Prior to the B31.3-2012 introduction of the sustained stress equation, there were differing opinions on the application of the SIF in this sustained stress – apply the SIF, ignore the SIF, or use 0.75 times the SIF. Users specified their choice through a configuration file setting – Set Sustained SIF Multiplier. The CAESAR II default was to apply the full SIF with an entry of 1.0 for this configuration setting.

The sustained stress equation in the 2012 Edition of B31.3 defines the moment multiplier as 0.75 times the SIF. Accordingly, the configuration file setting was altered to reflect this change, but the configuration file setting saved during the program installation, is incorrectly stored as 1.0. This means that sustained stresses apply a fully intensified moment rather than applying three quarters of the SIF to the bending moments. In this situation, the CAESAR II calculated sustained stresses are overly conservative.

The correction described on Smart Support will correct this error. It is necessary to repair the configuration file (CAESAR.CFG) in each folder where CAESAR II 2014 has been executed AND in the program’s SYSTEM directory. After making this change and rerunning models that were reported as overstressed, results may now show that there is no sustained stress problem. Keep in mind also, that a higher sustained stress will reduce the (Equation 1b) allowed stress range for expansion loads.

For additional details, please visiit Smart Support at:
https://smartsupport.intergraph.com

Dear Richard,

Please correct me If I am wrong.

These are my observations Regarding “SIF Multiplier for Sustained Stress Index”

According to CAESAR-II 6_2013 (Based on 2010 ASME B31.3 CODE)

Irrespective of user INPUT(in these three 0.00001, 0.75 & 1) in this option “SIF Multiplier for Sustained Stress Index”.

I think CAESAR-II is performing in this way, it takes 0.75*(sif value) and it compares with value 1. If 0.75*(sif) > 1 then it takes the value of 0.75*(sif), otherwise it takes 1.

So according to CAESAR-II version 6 no impact of user input in this option “SIF Multiplier for Sustained Stress Index”. It considers only 0.75 as multiplier and compares with 1. Is it TRUE?

According to CAESAR-II 7_2014 (Based on 2012 ASME B31.3 CODE)

CASE 1: If the user defines 0.000 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 2: If the user defines 0.75 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 3: If the user defines 1 as INPUT. CAESAR-II is considering Index value = 1*(SIF)
CASE 4: If the user defines 0.00001 as INPUT. CAESAR-II is considering Index value = 1

In all these cases 1, 2, 3 & 4. CAESAR-II is comparing with value 1. If calculated index value is greater than 1, then it takes the index value for calculations otherwise it takes 1.

So according to CAESAR-II version 7 there is an impact of user input (0.00000, 0.75, 0.0001 & 1) in this option “SIF Multiplier for Sustained Stress Index”. Is it TRUE.

If Code Equation or theory regarding this option is same then why this difference between CAESAR-II VERSION 6 and 7.

Everything you state is correct. But CAESAR II also must work properly for other piping codes that are similar to B31.3 2010 - that's why we introduced the "default value of 0.0" which is interpreted on a "per Code" basis.

Dear Richard,

Thanks for your reply..

Please clear these 2 doubts..

1. In CAESAR-II 5.3 (based on 2008 code)there is an impact of user input (in these three 0.00001, 0.75 & 1)in this option “SIF Multiplier for Sustained Stress Index”.

In CAESAR-II 6 (based on 2010 code) there is NO impact of user input (in these three 0.00001, 0.75 & 1) in this option “SIF Multiplier for Sustained Stress Index”.

Again In CAESAR-II 7 (based on 2012 code) there is an impact of user input (in these four 0.000, 0.00001, 0.75 & 1) in this option “SIF Multiplier for Sustained Stress Index”.

Particularly Why in CAESAR-II 6 version. There is NO impact of user input?. Any REASONS?

2. As you stated “the configuration file setting saved during the program installation, is incorrectly stored as 1.0. This means that sustained stresses apply a fully intensified moment rather than applying three quarters of the SIF to the bending moments. In this situation, the CAESAR II calculated sustained stresses are overly conservative.”

“It is necessary to repair the configuration file (CAESAR.CFG) in each folder where CAESAR II 2014 has been executed AND in the program’s SYSTEM directory”

Where it is happening. I didn’t change anything in config file. I checked in CAESAR-II 7 ( based on 2012 code) it is doing correctly.. Or I miss anything…

Dear Richard,

It’s shocking.. Just now I checked.

In CAESAR –II 5.3, 6, 7 versions.. there is an impact of user input (in these 0.000, 0.00001, 0.75 & 1) in this option “SIF Multiplier for Sustained Stress Index” for occasional [OCC] cases also.

But in the option name is SUSTAINED STRESS INDEX, it is taking for OCCASIONAL STRESS also.

Can you please clarify

Any comments...

Durga,

Rich is on vacation. I will respond.

You asked,

"In CAESAR-II 6 (based on 2010 code) there is NO impact of user input (in these three 0.00001, 0.75 & 1) in this option “SIF Multiplier for Sustained Stress Index”."

==> Yes, in CAESAR II 2013 R1 (6.10) we always use 0.75 multiplier for B31.3 sustained (and occasional) stress, which was in compliance with the code. So, there is no impact of this configuration setting for B31.3 calculation.

But, in CAESAR II 2014 (7.0) version, we added additional flexibility based on that configuration option. This would allow users to run older jobs, also some users may want to use "more applicable data".

Moreover, in CAESAR II 2014 (7.0) you can explicitly specify the SSI (sustained stress index, I) for each Tee. When you explicitly specify the SSI for the tee, then those value are always used irrespective of the configuration setting.


You asked

“It is necessary to repair the configuration file (CAESAR.CFG) in each folder where CAESAR II 2014 has been executed AND in the program’s SYSTEM directory”

==> In the folders that you created for using CAESAR II 2014, you will see a config file (Caesar.cfg), you need to verify this setting for each job folder for the 2014 version.

So, you can switch CAESAR II 2014 to various job folder that you created and then verify the setting using the configuration module.



You asked,

"But in the option name is SUSTAINED STRESS INDEX, it is taking for OCCASIONAL STRESS also."

==> Actually occasional load case is similar to sustained load case, except it occurs less frequent, like wind or seismic or some plant event. It is still a primary load (force based). You will take advantage of the occasional load factor to account of occasional nature of the load.

But, the computation method should be similar to sustained stress.

To clarify it, we can add a note in the help entry for this particular input field in the configuration module.


I hope this helps. The document on smart support portal (https://smartsupport.intergraph.com) goes in to details.

Dear Mandeep Singh,

Thanks for your response.

please clarify these questions.

Question: 1

As You said “ Yes, in CAESAR II 2013 R1 (6.10) we always use 0.75 multiplier for B31.3 sustained (and occasional) stress, which was in compliance with the code. So, there is no impact of this configuration setting for B31.3 calculation.”

If CAESAR-II is doing like that then I will agree, but what I observed is that ..

for Sustained as you said CAESAR-II “always using 0.75 multiplier” and compares with 1

But for Occasional based on input (0.00001, 0.75 & 1) it is taking like this..
CASE 1: If the user defines 0.00001 as INPUT. CAESAR-II is considering Index value = 1
CASE 2: If the user defines 0.75 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 3: If the user defines 1 as INPUT. CAESAR-II is considering Index value = 1*(SIF)

In all these cases 1, 2, 3 & 4. CAESAR-II is comparing with value 1. If calculated index value is greater than 1, then it takes the index value for calculations otherwise it takes 1.

My question is why for only OCC it is doing like this?

Question: 2

As You said “ In the folders that you created for using CAESAR II 2014, you will see a config file (Caesar.cfg), you need to verify this setting for each job folder for the 2014 version.”

But why and when we have to verify, As I observed CAESAR-II is taking correctly as per our Config setting.

As You said “So, you can switch CAESAR II 2014 to various job folder that you created and then verify the setting using the configuration module.”

What I understand, if I open a file from OLD version(5.3 or 6) to NEW version (2014) then we have to verify.. Pl correct me, if my understanding is wrong.

Question: 3

As You said “ Moreover, in CAESAR II 2014 (7.0) you can explicitly specify the SSI (sustained stress index, I) for each Tee. When you explicitly specify the SSI for the tee, then those value are always used irrespective of the configuration setting.”

So if user defined SSI, those values are used for Not only for SUS but also for OCC.. Is it correct ?

Question: 4

As You said “ Actually occasional load case is similar to sustained load case, except it occurs less frequent, like wind or seismic or some plant event. It is still a primary load (force based). You will take advantage of the occasional load factor to account of occasional nature of the load.”

Because of this setting user has no option to use a different multiplier for SUS and OCC. Is it correct.. or any provision to use different multiplier for SUS and OCC

Thanks in advance.

I'm afraid I'm a bit confused on this one. I thought that this setting was ignored now as a legacy setting, particularly with the Use SL formulation per para 320 set to true.

Am I reading in Mandeep's response that this SIF multiplier field is again active in the 2014 version?

please clarify these questions.

Question: 1

As You said “ Yes, in CAESAR II 2013 R1 (6.10) we always use 0.75 multiplier for B31.3 sustained (and occasional) stress, which was in compliance with the code. So, there is no impact of this configuration setting for B31.3 calculation.”

If CAESAR-II is doing like that then I will agree, but what I observed is that ..

for Sustained as you said CAESAR-II “always using 0.75 multiplier” and compares with 1

But for Occasional based on input (0.00001, 0.75 & 1) it is taking like this..
CASE 1: If the user defines 0.00001 as INPUT. CAESAR-II is considering Index value = 1
CASE 2: If the user defines 0.75 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 3: If the user defines 1 as INPUT. CAESAR-II is considering Index value = 1*(SIF)

In all these cases 1, 2, 3 & 4. CAESAR-II is comparing with value 1. If calculated index value is greater than 1, then it takes the index value for calculations otherwise it takes 1.

My question is why for only OCC it is doing like this?

Question: 2

As You said “ In the folders that you created for using CAESAR II 2014, you will see a config file (Caesar.cfg), you need to verify this setting for each job folder for the 2014 version.”

But why and when we have to verify, As I observed CAESAR-II is taking correctly as per our Config setting.

As You said “So, you can switch CAESAR II 2014 to various job folder that you created and then verify the setting using the configuration module.”

What I understand, if I open a file from OLD version(5.3 or 6) to NEW version (2014) then we have to verify.. Pl correct me, if my understanding is wrong.

Question: 3

As You said “ Moreover, in CAESAR II 2014 (7.0) you can explicitly specify the SSI (sustained stress index, I) for each Tee. When you explicitly specify the SSI for the tee, then those value are always used irrespective of the configuration setting.”

So if user defined SSI, those values are used for Not only for SUS but also for OCC.. Is it correct ?

Question: 4

As You said “ Actually occasional load case is similar to sustained load case, except it occurs less frequent, like wind or seismic or some plant event. It is still a primary load (force based). You will take advantage of the occasional load factor to account of occasional nature of the load.”

Because of this setting user has no option to use a different multiplier for SUS and OCC. Is it correct.. or any provision to use different multiplier for SUS and OCC

Thanks in advance

Dear Richard & Dave

Please help me in clearing these doubts..

The easiest thing to do is build a simple cantilever model with a tip load. You can easily determine the Code Stress, and alter the configuration setting to see its effect.

To comply with B31.3 2012, you want the directive set to the default value of 0.00. CAESAR II will then use 0.75 for B31.3 and 1.0 for other Codes similar to B31.3. You can also specify 0.75, but this will then apply to all Codes similar to B31.3 (which may not be applicable).

Dear Richard,
Thanks for your response.
I did that activity what you said and I checked in CAESAR-II 7 ( based on 2012 code) it is doing correctly.

According to CAESAR-II 7_2014 (Based on 2012 ASME B31.3 CODE)
CASE 1: If the user defines 0.000 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 2: If the user defines 0.75 as INPUT. CAESAR-II is considering Index value = 0.75*(SIF)
CASE 3: If the user defines 1 as INPUT. CAESAR-II is considering Index value = 1*(SIF)
CASE 4: If the user defines 0.00001 as INPUT. CAESAR-II is considering Index value = 1

But I am a bit confused about what you said

“ the configuration file setting saved during the program installation, is incorrectly stored as 1.0. This means that sustained stresses apply a fully intensified moment rather than applying three quarters of the SIF to the bending moments. In this situation, the CAESAR II calculated sustained stresses are overly conservative. “
“The correction described on Smart Support will correct this error. It is necessary to repair the configuration file (CAESAR.CFG) in each folder where CAESAR II 2014 has been executed AND in the program’s SYSTEM directory.”

In which version it is happening. (what you said above)

please correct me. if iam wrong...

This applies to v.7.00 only.

The master configuration file is saved in the \System folder, and is created during installation. It is this 1st run of the Configuratio Module that incorrectly sets the value of this Directive to 1.0 (instead of 0.0).

Dear Richard,

Thanks for your response. Now my doubt is clear.

I checked and what I observed..For the first time run after installation, in Configuration setup already sets the value of this Directive to 1.0. (that is why it shows in bold) (after user sets to 0.00 it turns to without bold because it is default settings)

As you said “. It is necessary to repair in 1. CEASAR.CFG in local folder. 2. Programs System Directory.”

I changed in the Configuration set up – SIF & STRESSES – SUS MULTIPLIER to 0.0. it is automatically changing in the CEASAR.CFG in local folder and in the Programs System Directory also..

But you said that we have to repair in programs system directory, is it required?. what I observed is .. it is automatically updating with what I change in CONFIG SET UP in CAESAR-II.

Please Correct me if I am wrong..

The configuration file in \System is used when there isn't a local configuration file. That's why we suggest you also correct that one (the one in \System).

Thank you very much.

My doubts are clear.