A Lagrangian Meshfree Computational Framework for Materials in Extreme Dynamic Conditions

Current cutting-edge scientific and engineering applications require the development of products and material systems under extreme working environments. This is particularly true for high-end equipment in fields such as aerospace, national security and defense, and advanced manufacturing, which often endure high temperature, high pressure, and high strain rate scenarios. There is an urgent need for breakthrough in fundamental extreme mechanics and computational simulation technologies for performance analysis and optimization of materials and structures in extreme conditions. This challenge imposes significant demands on the theoretical framework, high fidelity computational methods, and high-performance computing. This research starts from the mechanism of strongly coupled multiphysics processes, establishing a variational structure for the dynamic response of materials. By minimizing the effective potential, it reveals the competitive relationships of various energy dissipation mechanisms to predict the deformation, temperature, phase transformation, and failure of the system. Additionally, a Lagrangian meshfree framework is proposed to numerically solve complex physical phenomena such as large deformations, melting and vaporization, fluid-solid and thermal fluid-solid coupling, free surfaces, multi-body contact, and fracture under extreme conditions. The accuracy and performance of this framework are further validated in predicting the formation of micro-defects in metal additive manufacturing.