Application | PLAXIS 3D |
Issue status | Open |
First Affected Version | PLAXIS 3D 2018 |
Found in Version | PLAXIS 3D CONNECT Edition V21 |
Fixed and Released in Version | - |
Issue # | 700220 |
Date created | 24 September 2021 |
Date modified | 24 September 2021 |
Global boundary conditions for a specific phase can be defined at the Model conditions subtree in the Model explorer. These default displacement fixities should apply to soil volumes and structural elements, and any user-defined conditions defined always prevail over the ones shown in the Model conditions subtree.
However, if symmetry conditions apply and the nodes of beam elements are located at the tri-dimensional plane of symmetry, without being connected to a soil volume or other structural element, those default fixities that are defined at the Model conditions subtree will not be applied.
Note that when structural elements extend to the model boundary (XMin, XMax, YMin, YMax, ZMin, ZMax), where at least one displacement direction is fixed, they obtain at least two rotation fixities in the points on the boundary. In the current issue, although the default fixity is not correctly applied to the beam node, the inherent rotation fixities are not affected.
For instance, in the illustrated example the default fixity in the y-direction is not being correctly applied but the rotation in x and z will still be zero (φx=φz=0, φy= free).
Since user-defined conditions always prevail over the ones defined in the Model conditions subtree, applying a point prescribed displacement at the end-node where the beam is located is a workaround for such cases.
The steps to solve this are the following: