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A Homodyne Quadrature Laser Interferometer for Micro-Asperity Deformation Analysis
Iskra Mehanizmi d.o.o., Lipnica 8, Kropa 4245, Slovenia
Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana 1000, Slovenia
* Author to whom correspondence should be addressed.
Received: 31 October 2012; in revised form: 18 December 2012 / Accepted: 24 December 2012 / Published: 7 January 2013
Abstract: We report on the successful realization of a contactless, non-perturbing, displacement-measuring system for characterizing the surface roughness of polymer materials used in tribological applications. A single, time-dependent, scalar value, dubbed the collective micro-asperity deformation, is extracted from the normal-displacement measurements of normally loaded polymer samples. The displacement measurements with a sub-nanometer resolution are obtained with a homodyne quadrature laser interferometer. The measured collective micro-asperity deformation is critical for a determination of the real contact area and thus for the realistic contact conditions in tribological applications. The designed measuring system senses both the bulk creep as well as the micro-asperity creep occurring at the roughness peaks. The final results of our experimental measurements are three time-dependent values of the collective micro-asperity deformation for the three selected surface roughnesses. These values can be directly compared to theoretical deformation curves, which can be derived using existing real-contact-area models.
Keywords: micro-asperity; deformation; real contact area; roughness; polymer; creep; tribology; laser interferometry; homodyne detection; displacement
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MDPI and ACS Style
Pogačnik, A.; Požar, T.; Kalin, M.; Možina, J. A Homodyne Quadrature Laser Interferometer for Micro-Asperity Deformation Analysis. Sensors 2013, 13, 703-720.
Pogačnik A, Požar T, Kalin M, Možina J. A Homodyne Quadrature Laser Interferometer for Micro-Asperity Deformation Analysis. Sensors. 2013; 13(1):703-720.
Pogačnik, Aljaž; Požar, Tomaž; Kalin, Mitjan; Možina, Janez. 2013. "A Homodyne Quadrature Laser Interferometer for Micro-Asperity Deformation Analysis." Sensors 13, no. 1: 703-720.