NONLINEAR-WAVE PROPAGATION IN VISCOELASTIC TUBES - APPLICATION TO AORTIC RUPTURE

Recent statistical surveys into the causes of automobile fatalities have shown that traumatic rupture of the aorta followed by immediate exsanguination is responsible for a significant percentage of traffic deaths in the United States. The object of this investigation is to understand a possible mechanism for this failure. A mathematical analysis is presented of the motion of blood in a distensible viscoelastic segment of aorta subjected to a decelerative force field. Calculations of axial wall strain and strain-rate indicate that wave propagation resulting in abrupt shock-like transitions along the aortic wall may well account for the transverse ruptures observed, when compared with the limited amount of rupture data presently available. The analytic method and numerical solution by a two-step Lax-Wendroff differencing scheme are sufficiently general to describe a wide variety of initial and boundary conditions related to blunt impact to the thorax.