Hysteretic Behavior of the Lubricated Curved Surface Slider Under Variable Contact Pressure

Lubricated curved surface sliders (L‐CSSs) with modified ultrahigh‐molecular‐weight polyethylene (M‐UHMWPE) are highlighted in the prevention of bearing failure due to the high‐temperature degradation of friction materials during high‐speed operation. This is vital for seismic isolation in large‐span bridges; however, their hysteretic behavior under the variable contact pressure induced by seismic vertical actions is underexplored. For this reason, a theoretical model of the CSS under variable contact pressure was developed. It is evident that variable contact pressure primarily affects the hysteretic performance of the bearing by altering the restoring force and friction force in real‐time. Dynamic cyclic tests were conducted at contact pressures ranging from 30 to 90 MPa and frequencies from 0.01 to 0.03 Hz. Test results demonstrated stable hysteretic behavior, with breakaway and average friction coefficients exhibiting minimal fluctuations. The accumulative dissipated energy increased significantly with contact pressure, achieving a maximum gain of 362.25%, while the equivalent damping ratio exhibited a maximum change of 14.6%, initially decreasing and then increasing. Loading frequency had a minor effect, with accumulated dissipated energy decreasing by up to 7.5% and the equivalent damping ratio varying by up to 6.7%. Finally, a validated finite element model further analyzed the influence of the amplitude, frequency, and time phase of variable contact pressure, revealing an irregular parallelogram‐shaped hysteresis curve. The shape of hysteretic curves and energy dissipation capacity were significantly affected by these parameters. These findings enhance the understanding of L‐CSS performance in bridge seismic isolation, providing critical insights for design under dynamic loading conditions.