Failure site transition in Pb-free solder joints caused by manufacturing variabilities in BGA and MLF components in low cycle fatigue analysis

2010 ◽  
Vol 37 (3/4) ◽  
pp. 312 ◽  
Author(s):  
Leila J. Ladani
Keyword(s):  
Solder Joints ◽  
Low Cycle Fatigue ◽  
Fatigue Analysis ◽  
Cycle Fatigue ◽  
Free Solder ◽  
Failure Site

A Study on Strain Concentration Around V Notch in Lead Free Solder Material and the Low Cycle Fatigue Life

2015 ◽  
Author(s):  
Takashi Kawakami ◽  
Takahiro Kinoshita ◽  
Hirokazu Oriyama
Keyword(s):  
Fatigue Life ◽  
Solder Joints ◽  
Low Cycle Fatigue ◽  
Lead Free ◽  
Design Rule ◽  
Lead Free Solder ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Test Pieces ◽  
Free Solder

Solder joints are sometimes opened under thermal cyclic loads as low cycle fatigue phenomena. The fatigue crack is usually initiated around the edge of the interface where stress and strain very severely concentrate, having stress strain singularity. In this study, Sn-3.0Ag-0.5Cu test pieces with V shape notch were supplied to low cycle fatigue tests at 100°C. And inelastic stress strain simulations, which were based on time-dependent non-unified material model, were carried out under several cyclic load levels to obtain strain distributions around the bottom of the V notch. By results of fatigue test and inelastic simulation, the depth from the bottom of the V notch, where the strain range agrees with the prediction of the fatigue life based on smooth test pieces on Coffin-Manson rule, was investigated as the mechanical design rule for lead free solder joints.

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