Mengoni Marlène, Jones Alison C, Wilcox Ruth K
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK.
Institute of Medical and Biological Engineering, University of Leeds, UK.
J Mech Behav Biomed Mater. 2016 Oct;63:265-272. doi: 10.1016/j.jmbbm.2016.06.030. Epub 2016 Jul 5.
The aims of this study were to assess the damage and failure strengths of lamellar fibrous tissues, such as the anterior annulus fibrosus (AF), and to develop a mathematical model of damage propagation of the lamellae and inter-lamellar connections. This level of modelling is needed to accurately predict the effect of damage and failure induced by trauma or clinical interventions. 26 ovine anterior AF cuboid specimens from 11 lumbar intervertebral discs were tested in radial tension and mechanical parameters defining damage and failure were extracted from the in-vitro data. Equivalent 1D analytical models were developed to represent the specimen strength and the damage propagation, accounting for the specimen dimensions and number of lamellae. Model parameters were calibrated on the in-vitro data. Similar to stiffness values reported for other orientations, the outer annulus was found stronger than the inner annulus in the radial direction, with failure at higher stress values. The inner annulus failed more progressively, showing macroscopic failure at a higher strain value. The 1D analytical model of damage showed that lamellar damage is predominant in the failure mechanism of the AF. The analytical model of the connections between lamellae allowed us to represent separately damage processes in the lamellae and the inter-lamellar connections, which cannot be experimentally tested individually.
本研究的目的是评估层状纤维组织(如前纤维环(AF))的损伤和破坏强度,并建立一个关于薄片和薄片间连接损伤扩展的数学模型。需要这种建模水平来准确预测由创伤或临床干预引起的损伤和破坏的影响。对来自11个腰椎间盘的26个羊前AF长方体标本进行了径向拉伸测试,并从体外数据中提取了定义损伤和破坏的力学参数。开发了等效的一维分析模型来表示标本强度和损伤扩展,同时考虑了标本尺寸和薄片数量。模型参数根据体外数据进行了校准。与其他方向报道的刚度值类似,在径向方向上,外环比内环更强,在更高的应力值下发生破坏。内环的破坏更为渐进,在更高的应变值下出现宏观破坏。损伤的一维分析模型表明,薄片损伤在AF的破坏机制中占主导地位。薄片间连接的分析模型使我们能够分别表示薄片和薄片间连接中的损伤过程,而这些过程无法单独通过实验进行测试。