In caesar II 5.2, i am getting confuse on reading the report especially in spring hanger data.


The vertical movement of spring hangers in hanger table report is not matching with restraint summary extended report and displacement report.

for example.. my vertical movement is as follows as per caesar recommended load csae where hot youngs modulus used by caesar for operating case and hanger load case.

Node no 70 = 36 mm up in restraint summary extented report.
Node no 70 = 36 mm up in displacement report, but
Node no 70 = 49 mm up in hanger table report.

the difference is 13 mm in CAESAR II 5.2 ( using hot youngs modulus)


in other manner,my vertical movement is as follows as per caesar recommended load case where hot youngs modulus is changed to cold youngs modulus by us for operating case and hanger load case.

Node no 70 = 35 mm up in restraint summary extented report.
Node no 70 = 35 mm up in displacement report, but
Node no 70 = 38 mm up in hanger table report.

the difference is only 3 mm in CAESAR II 5.2 ( using cold youngs modulus)

In this case,

which one is correct approach? ( hot or cold young modulus for operating case and hanger load case in analysis)

why much difference is in hanger table report while using hot and cold youngs modulus not in restraint summary extented report and displacement report?

if i using hot youngs modulus, which displacements need to be taken for spring hanger design.

thanks in advance for your clarifications.

The results in the hanger table are those from the "design" of the springs - "before" they are analyzed as part of the system. Depending on the relative stiffness of the hangers and the piping system, you may see a slight variation in the displacement or load (at the hanger locations) between the design case against which the hangers are balanced versus your actual load cases with the hangers installed.

The can be a noticeable difference between the results when switching between the hot and the cold modulus values. The modulus value is used directly in the stiffness matrix formulation - which directly affects the system displacements.

Thank you richard,

but basically i am in critical piping analysis for power sector.

I feel that we can be get more precise results in operating case using hot young modulus only. because practically the piping (hot) youngs modulus in hot condition ( while in operation) is less compared to cold condition.

In this case,

Will The noticeable difference affect my piping system in practically against safety?

if it is not, shall we proceed with hot youngs modulus for my piping design and spring hanger design ?

please advise me. because i am in deciding position.

Thanks in advance

Regards
selvakumar

I don't think that question can be answered, every system is different.

I have never seen anyone use the hot modulus to design spring hangers. Remember, the hangers have to work in all positions for all load cases. Also, a hanger can balance the system in at most one position, all other positions will be unbalanced.

very Thanks richard for your clarification.

Regards
selva