An Airborne Electronic Equipment Kinetic Analysis And Thermal Stress Analysis

With the rapid development of the electronics industry, electronic equipment has been widely used in various industries, and brings ever-greater economic and social benefits. But the electronic equipment works in the circumstance subjected to temperature, vibration and shock. In order to improve the reliability of electronic equipment, thermal analysis and dynamic analysis is necessary.In this thesis thermal analysis and dynamic analysis are implemented based on the finite element method. The main contents of research are as follows:Firstly, finite element model of the case and its modules are established. This thesis analyzes the key steps in the finite element process of modeling, and studies the modeling method for circuit board of electronic equipments. To the module level, detailed modeling and mass equivalent methods are applied to establish the finite element model.Secondly, modal analysis is carried on. In the analysis process, we can't get the simulation results in the case that computer configuration is good enough and the time is long enough with traditional methods named full method, owning to the great number of elements and nodes. In order to solve this problem, this paper adopts sub-structure method. The natural frequency and mode shape of the equipment are obtained. There are little differences between the mode shape of the single modules and the module assembly modules, and the adjacent natural frequencies of the FEM model are close. These results show that the simulation of installation is correct; the natural frequencies of the FEM model are close among the adjacent nature frequencies, for the natural frequencies of several modules are close. In order to understand the dynamics of the model better, followed by the above qualified finite element models, random vibration analysis is carried on and stress nephogram is obtained. And analysis results were compared to test results to verify the accuracy of the finite element model.Finally, thermal stress analysis is carried on. The electronic equipment temperature is mutative because of the constant radiation of the power. Transient thermal analysis is applied to obtain the temperature distribution. Then the thermal units are converted to the corresponding structural units, and the obtained node temperature is applied to the model as load to analyze the structural stress. Synthesizing the results of the random vibration analysis, the comprehensive structure improvements recommendations are proposed.This thesis deals with dynamic analysis and thermal analysis of electronic equipments based on FEM. The results offer useful reference for electronic equipments structure design and PCB layout, also this method have some reference values to the design and analysis of electronic equipments. Especially, the sub-structure method has important reference value for the large-scale electronic equipments.