First of all stress relieving is not some magic process that somehow makes a material suitable-especially with carbon steel, or nickels, or stainlesses, etc. Unstressed carbon steel undergoes tremendous stresses in all manner of services everyday. Whether or not it is suitable for this particular service needs to be engineered, not just assumed that stress relief is better.
The advice on engineering is sound. But the process would be one, if you choose to do your own research as opposed to adopting whatever may be the industry standard, is to evaluate the stresses anticipated (a monumental undertaking)and then adopt a mechanical testing regime to determine how best to meet those requirements. This certainly is exactly what the motorcycle industry, and all other industries for that matter, have done from the very beginning.
If your engineers have decided on stress relief then I assume they either have some justifiction from the industry as a whole, either in data or literature, or they have data of their own. Without such their decision to stress relief is just as irresponsible as not to stress relief without justifying data.
A point I should have made in My previous post is that on the asumption that Your company expects to produce these frames for profit, the engineeres need to come up with a design and manufacturing method that produces a strong and durable frame WITHOUT THE NEED for stress relief. To develope a frame they should engineer to the best of their abilities, then build a frame or two, and atrach strain gages to all the heavily stressed areas. Then the bike needs to be built and driven hard over rough surfaces, and generally abused in every way. The data from the strain gages is analyzed and fixturing is built to duplicate the stresses of actual riding. Hydraulics are used to cycle the fixtures rapidly, and if the frame survives enough load cycles to indicate that fatigue is not going to be a problem You are ready to go into production. If not, revisions are made and the process repeated untill the problems are solved. Periodically production frames should be subject to these same tests to be sure that the frame as produced is good. Alternatly, You can do what everybody else is doing and hope for the best.
Dvae,
Your last post really demonstrates the difficulties and time consumption in doing this right. Good post.
Dave,
We are doing all of that, we have already attatched strain gages and accelerometers to the frames, road the bikes on a test track to simulate worst case scenarios, then we have put the entire vehical on a 2post cyclical shaker table that simulates the loads seen on the test track. We have corralated all of this data to the FEA that we did. So we are doing our homework.
Hey Choppperguy,
I want to apologize if my reply appeared crude or demeaning in any way, and did not infer you weren't knowledgeable. Your original post was quite brief and did not indicate the steps you have already performed. My response was due to the "custom" frames I have seen, some resulting failures due to poor welding technique or parameters in design & testing, and a near disaster that a riding bud had with his "custom" frame. I believe the gents here have given you "food-for-thought" so to speak, and also try to provide the best and most sound techniques to obtain your goal. I can understand your issue being in business and the need to be a profitable enterprise and yet provide a quality/value product. Your posts reveal you ARE doing your homework....I applaud that and hope you can complete your goals and maintain a profitable operation as all profitable business keep people working. Good luck & keep us posted on your final determinations...Denny
Chopperguy, I am glad to hear You are doing a complete job of R&D. As Denny mentioned, there are a lot who are not.
Denny is right. I think the brevity of your question and the elementary nature of it as well (PWHT or not) made us all believe (or maybe I only speak for myself) that you perhaps weren't as sophisticated as you obviously are. And therein lies the concern of many of the posts.
But in all reality sometimes these very elementary questions deserve reconsideration. Even when the engineering behind a certain approach matches that of a NASA project to Pluto. I believe that is where you are coming from.
It would not be the first time that a questioning of industry standards completely overturned orthodox thinking.
il assume that you considered sonic stress relieving. i dont know much about it except nascar, indy nasa formula one and a whole host of others use it.
here is a link to a whole bunch of stress relieving companies. i am sure you are way ahead of me on all this but you never know when the mouse can pull the thorn out of the lions paw.
http://www.thomasnet.com/products/stress-relieving-81111403-1.htmldarren
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