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Predicting fracture of solder joints with different constraint factors
Author(s) -
Nourani Amir,
Mirmehdi Sadegh,
Farrahi Gholamhossein,
Soroush Farid
Publication year - 2019
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/ffe.12920
Subject(s) - materials science , soldering , fracture (geology) , joint (building) , composite material , deformation (meteorology) , strain energy release rate , cohesive zone model , structural engineering , engineering
Double cantilever beam (DCB) specimens of 2.5‐mm‐long SAC305 solder joints were prepared with thickness of copper adherends varying from 8 to 21 mm each. The specimens were tested under mode I loading conditions (ie, pure opening mode with no shear component of loading) with a strain rate of 0.03 second −1 . The measured fracture load was used to calculate the critical strain energy release rate for crack initiation, J ci , in each case. Fracture behaviour showed a significant dependence on the adherend thickness; the J ci and plastic deformation of the solder at crack initiation decreased significantly with increase in adherend thickness. This behaviour was attributed to changes in stress distribution along the solder layer when the adherend thickness was varied. The capability of J ci as a property was then assessed to predict the fracture load of solder joints in specimens with different constraint levels caused by variations in adherend thicknesses. In light of the results obtained, a cohesive zone model (CZM) was developed to predict the fracture load of solder joints as a function of adherend thickness. Finally, a CZM with a single set of parameters was established to predict the fracture loads for all the cases. It was concluded that CZM was a better methodology to account for changes in degree of joint constraint imposed by bonding adherends.