Axial-and diametral-strain-controlled low-cycle fatigue tests were performed on carbon and low-alloy steels with both an axial and a diametral extensometer mounted on the same cylindrical specimen. The results obtained are summarized as follows. (1) Young's modulus, E, under cyclic plastic deformation was given by E=σ
a/ε
l<ea>=σ
a/(ε
l<ta>-ε
l<ea>), where σ
a is stress amplitude, and ε
l<ea>, ε
l<ea> and ε
l<pa> are total, elastic and plastic strain amplitudes in the axial direction, respectively. E was nearly equal to 206 GPa when ε
l<pa>=0, while it decreased with increasing ε
l<pa>. (2) Poisson's ratio for elastic and plastic strain, υ
e=-(ε
d<ea>/ε
l<ea>) and υ
p=-(ε
d<pa>/ε
l<pa>), were nearly equal to 0.3 and 0.5, respectinely, where ε
d<ea> and ε
d<pa> are diametral elastic and plastic strain amplitudes. (3) Strain-fatigue life properties for axial and diametral strain-controlled tests were coincident each other when the axial strain was calculated from the measured diametral strain through an equation of tranformation on the assumption that E=206GPa, υ
e=0.3 and υ
p=0.5.
抄録全体を表示