## 3 Results
### Mechanical Properties  
#### 3.2.1 Strength and Stiffness Bending Properties  
FRP-plywood improves the bending properties ofplywood. Stiffness (MOE) and resistance (MOR) are higher in the tests in the parallel direction than in the perpendicular one (Table 5).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**ID**} & \multicolumn{2}{c}{**Density (kg/m\({}^{3}\))**} & \multicolumn{2}{c}{**Moisture Content (\%)**} & \multicolumn{2}{c}{**Thickness Swelling (\%)**} & \multicolumn{2}{c}{**Water Absorption (g)**} \\ \cline{2-9}  & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** \\ \hline PVA–CF & 514.66 \({}^{\text{b}}\) & 11.53 & 9.01 \({}^{\text{a}}\) & 0.14 & 5.02 \({}^{\text{a}}\) & 0.69 & 0.59 \({}^{\text{c}}\) & 0.05 \\ \hline \hline \end{tabular}
\end{table}
Table 4: _Cont._  
Figure 3: Density profile of the composite panels.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**ID**} & \multicolumn{2}{c}{**MOE (MPa)**} & \multicolumn{2}{c}{**MOR(MPa)**} & \multicolumn{2}{c}{**Density (kg/m\({}^{3}\))**} & \multicolumn{2}{c}{**Moisture Content (\%)**} \\ \cline{2-9}  & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** & **Mean** & **St. Dev.** \\ \hline \multirow{9}{*}{Parallel direction} & P & 3371.75 \({}^{\text{a}}\) & 421.5 & 34.65 \({}^{\text{a}}\) & 4.7 & 473.98 \({}^{\text{a}}\) & 28.19 & 6.97 \({}^{\text{ab}}\) & 0.22 \\ \cline{2-9}  & ER–BF & 3680.43 \({}^{\text{a}}\) & 350.5 & 47.40 \({}^{\text{ab}}\) & 3.0 & 523.84 \({}^{\text{a}}\) & 5.87 & 7.23 \({}^{\text{ab}}\) & 0.66 \\ \cline{2-9}  & ER–CF & 4997.87 \({}^{\text{b}}\) & 381.3 & 52.95 \({}^{\text{b}}\) & 4.5 & 521.96 \({}^{\text{a}}\) & 22.10 & 7.35 \({}^{\text{a}}\) & 0.54 \\ \cline{2-9}  & PVA–BF & 4192.37 \({}^{\text{ab}}\) & 724.3 & 44.65 \({}^{\text{ab}}\) & 5.6 & 499.77 \({}^{\text{a}}\) & 17.78 & 7.03 \({}^{\text{ab}}\) & 0.32 \\ \cline{2-9}  & PVA–CF & 4739.29 \({}^{\text{b}}\) & 947.7 & 51.47 \({}^{\text{b}}\) & 10.2 & 527.17 \({}^{\text{a}}\) & 11.32 & 6.85 \({}^{\text{b}}\) & 0.45 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Results of strength and stiffness bending properties in the direction parallel and perpendicular to the fibers.  
In the parallel direction (Figure 4), the MOE increase varied between 9.2% and 42.8%, in the ER-BF (3680 MPa) and ER-CF (4998 MPa) samples, respectively. The MOR increase varied between 28.8% and 52.8%, in the PVA-BF (44.65 MPa) and ER-CF (52.95 MPa) samples, respectively.  
In the perpendicular direction (Figure 5), the MOE increase varied between 19.2% and 52.0%, in the PVA-BF (3188 MPa) and ER-CF (4066 MPa) samples, respectively. The MOR increase varied between 57.6% and 102.9%, in the ER-BF (39.52 MPa) and PVA-CF (50.89 MPa) samples, respectively.  
The load-deflection curves of the bending tests of the parallel and perpendicular samples had evidenced that FRP-plywood increase the maximum load and maximum deflection of plywood, these results are shown in Figures 6 and 7, respectively.  
In the parallel direction, the maximum load increased between 43.1% and 57.4%, for the PVA-BF (1.57 kN) and ER-CF (1.73 kN) samples, respectively. The maximum deflection increased between 1.8% and 37.5%, for the ER-CF (18.37 mm) and PVA-CF (24.82 mm) samples, respectively.  
In the perpendicular direction, the maximum load increased between 58.0% and 100.9%, for the ER-BF (1.31 kN) and PVA-CF (1.66 kN) samples, respectively. The maximum deflection increased between 37.3% and 86.2%, for the ER-CF (19.16 mm) and PVA-BF (25.99 mm) samples, respectively.  
Figure 4: Results of MOE, MOR and density of each sample in the parallel direction.