*NLTL
This option allows for mechanical analyses to be performed using the Large Deformation formulation. By default, the small deformation formulation is used.
This feature can be used to anticipate buckling. If buckling occurs, it causes a non-convergence in the solver. If the *NLTL card is enabled and the simulation fails to converge then an additional error message is shown in the log after failure:
Error: Solver failed to converge using Large Deformation Formulation. Buckling may have occurred.