In almost all scenarios of traumatic brain injuries (TBIs), the brain tissue goes under mechanical loading at high strain rates. In experimental works, it has also shown that brain tissue behavior is highly rate-dependent. We are presenting here the results of a study on mechanical properties of bovine brain tissue under unconfined compression tests at different rates. The tissue specimens are compressed with deformation rates of 10, 100, and 1000 mm/sec, respectively. We observed the tissue is showing a viscoelastic behavior and become stiffer under increasing strain rates. We developed a nonlinear viscoelastic rate-dependent constitutive model to be calibrated with the test results. The material parameters for this constitutive model have been validated for the above tested results. The model was examined against other rates and agrees well. The study will provide new insight into a better understanding of the rate-dependency behavior of the brain tissue under dynamic conditions. The work is a step forward in understanding the material characteristics of brain tissue for TBI analysis and prediction under loading or high kinematical motions.
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机译：在几乎所有创伤性脑损伤（TBI）情况下，脑组织都在高应变率下承受机械负荷。在实验工作中，它也显示出脑组织行为高度依赖于速率。我们在这里展示的是在无限制的压缩测试下以不同的速率对牛脑组织的力学性能进行研究的结果。组织标本分别以10、100和1000 mm / sec的变形速率压缩。我们观察到该组织显示出粘弹性行为，并且在应变率增加的情况下变硬。我们开发了一个非线性的粘弹性速率相关本构模型，可以根据测试结果进行校准。用于本构模型的材料参数已针对上述测试结果进行了验证。该模型已针对其他比率进行了检验，并取得了很好的共识。该研究将为更好地了解动态条件下脑组织的速率依赖性行为提供新的见解。这项工作是在了解负荷或高运动运动下TBI分析和预测脑组织的物质特性方面迈出的一步。
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