Park Gwansik, Kim Taewung, Forman Jason, Panzer Matthew B, Crandall Jeff R
a Center for Applied Biomechanics, University of Virginia , Charlottesville , VA , USA.
b Department of Mechanical Design Engineering , Korea Polytechnic University , Siheung-si , Korea.
Comput Methods Biomech Biomed Engin. 2017 Aug;20(11):1151-1166. doi: 10.1080/10255842.2017.1340459. Epub 2017 Jun 20.
The goal of this study was to predict the structural response of the femoral shaft under dynamic loading conditions using subject-specific finite element (SS-FE) models and to evaluate the prediction accuracy of the models in relation to the model complexity. In total, SS-FE models of 31 femur specimens were developed. Using those models, dynamic three-point bending and combined loading tests (bending with four different levels of axial compression) of bare femurs were simulated, and the prediction capabilities of five different levels of model complexity were evaluated based on the impact force time histories: baseline, mass-based scaled, structure-based scaled, geometric SS-FE, and heterogenized SS-FE models. Among the five levels of model complexity, the geometric SS-FE and the heterogenized SS-FE models showed statistically significant improvement on response prediction capability compared to the other model formulations whereas the difference between two SS-FE models was negligible. This result indicated the geometric SS-FE models, containing detailed geometric information from CT images with homogeneous linear isotropic elastic material properties, would be an optimal model complexity for prediction of structural response of the femoral shafts under the dynamic loading conditions. The average and the standard deviation of the RMS errors of the geometric SS-FE models for all the 31 cases was 0.46 kN and 0.66 kN, respectively. This study highlights the contribution of geometric variability on the structural response variation of the femoral shafts subjected to dynamic loading condition and the potential of geometric SS-FE models to capture the structural response variation of the femoral shafts.
本研究的目的是使用个体特异性有限元（SS-FE）模型预测股骨干在动态加载条件下的结构响应，并评估模型预测准确性与模型复杂性之间的关系。总共建立了31个股骨标本的SS-FE模型。利用这些模型，模拟了裸股骨的动态三点弯曲和联合加载试验（弯曲与四种不同水平的轴向压缩），并基于冲击力时间历程评估了五种不同模型复杂性水平的预测能力：基线模型、基于质量缩放模型、基于结构缩放模型、几何SS-FE模型和异质化SS-FE模型。在五种模型复杂性水平中，几何SS-FE模型和异质化SS-FE模型在响应预测能力方面相比其他模型公式有统计学上的显著提高，而两种SS-FE模型之间的差异可忽略不计。这一结果表明，包含来自CT图像的详细几何信息且具有均匀线性各向同性弹性材料属性的几何SS-FE模型，对于预测动态加载条件下股骨干的结构响应而言，将是一种最优的模型复杂性水平。31个案例中几何SS-FE模型的均方根误差的平均值和标准差分别为0.46 kN和0.66 kN。本研究突出了几何变异性对承受动态加载条件的股骨干结构响应变化的贡献，以及几何SS-FE模型捕捉股骨干结构响应变化的潜力。
