Influence of strain rate effect on behavior of solder joints under drop impact loadings

The strain rate dependent Johnson-Cook material model and the rate independent elastic-plastic model of lead-free solders were used to investigate influence of strain rate effect on the mechanical behavior of solder joints under drop impact loadings. Failure of the solder joints was predicted and the results were compared with the experimental observations. The strain rate effect of lead-free solders has no influence on the deflection of the PCB during the drop impact but has significant influence on the stress and strain in solder joints. The rate independent elastic-plastic solder material model always underestimates the stress and overestimates the strain of the solder joint. The material model that takes the strain rate effect into account can predict more realistic behavior of the solder joints.