Experimental–inverse investigation of frictional heating and interfacial heat partition in friction pendulum bearings

Frictional heating significantly influences the performance of friction pendulum bearings (FPBs), yet the mechanisms of heat generation and interfacial partition remain inadequately quantified. This study investigates frictional heating in FPBs using flat-plate sliding experiments under varied velocities, contact pressures, and surface roughness levels. Direct steel surface temperature measurements, enabled by a thin-film thermocouple technique, are integrated with a data-enabled, physics-based inverse framework to predict the transient surface temperature of the UHPF friction pad without assuming a priori fixed heat partition ratio. To our knowledge, this constitutes the first experimentally validated reconstruction of the pad interfacial temperature and transient heat-partition ratio for FPB-relevant contacts. The results indicate that frictional heating is dominated by deformational heat generation within the friction pad, leading to an initial heat partition into the steel plate that is negligible at sliding onset. As sliding proceeds, the heat partition ratio gradually increases toward a steady state, with the transition process primarily governed by interfacial thermal resistance rather than bulk conduction effects. Key thermal parameters are identified along with their credible ranges and evolution trends. The proposed approach offers a physically consistent foundation for refined frictional heating models and improved thermo-mechanical assessment of FPB systems and design-oriented simulation.