| Summary |
To use ETFE films in the architecture, it is important to investigate the viscous behavior of ETFE films such as strain rate dependence, creep and stress relaxation. And, analytic methods that describe a structural behavior of ETFE films are proposed as the elastio-plastic analysis and the visco-elastic analytic method which use the visco-elastic material parameters determined in the dynamic visco-elastic experiment. In previous work, we have proposed a stretching method of film in construction, and applied the visco-plastic analytic method that has extended to plastic region. But an influence of the residual stress and strain generated in production has not been sufficiently investigated. In this paper, we investigated an influence of the residual stress and strain in a uniaxial tensile experiment of annealed ETFE film, and we calculated the stress-strain curve based on the visco-plastic constitutive equation and evaluated a validity of that. Moreover, we described a structural behavior in tensile tests of the low strain rate and also enlarged an estimative equation for relationship between yield stress and strain rate dependence.
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