## 3 Experimental Investigation and Results
### Refinement and Enhancement  
The process of performing a static structural analysis involves the following main steps. * Model Preparation: Create a model of the structure to be analyzed using SolidWorks software. The details are shown in Figures 1 and 2. * Meshing: Divide the model into smaller finite elements through a process known as meshing. Convergence studies were conducted to determine the optimal element size, and it was found that an element size of 10 mm yielded the best results. The finite element model of the CBF utilized a hybrid grid type consisting of 552,400 elements. This modeling approach is similar to the modal analysis simulation. * Material Definition: Specify the material properties for each element in the model. This includes mechanical properties such as the Young's modulus of 88.7 GPa and density of 2.45 g/cm\({}^{3}\), which define how the material will respond to applied loads. * Boundary Conditions: Apply appropriate boundary conditions to the model, including constraints, loads, and supports. These boundary conditions mimic the real-world environment in which the structure operates. The structure of the CBF is attached to the chassis of a pickup truck with M12 bolts for fastening at eight points, as shown in Figure 9. The structure is designed to carry a total mass of 2000 kg and is uniformly distributed throughout the structure of the refrigerated container floor, calculated from the maximum number of ice loads of 100 bags, with each bag massing 20 kg. The main structure for carrying the load is the upper beam, which is made of seven square tubes, stacked on the C-channel beams. The square tubes of the structure that carries the weight has a size of 3 \(\times\) 1/5 inches. * Analysis Solution: Run the analysis using the ANSYS solver, which solves the governing equations of static equilibrium to determine the response of the structure under the applied loads. The solver calculates the Total deformation, Equivalent Von-Mises stress, Equivalent Von-Mises strain, Factor of Safety (FOS), and other relevant results for the structure. * Analyze and interpret the results obtained from the analysis. If necessary, refine the model, mesh, or analysis settings based on the results obtained. This iterative process allows for fine-tuning the analysis to achieve more accurate and reliable results. The simulation results suggest that the central part of the structure is the most vulnerable to damage when exposed to a load, with a maximum deformation of 0.41 mm. The \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Freq. Number** & **FEA (Hz)** & **EMA (Hz)** & **Freq. Difference (Hz)** \\ \hline
1 & 4.86 & 4.31 & 0.55 \\
2 & 9.48 & 8.87 & 0.61 \\
3 & 10.99 & 10.6 & 0.39 \\
4 & 11.85 & 10.9 & 0.95 \\
5 & 15.07 & 13.2 & 1.87 \\
6 & 21.95 & 23.8 & 1.85 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of natural frequencies found in ANSYS modal and experimental modal. structure experienced a maximum stress of 85 MPa at the connection point between the C-channel beam of the structure and the chassis. However, this area had an FOS value of 2.95. The location with the highest strain of the structure was at the same point as the location with the maximum deformation, with a size of 4.59 \(\times\) 10\({}^{-4}\) mm/mm. To improve the handling performance of the vehicle, a model of the vehicle's structure was created, and the impact of the mass of the side-swing doors on the structure of the vehicle was considered. The force generated by the mass of the side-swing doors, which is about 30 kg, combined with the total mass of the structure, is equal to 325 kg. After considering the weight exerted on all eight legs of the structure, it was observed that the weight on each leg was not equal. When viewed from above and facing the same direction as the vehicle, the shape of the mass distribution on the legs was tilted towards the left-bottom side of the vehicle, where the side-swing doors are installed. Leg 6 weighed 81 kg, which was more than leg 3 on the opposite side that weighed 49 kg.