Response prediction and verification for PCB with package due to thermal and random vibration coupling effects

Abstract

The printed circuit board (PCB) subject to vibration and thermal couple loading is of great interest. This work presents both theoretical analysis and experimental verification for the PCB in heating condition subject to random vibration. The designed heating pad is used as the heating source attached to the package on PCB by providing constant temperature inputs. The calibrated finite element model of PCB in fixture condition is employed to perform thermal analysis for the PCB subjected to the fixed high temperature at the package surface. The thermal response of the PCB can be determined, and thus the spectrum response analysis of the PCB including the thermal effect for random excitation according to JEDEC specification is carried out. The temperature distribution over the PCB in heating condition is monitored by the digital infrared thermography and compared with that of finite element analysis (FEA). The acceleration spectral responses on the PCB during random vibration test with thermal effect are also recorded. Results show that the predicted temperature distribution for the heated PCB and acceleration response due to thermal and random vibration compound loadings agree reasonably between the FEA and experiments. The stress fields on the PCB subject to the thermal input and random vibration excitation can then be obtained and evaluated for its possible fatigue failures due to the compound loading effects. This work presents the analytical solutions via the commercial FE code for the PCB subject to compound loadings for thermal input and random vibration excitation. The predicted results are well validated by comparing with experiments. The developed methodology will be beneficial for further study of PCB and its package reliability in considering both thermal and vibration inputs simultaneously.