The main goal of this study was to develop and implement an explicit nonlinear dynamic finite element methodology for investigating the crashworthiness of small, lightweight rigid bodies impacting soft soil. Aircraft crash dynamics are strongly influenced by the properties of the impact terrain, as different terrains produce different structural responses.
This work focuses on the characterization and validation of a numerical model for soft soil as an impact surface. The method used was based on a time-explicit Eulerian finite element (FE) analysis code. The approach was demonstrated through finite element simulations of penetrometer drop tests into soft soil.
An Eulerian-based FE method was chosen instead of the more common Lagrangian-based approach. This decision was made to reduce numerical instabilities that often occur in Lagrangian solvers when analyzing problems with large deformations, which are typical in crash scenarios. Such instabilities can prematurely terminate simulations and compromise results.
Explicit FE codes are widely used in nonlinear transient dynamic analyses. In this simulation, the projectile was modeled as a rigid body, while the soil was modeled as an Eulerian domain. During the analysis, the projectile penetrated the soil and created a cavity. Figures of the simulation results are shown below.
