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Shockwave Propagation and Dynamic Fracture of Hydrogels via Integrated Computational and Experimental Studies

通过综合计算和实验研究水凝胶的冲击波传播和动态断裂

基本信息

批准号：
1634188
负责人：
Douglas Spearot
金额：
$ 44.42万
依托单位：
University of Florida
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-08-01 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634188&HistoricalAwards=false
关键词：
Shockwave Propagation Dynamic Fracture Hydrogels

项目摘要

This award supports experimental and computational research to study the high deformation rate behavior of hydrogels. Hydrogels consist of a polymer network absorbed in water. Hydrogels are an important class of materials because their properties may be customized to mimic the behavior of many biological tissues. Accordingly, hydrogels are commonly used as tissue simulants for skin, muscles and human organs (lungs, heart, brain, etc.) in experiments to study traumatic injuries. Most prior research has focused on the behavior of hydrogels at low deformation rates. Unfortunately, such experiments do not mimic the conditions associated with tissue injuries caused by high rate deformation (e.g., sudden falls, skiing injuries, automobile accidents) and the effects of shockwave propagation (non-contact blast injuries to lungs, tissue and brain). The results of this research will provide the knowledge necessary to better understand shockwave propagation and related damage in biological tissues. Thus, this research will benefit military veterans and other citizens with traumatic soft tissue injuries. Furthermore, workforce development activities will contribute to the training of graduate and undergraduate students in experimental and simulation techniques. This research will provide an understanding of the fundamental physical mechanisms related to the dynamic behavior of hydrogels, such as variation in wave velocity as a function of propagation distance and water volume fraction. Further, this research will provide a first understanding of high rate viscosity in hydrogels as a function of water content, atomic scale stresses and strains during high rate shearing deformation, and the rate of crack growth in hydrogel samples. Experiments will be conducted using a unique polymer split Hopkinson pressure bar customized to study shockwave propagation and dynamic fracture in hydrogel materials. Molecular dynamics simulations will be conducted to study shockwave propagation and viscosity with atomic resolution. Combined, data from experiments and simulation will be used to improve hyperelastic constitutive models for the dynamic mechanical behavior of hydrogels. Experimental measurement and simulation of the high strain rate viscosity of hydrogels will be used to develop novel rate dependent cohesive zone models for predictive simulation of crack propagation in hydrogels.

该奖项支持实验和计算研究，以研究水凝胶的高变形率行为。水凝胶由吸收在水中的聚合物网络组成。水凝胶是一类重要的材料，因为它们的性质可以定制以模拟许多生物组织的行为。因此，水凝胶通常用作皮肤、肌肉和人体器官（肺、心脏、脑等）的组织模拟物。用于研究创伤性损伤。大多数先前的研究集中在低变形速率下的水凝胶的行为。不幸的是，这样的实验不能模拟与由高速率变形引起的组织损伤相关的条件（例如，突然福尔斯跌落、滑雪受伤、汽车事故）和冲击波传播的影响（对肺、组织和大脑的非接触性爆炸伤害）。这项研究的结果将提供必要的知识，以更好地了解冲击波的传播和生物组织中的相关损伤。因此，这项研究将有利于退伍军人和其他创伤性软组织损伤的公民。此外，劳动力发展活动将有助于对研究生和本科生进行实验和模拟技术方面的培训。这项研究将提供与水凝胶的动态行为相关的基本物理机制的理解，例如作为传播距离和水体积分数的函数的波速的变化。此外，这项研究将提供第一次了解水凝胶的高速率粘度作为水含量的函数，原子尺度的应力和应变在高速率剪切变形，和水凝胶样品中的裂纹生长速率。实验将使用一个独特的聚合物分离式霍普金森压杆定制研究冲击波传播和动态断裂水凝胶材料进行。将进行分子动力学模拟，以原子分辨率研究冲击波传播和粘度。结合，从实验和模拟的数据将被用来改善水凝胶的动态力学行为的超弹性本构模型。水凝胶的高应变速率粘度的实验测量和模拟将被用于开发新的速率依赖的内聚区模型，用于预测模拟水凝胶中的裂纹扩展。