Determination of curved surface slider behavior under different loading conditions

This study systematically investigates the variations in friction coefficient of both full-scale double-curved surface sliders and small-scale slider material under different loading conditions. First, wear tests were performed, and the corresponding friction coefficients obtained from full- and small-scale tests were compared. Second, full- and small-scale test results were used to assess the variations in static and dynamic friction coefficients under cyclic motions performed at both room- and low-temperature conditions. In the experimental program, not only the temperature and exposure time but also the normal stress level and the loading velocity were selected as parameters. Finally, a unified model was proposed to estimate the friction coefficient of full-scale isolator by means of small-scale test results. The key findings are as follows: (i) After 1000 m wearing tests, it seen that the hysteretic behavior of full-scale isolator remains unchanged. (ii) In low-temperature tests, due to formation of an ice layer at the sliding interface, which behaves like a lubricant, friction coefficients of both the isolator and the slider reduces substantially compared to ones obtained from room-temperature tests. (iii) Friction coefficients obtained from full- and small-scale tests (either wear or cyclic motion tests) results are very close to each other at room-temperature but not at low-temperature cases. (iv) The proposed formulation, which is calibrated based on small-scale test results, is accurate enough to estimate friction coefficients of full-scale isolator at room-temperature for a wide range of loading combinations.