Huang W, Yen R T
Department of Biomedical Engineering, The University of Memphis, Memphis, Tennessee 38152, USA.
J Appl Physiol (1985). 1998 Sep;85(3):867-73. doi: 10.1152/jappl.1998.85.3.867.
The zero-stress states of the pulmonary arteries and veins from order 3 to order 9 were determined in six normal human lungs within 15 h postmortem. The zero-stress state of each vessel was obtained by cutting the vessel transversely into a series of short rings, then cutting each ring radially, which caused the ring to spring open into a sector. Each sector was characterized by its opening angle. The mean opening angle varied between 92 and 163 degrees in the arterial tree and between 89 and 128 degrees in the venous tree. There was a tendency for opening angles to increase as the sizes of the arteries and veins increased. We computed the residual strains based on the experimental measurements and estimated the residual stresses according to Hooke's law. We found that the inner wall of a vessel at the state in which the internal pressure, external pressure, and longitudinal stress are all zero was under compression and the outer wall was in tension, and that the magnitude of compressive stress was greater than the magnitude of tensile stress.
在六具正常人体肺脏中，于死后15小时内确定了从3级到9级肺动脉和肺静脉的零应力状态。通过将血管横向切成一系列短环，然后沿径向切割每个环，使环弹开成扇形，从而获得每个血管的零应力状态。每个扇形的特征是其开口角度。在动脉树中，平均开口角度在92度至163度之间变化，在静脉树中，平均开口角度在89度至128度之间变化。随着动脉和静脉尺寸的增加，开口角度有增大的趋势。我们根据实验测量计算了残余应变，并根据胡克定律估算了残余应力。我们发现，在内部压力、外部压力和纵向应力均为零的状态下，血管内壁处于压缩状态，外壁处于拉伸状态，且压缩应力的大小大于拉伸应力的大小。
