Hi there,
I am modeling a circular tank with sloped base slab in STAAD (note the base slab has an opening in the middle and the slope is towards the opening). The internal diameter of the tank is 60m and the height is 6.2m.
To create the geometry, I used the section wizard to create a cone shape for the base slab and also cylinder for the wall. On completion, I merged the prototypes into STAAD Pro and then generated plate mesh for each surface. The problem is that whenever I run the analysis I get this error message: WARNING* PLATE NO. 2411(JOINTS 3257 - 3256 - 3277 - 3278) IS BADLY SHAPED, WARPED, NOT CONVEX, OR NOT NUMBERED COUNTER-CLOCKWISE. Note I get a lot of them and not just one plate.
I looked in the forum and found this solution error message comes. "IS BADLY SHAPED, WARPED, NOT CONVEX OR NOT NUMBERED COUNTER CLOCKWISE". What can i do to solve this?. I have renumbered the plates, checked for duplicate nodes and warped plates as per the solution but still when I run the analysis the error doesn't go away. I have tried generating plate mesh with both polygonal and quadrilateral meshing and I still get the same error. Can anyone help with this please?
This is a screenshot of the model prior to meshing. Thanks.
I think these warnings are reported due to too large aspect ratio of the edges of the plates at the cone. You can find an detailed explanation on this here: Badly shaped plate element - RAM | STAAD Wiki - RAM | STAAD - Bentley CommunitiesThe solution in this case would be to mesh the plates into the smaller elements which would have an aspect ratio closer to 1:1 but not greater that 1:4.
Thanks for your response, Modestas. Do you have any tips on how to mesh the plates so the aspect ratio is between 1:1 and 1:4 for such a geometry?
Select a plate or group of plates, then right click on it and select the option Generate Plate Mesh. In the mesh generation dialog, you may need to adjust the edge division to meet the aspect ratio requirement.
okay. Is it a suitable alternative to increase the number of divisions along length and along the periphery from section wizard prior to merging into STAAD Pro? See attached pictures of tank without meshing but plates divided using section wizard.
I'm thinking if I do this then there will be no need to generate mesh in STAAD since the plates are already divided into small pieces with reasonable aspect ratio. Please what are your thoughts on this approach?
Yes, this method is correct as well.