## 4 Materials and Methods
### Developing the Model  
Prior to performing the parametric analysis, the ABAQUS model was calibrated against experimental data. This was to ensure that the numerical model was replicating experimental data and academic literature. To calibrate the static model, experimental data was utilised from ACARP's C27040 project, where a double shear test was conducted on a 63T indented Sumo Cable Bolt provided by Jennmar. The calibration of the numerical model was not expected to be identical to the experimental data due to simplifications made when developing the model. The bolt was created as a smooth cylinder, where the experimental data tested an indented cable bolt. The three \begin{table}
\begin{tabular}{c c} \hline \hline
**Fine Mesh Seed Size (\%)** & **Computational Time (s)** \\ \hline
1 & 828 \\
2 & 341 \\
5 & 254 \\
10 & 239 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Computational times of different fine meshes in dynamic testing. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Part** & **Coarse Mesh Seed Size (mm)** & **Fine Mesh Seed Size (mm)** \\ \hline Bolt & 11.2 & 5.6 \\ Box & 30 & 5.6 \\ Sphere & N/A & 6 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Calibrated model mesh sizes. Figure 15: Force vs. displacement graph comparing mesh size of sphere in dynamic testing. concrete blocks of the laboratory experiment were not the same size, with the centre block being longer than the two boundary blocks. The developed model used three identically sized boxes to minimise the number of geometric parts required. The experimental test also included grouting of the bolt after the concrete blocks were poured, whilst the numerical model excluded grouting and utilised surface-to-surface contact properties to simulate grouting and frictional effects. Furthermore, the laboratory test of the indented 63T Sumo Cable Bolt used was only carried out once, thus the experimental data itself is not reliable. As only one test was conducted per specific bolt, manufacturing defects, instrumental errors and human errors can influence the results. To calibrate the static numerical model, a comparison of the results of the force vs. displacement of the 63T Sumo Cable Bolt was utilised, as shown below in Figure 16.  
The force vs. displacement graph of the calibrated and experimental data shows a similar trend in both the elastic and plastic regions, however, shows differing fracture mechanisms. The experimental data displayed an instantaneous fracture once ultimate shear force was reached, whereas the numerical model displayed a gradual fracture at peak shear force. This was expected due to how the numerical model applies and records shear force. The field and history outputs applied to the model recorded the displacement and reaction forces of the load cell (i.e., top of the concrete block). Once the recorded reaction force of the load begins to decrease, the bolt has fractured and is no longer resisting the applied force. Therefore, from the numerical data, the maximum displacement of the bolt at complete failure occurs at the peak shear force recorded. To the determine the accuracy of the calibration, the peak shear force and its respective displacement will be numerically compared. \[ \begin{array}{c}\frac{Max~{}Shear~{}Force~{}Calibrated}{Max~{}Shear~{}Force~{} Legitudinal}=\frac{647.92~{}\mathrm{NN}}{795.80~{}\mathrm{NN}}=81.44~{}\%~{}accuracy\\ \frac{Displacement~{}at~{}Failure~{}Calibrated}{Displacement~{}at~{}Failure~{} Legitudinal}=\frac{73.50~{}\mathrm{mm}}{92.82~{}\mathrm{mm}}=79.18~{}\%~{}accuracy\end{array} \]  
The numerical model displays an approximate accuracy of 80%, which is deemed reasonable for the simplifications utilised for developing the model. The factors impacting the accuracy of the calibration will be further discussed in the limitations section of this study. To calibrate the dynamic model, there was no available dynamically loaded double shear test experimental data, thus the calibrated static model was further built upon. [PERSON] et al.