STEAM TURBINE CAMPBELL, SODERMAM SAFE GOODMAN DIAGRAMS 1

[tomato5]

Hello! This subject is a little specialized so if in this forum there is not a specialist in this area, could you please guide me to the correct forum thank you


Briefly, could you tell me the difference between the above four diagrams

thank you very much

 

[csk62]

Soderberg, Goodman - Basically the same diagram, but different failure curves. Alternating stress on y-axis, mean stress on x-axis. Pretty standard for any mechanical engineering application.
Campbell, SAFE - Plots to see margin of exciting to natural freqs. for specified modes (SAFE diagram also takes into account the forcing and mode shapes)

Typically, you use the latter two to compute dynamic stress which you use for the first two.

More specific questions will give more specific responses.

 

[tomato5]

csk62

no, you have answered a lot, and thank you!

Are you a turbomachinery specialist in an operating plant, consultant ?

Does this system allow that if one is able to achieve an under standing with some one like yourself, then questions could be sent or exchanged with that person rather than many others?

Also, what is the means to contact the sponsors of this program for any other rules,regulations, etc.?

Best

in closing I recently read an internet article by a practicing engineer who indicated and supported his finding that the Goodman diagram is actually an erroneous and faulty exercise! but i have not verified that for myself

 

[csk62]

If you have any questions, this is the place to ask them.

The Goodman diagram is modified in any number of ways to suit the needs of the analysis. There is no "one" Goodman diagram.

I believe what you are referring to is the idea of the endurance limit in some Goodman diagrams. Technically there is no "endurance limit", as nothing can withstand an infinite number of cycles at any non zero-stress amplitude; so in this regard this is correct. However, practically, beyond a certain number of cycles, we can just simplify assumptions and call it "infinite" life.