Mixed-mode fracture load prediction in lead-free solder joints

Siva P.V. Nadimpalli, Jan K. Spelt

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Double cantilever beam (DCB) fracture specimens were made by joining copper bars with both continuous and discrete SAC305 solder layers of different lengths under standard surface mount (SMT) processing conditions. The specimens were then fractured under mode-I and various mixed-mode loading conditions. The loads corresponding to crack initiation in the continuous joints were used to calculate the critical strain energy release rate, Jci, at the various mode ratios using elastic-plastic finite element analysis (FEA). It was found that the Jci from the continuous joint DCBs provided a lower bound strength prediction for discrete 2. mm and 5. mm long joints at the various mode ratios. Additionally, these Jci values calculated from FEA using the measured fracture loads agreed reasonably with Jci estimated from measured crack opening displacements at crack initiation in both the continuous and discrete joints. Therefore, the critical strain energy release rate as a function of the mode ratio of loading is a promising fracture criterion that can be used to predict the strength of solder joints of arbitrary geometry subject to combined tensile and shear loads.

Original languageEnglish (US)
Pages (from-to)317-333
Number of pages17
JournalEngineering Fracture Mechanics
Issue number2
StatePublished - Jan 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


  • COD
  • Crack tip opening displacement
  • Critical strain energy release rate
  • Elastic-plastic finite element analysis
  • J-integral
  • Lead-free solder
  • Mixed-mode fracture
  • Strength prediction


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