数理塑性理論によるコピー用紙の引張負荷における応力-ひずみ関係の解析

抄紙方向に対して傾斜角をつけて切り出したコピー用紙を用いて引張試験を行い，応力-ひずみ関係を求めた。数理塑性理論に基づいて非線形領域における応力-ひずみ関係を相当応力-相当塑性ひずみ関係に変換し，理論の適用性について検討した。その結果，様々な傾斜角における相当応力-相当塑性ひずみ関係は互いによく一致しており，数理塑性理論が適用可能であることが示唆された。

Uniaxial tensile tests were conducted for off-axis copy paper to obtain stress-strain curves. It was shown that the stress-strain responses strongly depend on the off-axis angles. The nonlinear regions of the off-axis angle-dependent stress-strain relationships were transformed into the equivalent stress-equivalent plastic strain counterparts based on the mathematical theory of plasticity taking into account a Hill-type anisotropic yield criterion. The equivalent relationships were demonstrated to coincide almost uniquely regardless of the off-axis angles. This implied that the nonlinear stress-strain responses of copy paper can be predicted appropriately by using the mathematical theory of plasticity.