In the paper, the mechanical shock abilities of the three potting materials of hard material, silicone and paraffin wax for the ceramic packaging capacitors and metal packaging capacitors are investigated by mechanical shock tests. Results show that the mechanical shock resistance ability of the hard epoxy resin potting material is the strongest, and the mechanical shock resistance ability of the metal packaging component is more than the ceramic packaging. The mechanical shock resistance value of the epoxy resin potting material for metal packaging capacitors is in 20000g above.

The failure of aluminum alloy stringer on the tour airplane servicing in the coastal environment of the Fiji Islands were analyzed. Through the analysis of surface topographies and failure characteristics and the consideration of service environment, the evolvement of failure process and the failure mechanisms were analyzed. Findings showed that ultraviolet radiation, temperature, high-humidity and salt spray caused the aging failure of structure coating and then pitting corrosion occurred in the oxide film on aluminum alloy. With the ongoing corrosion along the grain boundary, intergranular corrosion appeared. When the intergranular corrosion continued developing to the adjacent layers, denudation occurred. The volume expansion effect of corrosion products caused the stress concentration on the tip of corroded area and resulted in the initiation of cracks.