A study on mesh size dependency of finite element blast structural analysis induced by non-uniform pressure distribution from high explosive blast wave

Accurate computational blast analysis can be an effective replacement for costly blast field test. HFPB (high fidelity physics based) blast analysis method including high strain rate dependent material models and appropriate blast wave models is a representative precise blast analysis method. HFPB blast analysis method can be used for various analyses such as structural analysis, retrofitting design analysis, fragmentation analysis, and energy absorbing analysis. When analyzing the behaviour of structure under blast loading by HFPB finite element methods, load gradient differences occurs dependent on the mesh size. This causes gaps between the explosive energy and internal energy of structures and the results of analysis become mesh-size-dependent. In this study, the analytical considerations were presented for mesh sensitivity due to non-uniform pressure load distribution on the structure subjected to blast wave of high explosive with relatively close stand-off. Through the analysis results, the maximum element size which ensures the mesh-size independent analysis results is suggested.