## 5 Result and Discussion
### Numerical Simulation of Thermal Shock Resistance
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & **Factor A** & \begin{tabular}{c} **Factor B** \\ **(Porosity)** \\ \end{tabular} & \begin{tabular}{c} **Factor C (Fiber** \\ **(Coating** \\ **Thickness)** \\ \end{tabular} & \
\begin{tabular}{c} **Factor C (Fiber** \\ **Content)** \\ \end{tabular} &
\begin{tabular}{c} **Mean SDEG** \\ **Value** \\ \end{tabular} \\ \hline
1 & 1 & 1 & 1 & 0.8800 \\ \hline
2 & 1 & 2 & 3 & 0.4201 \\ \hline
3 & 1 & 3 & 2 & 0.4440 \\ \hline
4 & 2 & 1 & 3 & 0.3808 \\ \hline
5 & 2 & 2 & 2 & 0.5839 \\ \hline
6 & 2 & 3 & 1 & 0.8688 \\ \hline
7 & 3 & 1 & 2 & 0.5147 \\ \hline
8 & 3 & 2 & 1 & 0.8873 \\ \hline
9 & 3 & 3 & 3 & 0.3857 \\ \hline \multirow{2}{*}{Level} & \begin{tabular}{c} Factor A \\ (Porosity) \\ \end{tabular} & \begin{tabular}{c} Factor B \\ (Coating \\ Thickness) \\ \end{tabular} & \
\begin{tabular}{c} Factor C (Fiber \\ Content) \\ \end{tabular} & \\ \hline K\({}_{1}\) & 1.74 & 1.78 & 2.64 \\ \hline K\({}_{2}\) & 1.83 & 1.89 & 1.54 \\ \hline K\({}_{3}\) & 1.79 & 1.70 & 1.19 \\ \hline k\({}_{1}\) & 0.58 & 0.59 & 0.88 \\ \hline k\({}_{2}\) & 0.61 & 0.63 & 0.51 \\ \hline k\({}_{3}\) & 0.60 & 0.57 & 0.40 \\ \hline R & 0.03 & 0.06 & 0.48 \\ \hline
\begin{tabular}{c} Priority of \\ Factors \\ \end{tabular} & \multicolumn{3}{c}{C \textgreater{} B \textgreater{} A} \\ \hline Optimal & \multicolumn{3}{c}{A\({}_{1}\)B\({}_{3}\)C\({}_{3}\) (No porosity 20\%, 100 \(\upmu\)m Thickness, and 60\%} \\ \multicolumn{3}{c}{Fiber Content)} \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Orthogonal simulation results and analysis of interlayer degradation efficiency (mean SDEG) after the second thermal shock. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**No.**} & **Factor A** & \begin{tabular}{c} **Factor B** \\ **(Coating** \\ **Thickness)** \\ \end{tabular} & \
\begin{tabular}{c} **Factor C (Fiber** \\ **Content)** \\ \end{tabular} &
\begin{tabular}{c} **Mean SDEG** \\ **Value** \\ \end{tabular} \\ \hline
1 & 1 & 1 & 1 & 0.8800 \\ \hline
2 & 1 & 2 & 3 & 0.4226 \\ \hline
3 & 1 & 3 & 2 & 0.4532 \\ \hline
4 & 2 & 1 & 3 & 0.3822 \\ \hline
5 & 2 & 2 & 2 & 0.5857 \\ \hline
6 & 2 & 3 & 1 & 0.8692 \\ \hline
7 & 3 & 1 & 2 & 0.5196 \\ \hline
8 & 3 & 2 & 1 & 0.8873 \\ \hline \multirow{2}{*}{Level} & \begin{tabular}{c} Factor A \\ (Porosity) \\ \end{tabular} & \
\begin{tabular}{c} Factor B \\ (Coating \\ Thickness) \\ \end{tabular} &
\begin{tabular}{c} Factor C (Fiber \\ Content) \\ \end{tabular} & \\ \hline K\({}_{1}\) & 1.76 & 1.78 & 2.64 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Orthogonal simulation results and analysis of interlayer degradation efficiency (mean SDEG) after the third thermal shock. The results of the triple thermal shock analysis of the C/CA substrate surface are detailed in Tables 9-11. Fiber content significantly influences the substrate's thermal shock resistance, while coating thickness has the least impact. After the initial thermal shock, configuration A\({}_{3}\)B\({}_{3}\)C\({}_{2}\) (20% porosity, 100 \(\upmu\)m thickness, and 30% fiber content) demonstrated good thermal shock resistance. Meanwhile, structure A\({}_{1}\)B\({}_{3}\)C\({}_{3}\) (porosity = 0%, 100 \(\upmu\)m thickness, and 60% fiber content) showed the best performance during subsequent shocks. The reason is similar to that of the transition layer. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**No.**} & **Factor A** & **Factor B** & **Factor C (Fiber Content)** & **Mean SDEG** \\  & **(Porosity)** & **(Coating Thickness)** & **Content)** & **Value** \\ \hline K\({}_{2}\) & 1.84 & 1.90 & 1.56 \\ \hline K\({}_{3}\) & 1.79 & 1.71 & 1.19 \\ \hline k\({}_{1}\) & 0.59 & 0.59 & 0.88 \\ \hline k\({}_{2}\) & 0.61 & 0.63 & 0.52 \\ \hline k\({}_{3}\) & 0.60 & 0.57 & 0.40 \\ \hline R & 0.03 & 0.06 & 0.48 \\ \hline Priority of & & & \\ Factors & & C \textgreater{} B \textgreater{} A & \\ \hline Optimal & & & \\ Configuration & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 8: _Cont._