Recent development of a coupled CFD/CSD methodology using an embedded approach

Abstract

A new algorithm for modeling the response of structures to severe airblast and fragment loading, including the modeling of large plastic deformations, structural failure and break-up, is described in this paper. The coupled Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD) methodologies required to describe these phenomena include the FEFL098 flow solver and DYNA3D structural solver. The original coupling between the two domains was based on the so-called "glued-mesh" approach, where the CFD and CSD interfaces match. Recent failure of this approach to model severe structural deformation, as well as crack propagation in steel and concrete, led us to the development and use of the "embedded-mesh" approach. Here, the CSD objects float through the CFD domain. While each approach has its own advantages, limitations and deficiencies, the embedded approach was proven to be superior for the problems modeled here. Critical applications of both approaches are described, including weapon detonation and fragmentation, airblast interaction with a reinforced concrete wall, and fragment/airblast interaction with a steel wall. The final applications model the interaction of an external airblast with a generic steel ship hull and a generic multi-chamber steel tower.