The end bosses are machined from aluminum alloy 6061-T651X extruded bar certified to ASTM B 221. Typical properties for this material are provided in Table 4. The end bosses are anodized to provide a galvanic barrier.
Table 4. Properties of 6060-T651X Aluminum Alloy
Wind Angle, deg
The composite shell is a multi-layered, angle-plied laminate structure produced by filament winding a continuous band of resin impregnated roving over the polymer liner. The design role of the composite shell is to resolve internal pressure loads and to provide the general strength and durability of the tank. The laminate architecture of the composite shell is shown in Table 5. Nominal wall thickness of the composite shell is 0.43 inch.
Table 5. Composite Shell Layer Architecture
The composite material is a continuous glass fiber-reinforced epoxy and is the load-carrying element of the tank. Glass fiber provides exceptional strength, lightweight construction, and durability. Glass roving is Owens-Corning 158B Type 30, with the trade name AdvantexTM. This material has improved corrosion resistance and environmental stability over previous forms of E-glass. Fiber volume fraction in the laminate is 55 to 60 percent. Typical properties for these materials are provided in Table 6.
Roving is a collection of several individual fiber threads
Alternative Underground Propane Tank Materials, Phase II—Final Report
September 2009 Battelle and Lincoln Composites