Military vehicles sustain damaging high impacts and shock loadings due to mine blasts, projectile impacts, and frontal or rear crashes. In all these cases, the vehicle structure and the bolts used in the structure may experience high impact loads. These loads may yield or damage the structure and the bolts. Only a limited amount of published literature describes the proper method for measuring and analyzing transient shock propagation across bolted connections for high-impact loading. Understanding, modeling, and simulating the vehicle response to these impact loadings is critical to designing better vehicle components. This will also help isolate critical components such as electronics and personnel from the shock.
This paper provides a detailed experimental setup and procedure for analyzing high-impact loading on structures with bolted joint connections. An air gun was used to fire an aluminum slug at high velocities on to a bolted structure to induce medium- and high-impact loading. Two structural configurations were evaluated: a hat section bolted to a flat plate, and two hat sections bolted together. Finite element models were created to simulate the damage and shock propagation phenomena during impact. Simulation predictions from detailed 3D solid element models and 2D shell element models were compared to experimental results, including shape deformation and accelerometer data at specific locations. A load cell recording impact force was also used for validation of the simulation. The simplified FE model developed for the bolted joint structure in this report reduced the computational time by one order and can be practically implemented in the full vehicle FE model for crash or blast analysis.