Imported axis orientation in AutoPIPE Nozzle is different than in AutoPIPE, why and can it be modified to match?
First let us look at the model in AutoPIPE (WalkThru.dat) and review the results:
AutoPIPE's results for each load case anchor loads:
Using AutoPIPE's Export command, Export the loads to AutoPIPE Nozzle, the following dialog appears:
Note: see note on dialog above.
Press the OK button to view Vessel / Nozzle orientation dialog. Make changes as required
1. Nozzle Axis direction is always +X axis or -X axis because AutoPIPE always exports the Anchor loads / Reference Loads based on Local axis orientation. Local axis for piping in AutoPIPE is always X axis refer to image below:
2. AutoPIPE Nozzle searches for the following file, apnozzle.map, in the current user's appdata folder
(ex. C:\Users \username \AppData \Local \VirtualStore \Program Files (x86)\Bentley \AutoPIPE Nozzle V8i \project ).
If the file contains a line with the name of the model being imported it will not show the Vessel Orientation dialog as it has already been mapped in this file.
Press OK button to import the loads into AutoPIPE Nozzle
Notice difference in loads between the applications.
AutoPIPE Nozzle imported loads
The forces and moments values are exactly the same with the exception of axis directions in some cases. This is as designed,
Question #1: Why are the AutoPIPE global Axis different than the AutoPIPE Nozzle axis where the axis of the pipe is always -X or +X?
Question #2: In AutoPIPE Nozzle on the Shell tab, adjusting the Nozzle Axis to Y, Does not adjust the load on the loads Tab, is this an error?
Answer: A general overview of axis system used for AutoPIPE and AutoPIPE nozzle along with an example is provided below. Hopefully this will cover the questions above.
AutoPIPE always reports the restrain reactions in Global Coordinate Systems. When exporting loads to AP Nozzle, AutoPIPE exports anchor loads in local coordinate system. This local coordinate system is defined based on the pipe attached to the anchor:
The global coordinate axis for the model will be shown at the bottom of the picture above. There are three forces applied to the point C00 (under Gravity load case) connected to the anchor:
In Global Coordinates:
FX = 100.0
FY = 200.0
FZ = 300.0
In Pipe local coordinate system, the forces applied on the anchor point C00 will be as below (refer to the transformation table for vertical up pipe):
Fx = 200.0
Fy = 300.0
Fz = 100.0
These local forces are exported to AutoPIPE nozzle. Note that there will be a difference in local X axis sign when a pipe is moving away from an anchor (as in the example above) and when a pipe is moving towards an anchor (shown in the picture below). This will have an impact while importing the forces in AP Nozzle.
On exporting the anchor loads to AutoPIPE Nozzle, AutoPIPE Nozzle displays the Vessel / Nozzle Orientation dialog as shown in the picture above. Note that this dialog is only displayed once for a new nozzle imported from a model. Once the orientation for that nozzle import is set, AutoPIPE will not show this dialog when re-importing the same nozzle ID from the same model. Note that the colored axis displayed on the diagrams for each Vessel/Nozzle orientation are the local coordinate axis as exported by AutoPIPE. AutoPIPE Global vertical direction is also displayed on these diagrams.
Note that a diagram of the Vessel and Nozzle is also displayed on the main window of AutoPIPE Nozzle. The diagram displayed on the Vessel / Nozzle Orientation dialog and the diagram displayed on the main AutoPIPE Nozzle window are just two different representation of the same system. The diagram shown on the "Vessel / Nozzle Orientation" helps in selecting the vessel /nozzle orientation by displaying the local loads directions with respect to AutoPIPE. This local axis is then transformed to AutoPIPE Nozzle axis system (as displayed on the main AutoPIPE Nozzle window, highlighted in light blue in the picture below). In AutoPIPE Nozzle axis system, X-axis is always vertical for nozzle loads imported from AutoPIPE. A positive shell axis (either Y or Z) is also set after axis rotation upon importing loads and points in to the screen (Z in the picture below).
This AutoPIPE Nozzle axis system represents the load directions as displayed under the Loads tab:
Note that after the initial loads import from AutoPIPE for a specific Nozzle ID, changing the Nozzle Axis, or Shell Axis on the Shell tab of AutoPIPE Nozzle does not modify / update the load values. The results may be invalid if you change a nozzle / shell axis.
Consider a weightless pipe connected to an anchor as displayed above. There are two forces each of 707 units applied in positive Global X and positive Global Z direction. This resolves in to a force value of 1000 units along the local pipe x-axis for the model above.
Analyze the model and export the anchor loads to Nozzle (File > Export > Nozzle Loads to AutoPIPE Nozzle). This launches AutoPIPE Nozzle with the "Importing AutoPIPE Nozzles" dialog:
Press OK on the "Importing AutoPIPE Nozzles" dialog. The Vessel / Nozzle Orientation dialog will be displayed:
Note that the axis displayed in the diagram above are same as AutoPIPE pipe local axis connected to the anchor. Press OK on the Vessel / Nozzle Orientation dialog and go to the Loads tab of AutoPIPE Nozzle:
As discussed, the two forces of 707 units are resolved in to 1000 units of force in local x axis of the pipe, which is also the local x axis of the nozzle in AutoPIPE Nozzle.
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Importing Nozzle Loads from AutoPIPE into AutoPIPE Nozzle