Problem description

When using free field elements for a Dynamic calculation in PLAXIS 3D AE.00 in order to simulate e.g. an earthquake, it can happen that the calculation is stopped with the following error:

   NaN found during calculation, probably severe divergence. [Error code: 39]

This error is triggered when a stress point inside the free field elements violates the failure criteria (e.g. Mohr Coulomb failure line) and becomes plastic.

Solution

This issue is now solved in PLAXIS 3D AE.01

For PLAXIS 3D AE.00, the problem will not appear when the free field elements are not in a plastic state. So increasing the strength of the soil materials, or use a linear elastic soil material in the soil next to the free field elements to avoid plastic behaviour will overcome this issue for this 3D AE.00 version.