Creep, Fatigue and Fire Resistance of Chemical Resistant Tank Sandwich Cores

Three important engineering parameters in the design of sandwich com posite chemical resistant tanks (i.e., flat sided tankage or externally loaded cylindrical tanks such as buried tanks or vacuum tanks) are creep, fatigue and fire resistance. In this study, the creep properties of end-grain balsa (EGB), hexagonal honeycombs constructed of aluminum or aramid fiber-paper and PVC cores were compared. In reverse bending fa tigue, properties of EGB and PVC cores were compared. Results indicate that EGB and 9.0 1b. Nomex honeycomb are the only cores investigated capable of operation at both room temperature and 160°F (71 °C). Further EGB has a fatigue limit 2 to 2.4 times that of PVC cores. While EGB by itself is an ASTM E-84 Class 2 material, with the proper skins and resin system, it can meet Class 1 requirements.