Collaborative Research: Simulating Iceberg Calving from Ice Shelves using a Damage Mechanics Model

该奖项支持开发一个模型，该模型可以模拟冰川冰的流动和断裂，（包括冰的缓慢蠕动），因为它在自身重量下一直蔓延到冰山完全失效和脱离（崩解）冰川和冰架（冰川冰的浮动扩展）。 由于冰山崩解占冰架损失质量的近50%，因此它在冰川和冰盖的质量平衡中起着重要作用，但仍然是一个知之甚少的过程。 冰山崩解也尚未在当前一代大陆尺度冰盖模型中得到考虑，这些模型用于最先进的气候模拟和海平面上升预测，因为模拟冰山崩解需要我们了解冰内裂缝的起始和传播时间范围从几秒钟到几十年甚至几个世纪。 为了解决这个问题，该项目的主要目标是通过将最初开发用于模拟金属和混凝土等准脆性材料断裂的物理和计算方法转化为冰川冰断裂来解决我们理解中的这一差距。 由于它是不可能的和不切实际的，以模拟在冰盖中的每个单独的裂纹的传播，我们将寻求一个“连续损伤力学”的方法，处理裂纹的集合在物理和物理上一致的方式来模拟大规模的故障。这将通过使用一种方法来实现，该方法可以模拟裂缝在与海洋的界面形成后发生的情况。该项目旨在提高我们预测格陵兰和南极冰盖命运的能力，并量化冰盖对未来几个世纪海平面上升的贡献。 要做到这一点，我们需要更好地理解为什么冰山可以超过新英格兰的小州，脱离和漂移远离冰架。 该项目的更广泛影响还包括通过定向研究项目和有针对性地让低收入地区代表性不足的少数群体参与小学和高中教育，开展研究生和本科生教育。 与代表性不足的少数民族的接触将包括在STEM领域为未来的职业道路提供咨询和规划，并在密歇根大学、范德比尔特大学和哥伦比亚大学主办的暑期实习项目中指导选定的学生。

Bassis/1341568This award supports the development of a model that can simulate both the flow and fracture of glacier ice, (including the slow creeping of that ice) as it spreads under its own weight all the way to the complete failure and detachment (calving) of icebergs from glaciers and ice shelves (floating expanses of glacier ice). Because iceberg calving accounts for nearly 50% of the mass lost from ice shelves, it plays an important role in the mass balance of glaciers and ice sheets, but remains a poorly understood process. Iceberg calving is also not yet accounted for in the current generation of continental-scale ice sheet models, which are used in state-of-the-art climate simulations and sea level rise projections, because simulating iceberg calving requires that we understand the initiation and propagation of fractures within the ice over timescales that can range from a few seconds to decades or even centuries. To address this problem, the primary objective of this project is to address this gap in our understanding by translating physical and computational approaches originally developed to simulate the fracture of quasi-brittle materials, like metals and concrete, to the fracture of glacier ice. Since it is both impossible and impractical to simulate the propagation of each individual crack in an ice sheet, we will seek a "continuum damage mechanics" approach that handles collections of cracks in a physically and thermodynamically consistent way to simulate failure at the large scale. This will be accomplished by using an approach that can simulate what happens to fractures after they form at the interface with the ocean. This project seeks to advance our ability to predict the fate of the Greenland and Antarctic ice sheets and to quantify the ice sheet contribution to sea level rise in the coming centuries. Accomplishing this requires that we have a better understanding of why icebergs that can exceed the size of small New England States, detach and drift away from ice shelves. The broader impacts of the project also include graduate and undergraduate education through directed research projects and targeted engagement of under-represented minorities in low-income regions at the elementary and high school levels. Engagement with under-represented minorities will include counseling and planning for future career paths in the STEM fields and mentoring selected students during summer internship programs hosted by the University of Michigan, Vanderbilt University and Columbia University.