Hi,

I have a clarification regarding Spring usage in CAESAR II V5.0.

Design Temp T1=150 deg C and Normal Temp T2= 45 deg C considered in Analysis. The following datas are considered in control hanger data dialog box:

Case 1:

No of Hanger design operating = 2
Multiple load case design options considered= 2-Operating case.(Normal temp)

The output of hanger data obtained is Hotload 12621N, Movement 3.036mm UP and Installed load 13259 N, with Fig 82, Size 13 and Spring rate 210N/mm (Anvil Catalogue considered).

Case 2:

No of Hanger design operating = 1
Multiple load case design options= blank. (i think CAESAR is considered the first case i.e design case)

The output of hanger data is Hotload 12622N, Movement 9.715mm up and Installed load 14663 N, with Fig 82, Size 13 and Spring rate 210N/mm.

Now i am calculating for normal temp case from the above case 2. From the restraint summary, The operating load (Normal temp) of 13843 N and movement of 3.904mm UP is considered with same Fig 82, Size 13 and Spring rate 210N/mm.

The installed load is calculated as 14663N for Normal temp case.

Why Case 1 and Case 2 are different, but i am considered both are Normal temp only?

Pl advice.

Case 1 designs the spring for T2, while Case 2 designs the spring for T1. In both cases the "restrained weight (hagner) load case" for the spring is the same, however the results of the "free thermal (hanger) load case" are different. So the actual spring data inserted into the model for your real load cases (OPE and SUS) are different - hence you get different results.

Remember, a spring can only balance the system in one position (case). As soon as the operating conditions vary, the spring is no longer balanced.