Concurrent Multiscale Moving-Window Scheme for Shock Wave Interaction with Material Microstructure

当一种材料在很短的时间内受到极大的压力和温度变化时，就会产生冲击波。当材料受到高速冲击时，在应用中通常会观察到这一点。设计抗冲击损伤的先进材料的需求推动了材料对冲击波响应的研究从纳米和微米级向大规模应用范围发展。这笔赠款由既定的激励竞争研究计划(EPSCoR)共同资助，支持对材料在冲击载荷下的多尺度响应的基础研究。它将提供关于冲击波如何在微观和纳米尺度上与材料特征相互作用导致宏观尺度上的变形和破坏的新知识。这项研究将加速为航空航天、汽车、基础设施和国防工业设计具有优异抗冲击性能的先进材料。此外，该项目将通过实验室研究，提供在材料科学、计算力学、应用物理和数学等跨学科领域对研究生和本科生进行教育和培训的机会。PI还将通过大学项目向K-12学生开展与科学和工程有关的外联活动。材料的冲击响应在本质上是多尺度的，在微观上引入了空洞、位错等缺陷，在宏观上引入了裂纹和塑性变形等缺陷。本文发展了一种原子域和连续域共存的并行多尺度方法来研究冲击波在材料中的传播及其与材料微观结构的相互作用。并发多尺度方案不能捕捉高速动态过程，如激波和运动的原子区。该框架使用基于控制体积的移动窗口方案，其中原子域跟随移动冲击波，以绕过当前技术水平方案的问题。利用这个新的框架，这项工作将研究微观组织的演变，冲击诱导缺陷的产生，以及微观结构特征(如晶界)对抗冲击性能的影响，如层裂强度。该框架将根据现有文献中关于冲击导致缺陷产生的实验数据进行系统验证。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Shock waves occur in a material when it is subjected to extreme pressure and temperature changes in a very short time. This is commonly observed in applications when a material is subjected to high speed impact. The need to design advanced materials resistant to shock damage has driven the research into the material's response to shock waves from the nano- and micro-meter scales to the large application scale. This grant, co-funded by the Established Program to Stimulate Competitive Research (EPSCoR), supports fundamental research into the multiscale response of the material when subjected to shock loading. It will provide new knowledge on how shock waves interact with material features at the micro and nano scales leading to deformation and failure at the macroscale. The research will accelerate the design of advanced materials with superior shock resistant properties for n aerospace, automotive, infrastructure and defense industries. Additionally, the project will provide opportunities to educate and train graduate and undergraduate students in the interdisciplinary areas of materials science, computational mechanics, and applied physics and mathematics through research in the laboratory. The PI will also engage in outreach activities related to science and engineering to K-12 students through university programs. Shock response of the material is multiscale in nature, introducing defects such as voids and dislocations at the microscale and cracks and plastic deformation at the macroscale. This work develops a concurrent multiscale method, with coexisting atomistic and continuum domains, to study shock wave propagation through a material and its interaction with material microstructure. State of the art concurrent multiscale schemes are unable to capture high speed dynamic processes such as shock waves and moving atomistic regions. The framework uses a control volume based moving-window scheme, where the atomistic domain follows a moving shock wave, to circumvent issues with current state of the art schemes. Using this new framework, the work will study microstructural evolution, shock induced defect generation, and the influence of microstructural features such as grain boundaries on shock resistance properties, e.g., spall strength. The framework will be systematically validated against existing experimental data on shock induced defect generation available in the literature.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.