## 3 Results and Discussion
### Crashworthiness Behaviors
This is because the internal structure of BS-3 and BS-5 is a quadrilateral and a pentagon, respectively, while the internal structure of BS-1 and BS-2 has no polygons. This demonstrates that by adding a polygon structure into the thin tube, the _EA_ and _SEA_ values can be increased, and the energy absorption capacity of the thin tube can be improved. Comparing BS-3 with BS-4, the _EA_ and _SEA_ values of BS-4 are 23.4% and 23.4% higher than those of BS-3, respectively. The internal structure of BS-4 is two quadrangles, while the internal structure of BS-3 is a quadrangle. Comparing BS-5 with BS-6, the _EA_ and _SEA_ values of BS-6 are 24.3% and 24.3% higher than those of BS-5, respectively. The internal structure of BS-6 contains two hexagons, while the internal structure of BS-5 is a hexagon. This demonstrates that the energy absorption capacity of the double-layer structure is stronger than that of the single-layer structure. Increasing the number of polygons in the thin tube effectively improves the energy absorption capacity. The _EA_ and _SEA_ values of BS-4, BS-6, and BS-7 are higher and close to those of other BSs, and their energy absorption capacity is stronger than that of other BSs, indicating that the energy absorption capacity of the double-layer structure inside the thin tube is generally superior to that of the single-layer structure. The highest value of BS-6 is 37.65 J and 363.99 J/kg respectively, and the _EA_ value is 2.9% and 12.4% higher than that of BS-4 and BS-7, respectively, whereas the _SEA_  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Types** & **Samples** & \ \begin{tabular}{c} **Mass** \\ **(g)** \\ \end{tabular}  & \begin{tabular}{c} **Impact Distance** \\ **(mm)** \\ \end{tabular}  & \(P_{\max}\) **(kN)** & _EA_ **(j)** & _SEA_ **(J/kg)** & \(P_{\infty}\) **(kN)** & _CLE_ \\ \hline \multirow{4}{*}{BS-1} & \#1 & 103.41 & 22.31 & 3.41 & 20.15 & 194.86 & 0.90 & 0.26 \\  & \#2 & 103.39 & 21.25 & 3.26 & 19.86 & 192.09 & 0.93 & 0.29 \\  & \#3 & 103.42 & 22.19 & 3.33 & 20.07 & 194.06 & 0.90 & 0.27 \\  & \#1 & 103.42 & 18.14 & 2.80 & 19.67 & 190.21 & 1.08 & 0.39 \\ BS-2 & \#2 & 103.41 & 18.46 & 2.85 & 20.12 & 194.57 & 1.09 & 0.38 \\  & \#3 & 103.38 & 17.68 & 2.62 & 19.23 & 186.01 & 1.09 & 0.42 \\  & \#1 & 103.39 & 6.63 & 7.91 & 29.05 & 280.97 & 4.38 & 0.55 \\ BS-3 & \#2 & 103.40 & 6.53 & 7.62 & 28.64 & 276.98 & 4.39 & 0.58 \\  & \#3 & 103.39 & 5.86 & 6.56 & 26.35 & 254.86 & 4.50 & 0.69 \\  & \#1 & 103.43 & 10.74 & 9.58 & 36.26 & 350.58 & 3.38 & 0.35 \\ BS-4 & \#2 & 103.44 & 11.62 & 10.22 & 37.19 & 359.53 & 3.20 & 0.31 \\  & \#3 & 103.41 & 9.78 & 8.89 & 36.21 & 350.16 & 3.70 & 0.42 \\  & \#1 & 103.39 & 11.96 & 9.70 & 29.63 & 286.58 & 2.48 & 0.26 \\ BS-5 & \#2 & 103.38 & 10.43 & 8.68 & 27.26 & 263.69 & 2.61 & 0.30 \\  & \#3 & 103.41 & 11.28 & 9.26 & 28.61 & 276.67 & 2.54 & 0.27 \\  & \#1 & 103.42 & 31.86 & 4.37 & 37.88 & 366.27 & 1.19 & 0.27 \\ BS-6 & \#2 & 103.44 & 30.52 & 4.32 & 36.72 & 354.99 & 1.20 & 0.28 \\  & \#3 & 103.42 & 32.65 & 4.43 & 38.34 & 370.72 & 1.17 & 0.26 \\  & \#1 & 103.41 & 27.29 & 5.07 & 32.11 & 310.51 & 1.18 & 0.23 \\ BS-7 & \#2 & 103.39 & 27.37 & 5.34 & 33.56 & 324.60 & 1.23 & 0.23 \\  &value is 2.9% and 12.4% higher than that of BS-4 and BS-7 respectively. Moreover, the \(P_{\text{max}}\) of BS-6 is likewise low, namely 54.2 and 16.6% lower than that of BS-4 and BS-7, respectively. The \(CLE\) value is 25% lower than that of BS-4 and 14.8% higher than that of BS-7. In general, in the impact test, the design of the two hexagon structures of BS-6 outperforms that of the two quadrilateral structures of BS-4 and the one quadrilateral structure and one hexagon structure of BS-7.