Dynamic Response and Vibration Isolation of Instrument Racks

This study examines the dynamic response of instrument racks in military airborne surveillance aircraft, addressing FAA strength requirements and MIL-STD-810H dynamic loads, including random vibrations and shock impacts. Two structural assumptions are considered flexible body and rigid body. In the flexible case, numerical analysis determines modal parameters to optimize LRU placement and mitigate resonance. In the rigid body case, the rack is connected to the aircraft floor via isolators with defined stiffness and damping, analysed under one- and two-plane symmetry. A 20g, 11ms shock load is simulated, optimizing isolator properties for vibration and impact isolation. The findings enhance rack design, ensuring structural integrity and electronic functionality in airborne environments.