Nagel Thomas, Kelly Daniel J
Trinity Centre for Bioengineering, Mechanical and Manufacturing Engineering, School of Engineering, Trinity College, Dublin 2, Ireland.
J Biomech Eng. 2010 Nov;132(11):114506. doi: 10.1115/1.4002589.
Constitutive models facilitate investigation into load bearing mechanisms of biological tissues and may aid attempts to engineer tissue replacements. In soft tissue models, a commonly made assumption is that collagen fibers can only bear tensile loads. Previous computational studies have demonstrated that radially aligned fibers stiffen a material in unconfined compression most by limiting lateral expansion while vertically aligned fibers buckle under the compressive loads. In this short communication, we show that in conjunction with swelling, these intuitive statements can be violated at small strains. Under such conditions, a tissue with fibers aligned parallel to the direction of load initially provides the greatest resistance to compression. The results are further put into the context of a Benninghoff architecture for articular cartilage. The predictions of this computational study demonstrate the effects of varying fiber orientations and an initial tare strain on the apparent material parameters obtained from unconfined compression tests of charged tissues.
本构模型有助于研究生物组织的承载机制，并可能有助于组织替代物的工程化尝试。在软组织模型中，一个常见的假设是胶原纤维只能承受拉伸载荷。先前的计算研究表明，径向排列的纤维在无侧限压缩中通过限制横向膨胀使材料变硬，而垂直排列的纤维在压缩载荷下会发生屈曲。在这篇简短的通讯中，我们表明，在小应变情况下，结合肿胀现象，这些直观的说法可能会被打破。在这种情况下，纤维与载荷方向平行排列的组织最初对压缩的抵抗力最大。研究结果进一步结合了关节软骨的本宁霍夫结构进行阐述。这项计算研究的预测结果表明了不同纤维取向和初始 tare 应变对从带电组织的无侧限压缩试验中获得的表观材料参数的影响。
