The following section will contain questions and answers pertaining to modeling vessels and/or nozzles in AutoPIPE.
It is strongly recommended that user take the time to actually perform these example models to better understand the command and procedure of this modeling approach.
See AutoPIPE's online help for additional information helpful when modeling nozzles on vessels / equipment.:
a. Tools> Model Options> Results> "Show rigid tee stress" check-box option
b. Insert> Extra Data> Reference Point command
Also, be cautious when applying Rigid properties to pipe (i.e. "Rigid options over Range" command), understand the commands settings; "Include Weight" and "Include Thermal Expansion".
As mentioned in the online help:
AutoPIPE will assign RIGID properties to this component, taking into account the weight and thermal expansion. The pipe modulus for the RIGID component is assumed 1000 times that of the regular pipe. No allowable stresses are computed for these components. If the total weight of the component RIGID is provided, it will be applied at the end point of the component. No warning will be issued if the weight of the component is zero
a) Nozzle flexibility if available from manufacturer to put back into the model as Anchor stiffnesses
b) Use operating instead of design conditions for nozzle checks
c) Nice feature in AutoPIPE is to use Reference Nodes at the compressor nozzles (with manufacturer allowables ) to quickly evaluate pass / fail for all operating load combinations
d) Comprehensive ASME VIII Div 1 or 2 flange analysis for all or selected flanges with all gasket, flange, bolt materials etc included and enveloped maximum or selected operating load conditions to be evaluated in the calculation… leakage rigidity check are also performed.
e) Support stiffness can be capture easily with integrating STAAD Structural model quickly in minutes into the AutoPIPE model with automatic or manual connections between piping and structure … this may cause nozzle loads to increase or decrease.
f) Handling fatigue issues – currently AutoPIPE CONNECT 10.00.00.10 non-nuclear codes have a pseudo method (verify current edition features), while nuclear code editions have full fatigue analysis features.
g) Full range of dynamic analysis – typically time history, harmonic and response spectrum…. e.g. for vibration, seismic, or fluid transient type events highly recommend using AutoPIPE because other programs can give completely incorrect results due to their modal analysis methodology is flawed for both simple and complex models (sometimes not capturing all the natural frequencies )….SEE HERE. For this reason even Chairman of ASME III committee no longer uses other programs, but now using AutoPIPE.
Nozzle loads calculation in AutoPipe Vessel. Change of máximum allowable stress criterion