| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | ALL | ||
| Environment: | N/A | ||
| Area: | Reports | ||
| Original Author: | Bentley Technical Support Group | ||
Dec 2014, AutoPIPE V8i 09.06.01.10
Problem:
To summarize, I have a gravity case, a thermal case, and a user case. My gravity case, for example, shows a -1224 pound force acting on my v-stop (compression only) support. Both my thermal and my user case actually cause the valve that is being supported to lift up. If I look at the Thermal case, I observe a "fake" reaction load of +1224 pounds at the v-stop. I understand the purpose of this is so that when Gravity + Thermal are actually added together, the net reaction force is 0 pounds. The same situation occurs with my User case (a fake reaction load of +1000 pounds).
The problem that results from this is when I combine Gravity + Thermal + User 1. Th e resulting reaction force at the v-stop is a +1000 pound force. Thus, this turns my compression only support into a tension support as well, but only up to the magnitude of the gravity reaction. I don't foresee this drastically changing my analysis, but it does present inaccurate loading in my supporting frame.
Solution:
There is no indication if this model is being run as a Linear analysis or Non-Linear analysis.
Assuming non-Linear analysis as the pipe is clearly moving off the support, suggest that you modify the "Initial case for Occ. loads" from Gr to OP1...OPn.
Under Load> Static Analysis results> See column labled "Initial State Occasional", set this value to OP1 - OPn (select a value other than GR). Re-run your analysis and review your results.
See AutoPIPE Help for details on this command.