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: 1521118
• 负责人: Joanna Austin
• 金额: $ 5.39万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1521118&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.

题目：职业：应力波载荷下生物材料空隙崩塌的动力学与损伤研究，项目负责人：Joanna austin，研究单位：伊利诺伊大学香槟分校，项目号：cbet - 0954769abstract摘要空隙崩塌在生物医学、水下推进和炸药等多种应用中造成了广泛的破坏。虽然对冲击引起的空洞塌陷的研究非常广泛，但如果存在波衰减机制或冲击速度较低，则会发生应力波加载。本研究的目的是量化加载波剖面对多孔洞破坏的水动力相互作用和损伤机制的影响。在分布载荷下，波剖面、空隙和空隙间长度尺度可以比较，这可能导致强耦合相互作用，并妨碍冲击波崩溃模型的直接应用，例如在生物医学应用中预测细胞和组织损伤。脉冲激光诱导波对组织和细胞的破坏可以带来巨大的生物医学治疗益处，例如延缓癌性肿瘤的生长，然而，也可能导致周围组织的严重附带损伤。创伤的一种机制是空洞受到压力脉冲的动态响应，压力脉冲由于与体内声学异质性相互作用而随着上升时间的增加而衰减。在这些载荷条件下组织损伤的预测模型对于使用这些强大的技术至关重要。智力优势：动态实验旨在强调应力波通过后空洞坍塌的相互作用和破坏机制。在生物医学应用中，斜波剖面（或上升时间）被发现比峰值压力与组织损伤有更好的相关性。据PI所知，在这些条件下的空洞塌陷以前还没有研究过。实验时间解析了空隙塌陷的可视化，周围材料的第一次速度场测量，以及内部和外部温度测量将在模型实验装置中进行，该装置允许在组织替代聚合物材料中精确放置2D和3D空隙阵列。PI的初步工作表明，内部体积历史是非线性的，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跨波总压力比的附加参数加以考察。在多个孔洞的情况下，速度测量显示应力波衍射响应上游孔洞，影响后续加载条件。坍缩抑制（屏蔽）和坍缩触发效应都被观察到，并将被量化。更广泛的影响准确预测组织和细胞损伤的能力对包括体外冲击波碎石术、激光诱导等离子体手术和超声在内的广泛生物医学应用的治疗选择产生了深远的影响。CAREER研究和教育计划通过将研究成果结合到三个年龄段的活动中来交织在一起：当地社区儿童、中学生和大学生。通过这一综合研究和教育计划，本科生将接触到跨学科的研究，并将展示他们的研究成果，向中学生展示机会，特别是通过女孩在数学，工程和科学（游戏）中的冒险和女孩做科学项目。这些项目针对的是中学阶段的女孩，这个阶段在学术环境中自尊心急剧下降的现象已经被广泛报道。航空航天工程游戏项目目前由PI与伊利诺斯州工程学院合作开发。总体目标是通过展示工程的社会有效性、机会广度和社区效益，并通过团队项目、接触大学、与榜样和导师会面提供学习机会，留住数学和科学领域有学术天赋的中学女生。PI还将继续她在招聘和指导工程专业本科生和研究生方面的成功记录，并继续参与诸如“女孩做科学”之类的外展活动。