基于拉伸压破试验的人体升主动脉内膜力学特性

Mechanical Characterization of Human Ascending Aorta Based on Tensile and Compression Test

为获取人体升主动脉内膜力学性质,利用单轴拉伸系统,设计升主动脉内膜压破及拉伸试验方案,获取人体升主动脉内膜力学性质.研究结果表明:人体升主动脉内膜最大压破力与厚度正相关;内膜的周向与纵向的应力-应变均呈非线性曲线关系,并存在各向异性,升主动脉内膜的纵向最大拉伸断裂应力大于周向,初始弹性模量分别为1 104、787 k Pa.因此,在对主动脉内膜破裂风险评估及建立主动脉壁本构方程时应考虑厚度;在夹层、动脉瘤扩张初期,原发破口易沿纵向继续撕裂.

To obtain mechanical characterization of human ascending aorta intima,by using the uniaxial tensile system, the mechanical characterization of the human ascending aorta intima were acquired by designed uniaxial and compression tensile test. The maximum rupture force of the human ascending aorta was found to have a positive correlation with thickness. The obtained resulted a significant anisotropy of human ascending aorta intima between circumferential and longitudinal directions,and non-linear stress- strain relationship curve was verified. The maximum tensile stress between longitudinal and circumferential directions of human ascending aorta intima was found that the longitudinal stress was higher. The initial elastic modulus calculated in longitudinal and circumferential directions were 1 104 kPa and 787 kPa. Therefore, the thickness should be taken into account within rupture assessment of aortic intima and the establishment of the human aorta constitutive equation. The primary break continues to tear along the longitudinal direction in the early stage of aortic dissection or aneurysm.