Shock level prediction in the space domain using explicit FEM on a simplified case study

Accurate prediction of mechanical shock levels before physical testing is essential for space system design and validation. Current modeling methodologies in the space industry are insufficiently mature, necessitating investigation and comparative analysis of alternative numerical approaches. Among these, the Finite Element Method (FEM) with explicit time integration, though less common in this domain, shows promise due to its adaptability in handling complex modeling. To establish a robust prediction methodology, a simplified test case—a stand-alone plate with a bolted dummy impacted by a steel ball—was analysed. Parametric studies were conducted on the numerical models, with results evaluated against experimental data using Shock Response Spectrum (SRS) and acceleration time histories. This study enables the development of a comprehensive shock analysis model by establishing modeling guidelines mostly based on SRS specifications, while incorporating novel approaches. The study presents core findings such as the feasibility of simplifying accelerometer modeling, recommended values for mesh element size, calculation and data extraction time steps, bulk viscosity and most importantly, the interface modeling. Guidelines and new approaches are provided for interface modeling based on strategic modeling choices such as the definition or omission of contact and preload, and based on the contact surface area ratio between the two components compared to the fixing sections.