軟化セルロイドの２軸クリープ変形 応力反転と除去がある場合のベクトル的性質

Abstract

The biaxial creep deformation behavior of celluloid softened by heating was tested under various stress patterns which consisted of loading, unloading and stress reversal processes. The results obtained in the experiments are summarized as follows.(1) Just after the abrupt change of stress pattern, the stress vector shifted its direction from that of creep strain increment vector. Their directions became coincided with each other with the lapse of time.(2) The angle between these two vectors became large during the partial unloading process.(3) As the stress level became high, the length of the creep strain curve up to the point where the directions of both vectors coincides became long.(4) Under the stress reversal, the variation of the corresponding creep strain component became especially large.(5) For the stress change with a mirror image pattern, the isotropic characteristics of creep deformation appeared as the number of stages increased.