An approach to life consumption monitoring of solder joints in operating temperature environment

This paper elaborates the 3T-approach to life consumption monitoring of solder joints in operating temperature environment without requiring simplification of operating loads. An overview of the 3T-approach is provided including assumptions made for a proposed realization in an avionic application. Associated implementation routines are highlighted and exemplified for a lead-free PBGA256 package with creep strain energy density (SEDcr) as damage metric. Factors that affect the prediction accuracy are investigated. A data resolution has been determined that delivers response surfaces that provide results comparable to 3-D finite-element (FE) simulations, while bearing two orders of magnitude higher computational efficiency. A stress-free temperature modification routine is proposed and proves to further mitigate accuracy problems.