## 4 Numerical Simulation
### Analysis of Numerical Results  
Taking the L-1-30 beam as an example, the simulation results are shown in Figure 14. Figure 14a,b show that the force of the overall steel frame was fully consistent with the force form of the flexural component. The stress in the area between the support and the loading point was relatively large, almost completely yielding. In Figure 14a,b, most of the mid-span area of the component yielded under tension, and the concrete in the compression zone in Figure 14c was crushed, indicating that the simulated beam was under bending failure. The simulation situation was the same as the test situation; Figure 14d shows the development of simulated beam cracks, which was similar to the development of test beam cracks. The cracks near the loading point were the densest and spread toward the middle of the span and the support. The deflection test and simulation values of the beam under different loads are shown in Figure 15. In the elastic stage, the slope of the deformation curve of the simulated value was greater than the deformation curve of the test value; that is, the rigidity of the simulated value was greater than the test rigidity. After entering the working stage with cracks, the simulated value and the test value had the same trend. The simulated value entered the failure stage first, but the difference in the ultimate flexural bearing capacity was not large. The simulation and test values of the ultimate flexural bearing capacity of each beam are shown in Table 6.  
Figure 14: Stress contours and damage contours. (**a**) The stress contours of the steel frame when the specimen yields under tension; (**b**) the stress contours of the steel wire mesh when the specimen yields under tension; (**c**) stress contours when concrete is crushed in the compression zone; (**d**) the damage contours of the concrete when the specimen yields under tension. Figure 13: Mesh generation. There was still a certain deviation between the simulation results and the test results, for three main reasons. One is the influence of material parameters. The elastic modulus of concrete was obtained from the stress-strain curve. The ratio of stress to strain is not a constant, but changes with the increase of load. When the concrete enters the plastic working state, its actual elastic modulus will decrease, and the concrete elastic modulus in the numerical simulation is the initial elastic modulus, resulting in higher rigidity than the experimental value. Second, the numerical simulation cannot simulate every link in the test. Both bamboo fiber and BFRP bars are relatively smooth rod-like objects, and relative slippage occurs under load. In the simulation process, the bond-slip relationship between these materials and concrete was not considered, resulting in a certain error in the results. The third is that there is a certain contingency in the production process of the specimen. The boundary conditions in the test and the boundary conditions of the numerical simulation cannot be the same, and, during the test loading process, when the specimen is deformed, the boundary conditions will change accordingly. The result will also change accordingly. The numerical simulation results of the flexural process of BFRP bar concrete beams reinforced with bamboo fiber and steel wire mesh were in good agreement with the test results, and the error between the test value and the simulated value was mostly within 5%. The errors of the specimens L-1/2-30 and L-1-0 were 15.1% and 14.1%, respectively, \begin{table}
\begin{tabular}{c c c c} \hline
**Specimen** & **Test Value (kN)** & **Simulation Value (kN)** & **(Simulation Value – Test Value)/Test Value (\%)** \\ \hline L-0-0 & 340 & 342 & 0.6 \\ L-0-30 & 329 & 330 & 0.3 \\ L-1/2-30 & 284 & 327 & 15.1 \\ L-1-0 & 397 & 341 & \(-\)14.1 \\ L-1-30 & 340 & 335 & \(-\)1.5 \\ L-1-45 & 343 & 339 & \(-\)1.2 \\ \hline \end{tabular}
\end{table} 
Table 6: Simulation value and test value of the flexural ultimate bearing capacity.