Question:
When using line releases, I cannot understand the failure definition. To which axis do the nonlinearities "Fixed if positive vz" and "Fixed if negative vz" refer?
Answer:
The positive and the negative directions refer to the axis system of the line release. The forces, such as vz, are related to the object on the original line.
In the following text, the definition will be explained briefly using the example of a release between a wall and a ceiling. If the wall is the released object, the definition of a failure for the lifting load would be as follows:
Between the floor slab and the wall, the "Fixed if negative vz" nonlinearity should be selected.
Between the wall and the ceiling above, the "Fixed if positive vz" nonlinearity should be selected.
If the failure is defined incorrectly, you can check it using the determined deformation diagram.