Use Soft Spring to Stabilize Model

Check this option to instruct the program to add soft springs attached to the ground to prevent instability. If you apply loads to an unstable design, it will translate and/or rotate as a rigid body. You should apply adequate restraints to prevent rigid body motion.

If you cannot stabilize the design by applying adequate restraints, turn on this flag and rerun the analysis. Animating the resulting deformed shape will show you excessive motion in one or more directions. You can then apply additional restraints to prevent rigid body motion. Repeat the analysis without activating this flag after fixing the problem.

In general, you should not activate this flag unless you ran the analysis and the program tells you that the constraints are not adequate, or you know that you have not specified adequate restraints.

This option is automatically applied for contact problems solved by the Direct Sparse solver.