Measurement of Friction in Dynamic Systems

摘要

The goal of this project concerned the development of an experimental method to accurately infer and identify friction force in a dynamic system. During this one-year project, it was proposed to develop a method to measure friction and identify its damping and tangential stiffness components. From the measurements between surfaces of selected materials, tangential stiffness, friction damping properties, and coefficient of friction values were inferred. These results favorably compared with computational results obtained using available theories. The regime of relative motion used in the tests was primarily in the microslip region, which closely replicates bolted joints in large space structures as well as contact dampers between gas turbine blades. A comparison of measurement results for tangential stiffness with those obtained using Cattaneo-Mindlin theory is shown in Fig 4 for two cases. The theoretical results agree well with those obtained from measurements for fresh surfaces, suggesting that the theories need further development for worn surfaces. This is a unique measurement device that allows repeatable and accurate measurements of relative motion and forces from which coefficient of friction, tangential stiffness, and friction damping properties can be inferred. Measurements are largely devoid of ancillary dynamic effects common in measurement systems.