NNA: Bridging the Atomistic Deformation Mechanisms to the Microscopic Adhesive-to-Cohesive Fracture at Ice-Metal Interfaces

冰冷表面上的结冰是许多工程应用中非常关注的话题，包括飞机、风力涡轮机和航行在极地海域的海船。然而，由于对许多基本问题缺乏答案，例如冰是如何从金属表面脱落的，以及是什么控制了从粘性(冰-金属界面处的断裂)到粘性(冰本身内的断裂)的断裂类型的转变，以最小的功率输入除冰(将冰从冷表面分离出来)的战略尚未确立。这项研究项目将通过确定冰-金属材料系统中粘结断裂的基本机制来促进界面力学的科学研究；将冰-金属界面结构与其冰粘合强度相关联；并支持寻找比现有方法消耗更少动力的除冰策略。该项目还将通过合理设计材料来抑制或增强冰粘附力，从而促进国家的健康、繁荣和福利，这将对在北极和寒冷天气运行的广泛安全关键基础设施产生影响，包括电信设备、输电线、汽车、海船和海上石油平台，以及日常环境中的食品和运输部门。随着这些进展，该项目将通过影响北极日益增长的海洋贸易的民用基础设施的设计和工程，支持NSF关于航行新北极的大想法(NNA)。作为项目的一部分，教育和外展活动将集中在招募本科生暑期，通过基于大学的项目向女性和少数族裔学生进行外联，以及从门户网站分发软件。该项目将结合多物理、多尺度的模拟和实验，即水的粗粒度建模、金属材料的新的并行原子-连续介质建模，以及在独特的结冰研究隧道设备中的实验，以阐明与冰-金属材料系统中粘结-粘结界面断裂相关的潜在物理学。计算机模型将被集成，以实现从原子到微尺度的多尺度固-液相互作用模拟，同时考虑到在实验装置中制造的冰-金属材料试件的真实微结构。这项研究将确定位错介导的塑性在粘结界面断裂中的作用，并量化冰-金属粘结强度及其对金属表面拓扑、化学和冰微结构的敏感性。这些模型将通过相关尺度的实验测量进行校准和验证。该项目还将为参与的学生提供广泛的知识和技能，包括结冰物理、防/除冰技术、力学、超级计算、材料加工和表征以及结冰隧道测试。几套冰-金属材料系统将在当地初中和高中设计、制造和分发，以说明金属表面的微小变化如何显著改变其冰粘附力。该奖项反映了NSF的法定使命，并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。

Ice accretion over cold surfaces is a topic of great concern for numerous engineering applications, including airplanes, wind turbines, and marine vessels sailing near polar seas. However, a strategy of de-icing (detaching ice from cold surfaces) with minimal power input is not well-established yet due to the lack of answers to many fundamental questions, such as how does the ice shed from a metallic surface and what controls the conversion of fracture type from adhesive (fracture at an ice-metal interface) to cohesive (fracture within ice itself) cracking? This research project will advance the science of interfacial mechanics by identifying the fundamental mechanisms for the adhesive-to-cohesive fracture in an ice-metal material system; correlate an ice-metal interface structure with its ice adhesion strength; and support the search of de-icing strategies that consume far less power than existing approaches. The project would also advance the national health, prosperity, and welfare by enabling a rational design of materials that either inhibit or enhance ice adhesion, with implications for a wide range of safety-critical infrastructures operating in arctic and cold weathers, including telecommunication equipment, power lines, automotive vehicles, marine vessels, and offshore oil platforms, along with the food and transport sectors in everyday environment. With these advancements, this project will support the NSF Big Idea on Navigating the New Arctic (NNA) through impact on the design and engineering of civil infrastructure for an increasing marine commerce in the Arctic. As part of project, education and outreach activities will focus on hiring undergraduate students for the summer, performing outreach to women and minority students through university-based programs, and dissemination of software from a web-portal.This project will combine multi-physics, multi-scale simulation and experimentation, i.e., coarse-grained modeling of water, novel concurrent atomistic-continuum modeling of metallic materials, and experiments in a unique Icing Research Tunnel facility, to elucidate the underlying physics pertinent to adhesive-to-cohesive interface fracture in ice-metal material systems. The computer models will be integrated to enable multiscale simulation of solid-liquid interaction from the atomistic to the microscale, while accounting for the realistic microstructure of ice-metal material specimens fabricated in the experimental facility. The research will determine the role of dislocation-mediated plasticity in an adhesive-to-cohesive interface fracture, and quantify the ice-metal adhesion strength and its sensitivity to metal surface topology, chemistry, and ice microstructure. The models will be calibrated and validated with experimental measurements at relevant scales. This project will also provide participating students a broad range of knowledge and skills in icing physics, anti-/de-icing technology, mechanics, supercomputing, material processing and characterization, and icing tunnel testing. Several kits of ice-metal material systems will be designed, fabricated and distributed in local middle and high schools for illustrating how slight changes of a metal surface can significantly change its ice adhesion strength.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.