Parameter optimization for the free-air blast simulation using an ALE method

Abstract

The demands for understanding the explosion phenomenon and designing protection facilities have increased due to worldwide terroristic attacks. Exerted blast pressure on the structures can cause structural failure such as local damage. A lot of blast experiments have been conducted to understand blast loading, but there is a limitation of time to prepare the experiment and enormous costs. Although alternative approaches through utilizing numerical analysis models have been attempted to overcome the limitations, parametric studies for accurate blast pressure calculation are rarely discussed. In this study, the free-air blast is numerically simulated using an Arbitrary Lagrangian-Eulerian (ALE), and pivotal parameters are optimized using error analysis. Through the comparison of simplified method and empirical formulas, the times series of blast pressure using the ALE method is verified. As a result, the maximum pressure value and decay constant in the pressure-time curve are affected by the four main variables: density of the mesh, advection factor, size of the air domain, and ALE calculation method. Using the optimized parameters, the blast loading can be precisely calculated, and it can be employed for the safety evaluation of structures under blast pressure.