NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Solder creep-fatigue interactions with flexible leaded partsWith flexible leaded parts, the solder-joint failure process involves a complex interplay of creep and fatigue mechanisms. To better understand the role of creep in typical multi-hour cyclic loading conditions, a specialized non-linear finite-element creep simulation computer program has been formulated. The numerical algorithm includes the complete part-lead-solder-PWB system, accounting for strain-rate dependence of creep on applied stress and temperature, and the role of the part-lead dimensions and flexibility that determine the total creep deflection (solder strain range) during stress relaxation. The computer program has been used to explore the effects of various solder creep-fatigue parameters such as lead height and stiffness, thermal-cycle test profile, and part/board differential thermal expansion properties. One of the most interesting findings is the strong presence of unidirectional creep-ratcheting that occurs during thermal cycling due to temperature dominated strain-rate effects. To corroborate the solder fatigue model predictions, a number of carefully controlled thermal-cycle tests have been conducted using special bimetallic test boards.
Document ID
19930071653
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Ross, R. G., Jr.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Wen, L. C.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mon, G. R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Jetter, E.
(JPL Pasadena, CA, United States)
Date Acquired
August 16, 2013
Publication Date
June 1, 1992
Publication Information
Publication: ASME, Transactions, Journal of Electronic Packaging
ISSN: 1043-7398
Subject Category
Mechanical Engineering
Report/Patent Number
ASME PAPER 91-WA/EEP-27
Accession Number
93A55650
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available