在武器内爆、高速撞击等多介质大变形问题中，流体动力学程序是不可或缺的数值模拟工具。对于界面拓扑结构变化的多介质大变形问题，多介质ALE方法是一种有效的数值模拟手段，已成为近年来流体动力学数值模拟领域的研究热点。在武器内爆多介质大变形需求背景下，我们已成功研制了适用于两物质混合的多介质ALE程序，但其还不能适应于物质穿透等界面大变形问题的数值模拟需求。本项目以两物质ALE程序为基础，通过界面重构、混合模型、重映算法三方面的研究，研制适用于三物质混合的多介质ALE程序。研究内容包括：（1）高效MOF界面重构算法研究，以提高界面重构的效率和健壮性；（2）界面感知的亚网格动力学混合模型研究，以提高混合模型的适用性；（3）交错型网格上的高阶守恒重映算法研究，以提高重映精度。通过这三方面的研究，建立对界面拓扑结构变化的多介质大变形问题的数值模拟能力，为多介质界面大变形问题研究提供有效的数值模拟工具。

Hydrocodes are necessary numerical tools in the fields of weapon implosion and high-velocity impact. Multi-material ALE method, which is effective to the large-deformation problems with changing-topology interfaces, has been the research hotspot in recent years. Aiming to meet the need of weapon implosion problems, we have developed the staggered two-material ALE program, but it cannot simulate the large-deformation penetration problems. Based on the developed two-material ALE programs, we will develop the staggered three-material ALE methods and relevant programs. This research consist of three parts: (1)Efficient MOF interface reconstruction, which is to improve the efficiency and robustness of interface reconstruction; (2)Interface-aware sub-scale dynamics closure model, which is to improve the application field of closure model; (3) Conservative flux-based multi-material remap for staggered multi-material ALE methods, which is to improve the accuracy of remapping. Through the study of three aspects of multi-material ALE, we will develop the simulation capability to the large-deformation problems with changing-topology interfaces, and provide an effective numerical simulation tool for multi-material large-deformation problems.