自然歪理論を用いて測定された予変形後の繰り返し荷重下での塑性変形挙動

（大きな剪断変形後の一定応力幅の繰り返し荷重下の歪挙動について）

抄録

The purpose of this study is to make clear the strain behavior obtained under cyclic loads after applying large pre-deformations on the basis of the Natural Strain theory. In our previous study, using the test specimens made of tough pitch copper which is already applied large pre-deformations of tension, shear, and combined load of them, the yield stresses with increase of the number of cycles have been investigated. As for yield phenomena in these studies, the decreasing tendency of yield stress has been mainly investigated under the condition of constant strain amplitude. Hence, detail studies under constant stress amplitude have not been done in our previous study. Therefore, in the present study, focusing on the pre-deformation of simple shear which is applied stress in the reverse direction with various values after large simple shear in the forward direction, the strain phenomena under cyclic loads are examined under constant stress amplitude.