Constitutive Behavior of Ocular Tissues Over a Range of Strain Rates
Constitutive Behavior of Ocular Tissues Over a Range of Strain Rates
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DOI：
10.1115/1.4006847
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发表时间：
2012-06-01
影响因子：
1.7
通讯作者：
Mallett, Kaitlyn
中科院分区：
文献类型：
--
作者：
Kim, Wonsuk;Argento, Alan;Mallett, Kaitlyn
牛巩膜和角膜组织的本构行为进行了测量，在拉伸和压缩，在准静态和中等应变率。实验进行的应变速率高达约50应变每秒的气动测试系统开发，以克服噪音和测量困难与时间相关的低阻抗材料的测试。在室温和自然牛体温的组织的结果是相似的，并表明，眼组织表现出非线性硬化的应变率增加，称为速率硬化的现象。例如，在29/s的拉伸应变速率下，发现角膜组织产生的应力是其在相同应变下准静态产生的应力的10倍。因此，常规的本构模型将严重低估由于适度的动态事件而在角膜巩膜壳中发生的应力。这对眼损伤模型的准确性、青光眼研究中的角巩膜壳应力场的研究和眼压测量具有意义。在各种应变率下的测量数据表示使用已被用来表示生物组织力学数据的本构模型的一般框架。在这里，它被扩展到代表眼组织在测试应变率范围内的测量数据。它的形式允许直接并入各种数字代码。认为本文开发的实验和分析方法适用于人眼组织的测试。[DOI电话：10.1115/1.4006847]
The constitutive behavior of bovine scleral and corneal tissues is measured in tension and compression, at quasi-static and moderate strain rates. Experiments are conducted at strain rates up to about 50 strain per second by a pneumatic testing system developed to overcome noise and measurement difficulties associated with the time dependent test of low impedance materials. Results for the tissues at room and the natural bovine body temperatures are similar and indicate that ocular tissue exhibits nonlinear stiffening for increasing strain rates, a phenomena termed rate hardening. For example, at a tensile strain rate of 29/s, corneal tissue is found to develop 10 times the stress that it does quasi-statically at the same strain. Thus, conventional constitutive models will grossly underpredict stresses occurring in the corneo-scleral shell due to moderate dynamic events. This has implication to the accuracy of ocular injury models, the study of the stress field in the corneo-scleral shell for glaucoma research and tonometry measurements. The measured data at various strain rates is represented using the general framework of a constitutive model that has been used to represent biological tissue mechanical data. Here it is extended to represent the measured data of the ocular tissues over the range of tested strain rates. Its form allows for straightforward incorporation in various numerical codes. The experimental and analytical methods developed here are felt to be applicable to the test of human ocular tissue. [DOI: 10.1115/1.4006847]