Friction Coefficient and Contact Pressure at the Aircraft Tire Bead–Rim Interface

Accurate characterization of the frictional behavior at the bead–rim interface of aircraft tires is essential for predicting tire service performance. Aircraft tires are subjected to high torque loads during landing impact and braking, which can readily induce relative slip between the tire and the rim. The interference fit between the tire and the rim generates extremely high contact pressure, while the interfacial friction coefficient exhibits significant pressure-dependent variation, which substantially affects the slip resistance of the interface. However, research on interfacial friction behavior under high-contact-pressure conditions remains relatively limited, and the underlying mechanisms are still not well understood. In this paper, an experimental setup is developed to evaluate the slip resistance of aircraft tires under static radial loads. Combined with numerical simulation methods, the friction coefficient at the bead–rim interface under high-contact-pressure conditions is calculated. The results indicate that as the contact pressure increases, the friction force between the bead and the rim decreases significantly, exhibiting a pronounced pressure-dependent characteristic. Through finite element analysis, the effects of bead wire type, bead heel profile, wire width, and bead interference on the contact pressure distribution are investigated. This study reveals the intrinsic mechanisms governing tire–rim frictional behavior and provides an important basis for optimizing tire–rim slip resistance design.