プラスチックスの引張破壊および圧縮破壊に及ぼす変形速度と環境温度の影響

抄録

The effect of deep freezing on the fracture behaviors of solid polymers has been investigated experimentally as a fundamental study of industrial cryogenic crushing operation.
The mechanical properties of polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC) are found to be critically dependent on the temperature (-180∼+120°C) at which they are deformed, as shown by the following equations (1)∼(3), but are independent of the strain-rate at which they are deformed, in the range of crosshead speed about 0.5 to 500mm/min. The values of true breaking stress σ_Bc, and breaking strain ε_Bc at the ductile-brittle fracture transition temperature T_c are the material-constants.
σ_B/σ_Bc={1-e^-(Tc/T)2}/(1-e^-1) (1)
ε_Bc/ε_B={1-_e^-(Tc/T)3}/(1-e^-1) (2)
ε_y=ε_B0=(1-e^-1)·ε_Bc=0.6321ε_Bc (3)