| Popis: |
This chapter is concerned with establishing the fatigue resistance of solder joints through a strain-life equation. Owing to the high sensitivity of solder joints to strain rate, such a relationship ought to be generated at the relevant amplitude and frequency, which is beyond the capability of a standard mechanical tester. This chapter reports the generation of the strain-life of solder joints at cyclic frequencies up to 150 Hz using a specially designed high-speed cyclic bend tester, which also allows control of the test temperature and environment. The fatigue life of solder joints has been found to decrease with increasing cyclic frequency and with decreasing temperature. The effect of strain rate has been incorporated as a rate function into the strain-life equation, similar to the creep function in creep-fatigue, to form a unified equation that facilitates design analysis. |
