Finite Element Analysis And Optimization Of Printed Circuit Board

During transporting, storing and handling, electronic equipments will be subjected to vibration and shock which can produce many different types of failure. Printed circuit board (PCB) is a key part of electronic equipments, and many flaws of electronic equipments originate from PCB. So the reliability of PCB is very important. In order to gain high reliability, when designing PCB these questions must be considered: Whether the first natural frequency of PCB is large enough or not? What are the dynamic characteristics of PCB and where are the weak points of PCB? How to improve its reliability?In this thesis, the PCB of a computer power supply is regarded as the specific object. Dynamic analysis and vibration fatigue analysis of this PCB are implemented based on finite element method. The PCB is optimized to improve its reliability. The main contents are as follows:1. Modeling of the PCB. It is the first step of finite element analysis. Because the PCB is difficult to model in detail, some simplifications are done. According to the usual finite element modeling methods used for PCB, the finite element model is created.2. Verifying the finite element model. Though the finite element model is created, dynamic analysis can't be carried out directly. Because the process of finite element modeling may be wrong, or the finite element model may be unreasonable, the finite element model must be verified first. To verify the process of finite element modeling is correct, static analysis is carried out. The results of static analysis show that the deformation of PCB is reasonable, so the conclusion that the process of finite element modeling is correct can be drawn. To verify the finite element model is reasonable, the modal parameters of PCB are calculated separately by experimental and finite element modal analysis. The results show that the consistency of simulation and experiment is not very good. So the finite element model is modified.3. Dynamic analysis and vibration fatigue analysis. Modal analysis, frequency response analysis, random vibration analysis and vibration fatigue analysis are carried out based on the modified finite element model. The first natural frequency of PCB is 57 Hz, and the dynamic response in the first natural frequency is the largest. Weak points are also found.