Optimal Placement Of Damping Materials In Vibration Isolator

The vibration isolation technique of payload attach fitting (PAF) refers to inserting isolators or the isolating PAF between the satellite and the launch vehicle to isolate the satellite axial/lateral vibration without any alterations of the existing satellite structure. The use of this vibration isolation technique can reduce the launch-induced dynamic loads and the quality control costs of the satellite, and to improve the satellite reliability during launch.In the introductory section, existing research work on the vibration isolation techniques is presented and discussed in detail. The theories and numerical methods for the dynamic analysis of structures with non-classical damping and topology optimization of continuum structures are discussed in the second chapter. In the next chapter, dampless system and the proportionally-damped system for the dynamic process are discussed, and then the structural displacement response of structures with non-proportional damping with respect to the damping material density under the harmonic excitation is studied. The complex modes of the reduced-order system are used when evaluating the dynamic response. Two sensitivity analysis schemes, the direct method and adjoint variable method, are employed and the efficiency of both algorithms is compared in the Chapter four. The numerical results show that the adjoint variable sensitivity analysis method is much more efficient than that of the direct method when a great number of design variables are involved. In the fifth chapter, a method similar to the SIMP is proposed for the topology optimization damping layers of structures. The numerical results have shown that the present optimization method is valid and effective in the layout design of the damping layer in a vibration isolator system.