The following appears when ever I try to analyze the model:
E801-5 ZERO ELEMENT STIFFNESS
Why and how to avoid?
Some where in the model is a Zero element stiffness that has been specified by the user or during the import process. However the warning message does not provide the node point or element location.
Suggest reviewing the entire model paying special attention to any 0.00 values or -ve value for items that should be +ve (ex. Pipe Wall thickness should be >0.00, Bend Radius should be >0.00, etc..). Here are a few methods to try:
1. Create a complete Tools> Model Input listing report and searching it for all 0.00 values. Be sure to review all the pipe properties and beam properties for each entry in the model.
2. Use the input grids go through each tab looking for estrange entries (note, double clicking on column heading will align the grids in chronological order increasing, doing it again orders in decreasing, double clicking top left most cell reorders grid back to normal, very helpfull feature). Set grids back to normal order before selecting another tab.
a. Bend radius has a -ve value (ex. -4.0) or bend too large to be drawn.
b. Bend number of cuts value is blank.
3. Confirm all pipe properties have valid values. Very few fields on this dialog should intentionally be set to 0.00. Again, confirm all values and update as needed.
4. Confirm all beam section Id have valid values >0.00 in all the dialog fields (ex. area, inertia, valid E value, Modulus, Poisson Ratio, Density, etc..). Nothing should have 0.00 or be blank. Update fields as needed.
5. Try to isolate the issue by assigning all the pipes one diameter and/or one material to see if the problem goes away. If the model includes beams too, the same applies to the beams, assign all beams to the same section ID . If the warning does not appear after these changes then it was definitely a pipe/beam property issue.
6. Some people have mentioned that this occurs after assigning soil properties. Again, be sure to check all soil properties have a positive value larger than 0.00.
7. Does your model have bend components? If yes, use Select> Bends> command and then press Modify> Bends command; this will open each bend dialog screen one at a time. Once a dialog is opened, press the keyboard TAB key until OK is highlighted, and then select OK to close the exiting dialog. The next bend dialog should automatically appear. Perform the same action until all bends have been processed. Now, analyze the model.
If you continue to experience this error message please log a Service Request with Bentley and send in a zipped file that contains an AutoPIPE APC file and screen shots as needed.
Note: there is a known issue where changing pipe properties from Press/Temp/PipeID grid could cause zero stiffness error for bends (1047301), this has been fixed in AutoPIPE 12.02.xx.xx and higher.: