Research on vibration reliability of solder joint based on modal experiment of PCBA

This paper investigates the dynamic behavior of printed circuit board assembly (PCBA) and the reliability of board-level solder joints under thermal–vibration combined load through modal experiments and finite element (FE) analysis. Firstly, a combination of free modal test and FE simulation was adopted to obtain the equivalent material parameters of bare printed circuit board (PCB), which were utilized in the FE modeling of PCBA, and the effectiveness of the FE model was verified by experimental modal analysis. Modal tests and simulations were performed at different temperatures (22 ℃, 60 ℃) to investigate the effect of temperature on the dynamic behavior of the PCBA. Then, narrow-band random vibration simulations with constant acceleration power spectral density (PSD) amplitude were conducted on the PCBA at different temperatures. Finally, the Steinberg model was adopted to predict the vibration lifetime of the weakest solder joint. The results indicate that modal analysis is an effective method for establishing FE models of PCBA, and the temperature change significantly affects the dynamic characteristics and vibration reliability of PCBA. As the temperature changes from 22 ℃ to 60 ℃, the natural frequencies of PCBA decrease. The stiffness of the PCBA decreases as the temperature rises, leading to increased vibration deformation of the PCBA and larger stress and strain in the solder joints and PCB. Furthermore, under vibration load, the fatigue life of the solder joints is reduced by 32% due to the increasing temperature.