Residual is too big. Check solution settings specified by *SOLU. Convergence may be caused by extremely non-linear material properties or poor processing conditions.
This error warns the user the residual is above the tolerance specified in *SOLU. The simulation will reduce the time step and attempt to continue the simulation. If this process occurs more times than maximum number of cutbacks allowed (also specified by the *SOLU) card, the simulation will abort.
Best Practices
- Thermal Simulations – To avoid convergence errors:
a. Increase the width of the *LATE Liquidus and Solidus temperatures.
b. Turn on relaxation, *SRLX with values 1, 0.4. If convergence continues to be problematic, increase this to 2, 0.4.
- Mechanical Simulations – To avoid convergence errors, turn on relaxation, *SRLX with values 1, 0.2. If convergence continues to be problematic, increase this to 2, 0.2.
Too many increments. Aborting Execution. Increase maximum number of allowable increments in *TRANS.
This error occurs if the number of increments specified by the *TRAN card is exceeded. Increase the maximum number of increments and rerun.
Too many cutbacks. Aborting Execution. Check material properties and processing parameters. Consider adding or increasing Newton-Raphson relaxation set by *RELA.
This error occurs if the number of cutbacks specified by the *TRAN card is exceeded. Cutbacks are caused by poor convergence. These can be improved by introducing or increasing solver relaxation via *RELA. The number of cutbacks can also be increased.
Plasticity algorithm fails to converge. Check material properties and processing parameters. Consider adding or increasing Newton-Raphson relaxation set by *RELA.
The time step required to solve is less than the minimum allowable time step specified in the *TRANS card. Rerun with numerical relaxation or reduce the minimum allowable time step.
This error occurs when the solver takes a series of cutbacks, reducing the time step to step forward to the next increment. If the time step the solver attempts to use is less than the minimum time step allowed in the *TRAN card, the solver will abort.
Error: Solver failed to converge using Large Deformation Formulation. Buckling may have occurred.
This error is shown in the case when a part scale simulation fails to converge and the Large Deformation card, *NLTL, has been enabled. This error indicates that the geometry and processing conditions are liable to buckle.