ポリプロピレンの応力-ひずみ曲線 (過応力論による検討)

抄録

The linear theory of viscoelasticity has been well formulated and successfully used. In comparison, however, the nonlinear viscoelastic-plastic behavior at finite strains is less understood because of several complexities peculiar to the polymer solids. In order to investigate a nonlinear constitutive law in polymers, torsion and compression tests were performed to reveal the effect of the strain rate, temperature and hydrostatic pressure on the stress-strain relations of polypropylene rods. The experimental results were compared with the numerical calculations based on an overstress theory. The overstress theory was found to be in good agreement with the experimental stress-strain behaviors, provided that the current strain is less than the previous strain.