Abbasi Mostafa, Barakat Mohammed S, Vahidkhah Koohyar, Azadani Ali N
The DU Cardiac Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO 80210, United States.
The DU Cardiac Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO 80210, United States.
J Mech Behav Biomed Mater. 2016 Sep;62:33-44. doi: 10.1016/j.jmbbm.2016.04.031. Epub 2016 Apr 30.
Computational modeling has an important role in design and assessment of medical devices. In computational simulations, considering accurate constitutive models is of the utmost importance to capture mechanical response of soft tissue and biomedical materials under physiological loading conditions. Lack of comprehensive three-dimensional constitutive models for soft tissue limits the effectiveness of computational modeling in research and development of medical devices. The aim of this study was to use inverse finite element (FE) analysis to determine three-dimensional mechanical properties of bovine pericardial leaflets of a surgical bioprosthesis under dynamic loading condition. Using inverse parameter estimation, 3D anisotropic Fung model parameters were estimated for the leaflets. The FE simulations were validated using experimental in-vitro measurements, and the impact of different constitutive material models was investigated on leaflet stress distribution. The results of this study showed that the anisotropic Fung model accurately simulated the leaflet deformation and coaptation during valve opening and closing. During systole, the peak stress reached to 3.17MPa at the leaflet boundary while during diastole high stress regions were primarily observed in the commissures with the peak stress of 1.17MPa. In addition, the Rayleigh damping coefficient that was introduced to FE simulations to simulate viscous damping effects of surrounding fluid was determined.
计算建模在医疗设备的设计和评估中具有重要作用。在计算模拟中,考虑精确的本构模型对于捕捉软组织和生物医学材料在生理载荷条件下的力学响应至关重要。缺乏针对软组织的全面三维本构模型限制了计算建模在医疗设备研发中的有效性。本研究的目的是使用逆有限元(FE)分析来确定手术生物假体的牛心包小叶在动态载荷条件下的三维力学性能。通过逆参数估计,估算了小叶的三维各向异性冯氏模型参数。使用体外实验测量对有限元模拟进行了验证,并研究了不同本构材料模型对小叶应力分布的影响。本研究结果表明,各向异性冯氏模型准确模拟了瓣膜开闭过程中小叶的变形和贴合。在收缩期,小叶边界处的峰值应力达到3.17MPa,而在舒张期,高应力区域主要出现在连合处,峰值应力为1.17MPa。此外,还确定了引入有限元模拟以模拟周围流体粘性阻尼效应的瑞利阻尼系数。