chap3_friction_SemII_140411_E.pptx - CHAPTER 3 FRICTION 1 Contents 3.1 Adhesion 3.2 Solid-solid contact 3.2.1 Factors affecting solid-solid contact

chap3_friction_SemII_140411_E.pptx - CHAPTER 3 FRICTION 1...

This preview shows page 1 - 10 out of 48 pages.

CHAPTER 3 FRICTION 1
Image of page 1
3.1 Adhesion Contents 3.2 Solid-solid contact 3.2.1 Factors affecting solid-solid contact 3.2.2 Effect of sliding on solid-solid contact 3.3 Friction 3.3.1 Introduction 3.3.2 Laws of sliding friction 3.3.3 Basic mechanisms of sliding friction 3.3.4 Friction transitions during sliding 3.3.5 Stick-slip 3.3.6 Rolling friction
Image of page 2
3.1 Adhesion When two surfaces are brought in to contact , adhesion or bonding across the interface can occur which requires a finite normal force, called adhesive force, to pull the two solids apart. Cohesion represents the atomic bonding forces associated within the material . (Adhesion an opposed to cohesion) Adhesion is the phenomenon that occurs when two surfaces are pressed together , either a pure normal force (load) under combined normal and shear forces. fig-chp3\chp3-fig1.pptx 3
Image of page 3
m = (3.1) Where m : coefficient of adhesion W’ : the normal tensile force W’ required for separation (normally referred to as adhesive force) W : normal compressive force W initially applied W’ typically increases linearly with an increase of W and m generally increases with duration of static contact and separation rate . fig-chp3\chp3-fig2.pptx 4 W’ W
Image of page 4
5
Image of page 5
Adhesion is a function of material pair and interface conditions such as : crystal structure solubility of one material into another chemical activity and separation of charges surface cleanliness normal load and temperature duration of contact and separation rate. 3-2 Solid-solid contact A representation contact between solids is shown schematically in fig-chp3\chp3-fig3.pptx 6
Image of page 6
7
Image of page 7
the 8
Image of page 8
3.2.2
Image of page 9
Image of page 10

You've reached the end of your free preview.

Want to read all 48 pages?

  • Fall '19
  • Msc. Amar Yemim

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture