200lbs.
as you might be able to guess from the "+" signs, both the residual stress and the applied load vectors are relevant. if residual stress is
-100lbs, fatigue load can be 400lbs. [this is how shot peening works.]
that explains one spring group, the simple bending spring, but what about torsion, the other major group like the wire of this kind of coil spring? the answer is the vector sum of applied load and residual stress.
since torsion stress resolves to 45°
and residual stress is at its highest positive level on the inside of the coil curve, you expect to see broken springs like this: .
from
where the 45° component of the fatigue surface is originating where one would expect if there were residual stress.
[for springs that have been properly stress relieved, we see fatigue initiate at rust or other surface damage - usually on the outside of the coil.from: ]
see? it's easy brent. but you'd know all this if you had the cattle, no just the hat.
quick, apply here!
Jim, you're one piece of work. Just because I choose not to bother with you doesn't imply anything about anything beyond the fact I don't feel like bothering with you.
Really. All that just to try to save face? If I cared to I would go through and pick it apart and demonstrate where you got things screwed up in your back yard learnin', had your terms twisted and have a basic inability to communicate with actual engineers. I don't even have the desire to read your drivel let alone go through and tell you how you've twisted the articles you cite again. The fact is you screwed up and were completely wrong about Ford coil springs.
At the end of the day Jim, I am a degreed engineer making a living in my field while you mess around with a Honda civic in your back yard under a tree or something similar. There are lots of people who work as engineers without degrees and a good number really know their stuff. If you were half as smart and knowledgable as you claim you wouldn't be doing what you do and did. The fact you didn't rise any higher is very telling. Of course to do so you would have actually had to put down your arrogance and learn to communicate with other people. I know you're jealous and thus behave the way you do towards me and anyone else who made it through formal schooling, but your failure is you.
but you're bothering with me now - pretzel logic idiot.
"engineers" that can't analyze a failure without a "drawing" are not engineers, they're a clueless joke.
nope, but you still don't know why. just like you obviously haven't spotted the mistake[s] in that publicity paper - because that's what it was - it's not an "engineering" paper at all. [frankly, it's absolutely incredible you'd say it was, but that's all part of your problem.] i was hoping you'd be able to look at the pretty pics and actually understand what you were seeing, but i badly misunderestimated you.
??????? you can't have a very competitive field! but then again, you can say anything you want on usenet.
bottom line, anyone /saying/ they have credentials on usenet is like the short guy driving the stacked s.u.v. - they're trying to compensate for something they not only don't have, but something they can't handle not having. if you knew what you were talking about, you'd simply prove it. instead, you just bluster and whine about credentials like the runty little dog trying to hump a leg. because you clearly don't know about the fundamental engineering disciplines of residual stress or fatigue, just like you don't understand hydrostatic stress on cup and cone fracture. and if you don't know about them, you sure as sweet little apples aren't qualified to say what someone else knows. [but i'm being too harsh - that's postgrad and bachelors simply don't learn that stuff. but even a bachelor should have a clue that these things exist, and you apparently don't.]
yup, i dropped out at 3rd grade. i write parking tickets for a living. but i can at least use a spel chekr.
No, I am telling you what I think of you.
You claimed that Ford springs were spec'd a certain way. Looking at one failure alone does not tell you the part specification. It tells you why that one part failed. From that one part you do not know if it met the requirements or not without the requirements. Only a back yard hack who has never spent a day doing real field failure analysis makes sweeping claims about how a manufacturer specifies its parts by looking at one or two or any small number of failed samples. To determine specification without a print you need samples across lots and ideally multiple suppliers. Otherwise you don't know if it is the specification that is the problem or if the supplier simply isn't meeting spec and it is not being caught. The later is quality problem that has to be addressed differently than specification problem.
This is just one of the areas you go into that shows what a know-nothing-arrogant backyard hack you are. You've never worked a day in your life in industry at it shows. You just want to sit back and be critical of those who do. Perhaps you wanted to and ended up wrenching for a living which is no excuse for your behavior. I used to teach techs who decided to get their engineering degrees, good people, I had respect for them and they for me. You on the other hand, I can see why you never could make the step up.
Once again your arrogance is on display. You know better than they do. Whatever doesn't match your backyard hackisms and twisted idea of terminology is their error, not yours. You're a real piece of work. If you are so damn brilliant, why don't you go get a real engineering job? Stop being a frustrated back yard hack and do it.
You play around with a honda civic in your yard. Go out there and get a real job doing this for a living if you think you're so smart and it's so easy. Ford is hiring, jobs are Dearborn which isn't exactly a plus, but you could go show them a thing or three about springs, right?
Stop projecting, Beam.
Just because I won't answer your questions means only that I don't want to be bothered with straightening out your twisted terminology and f***ed up ideas again. I've done it multiple times and your attempt to go on the offensive after you f***ed up this last time with springs is not going to be entertained. The fact of the matter is you could not comprehend an article written in plain English due to your own arrogance, biases, prejudices, and lack of experience in industry.
You are functionally unable to communicate properly with other people because you've developed a technical language of your own confusion. Usually I can figure out what you meant to say after a half dozen posts or more and then translate it into the proper terms, but I don't want to bother with it in your new avenue of face saving by diverting down roads of stress relief and other twisted facets that would take weeks to straighten you out on.. The simple fact is you were dead wrong about Ford springs and cannot prove a single one of your absurd claims. Your diversion is noted and speaks only about you, not me.
Are you unaware of the fact that spelling is a typical failing of engineers? (BTW I post by an old command line/terminal system which means no spell check) Of course when someone has no real argument, attack typography and spelling.
So, you just keep playing with that Honda or get off your ass and stop being a whiny jealous frustrated jerk and step up to the plate.
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