43. Ground Vibration Testing of the Predator B UAS with MTS Chin-Mount Structure

Ground vibration testing of a Predator® B Unmanned Aircraft System (UAS) developed by General Atomics Aeronautical Systems, Inc. (GA-ASI) was performed to validate analytic models and assess local and global structural dynamics. The aircraft was fitted with a unique sensor package: an up-looking turret chin-mounted on the forward fuselage. This sensor and its support structure participated in the global aircraft modes and required application-specific approaches to excite and measure all target modes. Specifically, testing was required to assess the structural dynamics of the chin-mount integration with a focus on any coupling with the airframe or strong local modes, either of which could potentially affect sensor performance. A combination of electrodynamic shaker positions, excitation types, and impact hammer inputs were employed to identify the modes of interest. A free-free boundary condition was simulated by suspending the aircraft overhead with a flexible bungee suspension.