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Subject: Re: Creep, Primary+Secondary
Author: Rick Fischer
Date: 2002-06-05 16:51:00

After looking in Material Model Combinations, 8.3.2 in the Structural
Analysis Guide, and apeing what I see there, I wonder if something like the
following might not be the way to go:

tb,creep,1,,,1 ! set primary creep to "strain hardening", TBOPT=1
tbdata,1,,,, ! creep values for primary creep model
tb,creep,1,,,10 ! set secondary creep to "Norton", tbopt=10
tbdata,1,,,, ! creep values for secondary creep model

"Ian Stewart" on 06/05/2002 02:41:50 PM

To:
cc:

Hi,

I am doing a creep analysis but I have faced a big problem!

First, I have chosen Explicit Creep (told to do it this way).
I have to do the creep analysis for the primary creep + secondary creep.

In other words, my model, obeys a primary creep equation for the
"Primary Creep Region", and following that, obeys a secondary creep
equation for the "Secondary Creep Region".

From my previous posts for help, I had found that I can apply both
Primary and Secondary equations at once.
I have entered Primary Creep Eq. with C6=1 and Secondary Creep Eq. with
C12=1 this way:
In /prep7:

tb,creep,1
tbdata, 1, 1/2*6.83e-54, 6.2, -1/2, , , 1
tbdata,7, 9.9e-56, 6.2, 0, 0, 0, 1

Would you please tell me what's wrong with this definition? The results
which I obtain with the above Creep Definition (for the desired primary
+secondary effect),are the same results which I get from JUST the
Primary Creep! In other words, it seems to me that the second equation
has no effect!

Please help me.

Ian Stewart
Rabet research
POBOX: 51390
Dubai, UAE
Tel:+971-4-2226338
Fax:+971-4-2218898

Posts possibly associated with message #38530AuthorDateScore
38495Creep, Primary+SecondaryIan Stewart rabet@2002/06/04 
38527Creep, Primary+SecondaryIan Stewart rabet@2002/06/05 
38528Re: Creep, Primary+SecondaryFernand Thomassy2002/06/05-10
38530Re: Creep, Primary+SecondaryRick Fischer2002/06/05