Finite element analysis and optimization of stress and strain of QFN solder joints under three-point bending

Abstract

Three-point bending stress analysis was carried out on the model using ANSYS software. The single factor analysis method was used to study the influence of different factors on the stress and strain of the interconnection solder joint under three-point bending load.Use SAC305 as the solder joint material. A single factor analysis of the stress and strain of different QFN solder joint materials was carried out.With the gap height, length and width of QFN solder joints as design variables, and the stress value of QFN solder joints as the target value, 15 groups of solder joint models with different levels and combinations were designed using response surface method, and the corresponding solder joint stress values were obtained. The regression equations of welding spot stress and structural parameters are established, and particle swarm optimization algorithm is used to optimize the structural parameters of welding spot. Particle swarm optimization is used to obtain the optimal combination of structural parameters of the solder joints: the gap height of the solder joint is 0.07 mm, the length of the solder joint is 0.75 mm, and the width of the solder joint is 0.22 mm; simulation verification of the optimal solder joint shows that the maximum stress is reduced small.