Karimi Alireza, Rahmati Seyyed Mohammadali, Navidbakhsh Mahdi
a School of Mechanical Engineering ; Iran University of Science and Technology ; Tehran , Iran.
Bioengineered. 2015;6(3):153-60. doi: 10.1080/21655979.2015.1036202.
The skin tissue has been shown to behave like a nonlinear anisotropic material. This study was aimed to employ a constitutive fiber family equation to characterize the nonlinear anisotropic mechanical behavior of the rat and mice skin tissues in different anatomical locations, including the abdomen and back, using histostructural and uniaxial data. The rat and mice skin tissues were excised from the animals' body and then the histological analyses were performed on each skin type to determine the mean fiber orientation angle. Afterward, the preconditioned skin tissues were subjected to a series of quasi-static axial and circumferential loads until the incidence of failure. The crucial role of fiber orientation was explicitly added into a proposed strain energy density function. The material coefficients were determined using the constrained nonlinear optimization method based on the axial and circumferential extension data of the rat and mice samples at different anatomical locations. The material coefficients of the skins were given with R(2) ≥ 0.998. The results revealed a significant load-bearing capacity and stiffness of the rat abdomen compared to the rat back tissues. In addition, the mice abdomen showed a higher stiffness in the axial direction in comparison with circumferential one, while the mice back displayed its highest stiffness in the circumferential direction. The material coefficients of the rat and mice skin tissues were determined and well compared to the experimental data. The optimized fiber angles were also compared to the experimental histological data, and in all cases less than 11.85% differences were observed in both the skin tissues.
皮肤组织已被证明表现得像一种非线性各向异性材料。本研究旨在采用本构纤维族方程，利用组织结构和单轴数据来表征大鼠和小鼠不同解剖部位（包括腹部和背部）皮肤组织的非线性各向异性力学行为。从动物体内切除大鼠和小鼠的皮肤组织，然后对每种皮肤类型进行组织学分析，以确定平均纤维取向角。之后，对预处理后的皮肤组织施加一系列准静态轴向和周向载荷，直至发生破坏。纤维取向的关键作用被明确纳入所提出的应变能密度函数中。基于大鼠和小鼠不同解剖部位样本的轴向和周向拉伸数据，采用约束非线性优化方法确定材料系数。皮肤的材料系数给出时R(2)≥0.998。结果显示，与大鼠背部组织相比，大鼠腹部具有显著的承载能力和刚度。此外，小鼠腹部在轴向方向上的刚度高于周向方向，而小鼠背部在周向方向上显示出最高的刚度。确定了大鼠和小鼠皮肤组织的材料系数，并与实验数据进行了很好的比较。还将优化后的纤维角度与实验组织学数据进行了比较，在两种皮肤组织中，所有情况下观察到的差异均小于11.85%。
