## 4 Simulation and Experimental Results  
The simulation results for the contact pressure distribution between the human body and the car-seat cushion are presented in Figure 13a for two cases: internal pneumatic spring (PSE) pressures of 0 kPa and 25 kPa. The simulations reveal a significant effect of increased internal pressure on the distribution of contact pressure. Specifically, raising the PSE pressure from 0 to 25 kPa causes the peak contact pressure to increase from 15.84 kPa to 18.67 kPa, illustrating the role of PSE pressure in altering pressure distribution. The experimental results, depicted in Figure 13b, were collected from a 75 kg participant with a height of 175 cm, seated on a car seat equipped with a pneumatic spring integrated into the cushion. The PSE internal pressure was adjusted between 0 and 25 kPa using an electro-pneumatic control system. High-resolution contact pressure data were captured using the Xsensor mapping system, detailed in Table 4, which employs capacitive sensor technology.  
A comparison between the simulation results and experimental data, illustrated in Figure 14, demonstrated strong agreement, with peak pressures ranging from 15.57 kPa to 18.67 kPa in the simulations and 16.78 kPa to 19.36 kPa in the experiments. The observed difference of approximately 3.5 kPa (20%) between peak pressures at 0 kPa and 25 kPa of PSE pressure validated the simulation model's ability to replicate realistic pressure distributions. These findings confirmed that the model accurately reflects the physical and mechanical characteristics of both the human body and the seat cushion integrated with the pneumatic spring.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sensor Matrix** & **Sensor Spacing** & **Technology** & **Scale** \\ \hline
48 \(\times\) 48 & 0.5 inch & capacitive & 0 \(\div\) 27 kPa \\ \hline \hline \end{tabular}
\end{table}
Table 4: Properties of the pressure mapping system.  
Figure 14: The desired internal pressure of the PSE from simulations (**left**) and experiments (**right**).  
Figure 13: The results of simulated (**a**) and experimental (**b**) contact pressure distribution.  
This validation highlights the effectiveness of the model in capturing key factors such as cushion geometry, pneumatic spring structure, material properties, and human-seat interactions. By reliably simulating contact pressure distribution, the model can supplement or replace physical experiments, offering a robust tool for optimizing the shape, materials, and structure of pneumatic spring devices to achieve optimal pressure distribution. The validated model also reduces the need for extensive physical testing by enabling the exploration of various test scenarios through parameter modifications in simulations.  
Such an approach not only minimizes costs associated with prototype production and testing but also accelerates the identification and rectification of design weaknesses. The concordant results provide a valuable foundation for studying the interplay between body shape, contact pressure, and occupant comfort. Moreover, the insights gained can drive the development of seat designs that enhance comfort during prolonged use, thereby advancing ergonomic standards in automotive seating.