Sliding friction: From microscopic contacts to Amontons’ law

Doctoral thesis English OPEN
Weber, B.A. (2017)
  • Subject:
    mesheuropmc: body regions | human activities | musculoskeletal system | integumentary system | musculoskeletal diseases

Most engineers describe sliding friction using the friction coefficient, the ratio of frictional force to normal force. While this proportionality is very simple, its origin is not trivial at all and has been subject of investigation for more than a century. The current... View more
  • References (5)

    2 Experimental Techniques 9 2.1 Elastic modulus . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.1 Shear modulus of wet sand . . . . . . . . . . . . . . . . 9 2.1.2 Young's modulus of polytetrafluoroethylene . . . . . . 11 2.2 Penetration hardness . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3 Friction tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.3.1 Friction experiments with a tensile tester . . . . . . . . 16 2.3.2 Friction experiments with a rheometer . . . . . . . . . . 17 Full rotations . . . . . . . . . . . . . . . . . . . . . . . . 18 2.4 Microscopy imaging . . . . . . . . . . . . . . . . . . . . . . . . 19 2.4.1 Fluorescence microscopy . . . . . . . . . . . . . . . . . 20 2.4.2 Atomic force microscopy . . . . . . . . . . . . . . . . . 23

    3 Sliding Friction on Wet and Dry Sand 27 3.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.3 Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

    5 Molecular Probes Reveal Deviations from Amontons' Law in MultiAsperity Frictional Contacts 55 5.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.3 Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

    6 The Onset of Sliding Friction 69 6.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 6.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 6.3 Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 6.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 6.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

    7 Molecular Insight into the Slipperiness of Ice 81 7.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 7.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 7.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 7.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

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