Bolted joints are the most common type of fastener in army vehicles and play a very important role in maintaining the structural integrity of combat vehicles. In combat, these vehicles may be subjected to various kinds of shock loading, such as initiated by a mine blast, projectile impact, or frontal crash.
This study analyzes the transient behavior of structures with bolted joints subjected to impact or shock loads using experimental methods and Finite Element Analysis (FEA). Factors such as damping that affect the bolted joint structures for shock loading are studied. Only a limited amount of published literature describes the proper method for analyzing transient shock propagation across bolted connections for high-impact loading. The initial case study focused on a simple cantilever beam with a bolted lap joint subjected to relatively low levels of impact force. The second case study used a flat plate bolted to a hat-section. These simple configurations are representative of structures found in many military ground vehicles that can be subjected to transient impact and blast loads. These structures were subjected to low-impact loading (non-destructive) using impact hammers and high-impact loading (destructive) using an air gun. The responses were measured using accelerometers. LS-DYNA FE solver was used to simulate the shock propagation in the bolted structures.
For all the bolted structures, the modal analysis was performed both experimentally and numerically. The results are in excellent agreement for the lower modes and exhibit a small deviation in the higher modes. Secondly, the time history responses of experimental and FE analysis are compared. This is a two-part paper. In this first paper, a simplified bolted connection (bolted cantilever beam) is used for studying the low-impact shock propagation.