Yield in Material

[RMXByker]

Good Morning Everyone,

I am working on some beam deflection problems for work. I am calculating not just if the outer surface of the material is going to yield or not but exactly how deep the yield penetrates the material. Is there a standard practice percentage that yield can go into the material before the percentage of material not in yield can no longer snap the other back?

Thank you,
RMX

 

[Twoballcane]

I'm sorry RMX, we are here to help you, and there is no need for insults. All of us on this board take our free time to help and also learn from others who are smarter than us. To make belittling and arrogant statements does not help the situation.

Yes I agree with you on the discrepancy between theory and practice, but you asked a theoretical question and you will get a theoretical answer. However, unless you have actually put strain gauges on the product and captured real data, pure observation of the product not breaking is still speculations of what the real stress are. You said that you have springs 10x the ultimate strength on the outer surface and still meet over a million cycles. Did you have strain gauges on the actual springs and found that it in deed in fact reached 10x its Su? If you have, more power to you. However, most of the time with analysis (theoretical) is to get you in the ball park of what is really going on with probably +/- 10% to 20% error. All in all it is just math. Not until you actually test it under real conditions you will know the real characteristics. That is why once you get real data; you can correlate or correct your analysis so that on the next iteration, your error will be less.




Tobalcane
"If you avoid failure, you also avoid success."

 

[RMXByker]

Understandable. I really do appreciate all your help. I am apparently not in a good mood by not getting a definitive answer. Thank you all for your help. I believe its time to get my hands dirty again and just move on to prototypes. Thank you all!

 

[rb1957]

did Cozzone mean anything to you ?

 

[RMXByker]

I spent some time looking into that and I haven't had enough time to work with it yet. Looks like I will be busy this holiday weekend...haha.

 

[boo1]

BMXByker, you start off with a beam deflection problem. Then switch too, "percentage of how deep the yield can penetrate the material and have the non-yielded portion pull it back into shape". Then change to, "plastic component that will flex around a snap feature and snap in behind it to create a positive snap". Later you tell us, "flexing this part a single time".

Mate sorry you are, "I am apparently not in a good mood by not getting a definitive answer". But consider, researching the subject before posting, provide all the information up front, and determine what you are really asking. What if you started with: I am trying to conduct a linear analysis of the extreme fiber stress of a delrin (or whatever it is) symmetrical section plastic part, flexing around a snap feature (uploaded drawing). The part will only be used once. The desire is to have the part......

See link at:

http://www.eng-tips.com/viewthread.cfm?qid=256804

Cheers
Boo1

 

[RMXByker]

Haha...that would have most certainly gotten to the end result faster. This will be kept in mind the next time...