In the previous paper, the authors had formulated a method of FEM modeling which could be applied to coupling analysis of liquid to structure in various FRP cylindrical liquid storage tanks. We employed multi-point constraint equations in the FEM and found that the simulation coincided well with the experimental results. In this paper, the effects of design parameters of FRP cylindrical liquid storage tanks on bulging frequencies are presented. The design parameters, such as a ratio of height/radius, circumferential stiffeners, Young's modulus of FRP, a radius of filet and a thickness distribution along the height are considered. As a result, the design criteria for avoiding the bulging frequencies to market sizes of FRP cylindrical liquid storage tank are presented and their structural safety is demonstrated under Kobe earthquake load.

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The interface-less composite of PE/PE was made by using the UHMWPE as braided fabric sandwiched between L-LDPE sheets. The effect of the fabrication condition on the tensile performance was estimated. As the fabrication conditions, fabricate temperature and compression time was chosen. At high fabricate temperature, the braided fabric melted. For long compression time, the braided fabric was damaged by heat. As a result, the suitable fabrication condition was found. Then, the effect of the attached tension for molding or the emulsion treatment before molding on the tensile performance was estimated. The tensile modulus and the tensile strength of the tension attached specimens are larger than that of the specimens without tension attached for molding. The tensile modulus and the tensile strength increase with the increase of the emulsion condensation. These effects was related to the bonding strength between the PE sheet and the PE braided fabric. Finally, the tensile strength of PE/PE composites was compaired to the PE/Epoxy composites. Although the strength of the PE/PE composites is 80% of PE/Epoxy, the strength of PE/PE composites can be equal or larger than that of PE/Epoxy by a tension attached for molding or by a emulsion treatment before molding.

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