An Embedded Mesh Method for Coupling Lagrangian and ALE Finite Element Models
Lawrence Livermore National Laboratory
Methods for coupling overlapping foreground and background discretizations (e.g. embedded mesh, overset and immersed boundary methods) can make tractable complex models (Fig. 1). Here, an embedded mesh approach is developed to couple foreground Lagrangian finite element meshes (or SPH discretizations) to a background ALE mesh [1,2]. A Lagrange multiplier approach is used to enforce velocity constraints at the interface. Modifications are made to the advection scheme to account for the background fluid flow around the foreground body. The schemes for computing the Lagrange multipliers and time integrating the explicit equations of motion were designed to be provably stable. Details of the stability analysis will be presented. It is also shown that the method has no deleterious affect on the stable Courant time steps i.e. there is no modification of the time step to account for the embedded mesh. Consequently, the proposed approach exhibits excellent robustness in a variety of rigorous analyses. Mesh studies are presented demonstrating convergence. Example problems including contact, penetration, blast, SPH foreground and failure with evolving fragmentation are also presented.
Date(s) - 11/30/2017
4:00 pm - 5:00 pm
1062 Bainer Classroom