Dynamic modal analysis and optimization of C-130 Project Oculus' mechanical arm/pod sensor deployment system using the finite element method.

摘要

The Department of Defense (DoD) and the United States Army National Guard (USARNG) have sponsored West Virginia University's Center for Industrial Research Applications (CIRA) to design, fabricate, test and optimize an articulating, mechanical arm/pod system. The mechanical arm/pod system will be designed to accommodate a 500-pound sensor payload deployable in flight from a C-130 Hercules military aircraft used for counter narco-terrorism efforts. During the overall deployment (translation and rotation) of the mechanical arm/pod system and in the final resting position for optimal operating conditions for the data acquisition sensors (DAS), the mechanical structure will be subjected to a variety of forces and vibrations from numerous sources.; Once a frequency range with assigned magnitudes is established, a formal vibration analysis will be conducted utilizing the Finite Element Method (FEM) and Modal Analysis with Pro-Engineer and Pro-Mechanica. The natural frequency modes for the mechanical arm/pod system will be computed in the x, y and z directions with three different geometrical configurations of the structural cross-member supports. Modifying the structural cross-members will affect the stiffness of the overall system, which in turn will vary the natural frequency range. Consequently, the goal is to design the mechanical arm/pod system as a function of mass and stiffness in order to increase or decrease the natural frequencies of the system to ensure resonance occurs outside the general vibration profile generated from the Rake test and to ensure adequate dampening of the vibrations occurs within the sensors' vibration tolerance values to ensure optimal performance.