The purpose of this study is to assess and model age-related changes in the mechanical properties of human fascia. The samples were divided into three age groups: group A-up to 60 years (mean age 52.5 ± 6 years), group B-61-80 years (mean age 70.4 ± 5.2 years), and group C-81-90 years (mean age 83.2 ± 2 years). A uniaxial tensile test was applied to fascia specimens cut perpendicular and parallel to fibers. The secant modulus at 5% strain, the maximum stress, and the stretch at maximum stress were calculated from the stress-stretch ratio curves. The results indicated an increase in the secant modulus with the increased age. The trend is clearer in the longitudinal direction. Considering the strain energy function which accounts the isotropic and non-isotropic response of the fascia where isotropic and anisotropic parts are split, we evaluated which material model is the most suitable to present isotropic mechanical behavior of the tissue. The experimental stress-stretch ratio curves were approximated using Mooney-Rivlin, Yeoh, and neo-Hookean strain energy functions and a good match between theoretical and experimental results was obtained. On the basis of objective function values and normalized mean square root error, we recommend using the Yeoh model to describe the isotropic mechanical behavior of human abdominal fascia. Graphical abstract .

中文翻译：

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人类腹部筋膜的力学性质与年龄相关的变化。

这项研究的目的是评估和建模与年龄相关的人筋膜机械特性的变化。样本分为三个年龄组：A组至60岁（平均年龄52.5±6岁），B-61-80岁组（平均年龄70.4±5.2岁）和C-81-90岁组（平均年龄83.2±2岁）。对垂直和平行于纤维切割的面板样品进行单轴拉伸试验。从应力-拉伸比曲线计算出5％应变下的割线模量，最大应力和最大应力下的拉伸。结果表明，随着年龄的增长，割线模量增加。在纵向上趋势更加明显。考虑到应变能函数，该函数考虑了各向同性和各向异性部分分开的面板的各向同性和非各向同性响应，我们评估了哪种材料模型最适合呈现组织的各向同性力学行为。使用Mooney-Rivlin，Yeoh和Neo-Hookean应变能函数对实验应力-拉伸比曲线进行了近似，并在理论和实验结果之间取得了良好的匹配。根据目标函数值和归一化的均方根误差，我们建议使用Yeoh模型描述人腹部筋膜的各向同性力学行为。图形概要 。根据目标函数值和归一化的均方根误差，我们建议使用Yeoh模型描述人腹部筋膜的各向同性力学行为。图形概要 。根据目标函数值和归一化的均方根误差，我们建议使用Yeoh模型描述人腹部筋膜的各向同性力学行为。图形概要 。