## 3 Results and Discussion
### Experimental Results at Non-Ambient Temperature
The coefficient of correlation is R2 = 0.9987. The same heating method was used to carry out SSGT of HMX-based booster. The time from taking out the acceptor charge from the refrigerator to ignition was controlled at 48-55 s. Equation (6) was used to calculate that the temperature of the acceptor charge when initiating the donor was 119.1-121.1 \({}^{\circ}\)C, approximately 120 \({}^{\circ}\)C. A total of six tests were carried out. Table 6 lists SSGT results at 120 \({}^{\circ}\)C. The critical thickness was found to be between 8.3 and 8.4 mm according to the experimental data. Based on the published ignition and growth model parameters of HMX-based booster, the parameters in the simulation calculation were adjusted to make the simulated results consistent with the test results so as to obtain the modeling parameters of HMX-based booster at normal temperature [36]. Referring to the rule of the JWL state equation and reactive rate equation for other explosives with changing temperature, it can be observed that most of the model constants remain unchanged; only a few of them require a small change depending on the temperature [5; 6; 7; 9; 10; 11; 12; 17; 37]. According to the test results of HMX-based booster at non-ambient temperature, the shock initiation equation parameters for the booster were optimized by changing two parameters: \(B\) in the JWL equation of state and G1 in the ignition and growth reactive rate equation. The state equation parameters of HMX-based booster at non-ambient temperatures could be obtained. Table 7 contains the adjusted model parameters for HMX-based booster. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Exp/num**} & \multicolumn{2}{c}{**PMMA Gap**} & \multirow{2}{*}{**Depth of Dent/mm**} & \multirow{2}{*}{**Go/No Go**} \\  & **Thickness/mm** & & \\ \hline
1 & 9.0 & 0.16 & No go \\
2 & 8.0 & 0.06 & Go \\
3 & 8.5 & 1.76 & No go \\
4 & 8.2 & 1.76 & Go \\
5 & 8.3 & 1.48 & Go \\
6 & 8.4 & 0.38 & No go \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Experimental results of SSGT at 120 \({}^{\circ}\)C.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{UNREACTED JWL} & \multicolumn{2}{c}{REACTED JWL} \\ \hline \(A\) (GPa) & 95,220 & \(A\) (GPa) & 614 \\ \(B\) (GPa) & –5.944 & \(B\) (GPa) & 10.89 \\ \(R_{1}\) & 14.1 & \(R_{1}\) & 4.41604 \\ \(R_{2}\) & 1.41 & \(R_{2}\) & 1.19 \\ \(\omega\) & 0.8867 & \(\omega\) & 0.33 \\ T\({}_{0}\)(K) & 298 K & E\({}_{0}\)(GPa) & 9.08 \\ Shear Modulus (GPa) & 5 & \(D\) (m/s) & 8212.5 \\ Yield Stress (GPa) & 0.2 & P\({}_{\text{CJ}}\) (GPa) & 30.4 \\ \(\rho\)(g/cm\({}^{3}\)) & 1.700 & & \\ \hline \hline \multicolumn{2}{c}{REACTION RATES} \\ \hline \(I\) (μs\({}^{-1}\)) & 4 \(\times\) 10\({}^{5}\) & \(g\) & 1.0 \\ \(b\) & 0.667 & \(z\) & 3.0 \\ \(a\) & 0.113 & F\({}_{\text{ignax}}\) & 0.1 \\ \(x\) & 4.0 & F\({}_{\text{G1 max}}\) & 0.5 \\ \(c\) & 0.667 & F\({}_{\text{G2 max}}\) &The complete shock initiation process simulation of the Go/No-go response is shown in Figure 8. Simulation results of shock initiation process and detonation pressure progress for SSGT: **(a)** Go case at 7.2 mm PMMA thickness; **(b)** No-go case at 7.3 mm PMMA thickness.when the shock wave passes through the PMMA and reaches the acceptor. In order to distinguish the Go/No-go response and the generation of transmitted and reflected waves, the pressure change process of simulation calculation was observed under different gap thicknesses. As the explosion proceeds, the pressure of the product gas changes the shape of the steel sleeve, but it does not affect the progress of the explosion. The detonation wave front of the donor reaches the upper interface of the PMMA after initiation, and the energy loss is converted into a pressure decrease. Pressure attenuation occurs through the PMMA. When the shock wave pressure at the bottom of the PMMA is greater than the critical initiation pressure of the acceptor, the transmitted wave into the acceptor causes ignition and detonation.