The solution transition procedure is useful in overcoming convergence problems in some difficult implicit static analyses. By this procedure, the analysis starts out as a static solution and automatically transitions to a transient dynamic solution based on a user-defined criterion. This procedure is applicable to all physics types.
An implicit static solution often has difficulty converging in the following circumstances:
Loss of contact (stiffness matrix can become singular due to rigid body motion)
Contact chattering
When the physics dictates that constraints cannot be applied on some parts
Local buckling
A transient dynamic simulation, especially a quasi-static simulation (TINTP,QUASI), works well in these scenarios as the mass matrix keeps the global matrix invertible. Furthermore, the algorithmic damping helps to stabilize the problem and suppresses the unwanted high-frequency response, therefore keeping the solution close to the static solution.
Once the solution overcomes the convergence difficulty, the analysis may attempt to come back to a static solution based on a user-specified criterion for time spent in the transient phase.
The following solution transition topics are available: