Ambient temperature/thermal stress range

Take a close look at the 'Expansion' value in the Modify -> Operating Pressure and temperature dialog box. If it's checked on Auto, then the program will calculate a value based on the temperature differential. You'll note that the expansion value for +100 deg is not exactly equal to the value for -100 deg. You can over ride this by unchecking the Auto box and entering a constant number.

Expansion

This field and the corresponding Auto checkbox are used to input the thermal expansion data for each operating case. For non-standard (NS) materials, the thermal expansion data can be entered and modified, . For standard and code materials, the field is not editable (grayed out) and the corresponding data is automatically retrieved from the material library for the appropriate temperature. For non-standard materials, the default value is zero for new models. For existing models with pipe identifiers defined with code or non-code materials then a new or existing pipe identifier changed to NS material will default to the previous expansion values. To override the automatic library value un-check the Auto option and enter the user-defined data.

more here:

Hi,

Thank you for your replay. I have additional question. I set the same thermal expansion for both temperature.

But if I change the temperature at dialog box- General Model options- for example from 0 to 50 deg then thermal stress are change, even if the delta T is the same and linear

thermal expansion values are the same.

From where this change come from?

Hello Pawel,

It is not clear what settings you currently have in your model.

Suggest to add more screen shots to provide a clear picture of what you are trying to accomplish.

Regards,

Mike Dattilio
Bentley Product Advantage Group Analyst
AutoPIPE Product Line Bentley Systems, Inc.
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Hi

Below is clear explanation with snaps.

I have operating temperature T1 -100 deg and T2 +100 deg (according to snap below).

I used the same linear thermal expansion for both temperatures as was stated above:

I made two test,

First one with ambient temperature/installation temperature equal to 0 deg:

then the thermal stress are 306.69 MPa at point A00:

Second test is with ambient temperature/installation temperature equal to 50 deg:

then the thermal stress are 302 MPa at point A00:

From where this small difference come from in computes thermal stress if we have the same delta T and same linear thermal expansion factor.

Hello Pawel, 

Review the pipe properties after changing the ambient temperature (specifically the Long Mod, Hoop mod, etc..). These values may change depending on ambient temp. 

Regards,

Mike Dattilio
Bentley Product Advantage Group Analyst
AutoPIPE Product Line Bentley Systems, Inc.
===================================================