Fuller and Tabor modelFuller and Tabor model

where:

K is the coefficient of reduction in adhesion by asperity deformation forces;

E is the Young's modulus [Pa];

σ is the standard deviation of the asperity height distribution (RMS) [m];

r is the average radius of curvature of individual asperities [m];

Δ is the change in surface energy on contact between the two surfaces [J/m2].

It is assumed that for K < 10 strong adhesion occurs, while for K > 10 It is assumed that for K < 10 strong adhesion occurs, while for K > 10

asperity deformation forces cause the net adhesion force for elastic asperity deformation forces cause the net adhesion force for elastic

materials to be small.materials to be small.

dependence of adhesion on surface roughness for elastic solids:

Schematic diagram of asperity junction growth under frictional force

where:

F is the friction force [N];

W is the normal force (load) [N];

Ar is the real area of contact with tangential force present [m2];

Aro is the real area of contact in the absence of tangential force [m2].

Adhesion between gear teeth resulting in scuffing

The Delamination theory of Wear