JKR Contact Mechanics Theory (contd...)

However this is not a problem, when the surfaces attract each other, so that the contact pressure is compressive not through the whole area of contact but only towards ther center and towards the periphery it is tensile:

This pressure distribution results in how the deformed profiles of the spheres contact each other, whereas in Hertzian mechanics, the interfaces meet tangentially, in this situation they meet perpendicularly with adhesive forces.

As a result, the actual contact radius is not equal to and . Here we will find out how to obtain this actual contact radius.