@Article{cmc.2014.040.165,
AUTHOR = {D.S.Liu, C.L.Hsu},
TITLE = {Optimization of Johnson-Cook Constitutive Model for Lead-free Solder Using Genetic Algorithm and Finite Element Simulations},
JOURNAL = {Computers, Materials \& Continua},
VOLUME = {40},
YEAR = {2014},
NUMBER = {3},
PAGES = {165--178},
URL = {http://www.techscience.com/cmc/v40n3/33469},
ISSN = {1546-2226},
ABSTRACT = {To ensure the reliability of microelectronics packages, the high strain rate deformation behavior of the solder joints must be properly understood. Accordingly, the present study proposes a hybrid experimental / numerical method for determining the optimal constants of the Johnson-Cook (J-C) constitutive model for 96.5Sn-3Ag-0.5Cu (SAC305) solder alloy. In the proposed approach, FEM simulations based on the J-C model are performed to describe the load-time response of an SAC305 ball solder joint under an impact velocity of 0.5 m/s. The optimal values of the constitutive model are then determined using an iterative Genetic Algorithm approach based on a comparison of the simulated load-time response and the experimental load-time response. The optimality of the optimized constants is demonstrated by comparing the experimental and simulation results for the load-time curves under impact speeds of 0.3 ∼ 1.0 m/s. It is shown that a good agreement exists between the two sets of results for all values of the impact speed. In other words, the results confirm the validity of the proposed hybrid approach as a means of evaluating the high strain-rate response of lead-free solder.},
DOI = {10.3970/cmc.2014.040.165}
}