Department of Mechanical Engineering, College of Engineering, Temple University, 1947N, 12th Street, Philadelphia, PA 19122, United States.
J Mech Behav Biomed Mater. 2014 Apr;32:132-144. doi: 10.1016/j.jmbbm.2013.12.021. Epub 2013 Dec 31.
In this study, a framework for understanding the propagation of stress waves in brain tissue under blast loading has been developed. It was shown that tissue nonlinearity and rate dependence are the key parameters in predicting the mechanical behavior under such loadings, as they determine whether traveling waves could become steeper and eventually evolve into shock discontinuities. To investigate this phenomenon, in the present study, brain tissue has been characterized as a quasi-linear viscoelastic (QLV) material and a nonlinear constitutive model has been developed for the tissue that spans from medium loading rates up to blast rates. It was shown that development of shock waves is possible inside the head in response to high rate compressive pressure waves. Finally, it was argued that injury to the nervous tissue at the microstructural level could be partly attributed to the high stress gradients with high rates generated at the shock front and this was proposed as a mechanism of injury in brain tissue.
在这项研究中，开发了一种理解爆炸载荷下脑组织中应力波传播的框架。结果表明，组织的非线性和率相关性是预测此类载荷下力学行为的关键参数，因为它们决定了行波是否会变得更陡，最终演变成冲击波不连续。为了研究这一现象，本研究将脑组织表征为准线性粘弹性（QLV）材料，并为组织开发了一种从中等加载速率到爆炸速率的非线性本构模型。结果表明，头部内部可能会因高速压缩压力波而产生冲击波。最后，有人认为，在微观结构水平上对神经组织的损伤部分归因于在冲击波前缘产生的高应变速率下的高应力梯度，这被认为是脑组织损伤的一种机制。
