| Summary: | 碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 94 === With the electronic packaging towards the rapid development of lead free process, the related research on the portable electronic devices subject to impact load is emphasized urgently. At present, the failure modes of fracturing in IMC layer and fracturing on IMC/solder boundary are mostly encountered due to drop test and cyclic bending test respectively. The purpose of this work is to use 3D numerical analysis software ANSYS/LS_DYNA, that were found to be a suitable numerical model for further analyzing the impact fracture of lead-free solder. The relationship between simulation and ball impact test system was compared and the effects of variable parameters on solder balls subjected to impact loading was investigated. Also, the transient deformation and fracturing of solder joints subjected to the impact load were studied numerically and experimentally. Then, the transient response and the failure modes of the solder joint due to impact load were predicted by varied strain rate tests.
From the numerical results, the strain rate mechanical properties of solder joint due to high can be effectively obtained. The difference of IMC strength caused three kinds of failure modes of the solder ball, however the failure mode of fracturing in IMC and a party of solder requires a model to simulate with more refined meshes. Different velocities affected the numerical results significantly. The higher the velocity of impact test applied, the lower the impact loading received. That is mainly attributed to the material parameters adopted of a solder ball is strongly dependent on the strain rate considered. Also, it is found that the impact test in reality does not result in a shear-dominant failure mode. While using dynamic simulation instead of the experiment, the damage process of solder joint can be observed. That provides a good reference and contrast for the experimental work in the future.
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