Bone aging involves structural and molecular modifications, especially at the level of type I tropocollagen. This macromolecule shows two main age-related alterations, which are the decrease of both molecular diameter (due to the loss of hydration) and number of hydrogen bonds. In this work, it is proposed to investigate the influence of these two parameters (molecular diameter and number of hydrogen bonds) on the mechanical behavior of tropocollagen using finite element method. To this end, a novel three-dimensional finite element model of collagen molecule accounting for hydrogen bonds was developed. Then, a numerical design of experiments for the diameter of tropocollagen and variations in the number of hydrogen bonds has been established. The mechanical properties ("load-strain" curve and apparent Young's modulus) of the collagen molecule were obtained by employing the proposed model to uniaxial tensile tests. The parametric study demonstrates that the mechanical properties of tropocollagen are slightly affected by the rate of hydration but considerably affected by variation of the number of hydrogen bonds. Finally, a fitted analytical function was deduced from the above results showing effects of the two parameters (hydration rate and hydrogen bonds) on the apparent Young's modulus of tropocollagen. This study could be useful to understand the influence of structural age modifications of tropocollagen on the macroscopic mechanical properties of bone.

中文翻译：

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水化和氢键数量对原胶原蛋白分子力学性能影响的数值模型。

骨老化涉及结构和分子修饰，尤其是在I型原胶原蛋白水平。该大分子显示出两个主要的与年龄相关的变化，即分子直径（由于失去水合作用）和氢键数量的减少。在这项工作中，建议使用有限元方法研究这两个参数（分子直径和氢键数）对原胶原蛋白力学行为的影响。为此，建立了一种新颖的三维分子胶原分子的三维氢键的有限元模型。然后，建立了对原胶原直径和氢键数量变化的实验数值设计。力学性能（“负荷-应变”曲线和明显的杨氏' 通过将所提出的模型用于单轴拉伸试验来获得胶原分子的s模量）。参数研究表明，原胶原蛋白的机械性能受水合速率的影响很小，但受氢键数量变化的影响很大。最后，由上述结果推导了拟合的分析函数，表明两个参数（水合速率和氢键）对原胶原的表观杨氏模量的影响。这项研究可能有助于理解对胶原蛋白的结构年龄的修改对骨骼的宏观力学性能的影响。参数研究表明，原胶原蛋白的机械性能受水合速率的影响很小，但受氢键数量变化的影响很大。最后，从上述结果推导了拟合的分析函数，表明两个参数（水合速率和氢键）对原胶原的表观杨氏模量的影响。这项研究可能有助于了解对胶原蛋白的结构年龄的修改对骨骼的宏观力学性能的影响。参数研究表明，原胶原蛋白的机械性能受水合速率的影响很小，但受氢键数量变化的影响很大。最后，由上述结果推导了拟合的分析函数，表明两个参数（水合速率和氢键）对原胶原的表观杨氏模量的影响。这项研究可能有助于了解对胶原蛋白的结构年龄的修改对骨骼的宏观力学性能的影响。