Abstract. Strong shocks in air blast lead to profound fluid-structure interaction (FSI) and structural damage and fragmentation. These complex phenomena in fluid/solid coupled systems pose considerable difficulties to conventional mesh-based numerical methods. In this work, an immersed Reproducing Kernel Particle Method (RKPM) framework is developed for modeling FSI problems in the shock regime. A variational multiscale approach is employed for the proposed immersed framework, termed variational multiscale immersed method (VMIM). The fine-scale solutions represent the residual of the coarse-scale equations, and the embedment of the fine-scale solutions results in a stabilized Petrov-Galerkin formulation, leading to increased accuracy and enhanced stability in the course-scale solutions. The proposed VMIM also exhibits a better convergence rate comparing to the conventional immersed method with comparable efficiency. The shock-enhanced meshfree algorithm is employed to ensure the enforcement of essential shock physics as well as to control the Gibbs phenomenon due to the shocks. The proposed immersed RKPM method allows an effective body-unfitted spatial discretization for the fluid/solid domains, suitable for the problem involves complex geometry. RKPM also naturally avoids computational challenges associated with low-quality meshes, allows efficient adaptive refinement and provides flexible control of continuity and locality in numerical approximations. Several numerical examples are examined to demonstrate the effectiveness of the proposed method for modeling FSI and air blast problems.

Bio. J. S. Chen is the William Prager Chair Professor of Structural Engineering Department, Professor of Mechanical and Aerospace Engineering Department, and the Director of Center for Extreme Events Research at UC San Diego. Before joining UCSD in October 2013, he was the Chancellor’s Professor of UCLA Civil & Environmental Engineering Department where he served as the Department Chair during 2007-2012. J. S. Chen’s research is in computational mechanics and multiscale materials modeling with specialization in the development of meshfree methods. He is the Past President of US Association for Computational Mechanics (USACM) and the Past Present of ASCE Engineering Mechanics Institute (EMI). He has received numerous awards, including the Computational Mechanics Award from International Association for Computational Mechanics (IACM), ICACE Award from International Chinese Association for Computational Mechanics (ICACM), the Ted Belytschko Applied Mechanics Award from ASME Applied Mechanics Division, the Belytschko Medal, U.S. Association for Computational Mechanics (USACM), among others. He is the Fellow of USACM, IACM, ASME, EMI, SES, ICACM, and ICCEES.