| For the shock and vibration isolation of packaging products during transport, this paper takes the printing circuit board (PCB) of radiogram Feng-Huo as the object of study. The theoretical analysis methods, combined with the finite-element-analysis (FEA) technique, are utilized to solve this problem. Printing circuit board (PCB) vibration-proof packaging design principles under random excitation conditions have mainly been considered.Firstly, the variance formula of linear system under random excitation is derived by pulse response function, then the response variance is used to evaluate the vibration isolation system, and two kinds of design methods are proposed based on critical components response of the product.Secondly, a two-degree-of-freedom (TDOF) vibration-proof packaging model is established for electronic product with printing circuit board (PCB) in it, then comparison of its vibration response with the response of single degree-of-freedom model. Results showed that TDOF model can be more appropriate. Meanwhile, this paper also proposed substitute effective mass for actual mass of PCB in simplified model, then the model may be more accurate and dependable.Thirdly, PCB vibration analysis is achieved by using ANSYS software, FEA software. The vibration response of PCB and simplified model subjected to random excitation are compared, their power spectral density (PSD) curves are in coincidence at the first natural frequency. The simplified model is established with an effective mass. The result shows that the substitute effective mass for actual mass of PCB are suitable. In this paper, the vibration response of TDOF is analyzed by use of the programming language APDL of ANSYS software, the PSD curve, transfer function and acceleration root-mean-square value of PCB are obtained.The research work and achievements in this paper supplies the insufficiency in the field of electronic products packaging and has a theoretical direction for the vibration-proof packaging design.
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