RE: Caesar

From: <Naha>
Date: Mon Dec 10 2007 - 07:20:00 EST

Mohsen,

From the limited data that you have shared, I understand that your solution (when you run the stress analysis) is not converging. This could happen because of an introduction of a non-linearity in the system, by dint of which the matrices do not converge. There might be a case of a guide with a gap and its combination of wind loading or seismic loading. There could also be cases of a combination of a friction support with any of the occassional load cases.

I would suggest, you run the analysis again, without friction. It should easily converge at a single solution, because you would effectively provide the system with just enough variables so as to make the same a "determinate" one. The boundary conditions need not be altered at this stage. If you are lucky enough to use the Power Piping code (ASME B31.1), you need to reintroduce the friction for your reports. I would, however, suggest re-introducing the same to check for the frictional effects - only for the forces arising there, with respect to the local design at those points.

With best regards,
Jaydeep Naha

Senior Manager - Mechanical Engineering Dept. Group Leader - Stress Analysis, Projects & Detailed Design

SIEMENS AG (Power Engg. Ltd.)
Email : <a href="/group/PipingDesign/post?postID=RwsNSujPyNyAoyGwf3zVvULn1vNpnU2Ncfd_QuDvBAswA0RZoIF7iIDb4UVoZzotHoKGmVqE05wLVYM4agdP">Jaydeep.Naha@siemens.com</a>

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From: <a href="/group/PipingDesign/post?postID=cgbCJzEwTwAGtJkmQc8R6Lrz1cDUSmq1XLOUC8ZNWrW8gIm3axT_xRLu9mCP8bBfXN2iWjPSZl50NJfPV6GUCvFHgA">PipingDesign@yahoogroups.com</a> [mailto:<a href="/group/PipingDesign/post?postID=cgbCJzEwTwAGtJkmQc8R6Lrz1cDUSmq1XLOUC8ZNWrW8gIm3axT_xRLu9mCP8bBfXN2iWjPSZl50NJfPV6GUCvFHgA">PipingDesign@yahoogroups.com</a>] On Behalf Of mohsen sabzalian
Sent: Montag, 10. Dezember 2007 09:46
To: <a href="/group/PipingDesign/post?postID=Z9Kz5kOO93I2wZXCkEZMEbPrGnNN3eobg6CiI12dx5FW6TJG9pcVRthBv8szLTDNTM-u8ZhtQw6W08tLW0dVTQPqsA">pipingdesign@yahoogroups.com</a> Subject: [PipingDesign] Caesar

Hi and good morning
I would appreciate if some one could advise me on what possibilties one meets diverging condition when calculating stress analysis of a program by CAESAR II.I am doing stress analyis over a medium pressure steam line and should designate the dimension of required loops to avoid any overstress condition.I enetered Caesar Software the avilable data of line and started to run the program but could not achieve the answer.I have studied the user guide but could not find the cause yet .Would you advise based on your repeatedly applying the CAESAR the probable problem which has resulted to this condition.I would like your comment how to go to converging and get good running of CAESAR.

Regards
Mohsen

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Received on Mon Dec 10 07:20:00 2007