MILITARY VEHICLE UNDERBODY ARMOR PLATE ATTACHMENT STUDY

In this paper a new bolt attachment method was explored, where the attaching bolts were divided into two sets. The first set of bolts was tightened and was used to connect the underbody plate to the hull under ordinary operations. The second set of bolts connecting the plate and the hull were not tightened and had some extra axial freedom. Under blast loading, the first set of bolts would break due to high tensile and shear loads, but the second set of bolts would survive due to extra axial freedom which allows the plate and the hull vibrate and separate from each other to a certain extent. A simulation model was developed to verify this concept. Three underbody plate-hull connection approaches were simulated and analyzed: 1) all tightened bolts, 2) some bolts not fully seated, 3) all bolts not fully seated. The simulation results show that with option 1), 100% of the bolts broke under the blast loading. With option 2) the not fully seated bolts survived and continued to attach the plate to the hull. And with option 3) all the bolts not fully seated also survived. This new concept might provide an improved approach for attaching the underbody armor plate to the vehicle hull which would enhance the occupant and vehicle survivability while reducing engineering complexity and cost.