Materials 2022 , 15 , 663
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Table5. BS for all considered models. The values in parentheses represent BS calculated using the FEM-Beam model without taking into account both corrugated layers.
EXP (Mean)
Theoretical EI/b (Nm)
FEM-Beam FEM [29]
Analytical
Face-up
Title1
(Nm)
(Nm)
(Nm)
(Nm)
EB BE EB BE EB BE EB BE EB BE EB BE
8.32 8.47
7.62 7.58 9.88 9.81 7.61 7.53 7.53 7.45
7.13 7.84
8.20 (8.14)
8.11
Board1
10.97 11.58
11.15 11.65
12.14 (12.02)
11.92
Board2
7.25 9.50 9.10
7.15 7.85 7.24 7.98
8.23 (8.15)
8.12
Board3
8.32 (8.27)
8.24
Board4
11.10 11.46 12.97
10.42 10.37
10.89 11.52
11.99 (11.89)
11.78
Board5
8.20 9.12
8.45 8.40
8.86 9.27
9.67 (9.60)
9.60
Board6
As the differences in the results summarized in Table 5, especially the differences between the experimental measurements and all computational models, suggest some errors in the experimental data, the sensitivity analysis was performed in the last step. This analysis was to show which of the parameters have the greatest impact on BS and therefore to point out which measurements require careful re-checking in order to find possible inaccuracies in experimental data presented in [29]. Figure 13 presents all sensitivities of BS in two configurations: EB and BE with respect to mechanical properties of corrugated board and the flute geometric parameters. All graphs in Figure 13 show the BS sensitivity to 10% perturbations of (a) thickness of all corrugated cardboard layers, (b) liners stiffness moduli as well as (c) E and B wave heights. All other parameters do not affect the bending stiffness in both wave orientation (E wave up or B wave up). Certainly, the shape of the corrugated layer (apart from the amplitude) has no effect on BS because, as already proved in this paper, the flute itself contributes less than 1% to overall bending stiffness of corrugated cardboard.
( a )
( b )
Figure13. Cont .
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