CAREER: Dynamics and Damage of Void Collapse in Biological Materials Under Stress Wave Loading

职业：应力波载荷下生物材料中空洞塌陷的动力学和损伤

• 批准号: 0954769
• 负责人: Joanna Austin
• 金额: $ 40万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0954769&HistoricalAwards=false
• 关键词: CAREER; Dynamics; Damage; Void; Collapse

Title: CAREER: Dynamics and Damage of Void Collapse in Biological Materials Under Stress Wave LoadingPrincipal Investigator: Joanna AustinInstitution: U of Ill Urbana-ChampaignProposal No: CBET-0954769AbstractCollapsing voids cause extensive damage in diverse applications from biomedicine to underwater propulsion to explosives. While there is extensive research into shock induced void collapse, if there are mechanisms for wave attenuation or if the impact velocity is relatively low, stress wave loading will instead occur. The objective of this research is to quantify the effect of loading wave profile on the hydrodynamic interaction and damage mechanisms of multiple void collapse. Under distributed loading, the wave profile and void and inter-void length scales can be comparable, potentially resulting in a strongly coupled interaction and precluding the direct application of shock wave collapse models, for example to predict cell and tissue injury in biomedical applications. Tissue and cell destruction by pulsed laser induced waves can have enormous biomedical treatment benefits for example in retards to cancerous tumor growth, however, severe collateral damage of surrounding tissue can also result. One mechanism for trauma is the dynamic response of voids subjected to the pressure pulse, which is attenuated from an initial shock with an increase in rise time by interaction with acoustic heterogeneities in the body. Predictive models for tissue damage under these loading conditions are critical to the use of these powerful techniques.Intellectual Merit:Dynamic experiments are designed to highlight the interaction and damage mechanisms of voids collapsing after passage of a stress wave. In biomedical applications, the ramped wave profile (or rise time) is found to correlate better with tissue damage than the peak pressure. To the PI's knowledge, the collapse of voids under these conditions has not been previously studied. Experimental time resolved visualizations of void collapse, the first velocity field measurements in the surrounding material, and internal and external temperature measurements will be carried out in a model experimental setup which allows accurate placement of 2D and 3D void arrays in a tissue surrogate polymer material. Initial work by the PI has shown the internal volume history is nonlinear, in agreement with simulations but in contrast to existing linear experimental data fits. The role of rise time will be examined as additional parameter to the overall pressure ratio across the wave. In the case of multiple voids, velocity measurements show the stress wave diffracts in response to the upstream void, affecting the subsequent loading condition. Both collapse-inhibiting (shielding) and collapse triggering effects are observed and will be quantified.Broader impacts The capability for accurate prediction of tissue and cellular damage has a profound impact on treatment options across a broad range of biomedical applications including extracorporeal shock wave lithotripsy, laser induced plasma surgery, and ultrasound. The CAREER research and educational plans are interwoven through the incorporation of research results in hands on activities that reach three age groups: local community children, middle school students, and undergraduate students.Through this integrated research and education plan, undergraduate students will be exposed to interdisciplinary study and will showcase their research results to demonstrate opportunities to middle school students, particularly through the Girls Adventures in Mathematics, Engineering, and Science (GAMES)and Girls Do Science programs. These programs target girls at middle school age level, when a dramatic decrease in self esteem in academic settings has been widely reported. The Aerospace Engineering GAMES program is currently being developed by the PI in coordination with the College of Engineering at Illinois. The overarching goal is retention of academically talented middle school girls in math and science by demonstrating the social validity, breadth of opportunity, and the community benefits of engineering, and by providing the opportunity for learning through team based projects, exposure to the University, and meetings with role models and mentors. The PI will also continue her successful record of recruiting and mentoring undergraduate and graduate students in engineering, as well as on going participation in outreach activities such as Girls Do Science.

职务名称：职业：应力波作用下生物材料中空洞塌陷的动力学和损伤主要研究者：Joanna Austin机构：伊利诺伊大学厄巴纳-香槟分校提案号：CBET-0954769摘要塌陷空洞在从生物医学到水下推进到爆炸物的各种应用中造成广泛的损伤。虽然对冲击引起的空隙塌陷有广泛的研究，但如果存在波衰减的机制或如果冲击速度相对较低，则会发生应力波加载。本研究的目的是量化的影响，加载波的轮廓上的水动力相互作用和损伤机制的多个空洞崩溃。在分布载荷下，波形和空隙和空隙间长度尺度可以是相当的，可能导致强耦合相互作用，并排除冲击波塌陷模型的直接应用，例如预测生物医学应用中的细胞和组织损伤。由脉冲激光诱导波引起的组织和细胞破坏可以具有巨大的生物医学治疗益处，例如延缓癌性肿瘤生长，然而，也可能导致周围组织的严重附带损伤。创伤的一种机制是受到压力脉冲的空隙的动态响应，压力脉冲通过与体内声学不均匀性的相互作用从初始冲击随着上升时间的增加而衰减。这些负载条件下的组织损伤的预测模型是至关重要的使用这些强大的technology.Intellectual优点：动态实验的目的是突出的相互作用和破坏机制的空洞崩溃后，通过应力波。在生物医学应用中，发现斜坡波轮廓（或上升时间）比峰值压力更好地与组织损伤相关。据PI所知，在这些条件下的空隙坍塌以前没有研究过。 将在模型实验装置中进行空隙塌陷的实验时间分辨可视化、周围材料中的第一速度场测量以及内部和外部温度测量，该模型实验装置允许在组织替代聚合物材料中准确放置2D和3D空隙阵列。PI的初步工作表明，内部体积的历史是非线性的，与模拟一致，但与现有的线性实验数据拟合相反。上升时间的作用将作为波上总压力比的附加参数进行研究。在多个空隙的情况下，速度测量显示应力波衍射响应于上游空隙，影响随后的加载条件。 更广泛的影响准确预测组织和细胞损伤的能力对广泛的生物医学应用（包括体外冲击波碎石术、激光诱导等离子体手术和超声波）的治疗方案产生了深远的影响。职业研究和教育计划通过将研究成果结合在针对三个年龄组的活动中而相互交织：当地社区儿童，中学生和本科生。通过这个综合研究和教育计划，本科生将接触到跨学科的学习，并将展示他们的研究成果，向中学生展示机会，特别是通过女孩数学、工程和科学冒险（游戏）和女孩做科学方案。这些方案针对的是中学年龄段的女孩，据广泛报道，这一年龄段的女孩在学习环境中自尊心急剧下降。航空航天工程游戏计划目前正在开发的PI与工程学院在伊利诺伊州的协调。总体目标是通过展示社会有效性，机会的广度和工程的社区效益，并通过团队项目，接触大学，以及与榜样和导师的会议提供学习机会，在数学和科学方面保留学术才华的中学女生。PI还将继续招聘和指导工程本科生和研究生的成功记录，以及继续参与外展活动，如女孩做科学。