| Summary |
ETFE film has excellent transparency and weather resistance, and is increasingly being used for the roofs and outer walls of flora and fauna, stadiums, and buildings. ETFE film has lower strength and rigidity than film materials with woven fabric, and when stress exceeds the yield point, large plastic deformation occurs. In addition, it is indispensable to properly consider the properties peculiar to the film in the design, such as creep and relaxation becoming remarkable at a stress degree of 1/2 to 2/3 or more of the yield point at room temperature. In this paper, we compare the mechanical properties of two types of ETFE films with different elongation properties, and then consider their effects on the structural behavior of the film structure. TYPE-X modified by changing the composition of ETFE polymer has higher transparency than TYPE-N, and the stress level (proof stress) at the same strain is about 15 to 50% higher. In particular, the stress level before and after the first yield point is about 1.5 times, and even when a curved structure such as an air cushion receives an external force such as wind pressure, it is possible to exert about 1.5 times the proof stress.
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