Modeling of Confined Explosions: An Uncoupled Eulerian-Lagrangian Approach for Blast Wave Propagation and Structural Assessment

The pressure histories resulting from blast wave interactions with structures are highly influenced by the level of confinement. Fully confined blast events are more severe than their unconfined counterparts due to multiple wave reflections and residual quasi-static pressures, which result in prolonged shock-structure interactions and complex pressure profiles. Most experimental studies have primarily focused on spherical or hemispherical blast waves in free-field conditions, supporting simplified models like the CONWEP algorithm commonly integrated into Finite Element (FE) solvers for unconfined explosions. However, this approach is unsuitable for more complicated scenarios, such as explosions in confined scenarios. The current study presents an approach that integrates CFD with a FE framework. This work focuses on extending the capabilities of the FE solver Abaqus/Explicit to handle these complex load histories, which are beyond the scope of its default built-in configurations. User-defined subroutines are developed to enable an Uncoupled Lagrangian-Eulerian (UEL) framework. CFD simulations are performed independently to calculate pressure histories, then they are subsequently mapped onto structural FE models as input loads. The results demonstrate that the proposed framework extends the range of scenarios that can be analysed for blast wave propagation and its effects on structures. By employing this uncoupled approach, diverse structural simulations can be performed using a single FE model. This study provides a numerical tool for simulating confined explosions, with applications in industrial safety and structural design facilitating improved engineering designs for mitigating blast effects.