Systems Operating in the Creep Regime

RE: Systems Operating in the Creep Regime

K R — Mon, 03 Feb 2014 16:23:35 GMT

There is no creep procedure in B31.1 or B31.3. You will be improvising when doing so in these codes. B31.3 allowable stress accounts for creep, but it probably assumes a large lifetime and I would expected it to be conservative.

RE: Systems Operating in the Creep Regime

samhuff — Mon, 03 Feb 2014 15:21:30 GMT

I've never used that code, I will look into it. The concern I would have is running a system for ASME B31.1 under EN13480 and trying to verify that it is an "apples to apples"

RE: Systems Operating in the Creep Regime

K R — Sat, 01 Feb 2014 08:27:46 GMT

AutoPIPE already handles creep. You just need to use the European EN13480 piping code. You can specify the lifetime in hours in the same screen where you specify the piping code.

RE: Systems Operating in the Creep Regime

samhuff — Thu, 30 Jan 2014 13:13:25 GMT

Mike, any word on this? if there needs to be any type of dialog, feel free to contact me. I can email you my contact info if needed.

RE: Systems Operating in the Creep Regime

Mike Dattilio — Thu, 16 Jan 2014 15:13:09 GMT

Hello All,

I have sent your questions to the CAE development team for further review.

I will send you more information as I receive it.

Thanks for your time

Regards,

Mike Dattilio

RE: Systems Operating in the Creep Regime

samhuff — Tue, 14 Jan 2014 17:31:50 GMT

Perhaps a time dependent dynamic calculation. As creep forms in a system the yield strength decreases, so the allowable stress decreases as well. Modeling and analyzing a creep regime system will work fine for the first ~1,000 hours, but after that its irrelevant as the piping has started to change and will not act in the same way.

I have heard other software, such as ANSYS, can perform this calculation. Since AutoPIPE is one of the bigger players, just wondering if there was a plan for this calculation in the future.

RE: Systems Operating in the Creep Regime

K R — Sun, 12 Jan 2014 17:02:44 GMT

The Euro code EN13480 in AutoPIPE handles materials in the creep range. It contains many ASME materials when you select the source as ASME. There is a recent related post on how to change piping code from ASME to euro and adjusting the material after conversion.

RE: Systems Operating in the Creep Regime

HVN — Sat, 11 Jan 2014 12:16:34 GMT

Good question> What possibilities are you thinking about? Keep in mind creep (fatigue/rupture) is a time-dependent failure (mode) that cant be modelled through static analysis. Most design codes do not provide very specific rules for evaluation, afaik.