EFFECT OF DROP ANGLE VARIATION AND RESTRAINT MECHANISMS ON SURFACE MOUNT ELECTRONICS UNDER HIGH G SHOCK

摘要

Defense and Aerospace applications increasingly rely on commercial off-the shelf electronics. Electronics in defense applications may be exposed to harsh environments including high-g acceleration loads. The horizontal board configuration is most frequently tested. However, other shock orientations may be more damaging depending on technology and design. The out-of-plane displacement and strain values highly depend on the angle of shock on the electronic components in the printed circuit board. The effect of variation in drop angle under high G conditions, and efficacy of supplemental restraint mechanisms on the reliability have not been studied at high-g acceleration loads in the range of 10,000g-50,000g. In this study the reliability of fine-pitch electronics and large 3640 capacitors with COG dielectric has been studied in presence of potting compounds, different shock orientations. A circular printed circuit board has been designed with daisy-chained packages. The drop angle has been varied from zero-degree to 30-degree. A drop-tower with dual mass shock amplifier has been used to achieve the desired acceleration pulse. Transient dynamic deformation has been measured using high-speed imaging in conjunction with digital image correlation.