Development of a multi scale ice material model for the simulation of brittle ice structure interaction

冰雪覆盖的海域对各利益攸关方具有吸引力。这包括例如石油和天然气、海军和渔业。与此同时，众所周知，海冰可能造成重大损害。因此，对在这些地区作业的船舶和海上结构物的可靠冰荷载设计方法的需求增加。目前，这主要是通过经验方法或模型比例的冰试验来完成的。这两种方法都有缺点。经验方法不能预测冰引起的负载具有足够的准确性，只给全球冰荷载。模态尺度冰试验与诸如尺度律或人工弱化冰的制造方法等有争议的话题有关，在这方面，冰相互作用的数值模拟是一种理想的工具。模拟包括设计过程中的其他方面，例如当前方法未涵盖的局部载荷或可变形结构。然而，模拟的准确性受到现有冰材料模型的限制，这些模型只能部分地捕捉复杂的冰行为。本研究的目的是识别冰荷载作用下脆性冰结构相互作用（ISI）的主要特征。一个多尺度的冰材料模型是要发展，反映这些主要特征。关键概念是使用子模型，其中每个子模型反映ISI的另一个方面，以及可扩展性，即材料模型对不同尺度的适用性。将使用三个子模型，一个将反映冰的整体行为，例如弹性，断裂模型将反映多个宏观断裂，最后是材料特性变化的随机模型。此外，每个子模型将通过不同规模的广泛实验进行验证。最终，完整的材料模型将通过大规模的实验室实验进行验证。将建立一系列有据可查的基准实验，以比较和验证其他研究人员的冰材料模型。此外，现有的大数据实验数据库将在本项目中使用和扩展。基准和数据库都将向公众开放。假设成功，未来将转移到盐冰的全面应用是可以实现的。

Ice covered sea areas have become attractive for various stakeholders. This includes e.g. oil and gas, navy and fishing. At the same time it is known that sea ice can cause significant damage. Hence the need for reliable ice load design methods for ships and offshore structures operating in these areas has increased. At present, this is mostly done with empirical methods or model scale ice tests. Both methods come with drawbacks. Empirical methods fail to predict ice-induced loading with sufficient accuracy and only give global ice loads. Mode scale ice tests are linked to controversial topics such as scaling laws or ways of making artificially weakened ice.In this regard, numerical simulations of ice interaction are a desirable tool. Simulations include additional aspects in the design process such as local loads or deformable structures which are not covered by current methods. However, the accuracy of simulations is limited by available ice material models, which only partially capture complex ice behavior. This research aims to identify dominant features of brittle ice structure interaction (ISI) with regard to ice loads. A multi-scale ice material model is to be developed which reflects these dominant features. The key concepts are the use of sub models, where every sub model reflects another aspect of ISI, and scalability, i.e. applicability of the material model to different scales. Three sub models will be used, one will reflect the bulk behavior of ice, e.g. elasticity, a fracture model will reflect multiple macro fractures and finally a stochastic model for the variation of material properties. Further, each sub model will be verified with a broad range of experiments on different scales. Ultimately, the complete material model will be verified against a large scale laboratory experiment. A series of well documented benchmark experiments will be established for comparison and verification of ice material models from other researchers. Additionally, an existing large data experimental data base will be used and extended within this project. Both the benchmarks and the data base will be made available to the public.Presuming success, a future transfer to full scale applications with saline ice is within reach.