I am doing an analysis of flexibility of a pipe and I have has several disadvantages.
Once I had entered all the data at caesar, I make the run but did not converge.
First, I followed the advice of the technical reference manual about friction problems:
The default friction stiffness is 1,000,000 lb./in. This value should be decreased to improve convergence.
But the problem continued.
Finally, I got tested to eliminate the nonlinear restraints (MU) to see if there was convergence, and find a solution (an ideal solution but a solution)
I make the run, and the results obtained did not meet the parameters of ASME B31.4. What do you recommend? I placed anchor blocks at the beginning and end of the pipe, and I put guides as the ASME B31.4 recommends (every 50 meters).
If some one could help me... I would appreciate your help

You entered into the classical trap of friction. This question will remains uncertain for ages and need some logical remedies for system solution.

I am uncertain about the boundry conditions(Anchor blocks) which you are talking about. But reagarding convergence problem we are always open with several options to solve it.

First option is reducing default friction stiffnesses which will inturn reduce the load values on restraint. My opinion would be to take stiffness from structure guy rather than assuming by your own.

Second option is to observe the non convergence algorithm of caesar and remove friction from selective supports if they are not near to equipments nozzle or critical areas. More smartely , one can observe the system visually and predict the liftoff supports and remove friction from there before making a run.

Third option is to make the system linear with pure Y support and guides with 0 gaps.Now you have to ensure that none of your pure Y support takes a positive load there.If it does so, you can allow it to lift there or make it hold down if load is feeble and doesnt make a stress/flange failure nearby.


Refer the attached file for more information on non convergence algorithm in caesar.

Thank you so much for your help Alkesh...

I followed your advice and I made the changes that you recommended me. Also, the file you sent me, helped me to understand better the information provided by CAESAR through the incore solver.

Very grateful for your help.

Regards

Daniel 23