sustained stress calculation in CEASAR II

Posted by: Raju Soni

sustained stress calculation in CEASAR II - 06/06/06 06:14 AM

Dear all,
can anyone tell me reagarding sustain stress calculation through CEASAR. in CEASAR if u go to configure setup/sif/.. and there is a option called PD/4t. by default it is inactive but when u activate this ur sustained stress will be changed upto 40%. after activation ur stress value will be more. can anyone tell me the reason of this variation
Posted by: Richard Ay

Re: sustained stress calculation in CEASAR II - 06/06/06 07:37 AM

Most piping codes provide two equations for the "longitudinal pressure stress" component. The code prints "PD/4t" in the "code equation, but unfortunately this is a "thin wall approximation", and as you found, can be in error by a large amount.

The alternate equation, which is the CAESAR II default is: "P * Di^2 / (Do^2 - Di^2)".

When you check the checkbox in the configuration, you instruct CAESAR II to use PD/4t instead of the more exact form of the equation. This may be necessary to benchmark an existing system or a previous analysis made with older software.