Abstract
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.
