| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 97 === This thesis studies mainly the random vibration of PCBs (Printed Circuit Boards) equipped on the electronic products excited by random acceleration excitations. In the analysis, the elastic modulus and the gasket stiffness of the support of PCBs are assumed to be random parameters. The PCB is considered as a thin elastic plate element, and the electric element amounted on it is a spring-mass system. The gasket between the PCB and chassis can be made of visco-elastic materials, which behave as the linear spring and damping. First, the equations of motion of a multi-degree of freedom system are derived assuming the PCB to be rigid. Next considering the PCB as a thin elastic rectangular plate with random parameters, the equations of motion of the continuous system are derived by using the modal expansion and perturbation method. The mean square responses of the PCB under the white and non-white process acceleration excitations are evaluated by using a recursive algorithm, and the autocorrelation function of the PCB’s deflection and its steady state mean square value are formulated in the frequency domain. Several numerical examples are illustrated to study the effects of random parameters on the deflection of the PCB. The numerical results are also compared with those using the Monte Carlo simulation, and the excellent agreement between the two results is obtained.
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