## 3 Results and Discussion
### Comparison with Experimental Study  
Load vs. displacement plots for each standard and flute type (both experimental and FEA results) are shown in Figures 11 and 12, and ECT values analyzed from these plots are shown in Figure 13. The load vs. displacement plot of the experiment showed a lower initial stiffness region (circled area in Figure 11) potentially caused by the initial flattening and crushing of the top and bottom cutting surface. This segment of the plot was missing from the plots produced by the FEA because the FE model assumed perfect samples and could not model damage caused by the sample preparation process. When the measured ECT values were compared to the FE prediction, it was found that the FE model consistently overpredicted the measured ECT values by approximately 19 kN/m (FEFCO No.8)-43 kN/m (KS M 7063-1 method A). The difference between the measured ECT of KS M 7063-1 method A and TAPPI T 838 was small, but the measured ECT values of FEFCO No.8 were consistently less than that of KS M 7063-1 method A and TAPPI T 838: 33% less (A/F), 19% less (B/F), 27% less (AB/F), and 25% less (BB/F). This agrees with the results found by other studies; in particular, [PERSON] [21] found that there was a 31% ECT difference between TAPPI T 838 and FEFCO No.8. Based on the one-way ANOVA analysis [40] shown in Table 4, there was not a statistically significant difference  
Figure 11: Comparison of load vs. displacement plots produced by the FE model and the experiment for single-wall corrugated boards, they should be listed as: (**a**) KS M 7063-1 method A; (**b**) TAPPI T 838; (**c**) FEFCO No.8. Figure 12: Comparison of load vs. displacement plots produced by the FE model and the experiment for double-wall corrugated boards; they should be listed as: (**a**) KS M 7063-1 method A; (**b**) TAPPI T 838; (**c**) FEFCO No.8. between ECT values measured using KS M 7063-1 method A and TAPPI T 838 (\(p>0.05\)), but there was a significant difference between ECT values measured using FEFCO No.8 and the other two standards (\(p<0.05\)). Similar to the FE prediction for the KS M 7063-1 method, AB/F and A/F had greater ECT than BB/F and B/F, while for FEFCO No.8 the opposite trend was observed. For TAPPI T 838, there was a mixed trend compared to the other standards. Though the magnitude of the experimental ECT values was different from the magnitude of the values produced by the FEA, there were similar trends depending on the standards and flute type. The main cause of the difference between the magnitude of the experimental ECT and FEA ECT values have been that the connection between the liner and flute was treated as a shared node instead of the actual condition of the connection using an adhesive. It was similar to the results of FEA ECT analysis, which differed by up to 45% from the results of the experiment of corrugated paper presented in the previous study [41]. In this study, simulations were conducted under the assumption that the liner and flute are fully bonding, and the theoretical interpretation of the adhesion properties is necessary, considering that the property of the adhesive is one of the important factors determining the strength of the corrugated paperboard during the adhesion process between the liner and flute of corrugated paperboard. This difference also affected the failure mode difference between them. In the FEA, the failure mode was the localized buckling of the liner and the delamination between the liner and the flutes. However, in the experiment, delamination between the liner and flutes (mainly for KS M 7063-1 method A and TAPPI T 838) or edge crushing (mainly for FEFCO No.8) caused local buckling of the liner.