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Determination of passive vibration isolation characteristics of jet aircraft avionics

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2019
Eker, Zafer
Airborne electronics are subjected to adverse effects of vibration exposure that is defined by military standards to be used in the design stage. It is important to ensure the sustainability of such equipment through vibration isolation. Passive isolation mechanism distinguishes as the simplest practice for this purpose, which is applied in this study. In this thesis, a complete design of the isolation system is achieved by creating the representative mathematical model, implementing the vibration analysis followed by the optimization analysis and simulating the possible deviations of system properties. Rigid body connected to the rigid base through resilient elements is modeled with six degrees-of-freedom. Viscous damper is considered in the formulation as the damping mechanism to represent realistic conditions. It is allowed for describing the system by resilient element stiffness, damping, position and orientation of installation beside the body mass. Following the definition of spatial properties in the theoretical model, normal modes and response analysis based on random excitation are carried out. Thereafter, system of optimum stiffness and damping is searched by aiming the minimum acceleration response under pre-determined constraints in the optimization problem. Eventually, Monte Carlo simulation is performed to consider possible deviations of the system spatial properties from their nominal values during the actual application. Though the employed techniques herein are general, they are demonstrated through the application on jet aircraft avionics. Entire analysis process is applied by the developed computer code in the open software Python environment. It is also brought into use via a GUI