# Crasworthiness Analysis to Evaluate the Performance of TDM-Shielded Street Poles Using FEA
## Methodology
### FEA Model
Finally, the model, as shown in Figure 3, visualizes the final assembly of the impact crash setup to be simulated using the Abaqus/Explicit solver. The impact analysis will be performed both using frontal and corner crash procedures as similarly conducted by [PERSON] et al. [1]. The first set of FEA simulations will analyze the thickness of the TDM required to make sufficient mitigations of the impact energy absorbed by both the vehicle and the street pole. The thickness of the TDM shielding will therefore be parameterized \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Material**} & **Young’s Modulus** & \multirow{2}{*}{**Poisson’s Ratio**} & **Yield Stress** & **Density** \\  & **[GPa]** & & **[MPa]** & **[kgm\({}^{-3}\)]** \\ \hline Aluminium-5052 & 68.9 & 0.33 & 140 & 2690 \\ Aluminium-6061 & 69.5 & 0.33 & 220 & 2780 \\ Steel ASTM A36 & 210 & 0.29 & 247.5 & 7869 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Mechanical Elasticity and Density Properties of the aluminum alloys and steel grade used in this paper. The values are the same as the ones that were simulated in [1]. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{**Fracture Strain**} & \multicolumn{2}{c}{**Displacement after Fracture**} \\  & & **[m]** \\ \hline Aluminium-5052 & 0.105 & 0.002625 \\ Aluminium-6061 & 0.061 & 0.001525 \\ Steel ASTM A36 & 0.24 & 0.006 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Fracture values of the metals used in the paper as was done in [1]. according to the thicknesses stated in the previous section to satisfy this objective. The second set of simulations will be conducted to analyze the variation of velocity of the vehicle and its impact on the mitigation of energy absorption that the TDM layer will provide. The vehicle speeds used in this study are 12 ms\({}^{-1}\), 17 ms\({}^{-1}\) and 22 ms\({}^{-1}\), which are identical to those used in the study [1]. Figure 3: Model setup of the (**a**) vehicle colliding against a TDM-shielded steel street pole with supporting top views to observe the (**b**) corner collision and (**c**) frontal collision scenarios. Figure 2: Sensitivity analysis of Reinforced TDM Pole Mesh tested using 23,500 elements, 27,000 elements and 50,000 elements. Some assumptions in the FEA model were also considered during this study. Firstly, to compensate for the full mass of the vehicle, a point mass was declared. This point mass is a numerical representation of the entire vehicle to compensate for the missing kinetic energy, as the model lacks the middle and rear body, as well as its respective components, such as the rear wheel, windows, and axles. Furthermore, the stiffness of the overall vehicle is important as well. Since the FEA model was missing key elements presented in the previous statements, the engine was therefore modeled as a complete solid to compensate for this. Moreover, the tires of the vehicle and the front axle were also modeled to introduce further rigidity to the FEA model. Finally, to avoid further complexities in contact analysis for the FEA model, the front of the vehicle's shell was modeled as a single continuous sheet of aluminum rather than individual components. Additional assumptions, such as the interaction between the vehicle and the street pole, were modeled using frictionless interaction properties because it is expected that there will be many self-contacts during the analysis, as well as contact between many materials. This could slow down the calculation, as well as introduce instabilities to the analysis. Moreover, since the study is performed on vehicles at high speeds, friction can be ignored. Furthermore, the material model of the discarded tire is assumed to be only hyperelastic with a stable Poisson's Ratio of 0.45. Additionally, no additional parameters, such as viscoelasticity, hyper plasticity and viscous plasticity, are considered. Damage parameters, such as the crushable foam mechanics, are also not considered in this study.