The following occurs when trying to run an analysis:
---------------------------Error--------------------------- E801-4: Zero length element---------------------------OK ---------------------------
How to resolve this issue?
The problem is that AutoPIPE is seeing a pipe length = 0.00. At some point in the model there are 2 node points are essentially occupying the same point in space. Thus producing this error message. However, where are these 2 node points? There are 2 popular approaches to finding these node points.
1. In the Input grid select the points tab:
2. Double click on the column heading "Length".
3. Search for non-grayed out cells, example A01.
4. Place grid back into original order by double clicking the top Left corner cell.
5. Review the issue an determine the best course of action.
Another common location for this error is about a bend component. A bend is comprised of 4 node points: 1. Near, 2. Far, 3. Mid, 4. TIP. IF an AutoPIPE component is placed directly atop the Bend's Near or Far node points this message will appear. Again, best course of action is to move the AutoPIPE component or node point a short distance away from the Bend's Near and Far locations
There are a couple of trick to finding these locations.
1. Select All bends in the model and look for components / node points that are directly atop the bend's near or far points.
2. Look at the Bend tab of the input grids to see what bend radius are used in the model, calculate the bend radius distance, sort the Points tab based on length calculated, and review each occurrence where the length equaled the bend radius.
Bend radius = Long, pipe size is 6" or 8" dia, bend radius for long bend is 1.5 times nominal pipe OD., 6x1.5 = 9", 8x1.5 = 12", search points tab for 9" and 12", review each location for potential issues.
In this model only, there was a segment that has Zero Length, best option in this case was to delete the entire segment.
Using AutoPIPE commands, Select Segment (ex. C) and press Delete button to delete it from the model.
In another scenario the problem may be fixed by 1 of 2 additional methods
1. Removing the offending node point
Example: node point C01 is atop of Bend C02N node point. Delete C01 if not required
2. If 2 node points are directly atop one another in 3D space, insert a small distance between the 2 node points to prevent this message from being displayed. (ex. length greater than 0.01").
Example: the reducer small end point is directly atop of the Bend's Far (ex. B33F) node point. Add a small distance more between these 2 components.
This scenario occurred after importing a PXF model. Upon closer inspection of the original model in OpenPLANT, it was determined that there was a very small pipe run = 0.026 inches. Sometimes a completely review the original model looking for such modeling errors helps when translating the model to AutoPIPE.
Left Image:below of original model and Right image below of hidden pipe to show segment that is causing the problem in AutoPIPE.