Finite Element Modeling of Preloaded Bolt Under Static Three-Point Bending Load

The objective of this project was to develop innovative lightweight mine-protected fasteners for blast protection appliqués. Blast protection appliqués are used on tactical and combat ground vehicles as a method of deflecting or mitigating the effects of anti-vehicular mine blasts or attack by Improvised Explosive Devices (IEDs). A critical and weakest component of these appliqués is the fastener joints. Currently, industrial bolts are commonly used for attaching blast protection appliqués to vehicles due to simplicity. However, under blast conditions, these bolts can often shear off causing secondary fragments and projectiles which may impact the vehicle and crew, causing additional damage and injury to the vehicle personnel. This study focused on conducting three-point bending tests to evaluate different bolt materials. Bolt preload or stress initialization was simulated via LS-DYNA® Implicit with two separate analyses. Also a similar two-step initial strain analysis was performed using NEiNastran. The simulated results will be compared with test data. Future work will include finite element modeling and testing of fasteners under dynamic, ballistic, and blast loads.