JKR and Other Adhesion Models

DMT Model

 For DMT Model, the approximate expression for the contact radius is given as

(20)

or

(21)

Variation of the nondimensional contact radius with the nondimensional force as predicted by the DMT model is shown in Figure 2 and is compared with the JKR model.  Note that for , Equation (21) and Figure 2 shows that .

The corresponding resistance moment as a function of nondimensional force as predicted by the DMT model is given as

(22)

The variation of the resistance moment as predicted by the DMT model is also shown in Figure 3. The corresponding maximum resistance moment is

(23)

Note also that the maximum force (the poll-off force) is given by

(24)

and

(25)

Comparing Equations (17) and (23) shows that the JKR model predicts a larger resistance moment. That is

,  ( )

(26)

The resistance moment predicted by the JKR and the DMT models in dimensional form are given as

,

(27)