| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | ALL; |
| Environment: | N/A |
| Area: | Piping code |
| Original Author: | Bentley Technical Support Group |
| Date Logged & Current Version | Nov. 2016 10.01.00.09 |
Problem:
What does Vmin mean on the Pipe Properties dialog and Press/Temp/PipeID tab of the input grids in AutoPIPE?
Pipe Properties dialog = Poisson's Vmin (Va/h)
Press/Temp/Pipe id grid tab = Poisson's Vmin(Va/h)
Why are the labels different and what do they mean?
Solution:
The Pipe properties input is taking "Vh/a" at ambient temperature, whereas, the Press/Temp/PipeID tab is taking the same value "Vh/a" at the temperature defined for each thermal case. The Press/Temp/PipeID "Vh/a" value, if available, is used when setting a hot modulus case in the analysis set.
The basic relation between the two Poisson ratio's and the two moduli are:
Where:
Eh = Hoop elastic modulus
Ea = Axial elastic modulus
Vh/a = Poisson ratio axial to hoop strain caused by stress in hoop direction - This is what AutoPIPE Pipe Properties and Press/Temp/PipeID tab of the input grids inputs require the user to input
Va/h = Poisson ratio hoop to axial strain caused by stress in axial direction
The term Vmin is confusing. As mentioned, there is a contradiction in AutoPIPE labels for these 2 locations and suggest that both be relabelled as "Vh/a = Va/h*Eh/Ea" or for brevity, simply Vh/a.
This suggested enhancement has been logged under TFS-E625865 and will be included in a future version of the program. Until such time, again, enter Vh/a value in the inputs [At ambient temperature for Pipe Properties dialog, At temperature vale for Press/Temp/Pipeid grid column]