Dynamic response of bolted armored vehicle bodies under blast loading conditions

Today’s military armored vehicles have weak occupant protection against improvised explosive device (IED) impacts. This paper investigates a bolted armor vehicle body structure utilizing ultra-high-strength steel (UHSS) panels. Compared to traditional welded structures, this design enhances production efficiency and reduces manufacturing costs. This study conducted a 6 kg TNT underbody blast test on the aforementioned bolted vehicle body according to AEP-55 and NATO 4569 standards. A corresponding finite element model was established to simulate the 6 kg TNT underbody explosion. The simulation results, including structural failure locations and acceleration responses during the blast event, were compared with experimental data, validating the accuracy of the full-vehicle nonlinear model. The simulated structural failure locations and acceleration responses were compared with experimental results, validating the accuracy of the nonlinear full-vehicle model. Furthermore, the stress distribution of the bolted armor body (without additional mine-protection components), bolt stress-strain behavior, and failure modes were analyzed under underbody and side blast scenarios. Results indicate that under 2 kg TNT underbody blasts and 10 kg TNT side blasts, the bolts remained intact, but the panels reached their load-bearing limit. Thus, the proposed bolted armor body structure can effectively replace traditional welded designs. By employing higher-strength armor steel, it significantly enhances the survivability of combat personnel in battlefield environments.