Applies To | |||
Product(s): | AutoPIPE, | ||
Version(s): | 2004, XM, & V8i | ||
Environment: | N/A | ||
Area: | Analyze | ||
Subarea: | |||
Original Author: | Bentley Technical Support Group | ||
Dynamic Analysis FAQ:
Force Spectrum
General Comments, Questions, and Answers
Item #1:
There is some confusion on how AutoPIPE closes the gap of a support in a dynamic analysis. It isn’t clear how this makes sense that the program will apply a support at a point where the pipe may not actually be moving enough lose the gap and to reach the support in reality. Anyclarification on this?
Answer: All AutoPIPE Dynamic analysis require that a modal analysis be performed. From AutoPIPE online help:
AutoPIPE lumps the mass of the pipe, components and contents, etc. at the associated node point. This assumption yields a diagonal mass matrix with no mass coupling terms. There are three mass degrees of freedom per node. Rotational mass is ignored, except for points with eccentric weights, specified using the Insert/Xtra data/Weight command). At these points there may be up to three additional rotational masses and thus three additional mass degrees of freedom.
It should be noted that for the eccentric weight, the coupling terms between the translational and rotational degrees of freedom are neglected. The structure is assumed to be linear and thus all gaps, friction and soil yielding is ignored.
Item #2:
Program should block dynamic analysis if static analysis set #1 not analyzed.
Answer: This has been logged as a new enhancement under CAE-CR-10998. The internal setup of all the dynamic cases still rests with analysis set #1. If analysis set #1 is not analyzed with dynamic loads specified, your dynamic cases cannot be setup properly.
Item #3
For V-Stop type support, like rod hanger, is AutoPIPE capable of deactivating the support in dynamic analysis in the analysis when it is active in static analysis?
Answer: No, supports cannot be diactivated for a dynamic analysis. Only work around is to create a model with the support actually removed for dynamic analysis.
See Also
External Links
Bentley Technical Support KnowledgeBase
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