Table1_Effects of different preservation on the mechanical properties of cortical bone under quasi-static and dynamic compression.XLSX

Introduction: Mechanical properties of biological tissue are important for numerical simulations. Preservative treatments are necessary for disinfection and long-term storage when conducting biomechanical experimentation on materials. However, few studies have been focused on the effect of preservation on the mechanical properties of bone in a wide strain rate. The purpose of this study was to evaluate the influence of formalin and dehydration on the intrinsic mechanical properties of cortical bone from quasi-static to dynamic compression.Methods: Cube specimens were prepared from pig femur and divided into three groups (fresh, formalin, and dehydration). All samples underwent static and dynamic compression at a strain rate from 10−3 s−1 to 103 s−1. The ultimate stress, ultimate strain, elastic modulus, and strain-rate sensitivity exponent were calculated. A one-way ANOVA test was performed to determine if the preservation method showed significant differences in mechanical properties under at different strain rates. The morphology of the macroscopic and microscopic structure of bones was observed.Results: The results show that ultimate stress and ultimate strain increased as the strain rate increased, while the elastic modulus decreased. Formalin fixation and dehydration did not affect elastic modulus significantly whereas significantly increased the ultimate strain and ultimate stress. The strain-rate sensitivity exponent was the highest in the fresh group, followed by the formalin group and dehydration group. Different fracture mechanisms were observed on the fractured surface, with fresh and preserved bone tending to fracture along the oblique direction, and dried bone tending to fracture along the axial direction.Discussion: In conclusion, preservation with both formalin and dehydration showed an influence on mechanical properties. The influence of the preservation method on material properties should be fully considered in developing a numerical simulation model, especially for high strain rate simulation.

引言：生物组织的力学性质对于数值模拟至关重要。在生物力学实验中对材料进行消毒和长期储存时，必要的防腐处理不可或缺。然而，关于防腐对骨骼在宽应变率范围内力学性质影响的研究尚显不足。本研究旨在评估甲醛固定和脱水对皮质骨从准静态到动态压缩的固有力学性质的影响。方法：从猪股骨制备立方体样本，分为三组（新鲜、甲醛固定和脱水）。所有样本在应变率从10−3 s−1到103 s−1的范围内进行了静态和动态压缩。计算了极限应力、极限应变、弹性模量和应变率敏感性指数。通过单因素方差分析（ANOVA）测试，以确定不同应变率下防腐方法对力学性质是否有显著差异。观察了骨骼宏观和微观结构的形态。结果：结果显示，随着应变率的增加，极限应力和极限应变增加，而弹性模量降低。甲醛固定和脱水对弹性模量影响不显著，但显著增加了极限应变和极限应力。应变率敏感性指数在新鲜组中最高，其次是甲醛固定组，最后是脱水组。在断裂表面上观察到不同的断裂机制，新鲜和防腐的骨骼倾向于沿斜向断裂，而干燥的骨骼倾向于沿轴向断裂。讨论：总之，甲醛固定和脱水防腐均对力学性质产生了影响。在开发数值模拟模型时，应充分考虑防腐方法对材料性质的影响，尤其是在高应变率模拟中。