皮质骨试样制备及其材料参数识别方法研究

发布时间：2019-08-08 07:06

【摘要】：有限元方法已经成为损伤生物力学研究的重要手段,准确的皮质骨材料本构参数对研究人体冲击损伤和人工骨骼等医学问题具有重要意义。基于长骨皮质骨的生理结构,提出批量制备高精度规则试样的加工方法,并开展准静态三点弯曲试验;采用基于梁理论和基于特定样本有限元模型优化反求两种方法,研究皮质骨材料的各向异性和区域差异,并通过线性回归分析建立两种识别方法所得材料参数的回归模型。制备横向和轴向试样各16个,所提出的试样制备方法能够保证试样间的尺寸偏差不超过4%,基于梁理论方法求得的新鲜牛股骨皮质骨轴向和横向试样的杨氏模量分别为(21.70±3.33)GPa和(14.47±2.10)GPa,极限应力分别为(249.21±38.83)MPa和(106.81±21.05)MPa,极限应变分别为1.95%±0.35%和1.06%±0.20%,与文献结果吻合。对利用优化方法和梁理论方法求得的杨氏模量、屈服应力和有效塑性应变进行线性回归分析,回归模型拟合精度分别为96.4%、98.7%和89.3%(P0.05)。研究结果表明,所提出的试样制备方法能够高效地加工尺寸精度较高的规则试样,并良好地保持试样的生物力学特性。在皮质骨准静态三点弯曲试验中,基于特定样本有限元模型的材料参数反求方法能够识别更准确的材料本构参数,而基于梁理论识别参数的回归模型则能够快速准确地预测皮质骨的弹性模量、屈服应力和有效塑性应变。
[Abstract]:Finite element method has become an important means to study the biomechanical study of injury. Accurate constitutive parameters of cortical bone materials are of great significance to the study of medical problems such as human impact injury and artificial bone. Based on the physiological structure of long bone cortical bone, the processing method of batch preparation of high precision regular samples was proposed, and the quasi-static three-point bending test was carried out. the anisotropy and regional difference of cortical bone materials were studied by using beam theory and finite element model optimization based on specific samples, and the regression model of material parameters obtained by the two identification methods was established by linear regression analysis. The proposed sample preparation method can ensure that the size deviation between samples does not exceed 4%. The Young's modulus of fresh bovine cortical bone based on beam theory is (21.70 卤3.33) GPa and (14.47 卤2.10) GPa, respectively. The ultimate stresses are (249.21 卤38.83) MPa and (106.81 卤21.05) MPa, respectively. The ultimate strain is 1.95% 卤0.35% and 1.06% 卤0.20%, respectively, which is in good agreement with the results in the literature. Linear regression analysis was carried out on Young's modulus, yield stress and effective plastic strain obtained by optimization method and beam theory method. The fitting accuracy of the regression model was 96.4%, 98.7% and 89.3%, respectively (P 0.05). The results show that the proposed sample preparation method can efficiently process regular samples with high dimensional accuracy and maintain the biomechanical properties of the samples. In the quasi-static three-point bending test of cortical bone, the reverse method of material parameters based on the finite element model of specific samples can identify more accurate material constitutive parameters, while the regression model based on beam theory can quickly and accurately predict the elastic modulus, yield stress and effective plastic strain of cortical bone.
【作者单位】：湖南大学汽车车身先进设计制造国家重点实验室;
【基金】：国家自然科学基金(51205118) 中央高校基本科研业务费(531107040162) 湖南大学汽车车身先进设计制造国家重点实验室自主研究课题(51475002)
【分类号】：R687;R318.08

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