Hello all,

Is it likely that future versions of Caesar II will include Pressure Relief Safety Valve (PRSV) modeling? It seems dubious to simulate a PRSV by using two valves. Is there a more reasonable way to model a PRSV that anyone knows of?

Thank you!

Frankly, I'm not ready to pay extra just to have a "more reasonable" model in the next version... For the calculation purposes it is enough to have a model with one rigid (or two rigid bodies at 90 degree angle) and associated weight. BTW, where is the gravity center of a PRSV?

I think it is only inevitable that software simulates the visual aspects of modeling in more detail as computers become more powerful. It is analytically extraneous, but it does make communication between engineers and "non"-engineers easier. Adding features such as a PRSV lessens the learning curve of software and makes software more intuitive. It is part of the reason that SolidWorks has become the CAD software of choice in a lot engineering schools. It is visually appealing and intuitive.

With regard to the cost of a new version of software, I imagine that new versions (and the inevitable termination of support for old versions) will come out anyway. These companies might as well add some tools to their toolboxes if they are going to progress their software and charge exorbitant amounts of money.

Back to Caesar II, how does Caesar account for two rigids at exact right angles (90 degree PRSV) without an elbow. Is it accounting for a right angle stress intensity?

Thank you!

Just keep in mind that any CAESAR II element is no more than a "stick"; actually it is not a "volume" or "solid" as shown on graphics. For this reason a funny PRVS (two cone volumes in apex joint to make a right angle of axes?) will not improve the calculation.

An elbow is also a pair of sticks in right angle. It has special properties (stress intensification and flexibility) as defined by Codes. It is not the case of a PRSV.

You don't need to evaluate stress in a valve or in a PRSV because they are inherent stiff hence not so "sensitive" as the adjacent piping. If you need it, I think Caesar is not the tool you are looking for.

Remaining at "stick" level of PRSV, I would like to improve the calculation by simulating at least the correct center of gravity. Do you expect a Vendor will show you this information?

Difficult to say. That information is likely captured with their CAD program, but it isn't freely released in the same way that dimensions and weights are.

Thank you for explaining the functionality for me. I was trained with SolidWorks in college, so it is difficult for me to see the nodes approach.

Mariog is correct, piping flexibility programs use a 3D Beam Element to solve the FEA solution to [K] {x} = {f}. A 3D Beam Element is an infinitely thin stick - there is no sense of volume, or a shell surface.

A rigid element is a 3D Beam Element that is much stiffer than the connecting pipe elements. You don't know the cross-section of the rigid, it is simply a numeric construct used to transfer forces and moments (unaltered) from its start node to its end node.

Makes sense. Thanks all.