Dear Users,

I'm doing a dynamic analysis as per ASME III. I'm able to find the occ load factor selection tab for the static load cases screen. However, for dynamic analysis, i'm not able to change this load factor that seems to be 1,2 as a factory setting.

Second question: I'm performing an analysis of a piping systim that comprises an ASME III scope and B31.1 scope. I guess that applying an occ load factor for each section of the system is not possible with ceasar, but I drop the question just in case somebody may know a trick...

Many thanks for your help.

Regards,

AMS - Spain

You can set the default Occasional Load factor in the Configuration. You are correct, you can't change this factor on part of the system.

Run the analysis twice - once using the occasional load factor for ASME III and again with the B31.1 occasional load factor.

Dear Sir,

I am using CAESAR II for ASME Section III, NC piping. I changed the occasional load factor to 1.2, 1.5 and 2.0, in Configuration, as recommended in Technical Reference Manual to account for Level A,B; Level C and Level D operating conditions. I expected the allowable limits to change in CAESAR II output. However, it did not change. As a radical step, I changed the factor to 5.0. Even then it did not change. I am unable to proceed, as there appears to be a problem. Request, any user to help me.

regards,
S. Raghava Chary

For load cases designated as OCC, you should see the allowable stress reported as k*Sh, where "k" is the value you set in the Configuration. If you're not seeing this, send the job in to TechSupport so we can look at it.

I tried many options for changing the OCC limit so that it can be applied to level C and D operating conditions. From many iterations I made running CAESAR II, I get the following information. The occsional load factor can be modified at three places.
1. In static load run. Any factor > 1.2 is acceptable for CAESAR II. The sustained stress allowable limit is multiplied by this factor and made applicable to load cases designated as OCC.
2. In CAESAR File, read in Notepad, the occasional load factor can be modified. It has not made any change to the allowable stress.
3. In configuration file, (SIF and Stress), when the CAESAR II is open. This also has not helped me.
4. I did not get k*Sh in any of the modules.

5. Another inportant query is about replacing Sh with Sm for performing analysis with NC and ND codes, as recommended in TR manual. Why and how it can be done?

Request: a reply from any user who has used CAESAR II for NC and ND Codes and/or developer of the software.

Regards,
S. Raghava Chary.

In continuation of the above, 1 is applicable to static analysis runs only.
For dynamic analysis runs, which I tried with 2 and 3 above, there was no use.

Regards,
S. raghava Chary

CAESAR II does not perform the “alternative” methods described in NC-3654.2(b) and NC-3655(b). What it does do is:

Equation (8) is implemented for load cases designated as (SUS).

Equation (9) is implemented for load cases designated as (OCC). The allowable stress is determined depending upon the value currently set in the “Occasional Load Factor” in the “SIFs and Stresses” tab. If you have the value 0 (default) or 20 (20% increase over SUS values) you will get the lesser of 1.2*1.5Sh = 1.8Sh or 1.5Sy, which corresponds to Service Level A/B. If you have the value 50 (50% increase over SUS values) you will get the lesser of 1.5*1.5Sh = 2.25Sh or 1.8Sy, which corresponds to Service Level C. If you have the value 100 (100% increase over SUS values) you will get the lesser of 2.0*1.5Sh = 3.0Sh or 2.0Sy, which corresponds to Service Level D.

Either equation 10 or 11 is implemented for load cases labeled as (EXP), depending upon whether “Liberal Stress Allowable” is deactivated or activated, respectively, in the Special Execution Options. In the latter case, equation 11 is slightly rearranged, as so:

Ste = iMc/Z <= (Sa + Sh) – PDo/4tn – 0.75i(Ma/Z)

Equation 10a is not implemented.

Equation 11a is not implemented.
The following equations are not implemented for Service Level D in CAESAR II:

B2*( Do/2I)Mw<0.5 Sm;
B1(PdDo/2t)+B2(Do/2I)Me<3 Sm
C2Mam*Do/2I <S1
Fam/Am < S2

Since CAESAR II does not perform the “alternative” method, there is no need to change the B2 stress indices for Level D.

CAESAR II may not perform analysis using alternate rules. But it should consider allowable limits of levels C and D
of NC and ND Codes. In dynamic analysis, applying user provided response spectrum and combining
stresses with a static load (OCC load criteria), the allowable limit is dictated by equation 9 of levels A and B, i.e. 1.8*Sh.

For levels C and D, we have
higher allowable limits (NC 3654.2 (a), 2.25 Sh and NC 3655, 3Sh respectively). Whatever change I make to "SIF and Stress" module in Configuration file or to CAESAR.CFG file in Notepad, (50 or 100 as recommended here) the allowable stress remains at 1.8*Sh only.
This requires manual interpretation of the analysis results for the purpose of code compliance which creates confusion. This may pl. be addressed.

I do not find the stress to be used as Sm instead of Sh. All the equations, i.e. 9 to 11, use Sh only.
TR manual of CAESAR and the reply as above recommends replacing Sh with Sm. I am unable to understand this requirement.
Pl. clarify.

Regards,

S. Raghava Chary