How T V, Annis D
Institute of Medical and Dental Bioengineering, University of Liverpool, United Kingdom.
J Biomed Mater Res. 1987 Sep;21(9):1093-108. doi: 10.1002/jbm.820210904.
A method of evaluating the in vitro viscoelastic properties of microfibrous Biomer poly(ether-urethane-urea) vascular prostheses is outlined. Quasi-static and dynamic tests were carried out on Biomer grafts of diameter between 3.4 mm and 3.8 mm and wall thickness between 0.25 mm and 0.55 mm. It is shown that the quasi-static compliance of a Biomer graft may be determined from an equation relating transmural pressure, radius, and longitudinal strains in terms of the graft dimensions and material constants. The dynamic compliance spectra were evaluated as a function of the longitudinal and circumferential strains and temperature. Although the ratio of dynamic compliance to quasi-static compliance was linearly related to the logarithm of frequency it was not significantly affected by strains or temperature over the relevant ranges studied. Employing the usual assumptions of linear isotropic incremental elastic theory the dynamic elastic and viscous moduli were calculated as a function of frequency. Biomer grafts were more viscous than canine carotid and femoral arteries, especially at the higher frequencies. The variation in the ratio of dynamic to static incremental modulus with frequency was similar to that observed in the femoral arteries by Bergel (J. Physiol., 156, 458-469 (1961)).
概述了一种评估微纤维生物材料聚（醚 - 聚氨酯 - 脲）血管假体体外粘弹性特性的方法。对直径在3.4毫米至3.8毫米之间且壁厚在0.25毫米至0.55毫米之间的生物材料移植物进行了准静态和动态测试。结果表明，生物材料移植物的准静态顺应性可以根据一个涉及跨壁压力、半径和纵向应变的方程来确定，该方程与移植物尺寸和材料常数有关。动态顺应性谱作为纵向和周向应变以及温度的函数进行了评估。尽管动态顺应性与准静态顺应性的比值与频率的对数呈线性关系，但在所研究的相关范围内，它不受应变或温度的显著影响。采用线性各向同性增量弹性理论的常用假设，计算了动态弹性模量和粘性模量作为频率的函数。生物材料移植物比犬类颈动脉和股动脉更具粘性，尤其是在较高频率时。动态与静态增量模量之比随频率的变化与Bergel（《生理学杂志》，156, 458 - 469 (1961)）在股动脉中观察到的情况相似。
