Dear all,
In dynamic analyis->control paramenters->static Load Case for Nonlinear Restraint status

after refer the F1 help,i still don't know
which load case should be choosed ?

my load case:
4)WW+HP+H(HYD)
5)W+D1+T1+P1+H(OPE)
6)W+D2+T2+P1+H(OPE)
7)W+D3+T3+P1+H(OPE)
8)W+P1+H(SUS)
9)W+D1+T1+P1+H+U1(OPE) seismic
10)W+D1+T1+P1+H+U2(OPE) seismic


which one should be choosed, and what is the
choose criterion?
thanks

Best Regards,

The answer is.. which restraint status of the pipe
you will choose for the dynamic analyses.
Caesar can not make a dynamic analysis with nonlinear restraints.

Seismic loads give primary stress.
Why do you combination with secondary loads ?
This combination that you choose ist only for the stress in the support necessary.
An here load Case "HS" "Mean(H) und special(S) loads".

i am sorry ,i can't know your meaning clearly.maybe my english is a little bit poor.

4)WW+HP+H(HYD)
5)W+D1+T1+P1+H(OPE)
6)W+D2+T2+P1+H(OPE)
7)W+D3+T3+P1+H(OPE)
8)W+P1+H(SUS)
9)W+D1+T1+P1+H+U1(OPE) seismic
10)W+D1+T1+P1+H+U2(OPE) seismic

are part of my static load case.
and In dynamic analyis->control paramenters->static Load Case for Nonlinear Restraint status

CII let me choose one from the above 7 case.
i use dynamic analysis for steam hammer not earthquick ,because earthquick was analysised in static method by input g's value,not dynamic mothod


hope you can know what i mean,thank you!

Oh, i got it ,do you mean that my static load case :
9)W+D1+T1+P1+H+U1(OPE) seismic
10)W+D1+T1+P1+H+U2(OPE) seismic

are not correct?

Tha load D1 (steam hammer) and the load U (static seismic) must not be combination !

Your load case for the primäry stress must be
W+D1+P1+H (OCC)and a another load case..
W+P1+H+U (OCC).
Dynamic loads which effect "short time" are not (OPE).
Dynamic combination with T1 you need only for the "support stress calculation" (here load case
HS).
Best Regards..

D1 from the static load sets refers to "displacement set one" not "dynamic case one".

Use all load cases associated with the hammer event. My guess is that it will be either 5, 6 and/or 7. If the nonlinear support configuration does not change between 5, 6 & 7 then use any one. If the supports' actions change (active to inactive) between these cases, I would probably run a few of them to see what's the worst and use that.

I agree that the static seismic analyses (9 & 10) above would be appropriate for calculating a structural response (notice I didn't say "the" structural response) to the seismic event while the system is in operation. (Other cases would include "W+D1+T1+P1+H-U1", etc.) It is not, however, a proper check of code-defined occasional stresses.

Dear Dave,

yes,
i only list part of my static load case,
a complete one are:

.....(hanger case)
4)WW+HP+H(HYD)
5)W+D1+T1+P1+H(OPE) T1=566.6^c OPE TEMP
6)W+D2+T2+P1+H(OPE) T2=0^C START UP TEMP
7)W+D3+T3+P1+H(OPE) T3=574^c DESIGN TEMP
8)W+P1+H(SUS)
9)W+D1+T1+P1+H+U1(OPE) seismic FOR NOZZLE RESTRAINTS IN SEISMIC U1
10)W+D1+T1+P1+H+U2(OPE) seismic ...
11)W+D1+T1+P1+H-U1(OPE) seismic ...
12)W+D1+T1+P1+H-U2(OPE) seismic ...
13)L5-L8(EXP)
14)L6-L8(EXP)
15)L7-L8(EXP)
16)L9-L5 (occ) algebraic
17)L10-L5 (occ) algebraic
18)L11-L5 (occ) algebraic
19)L12-L5 (occ) algebraic
20)L16+L8 (occ) scalar FOR SEISMIC U1 STRESS
21)L17+L8 (occ) scalar ...
22)L18+L8 (occ) scalar ...
23)L19+L8 (occ) scalar ...

do you think the above load case is complete for seismic?

then,in dynamic analysis, I combine D1(steam hammer ,not the D1 in static) with L8 for steam hammer stress,
but if i want to check the nozzle
restraints to see if they are exceed limits when the hammer occur in 566.6^C when the valve sudden shut down, i don't know how to do.
i combine D1 with L5 to see nozzle restraints, does it right?


other question,"I would probably run a few of them to see what's the worst and use that."
what is the "worst" mean?

BEST REGARDS,

Yes, I believe you have address seismic load evaluation with the load cases you list.

With the large number of load cases you may want to use some of the other load case "combinations" to simplify review. For example, add L24=L20,L21,L22,L23 (display stress only, listing the MAXIMUM value from these load cases).

In dynamics, yes, sum D1 and S8 to review these hammer stresses.

For the hammer reactions I would review S5 plus D1 and S5 minus D1 but CAESAR II will lose all signs in these combinations so you'll have to do this outside of CAESAR II.

"Worst" - calculate the natural frequencies based on the restraint configuration (from either L5, L6 or L7) that produces the highest loads or stresses.

Here ,

I should thank Ohliger and Dave,

I really appreciate your time!

Thank you!

Best Regards!