Nowadays, the investigation of aortic wall biomechanics is a fundamental tool in clinical research and vascular prosthesis design. This study aims at analyzing the biomechanical behavior of aortic tissues using a coupled experimental and computational approach. Considering the typical fiber-reinforced configuration of aortic tissues, uni-axial tensile tests along six different loading directions were performed on specimens from pig aorta. Starting from the obtained experimental data, a suitable constitutive framework was defined and a methodology for the identification of the constitutive parameters was developed using the inverse analysis of mechanical tests. Transversal stretch versus loading stretch and nominal stress versus loading stretch curves were evaluated, showing the anisotropic and nonlinear mechanical behavior determined by tissue conformation with fibers distributed along preferential directions. In detail, experimental data showed different mechanical responses between longitudinal and circumferential directions, with a greater tissue stiffness along the longitudinal one. The reliability of the developed constitutive framework was evaluated by the comparison between experimental data and model results. The mentioned analysis can be considered as a useful tool for the development of reliable computational models, which allow a better understanding of the pathophysiology of cardiovascular diseases and can be applied for a proper planning of surgical procedures.

中文翻译：

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一种表征主动脉组织各向异性力学行为的实验和数值方法

如今，主动脉壁生物力学的研究是临床研究和血管假体设计的基本工具。本研究旨在使用耦合的实验和计算方法分析主动脉组织的生物力学行为。考虑到主动脉组织的典型纤维增强结构，对来自猪主动脉的样本进行了沿六个不同加载方向的单轴拉伸试验。从获得的实验数据出发，定义了一个合适的本构框架，并使用力学测试的逆分析开发了一种识别本构参数的方法。横向拉伸与加载拉伸和名义应力与加载拉伸曲线进行了评估，显示了由组织构象决定的各向异性和非线性机械行为，其中纤维沿优先方向分布。详细地，实验数据显示纵向和圆周方向之间的不同机械响应，沿纵向方向具有更大的组织刚度。通过比较实验数据和模型结果来评估所开发的本构框架的可靠性。上述分析可以被认为是开发可靠计算模型的有用工具，可以更好地了解心血管疾病的病理生理学，并可用于正确规划外科手术。实验数据显示纵向和圆周方向之间的机械响应不同，沿纵向的组织刚度更大。通过比较实验数据和模型结果来评估所开发的本构框架的可靠性。上述分析可以被认为是开发可靠计算模型的有用工具，可以更好地了解心血管疾病的病理生理学，并可用于正确规划外科手术。实验数据显示纵向和圆周方向之间的机械响应不同，沿纵向的组织刚度更大。通过比较实验数据和模型结果来评估所开发的本构框架的可靠性。上述分析可以被认为是开发可靠计算模型的有用工具，可以更好地了解心血管疾病的病理生理学，并可用于正确规划外科手术。