Axial distortion of airways in the lung.
Axial loads were applied around the circumference of an airway lumen by pulling on a cup-shaped anchor that embedded itself in the airway wall. Axial displacements were measured as a function of distance from the load, and the data were compared to the results of mathematical analyses of continuum mechanics models. In the modeling it was assumed that the elastic tube representing the airway is bonded to the surrounding elastic continuum representing the parenchyma and that axial forces are transmitted between the tube and the continuum by shear stresses at the interface. The agreement between the measured and computed axial displacements supports the hypothesis that the shear stresses are the dominant coupling mechanism. The following quantitative relations between force and displacement were obtained. The axial displacement produced by the load L was approximately 0.05 L/pi alpha mu, where alpha is the airway radius and mu is the shear modulus of the parenchyma. The displacement decayed to approximately one-half this maximal value at two diameters from the load.
D000818:Animals; D004285:Dogs; D008168:Lung / Q000033:anatomy & histology*; D008953:Models, Anatomic; D013314:Stress, Mechanical