Equivalent Modeling And Solder Joint Strain Prediction Of Printed Circuit Boards With In-Line Components

Accurate modeling of component-containing boards are the basis for analysis and optimization of their dynamics.As an important component on the circuit board,the existence of in-line components affects the dynamic characteristics of the circuit board.At the same time,its solder joint connection with the board is also affected by external shock and vibration.Dynamic characteristics and solder joint connections are the direct acting factors for the reliability of the boards with in-line components.Therefore,these two aspects are the research focus of dynamic analysis of electronic components.The mechanical properties of the boards with in-line components were studied from two aspects in this paper,: dynamic characteristics and the stress level of solder joint connection.In order to improve the simulation accuracy of the dynamic characteristics of the component circuit board,the finite element model of circuit boards was modified firstly.Due to the complicated material composition of the circuit board,the material of the circuit board was regarded as an-isotropic and isotropic respectively for modal analysis,and the elastic modulus and other parameters were modified with the experimental frequency as the objective.The correction results of the two board modeling methods were verified and compared by static analysis and strain experiments.Considering the influence of the in-line components on the dynamic characteristics of the whole circuit board,the finite element modeling methods of the circuit board with in-line components were studied,and each modeling method was optimized with the experimental frequency as the target.The modeling methods were applied to other circuit board with in-line components to complete the whole process from the modeling and modification of the circuit board to the modeling of the circuit board with components.Aiming at the strain distribution research of solder joints,the similarity theory and research method were applied to the deformation research of micro-structures of electronic components.The similarity criterion of epoxy resin board,which is PCB substrate,was derived by dimensional analysis method,and the similarity criteria were verified by the modal experiment and the strain test.Considering the similarity criteria validated by finite element analysis,the effects of two common finite element modeling factors on the similarity relationship were studied.The similarity relationship of the strain of the in-line component solder joint under static load was verified by the finite element analysis method.A scheme for predicting the strain of solder joints based on similarity theory was proposed,and the shortcomings were pointed out.The similar structure of the circuit board with in-line components was designed and made based on similarity theory and model test.The material parameters of main components were modified hierarchically to improve the simulation accuracy of the similar structure.Taking the solder joint of the similar structure as the research object,the modeling method of weld seams and solder joints were studied.The reliability of the modeling was verified by static experimental results.At the same time,the strain distribution characteristics of solder joints were studied by means of modeling simulation and strain experiment.Based on the assumption that the strain transfer rate was consistent,combined with the strain experimental values,the joint strain samples were predicted.According to the sample data of the solder joints,the interval estimation of the mean value of the solder joint strain at a certain confidence level was completed.