Equation (12) shows that the higher the amplitude of the corrugated structure, the higher the second area moment. Figure 9a shows the load-deflection curve obtained from the SCS fabricated with = 4 and 10 and the results of the second area moment derived from the results. The results of SCS fabricated with = 6 and 8 are shown in Supporting information (Figure S2). The translucent lines in the graph show the results of the three measurements, and the opaque lines show the averaged results. First, we evaluate the stiffness of the SCS fabricated with = 10 (Figure 9a(i)). The upper left of the photographs shows the SCS for = 10 with L  = 5, 10, and 15 mm. From the load-deflection curve, the higher the linewidth, the larger the slope of the initial stage, and the higher the stiffness. As a result, the second area moment also increases. Therefore, as in Equation (12), the higher the linewidth and amplitude of the SCS for = 10, the more stiff the structure with a higher second area moment. Next, we evaluated the stiffness of the structure with = 4 (Figure 9a(ii)). For the structure with = 4, there was no increase in the slope of the initial stage with the increase in linewidth, and the stiffness results had a different trend from Equation (12). In addition, although the SCS was fabricated with the same linewidth, there was a significant variation in the three tests. We found that the structural characteristics can be typical for the self-folded corrugated structures such as the SCS. The fewer the number of lines, the more expansive the line interval, and the less the corrugated structure could be maintained during the three-point bending test.
 
Figure 9b shows the stiffness distribution of the fabricated SCS. Due to the reaction between the paper and printed solution, the stiffness of the crease parts increased in the SCS. However, the stiffness of the straight-line parts connecting the creases remained low because no new components were added and no hard compression was used to process it. Therefore, if there are fewer lines, there are more straight-line parts with low stiffness; thus, there is a higher possibility of deformation during the three-point bending test. Figure 9c shows the structure with = 4 and 10 just after the end of the three-point bending test. Compared to the structure with = 10, the structure with = 4 undergoes significant deformation. Therefore, we consider that the increase in stiffness with amplitude could not be confirmed for the structure with n = 4. Thus, increasing the linewidth and amplitude is not sufficient to design an SCS with high stiffness; considering the stiffness distribution over the entire SCS is also necessary.