Numerical Investigation of a Hollow D-Shaped Window Seal for High-Altitude Pressurized Barracks Under Pre-Compression and Pressure Differential

In plateau constant-pressure barracks, indoor pressure is maintained above outdoor pressure, placing window seals under a sustained pressure differential after installation pre-compression. This study develops a two-dimensional nonlinear contact model of a hollow D-shaped silicone rubber sealing strip, a pressure bead, and a mounting groove using the fluid pressure penetration method. A sequential pre-compression and pressure-differential loading procedure was applied to investigate the effects of fluid pressures of 5, 15 and 25 kPa and compression ratios (CRs) of 10%, 15%, 20% and 25% on contact behavior, while additional stress analyses were conducted at compression ratios of 10%, 20%, and 30%. Most investigated cases exhibit an asymmetric double-peak contact-pressure distribution, with a lower-pressure region between the two peaks, with lower pressure in the central region and higher peaks on both sides. Increasing fluid pressure redistributes the contact load toward the low-pressure side, whereas increasing compression strengthens interfacial constraint and reduces the sensitivity of the contact state to pressure variations. At a compression ratio of 25%, the contact-pressure curves under different fluid pressures show high consistency and stable peak positions. Within the investigated conditions, CR = 25% is recommended as a numerical reference for the representative straight section because of its favorable contact length and reduced peak-pressure sensitivity to a pressure differential. This recommendation concerns numerical contact characteristics and does not establish optimum airtightness or a minimum leakage rate.