Steel and aluminum have been used for different parts of military vehicles for many years. One component of particular interest to be made of aluminum rather than steel is the vehicle hull because the same level of protection could be achieved at a lighter weight. A rectangular surrogate vehicle finite element model was built to study the hull deflection when a steel or aluminum hull was present at various thicknesses and exposed to a blast loading event. The thickness of the side walls in the model was also studied to determine if it had an effect on the hull deflection. Based on the results and trends of the material and side wall studies conducted, a more robust surrogate finite element model could be built that more closely represented the weight and size of a standard military vehicle.