Key Techniques In The Research On The Dynamic Responses Of The Electronic Equipments

In this thesis, based on the theory of mechanical vibration and the principle in finite element method, the dynamic response of a typical structure of electronic equipments is studied with the function of ANSYS for modal analysis, transient analysis and random vibration (PSD) analysis.The emphasis is put on the key techniques in the dynamic analysis for electronic equipments. Two methods for modeling the PCBs in electronic equipments are proposed. The characters of the tandem assembly structure are analyzed in detail, also 6 different FE models of the tandem assembly structure are built with 6 different methods, the best modeling method is selected by the comparison of the modal results for the FE models. The old method, which used to determine the dynamic response under the action of time-dependent acceleration loads on the base, related with the displacement calculated from time integration, called Equivalent Displacement Method (EDM), is improved. To substitute the old method, a new idea related with inertia force is proposed, called Equivalent Inertia Force Method (EIFM), at the same time the disadvantages of EDM are conquered, also the feasibility and rationality of EIFM is shown by an example. The way with which the environments of GJB vibration tests are described in the process of FEA is developed.Finally, the FE model of an airborne electronic equipments is built by means of characterization modeling, partial nodes merging or coupling, and so on. Also the dynamic responses are calculated under the action of the environments of GJB vibration tests. Then modal analysis results, transient response results and random response results are checked and analyzed on the base of practical experience and the comparison with related test results. In the end, the conclusion is that the results are approximately consistent with the practice. The defect of the structure can be disclosed with the way of Finite Element Analysis (FEA).