Random vibration test for electronic assemblies fatigue life estimation

In this study both finite element modeling and experimental techniques are employed to study the reliability of electronics components under random vibration loading conditions. A fatigue life estimation procedure, that would help analyst to make relatively accurate prediction of induced fatigue life, Finite Element model of the test vehicle is built using ANSYS software. The model is first validated by correlating the natural frequencies, mode shapes and transmissibility functions from simulation with experimentally measured ones. The model is then used to simulate both sinusoidal and random vibration tests to obtain the stress and the response spectrum at critical solder interconnects respectively. Results show that the corner solder ball experience the highest stress level under both tests, hence averaged stress at this solder ball was used the construct the S-N curve of the solder material and later to calculate the fatigue life using Steinberg method. A comparison between simulation and experimental results is conducted at the end and a good correlation is obtained.