Numerical Stability

Numerical stability refers to the ability of the solver to produce reliable results despite approximation, round-off, and conditioning effects.

Common causes of numerical instability include:

• Insufficient boundary constraints.
• Poor element quality.
• Very large stiffness contrasts.
• Nearly incompressible materials with unsuitable elements.
• Inconsistent units.
• Ill-conditioned stiffness matrices.

Solver warnings should be investigated before accepting results.