School of Engineering and Information Technology, The University of New South Wales, ACT 2600, Australia.
School of Engineering and Information Technology, The University of New South Wales, ACT 2600, Australia.
J Mech Behav Biomed Mater. 2019 Feb;90:404-416. doi: 10.1016/j.jmbbm.2018.10.032. Epub 2018 Oct 30.
Bone is a complex hierarchal structured material with varying porosity and mechanical properties. In particular, human cranial bone is essentially a natural composite consisting of low porosity outer and inner tables and a cancellous interior, or diploë. Experimental studies of biomechanically accurate cranial bone analogues are of high importance for biomechanical, forensics, and clinical researchers, which could improve the understanding and prevention of traumatic injury. Many reported studies use commercially available bone surrogates to draw biomechanical and forensics conclusions; however, their mechanical properties are not tabulated over a range of strain rates. This study elucidates the mechanical viability of three leading commercially available bone surrogates, i.e. Synbone, Sawbone, and Bonesim, over a large range of strain rates (10 to 10 s). Quasi-static compression testing was conducted using a universal testing machine and a Split-Hopkinson Pressure bar system equipped with high-speed video was used to determine the dynamic mechanical behavior of these materials. Micro-computed X-ray tomography (XRT) were performed on each material to investigate their pore structures and distributions. All materials exhibited strain rate dependent strength behavior, particularly at high loading rates (≥10 s). The Young's modulus was found to increase with strain rate from 10 to 10 s for transversely and longitudinally loaded surrogate materials except for Synbone and the higher density Bonesim. The higher density Bonesim was determined to be the most suitable cranial bone simulant tested based on a combination of transverse Young's Modulus (1500 MPa), yield strength (19 MPa), ultimate strength (49 MPa), and ultimate strain (17%). These materials show limited promise for applications where the measured elastic properties and strengths are of interest.
骨是一种具有不同孔隙率和机械性能的复杂层次结构材料。特别是，人类颅骨基本上是一种天然复合材料，由低孔隙率的外板和内板以及松质内部组成，或板障。对生物力学准确的颅骨类似物进行实验研究对于生物力学、法医学和临床研究人员非常重要，这可以提高对创伤性损伤的理解和预防。许多报道的研究使用市售的骨替代物来得出生物力学和法医学结论；然而，它们的机械性能并未在一系列应变速率下列出。本研究阐明了三种市售领先的骨替代物，即 Synbone、Sawbone 和 Bonesim，在很大的应变速率范围内（10 到 10 s）的力学可行性。使用万能试验机进行准静态压缩测试，配备高速摄像机的分裂 Hopkinson 压杆系统用于确定这些材料的动态力学行为。对每种材料进行微计算机断层扫描（XRT）以研究其孔隙结构和分布。所有材料均表现出应变率依赖性强度行为，特别是在高加载速率（≥10 s）下。发现杨氏模量随应变速率从 10 到 10 s 增加，除 Synbone 和密度较高的 Bonesim 外，横向和纵向加载的替代材料的杨氏模量都增加了。根据横向杨氏模量（1500 MPa）、屈服强度（19 MPa）、极限强度（49 MPa）和极限应变（17%）的组合，确定较高密度的 Bonesim 是测试过的最适合的颅骨模拟材料。这些材料在测量弹性特性和强度感兴趣的应用中具有有限的应用前景。
