FINITE ELEMENT MODEL OF COLLAPSING TRACHEA.

The collapsing shape and the transmural pressure-area (p-A) law of the human trachea is studied using a finite-element model. The model takes into account the dimensions of the three tracheal tissues. Material constants of the cartilage and the soft tissues are computed from the stress-strain relationships. The initial configuration is decomposed into a finite number of hexahedrons. The numerical model uses augmented Lagrangian techniques. An inner movement of the ventrolateral wall is observed. The p-A relationship is sigmoidal: the tracheal compliance is higher for slightly negative transmural pressures.