Centro de Investigación Científica de Yucatán, A.C., Unidad de Materiales, Calle 43 No. 130 x 32y 34, Col. Chuburná de Hidalgo, 97205 Mérida, Yucatán, Mexico.
Centro de Investigación y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, km 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán, Mexico.
J Mech Behav Biomed Mater. 2018 Mar;79:332-340. doi: 10.1016/j.jmbbm.2017.12.031. Epub 2018 Jan 6.
The circumferential compliance and burst strength of vascular grafts are predicted through the conically modified von Mises and elasticity theories, providing an analytical closed form solution for both parameters. Besides the graft's radii, the model for circumferential compliance depends solely on the elastic modulus and Poisson's ratio of the polymer material, and its accuracy was verified by finite element analysis and measurements. The analytical expression of the burst strength requires accurate determination of the material's tensile and compressive yield stress, which were carefully obtained by using digital image correlation measurements in uniaxial tensile and compressive tests of the constitutive material. The average measured circumferential compliance and burst strength of an 8mm graft made of a commonly used biomaterial, Tecoflex SG-80A, are 1.05%/100mmHg and 34.1psi (1763mmHg) and the proposed analytical predictions fall within the experimental scattering. Thus, it is shown that the circumferential compliance and burst strength of vascular grafts can be analytically predicted by knowing the elastic and yield material properties accurately, without needing to actually test the graft under radial pressure. This is a major advantage which can aid in the design and tailoring of vascular grafts.
通过锥形修正的 von Mises 和弹性理论来预测血管移植物的周向顺应性和破裂强度，为这两个参数提供了一个解析的封闭形式解。除了移植物的半径外，周向顺应性的模型仅取决于聚合物材料的弹性模量和泊松比，其准确性通过有限元分析和测量得到了验证。破裂强度的解析表达式需要准确确定材料的拉伸和压缩屈服应力，这些应力是通过在组成材料的单向拉伸和压缩测试中使用数字图像相关测量仔细获得的。由常用生物材料 Tecoflex SG-80A 制成的 8mm 移植物的平均测量周向顺应性和破裂强度分别为 1.05%/100mmHg 和 34.1psi（1763mmHg），并且提出的分析预测值落在实验散射范围内。因此，结果表明，通过准确了解弹性和屈服材料特性，可以对血管移植物的周向顺应性和破裂强度进行分析预测，而无需实际在径向压力下测试移植物。这是一个主要优势，可以帮助设计和定制血管移植物。
