Problem description

In cases where you have a circular tunnel designed (i.e. one segment of 360 degrees) and at least an inside (positive) interface is assigned to the tunnel, the model will not be able to be meshed in PLAXIS 2D AE due to this inside interface on a full circle.

Figure 1. Tunnel shape with inside interface

The program will give the following error:
    Meshing failed with the following error:
    Mesh output file not found

Solution

This issue is now solved since PLAXIS 2D 2015.00: now a circular tunnel will by default consist of two segments in stead of just one. This prevents this issue to occur. Note: for full circular shapes the above mentioned problem may still occur.

In older versions, this issue can be solved if instead of one segment the circular tunnel is designed with two segments of 180 degrees each:

1. inside the tunnel designer using the “Free” shape type option in the “General” window of the “Cross section” tab.
2. In the Segments tab, add one arc of 180° with the correct radius
3. Then press the symmetric close button to make the other symmetric half
4. Then in the “Properties” tab the positive interface can be assigned to both segments, along with other user features (e.g. plates)
5. And then do not forget to Regenerate the tunnel

Now the model will have no problem generating the mesh.

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Figure 2. Workaround step 1: set the shape to Free

Figure 3. Workaround step 2 and 3:
add a segment of 180 degrees and symmetrically close the tunnel

Figure 4. Workaround step 4: Add Properties to the segments