Prediction of femoral fracture load using finite element models: an examination of stress- and strain-based failure theories
Prediction of femoral fracture load using finite element models: an examination of stress- and strain-based failure theories
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DOI：
10.1016/s0021-9290(99)00152-9
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发表时间：
2000-02-01
影响因子：
2.4
通讯作者：
Rossi, SA
中科院分区：
文献类型：
--
作者：
Keyak, JH;Rossi, SA
有限元（FE）模型通常用于对骨失效建模。然而.目前还没有证实骨的失效理论。在这项研究中，我们研究了九个应力和应变为基础的故障理论，其中六个可以解释拉伸和压缩材料强度的差异的性能。使用自动生成的、基于计算机断层扫描的股骨有限元模型，评价了变形能、霍夫曼和基于应变的霍夫曼模拟、最大法向应力、最大法向应变、最大剪切应变、最大剪切应力（tau（max））、库仑-莫尔和修正的莫尔失效理论。在两种载荷配置下检查了18对匹配的近端股骨，一种是在单肢站立时的近似关节载荷，另一种是模拟跌倒时的冲击。进行了力学测试，以评估模型和失效理论在预测股骨骨折载荷方面的性能。对于两种载荷条件和所有失效标准，测量的和FE计算的断裂载荷显著相关（p小于或等于0.001）。畸变能和τ（最大值）失效理论是最可靠的，为两种非常不同的载荷条件提供了最一致的强大有限元模型性能。与更简单的变形能和tau（max）理论相比，所研究的更复杂的失效理论和基于应变的理论并没有提高性能，并且通常会降低性能，即使在拉伸和压缩失效特性之间存在差异时也是如此。变形能和τ（max）理论的相对较强的性能支持剪切/变形是股骨骨折过程中重要失效模式的假设。(C)2000爱思唯尔科技有限公司版权所有。
Finite element (FE) models are often used to model bone failure. However. no failure theory for bone has been validated at this time. In this study, we examined the performance of nine stress- and strain-based failure theories, six of which could account for differences in tensile and compressive material strengths. The distortion energy, Hoffman and a strain-based Hoffman analog, maximum normal stress, maximum normal strain, maximum shear strain, maximum shear stress (tau(max)), Coulomb-Mohr, and modified Mohr failure theories were evaluated using automatically generated, computed tomographic scan-based FE models of the femur. Eighteen matched pairs of proximal femora were examined in two load configurations, one approximating joint loading during single-limb stance and one simulating impact from a fall. Mechanical testing was performed to assess model and failure theory performance in the context of predicting femoral fracture load. Measured and FE-computed fracture load were significantly correlated for both loading conditions and all failure criteria (p less than or equal to 0.001). The distortion energy and tau(max) failure theories were the most robust of those examined, providing the most consistently strong FE model performance for two very different loading conditions. The more complex failure theories and the strain-based theories examined did not improve performance over the simpler distortion energy and tau(max) theories, and often degraded performance, even when differences between tensile and compressive failure properties were represented. The relatively strong performance of the distortion energy and tau(max) theories supports the hypothesis that shear/distortion is an important failure mode during femoral fracture. (C) 2000 Elsevier Science Ltd. All rights reserved.