Midas FEA static contact analysis models bodies that may touch, separate, or weld without allowing physical penetration, using contact detection and penalty enforcement.
How It Works
The manual describes general contact and weld contact. Master and slave surfaces can be swapped, but the master surface should generally be the stiffer, more rigid, or coarser side for stable results. Contact is enforced with penalty springs, so contact force is proportional to penetration distance.
The contact search is divided into global search, local search, and contact point search. Global search reduces cost with bucket sorting. Local search finds the nearest master surface. Contact point search solves for the closest point on an isoparametric master surface, using Newton-Raphson iteration for local coordinates.
The manual distinguishes symmetric weld contact and symmetric general contact, notes that self-contact is not supported, and describes automatic adjustment of initial penetration by moving slave nodes. Contact force output is reported on the slave contact surface in global coordinates.
Solver Development Notes
Separate contact search, gap evaluation, force calculation, and tangent contribution in code.
Add tests for no contact, initial overclosure, sliding, separation, recontact, and welded contact.
Keep penalty stiffness scaling explicit because it controls both penetration error and conditioning.
Report contact status and contact forces as first-class verification data.
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