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Nonlinear Dynamics of Human Aortas for Material Characterization
Physical Review X ( IF 12.5 ) Pub Date : 2020-01-23 , DOI: 10.1103/physrevx.10.011015
Marco Amabili , Prabakaran Balasubramanian , Isabella Bozzo , Ivan D. Breslavsky , Giovanni Ferrari , Giulio Franchini , Francesco Giovanniello , Chloé Pogue

Evaluating the nonlinear dynamics of human descending thoracic aortas is essential for building the next generation of vascular prostheses. This study characterizes the nonlinear dynamics, viscoelastic material properties, and fluid-structure interaction of 11 ex-vivo human descending thoracic aortas the full range of physiological heart rates. The aortic segments are harvested from heart-beating donors screened for transplants. A mock circulatory loop is developed to reproduce physiological pulsatile pressure and flow. The results show cyclic axisymmetric diameter changes, which are satisfactorily compared to in-vivo measurements at a resting pulse rate of 60 bpm, with an additional bending vibration. An increase of the dynamic stiffness (i.e., storage modulus) with age is also observed. This increase is accompanied by a strong reduction with age of the cyclic diameter change during the heart pulsation at 60 bpm and by a significant reduction of the loss factor (i.e., damping). Large dissipation is observed at higher pulse rates due to the combined effects of fluid-structure interaction and viscoelasticity of the aortic wall. This study presents data necessary for developing innovative grafts that better mimic the dynamics of the aorta.

中文翻译:

人类主动脉的非线性动力学用于材料表征

评估人类胸主动脉下降的非线性动力学对于构建下一代人工血管至关重要。这项研究的特点是非线性动力学,粘弹性材料的属性,以及11个离体人类降胸主动脉在整个生理心率范围内的流体-结构相互作用。从筛选出移植物的心跳供体中收获主动脉段。建立了模拟循环回路,以再现生理脉动压力和流量。结果表明,与活体内相比,循环的轴对称直径变化令人满意以60 bpm的静息脉冲速率进行测量,并产生额外的弯曲振动。还观察到动态刚度(即储能模量)随年龄的增加。这种增加伴随着心脏搏动在60 bpm时周期性直径变化的年龄大大降低,并且损耗因子(即阻尼)显着降低。由于流体结构相互作用和主动脉壁粘弹性的综合作用,在较高的脉冲频率下观察到较大的耗散。这项研究提供了开发创新的移植物以更好地模拟主动脉动力学所必需的数据。
更新日期:2020-01-23
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