A constitutive model for lead-free solders considering the damage effect at high strain rates

The rate-dependent Johnson-Cook material model can predict the stresses and strains of lead-free solder when the strain rate is relatively low (600 s^-1). At higher strain rates (1200 s^-1 or above), the stress-strain curves predicted by Johnson-Cook model do not agree well with the experimental results when the strain exceeds a threshold value. In this paper, the damage effect is considered into the impact process of lead-free solder specimens.