Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, PO Box 647, Dunedin 9054, New Zealand.
Department of Anatomy, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
J Mech Behav Biomed Mater. 2018 Jan;77:609-615. doi: 10.1016/j.jmbbm.2017.10.026. Epub 2017 Oct 24.
Blunt force impacts to the head and the resulting internal force transmission to the brain and other cranial tissue are difficult to measure. To model blunt force impact scenarios, the compressive properties resembling tissue elasticity are of importance. Therefore, this study investigated and compared the elastic behavior of gelatin, alginate, agar/glycerol and agar/glycerol/water simulant materials to that of porcine brain in a fresh and unfixed condition. Specimens, 10 × 10 × 10mm, were fabricated and tested at 22°C, apart from gelatin which was conditioned to 4°C prior to testing. For comparison, fresh porcine brains were sourced and prepared to the same dimensions as the simulants. Specimens underwent compression tests at crosshead displacement rates of 2.5, 10 and 16mms (equivalent to strain rates of 0.25, 1 and 1.6s), obtaining apparent elastic moduli values at different strain rate intervals (0-0.2, 0.2-0.4 and 0.4-0.5). The results of this study indicate that overall all simulant materials had an apparent elastic moduli similar in magnitude across all strain ranges compared to brain, even though comparatively higher, especially the apparent elastic moduli values of alginate. In conclusion, while agar/glycerol/water and agar/glycerol had similar apparent elastic moduli in magnitude and the closest apparent elastic moduli in the initial strain range (E), gelatin showed the most similar values to fresh porcine brain at the transitional (E) and higher strain range (E). The simulant materials and the fresh porcine brain exhibited strain rate dependent behavior, with increasing elastic moduli upon increasing loading velocities.
钝性力撞击头部会导致内部力传递到大脑和其他颅组织，这种力很难测量。为了模拟钝性力撞击情况，具有类似组织弹性的压缩特性非常重要。因此，本研究调查并比较了明胶、海藻酸盐、琼脂/甘油和琼脂/甘油/水模拟材料在新鲜且未经固定状态下的弹性行为与猪脑的弹性行为。除明胶在测试前需在 4°C 下进行调节外，其余标本均为 10×10×10mm 规格，并在 22°C 下进行测试。为了进行比较，还采集了新鲜的猪脑并制备成与模拟材料相同尺寸的标本。标本在十字头位移速率为 2.5、10 和 16mms（相当于应变率为 0.25、1 和 1.6s）下进行压缩测试，在不同应变率间隔（0-0.2、0.2-0.4 和 0.4-0.5）下获得了明显的弹性模量值。本研究结果表明，与大脑相比，所有模拟材料的整体表观弹性模量在所有应变范围内都具有相似的大小，尽管琼脂/甘油/水和琼脂/甘油的表观弹性模量值相对较高，特别是海藻酸盐的表观弹性模量值。总的来说，尽管琼脂/甘油/水和琼脂/甘油在大小上具有相似的表观弹性模量，并且在初始应变范围内（E）具有最接近的表观弹性模量，但明胶在过渡（E）和更高应变范围内（E）表现出与新鲜猪脑最相似的值。模拟材料和新鲜猪脑表现出应变率依赖性行为，随着加载速度的增加，弹性模量增加。
