Figure 6.

Sensitivity of failure mode with respect to relative mucosal thickness for a circular cross-section with $R_{\mathrm{I}}:R_{\mathrm{II}}=1.0$. Larger relative mucosal thicknesses represents smaller bronchi away from the trachea; smaller relative mucosal thicknesses represents larger bronchi close to the trachea. With increasing relative mucosal thickness, the number of folds decreases. With the decreasing number of folds, the critical growth ϑ at the first contact becomes significantly smaller. This might indicate that smaller bronchi with a larger relative mucosal thickness are at a higher risk of airflow obstruction than larger bronchi with a smaller relative mucosal thickness.