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I have a valve with a stream purged stuffing box that is designed and rated for 50 psi, and the maximum purge pressure is 100 psi. Is there a code exemption for the purge pressure being that the flow rate of the purge is insignificant to the flow rate of the valve - like a drop in the ocean...

I want to create a MathCad sheet that has an image with inputs on top representing dimensions. This is only to visually assist the user, so correct variables are inserted. Any ideas how to do this?

I just installed Simulation 2013 and the issues with plate assemblies have been fixed.

Thanks for the tip. We most do static stress analysis so I do not think it has become an issue yet.

I'll give it a try...thanks

It can be, but creep needs to be considered.

Yeah...Thanks a lot for taking the time to walk me through this. Another step on my never ending quest to understanding ASME Sec VIII!

Ok, think I got this. A highly localized stress at a discontinuity (corner of strap welded to vessel for instance) should be evaluated as a primary local membrane (1.5S) when the FEA is set to membrane only, and then if set to membrane + bending, evaluated as a peak (3S). If that statement is...

Is setting the software to membrane only and then setting it to membrane + bending enough differentiate the two? What about peak stresses at discontinuities when the software is set to show only membrane stresses?

My confusion is where a peak (3Sa) becomes a local (1.5Sa). For example, if I have a peak at a discontinuity, at what distance from that discontinuity would I stop evaluating the stress for 3Sa and start to evaluate at 1.5Sa. It seems like it might be a common area of confusion because I found...

I probably should have mentioned earlier that the report I am looking at was created with plate elements. Is there a determined distance away from a hot-spot where primary local stresses are evaluated and then another distance where general primary stresses are evaluated?

Yes, the entire model is a plate model (zero thickness). Tech support at Simulation said the problem with plate assemblies is a known issue. Are you suggesting building the models as solids and then extracting mid-surfaces before bringing into Simulations? Are there any problems or gaps that...

I have gone back and read the code, but I still am not confident that I understand this. Is it true that a stress greater than 1.1S that is > sqrt(r*t) from a discontinuity should be considered a Pm? Maybe another way to say that is a stress that exceeds 1.1S and is greater than sqrt(r*t) from...

Thanks, I will look into API-579; I think the desired life is known. One more question on this same subject if you don't mind. I have read in the code that stresses a distance of SQRT(R*t) away from a peak should be considered local primary. If the peak stress are caused by a strap on a...

Temperature is 1,000 deg F. I will look into Section II, part D and see if that will work. I am attempting to prove that the peak stresses of my FEA will relax and are not areas of concern. There is some debate as to where local primary stresses become peak stresses.

Can anyone guide me toward where I can find stress/strain curves for SA516 gr 70 at elevated temperatures? I am working on a non-linear analysis and need these properties. Thanks in advance.

Can anyone give me any tips on importing plate models into autodesk mechanical simulation 2012. I have been drawing models in autocad 3d because simulation will not accept inventor assemblies. I have had some luck when converting to .sat files, but none with .iges or .step. I usually get a...

What would be a general outline for analyzing a stress concentration in the creep regime from an elastic analysis? Is it outlined well in APC 579? I have not been able to get access to this code.

"Are the stress allowables applicable for stress results from an elastic - plastic analysis? " After thinking more about this, I do not think that they are. I think I need to do Viscoplastic analysis, but I do not know where to get those properties from. It seems very hard to find material...

Thanks normet and TGS4; I will look into API-579.