I-beam structure under blast loading-Eulerian mesh density study

Dynamic response of an I-beam structure subjected to shock wave produced by the detonation of high explosive (HE) materials is presented in this paper. LS-DYNA, a 3-D explicit, finite element computer code is used to study this behaviour. A coupled analysis between Lagrangian formulation (solid material) and Eulerian formulation (gas medium) was performed. The latest extensive research in this area indicates that the finite element analyses of such problems require complex meshes for Euler and Lagrange formulation. This research is focused on Euler mesh density influence on coupled analysis results. The principal objective of this paper is to compare various mesh density Eulerian models in respect to accuracy and computing time and asses the limit of element size. The Eulerian domains (Air and HE) were developed with various element size from 10 mm up to 30 mm. Results from all the analysis cases show how the Eulerian mesh element size influences on the global response of the column. Models with coarse meshes give much lower dynamic response then models with finer meshes. The resultant velocity vectors were also presented to illustrate the characteristic of blast wave propagation. Moreover the numerical models computational efficiency was compared are respect of CPU Time. Models with complex meshes (below 20 mm) are very computationally expensive.