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Mechanical and failure properties of human cerebral blood vessels.

机译：人脑血管的力学和失效特性。

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摘要

Human cerebral blood vessels are frequently damaged in head impact, such as occurs in falls, contact sports, or vehicular collisions, resulting in intracranial bleeding. As an integral part of the support structure for the brain, these vessels also play a key role in the load response of the cranial contents. An understanding of the mechanical behavior of these arteries and veins, as well as their limiting loads, is thus required for a proper understanding and modeling of traumatic brain injury—as well as providing substantial assistance in preventive measures and even diagnosis and treatment. It is believed that axial stretching is the dominant loading mode for the blood vessels, regardless of the nature of the insult.; A total of 43 arteries and 24 veins from the cortical surface of the temporal lobe of the cerebrum were harvested from healthy patients in surgery and from cadavers in autopsy and successfully tested for mechanical properties. Most of the vessels were stretched to failure in the longitudinal direction, some quasi-statically and some dynamically, while a few arteries were inflated to failure. The significance of specimen and experiment parameters was determined through multivariate analysis of variance (MANOVA) testing. Longitudinal test results demonstrate that the arteries were considerably stiffer than the veins, carrying approximately twice as much stress as the veins at failure but withstanding only half as much stretch. Autopsy specimens were found to carry substantially less stress at failure than surgical samples, and no significant rate dependence was measured over a strain rate range of three orders of magnitude. Differences between tests resulting in failure at the grip and those rupturing in midsection were not found to be significant, and the extent of preconditioning was shown to be influential in measurements on arteries. Inflation tests on arteries demonstrated, as expected, that at a chosen circumferential stretch, circumferential stresses increase with more extensive axial stretches. Cortical arteries appear to be stiffer and stronger in the longitudinal direction than they are circumferentially. With regard to modeling, uniaxial vessel behavior over a limited span can be accurately represented by an exponential function, but a popular, two-dimensional constitutive model is shown to have major shortcomings in simulating combined inflation and stretch of the cortical arteries.
机译：人脑血管经常在头部撞击中受损，例如跌倒，接触运动或车辆碰撞时发生，从而导致颅内出血。作为大脑支撑结构的组成部分，这些血管在颅内内容物的负荷反应中也起着关键作用。因此，需要对这些动脉和静脉的机械行为及其有限的负荷进行了解，以便正确地了解和建模脑部创伤，并在预防措施甚至诊断和治疗方面提供实质性帮助。可以认为，轴向拉伸是血管的主要加载方式，而与侮辱的性质无关。从健康的外科手术患者和尸体尸体尸检中，共采集了大脑颞叶皮质表面的43条动脉和24条静脉，并成功进行了力学性能测试。大多数血管在纵向上拉伸至衰竭，有些是准静态的，有些是动态拉伸的，而一些动脉则膨胀至失效。通过多变量方差分析（MANOVA）测试确定样本和实验参数的重要性。纵向测试结果表明，动脉比静脉坚硬得多，承受的压力约为破裂时静脉的两倍，但仅承受一半的拉伸。发现尸体解剖标本在破坏时所承受的应力比外科手术标本要小得多，并且在三个数量级的应变速率范围内未测量到显着的速率依赖性。导致握力失败和中段破裂的测试之间的差异没有显着性，并且预处理的程度对动脉测量有影响。如预期的那样，对动脉的充气测试表明，在选定的周向拉伸范围内，周向应力会随着轴向拉伸范围的扩大而增加。皮质动脉在纵向上似乎比周向更硬，更坚固。关于建模，可以通过指数函数准确表示有限范围内的单轴血管行为，但是显示了一种流行的二维本构模型在模拟皮层动脉的联合膨胀和伸展方面存在主要缺陷。

著录项

  • 作者

    Monson, Kenneth LaVaun.;

  • 作者单位

    University of California, Berkeley.;

  • 授予单位 University of California, Berkeley.;
  • 学科 Engineering Mechanical.; Engineering Biomedical.; Health Sciences Medicine and Surgery.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 163 p.
  • 总页数 163
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;生物医学工程;
  • 关键词

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