Vibration Performance Test And And Analysis Of Printed Circuit Board Of Data Acquisition Instrument

The vibration of data acquisition instrument has an important influence on the reliability of its internal printed circuit board.In this paper,experimental modal analysis and theoretical modal analysis of a printed circuit board of a power data acquisition instrument are studied.The excitation and response signals are collected by DASP software,the modal parameters are obtained by analyzing the collected data.In theoretical modal analysis,the finite element model is established by Hypermesh finite element software,the modal parameters are calculated by Lanczos algorithm.The main contents of this topic can be divided into the following parts.1.This paper refers to the relevant literature and introduces the current situation of research method of printed circuit boards at home and abroad.2.In this paper,the theoretical basis,analysis flow and parameter identification methods for experimental modal analysis and theoretical modal analysis are introduced,the research objectives of printed circuit board is briefly introduced.3.The modal tests of printed circuit boards under both free and constrained conditions are carried out by single-point input and single-point output signal acquisition.In the free-state modal test,the excitation and response signals can be collected completely by using the 4-fold basis time-varying basis technology and the modal parameters can be identified by the least square complex frequency domain method.Constrained state test,using 1g sinusoidal sweep excitation printed circuit board,the frequency response function was analyzed to obtain the modal frequency.The dynamic characteristics of printed circuit boards are obtained through experimental modal analysis and the modal test method is mastered.4.Material mechanics experiments are used to obtain material parameters of PCB and prepare for theoretical modal analysis.The modulus of elasticity is calculated by changing the force and displacement of the bending test.Torsional force and displacement were measured and shear modulus was calculated.Poisson's ratio is calculated according to elastic modulus and shear modulus,which is compared with Poisson's ratio obtained by electrical measurement method and the feasibility of bending and torsion tests also verified.5.Using the hypermesh finite element software,the 2D and 3D mesh models were established respectively,and the Lanczos algorithm was used to calculate the modal results in the free state and the constrained state.The analysis results of the two models are compared with the experimental modal analysis results to determine that the 3D mesh model is closer to the PCB substrate,and the accuracy of the model is further verified by the Modal Assurance Criterion(MAC).For the 3D model mesh size optimization,the mesh size was reduced to 1.1mm and 0.7mm respectively.It was found that the free state modal analysis results did not change much when the mesh size was reduced to 0.7mm,but the constraint state modal analysis results.The error with the test results is smaller.