Contact Errors
What a valid contact definition needs, and why a contact result may be unavailable.
If you only have 2 minutes
Almost every contact error is a setup problem in how the contact or its activation schedule is defined, not solver tuning. There is no contact stiffness to tune: Dr.Q enforces contact with Lagrange multipliers, so the fixes below are about defining the contact correctly. See Contact Mechanics for how contact works.
Defining a contact
- Error 299: a contact needs to know what it applies to. Give it
body_ids, a location, or both. - Error 305: two explicit contact zones select the same candidate with incompatible types. Don't define overlapping zones with conflicting contact types on the same interface.
- Error 316: the friction law parameters are invalid (for example a negative friction coefficient). Use physically valid values.
- Error 288: bonded coupling requires a solid element face. Contact and bonding act on the faces of solid (volumetric) meshes; beams and shells are not contact or bond surfaces. Bonded interfaces additionally support only triangular faces today.
Contact activation schedules
If you drive a contact with an activation schedule, its times must be well-formed:
- Error 300: the schedule must provide a state at time zero.
- Error 301: it cannot contain negative times.
- Error 302: its times must be strictly increasing.
Contact results are unavailable
These fire when you request a contact result that doesn't exist:
- Error 298: the contact zone has no contact Gauss points. Nothing is actually touching there, so there is no aggregate result to compute. Check that the surfaces are in contact where you expected.
- Error 303: the contact is inactive at the time you asked for. Query a time when it is active, or check the activation schedule.
If contact won't converge
Contact convergence is a nonlinear-solver problem, not a contact-definition one. Frictional and large-sliding contact are iteration-heavy and can struggle when the contact area changes rapidly. Start with bonded or frictionless contact to confirm the model, introduce friction only when sliding matters, and use the activation schedule to bring contact in gradually. See Nonlinear Convergence Errors for the solver side.