Biomechanics of Arterial Walls under Supra-Physiological Loading Conditions

超生理负荷条件下动脉壁的生物力学

基本信息

批准号：
166835325
负责人：
Professor Dr.-Ing. Daniel Balzani
金额：
--
依托单位：
Institut für Biomechanik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/166835325?language=en
关键词：
Biomechanics Arterial Walls under Supra

项目摘要

In this research project supra-physiological loading situations of arterial walls, e.g., occurring during balloon angioplasty, are described. Under such loading conditions microscopic damage on the interfibrillar level is induced in the tissue leading to a complex softening hysteresis observed in the stress-strain response. To describe this behavior, damage models were developed in the first phase of this project on the basis of continuum damage mechanics. These models were compared with experiments and a good correlation could be shown. However, the loss of ellipticity, which is typically observed for damage mechanics formulations, may lead to mesh-dependent solutions and the loss of material stability. In order to solve these substantial fundamental problems, mathematically secured and robust modeling approaches are central task in this second phase. The basis is the construction of an incremental variational formulation for damage in soft biological tissues which enables convexification. Thereby, the loss of ellipticity can be precluded and mesh-independent solutions as well as material stability are ensured. Essentially, efficient models and algorithms are planned to be developed on the basis of relaxed incremental variational formulations, which reflect the specific characteristics of the damage hysteresis in soft biological tissues. Starting from a rather phenomenological but efficient approach which is to be constructed first, a model has to be developed, which takes into account fiber dispersion. Thereby damage evolution is described by a progressive recruitment of individual fiber orientations. In order to enable an optimized parameter adjustment in the sense of a least-square minimization in reasonable time also for this model, a surrogate model is planned to be constructed and used during parameter optimization. The developed formulations have to be implemented in a finite-element program. Then they have to be analyzed with respect to their performance on the basis of boundary value problems where diseased arterial walls are simulated.

在这项研究项目中，描述了动脉壁的超生理负荷情况，例如在气球血管成形术期间发生。在这种载荷条件下，在组织中诱导了纤维化水平上的微观损伤，导致在应力 - 应变反应中观察到的复杂的软化滞后。为了描述这种行为，在该项目的第一阶段开发了损害模型，基于连续性损害力学。将这些模型与实验进行了比较，并且可以显示良好的相关性。但是，通常观察到损伤力学制剂的椭圆度的丧失可能导致网状依赖性溶液和材料稳定性的损失。为了解决这些重大的基本问题，在第二阶段，数学上有保护和健壮的建模方法是核心任务。基础是构建一种增量变分制，以造成软生物组织中损伤的损害，从而实现凸的化。因此，可以防止椭圆度的丧失，并确保与网格无关的解决方案以及材料稳定性。本质上，计划基于松弛的增量变分制配方开发有效的模型和算法，这反映了软生物组织中损伤滞后的特定特征。从要首先构建的相当现象学但有效的方法开始，必须开发一个模型，考虑到纤维分散。因此，通过逐步募集单个纤维取向来描述损害演变。为了在合理时间内最小化最小化的意义上，还计划在参数优化期间构建和使用替代模型。开发的配方必须在有限元程序中实现。然后，必须根据模拟患病的动脉壁的边界价值问题对其性能进行分析。