Symptom: cells invert when the structure accelerates, triggering solver stop.
Likely causes
- Mesh smoothing strength too low.
- Boundary motion exceeds local cell size.
- Mesh quality targets too lenient.
Tests to run
- Reduce structural step size for the first 10-20 steps.
- Increase smoothing iterations and stiffness near high curvature zones.
- Add an intermediate remesh trigger based on Jacobian thresholds.