Page 100 - Tribology in Machine Design

86 Tribology in machine design

where R is the undeformed radius of curvature and E denotes the elastic
modulus of a material.
Employing these contact radii in the low and high speed cases discussed
in the previous section gives the following equations for the average
increase in contact temperature
- plastic deformation, low speed (L<0.1)

- plastic deformation, high speed (L> 100),

- elastic deformation, low speed (L < 0.1),

- elastic deformation, high speed (L> 100),

3.7.8. Maximum attainable flash temperature
The maximum average temperature will occur when the maximum load per
unit area occurs, which is when the load is carried by a plastically deformed
contact. Under this condition the N and L variables discussed previously
become

Then at low speeds (L<0.1), the heat supply is equally divided between
surfaces 1 and 2, and the surface temperatures are

At moderate speeds (0.1 ^L^ 5), less than half the heat is supplied to body
1, and therefore

where /? ranges from about 0.95 at L=0.1 to about 0.5 at L = 5. At very high
speeds (L> 100), practically all the heat is supplied to body 2, and then

At lower speeds (5<L< 100), less heat is supplied to body 2 and