2017 年 58 巻 673 号 p. 151-155
Mechanical experiments have been performed to investigate the dynamic creasing characteristics of coated paperboard mainly used in the food packaging industry. The correlation between the time-dependent relaxation of bending resistance at a specified folded position and the dynamic release behavior of creased paperboard was experimentally investigated for a time period of 0.1-1000s. The transition of in-plane tensile stress relaxation and that of bending moment relaxation were detected in the time period of 10-30s in a specified paperboard, when using a constant deformation rate for creating the initially loaded state. We varied the stopping time of the folded state of a creased part, and analyzed the time-dependent released behavior (unfolded deformation) using the improved relaxation model, which is based on the power rule of relaxation time. The results obtained with this model show a good fit to the experimental results, and the proposed release time of the unfolding process is found to be almost independent of the stopping time.