JKR and Other Adhesion Models
DMT Model
For DMT Model, the approximate expression for the contact radius is given as
![](formulas2/image078.gif) |
(20) |
or
![](formulas2/image080.gif) |
(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
![](formulas2/image084.gif) |
(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
![](formulas2/image086.gif) |
(23) |
Note also that the maximum force (the poll-off force) is given by
![](formulas2/image088.gif) |
(24) |
and
![](formulas2/image090.gif) |
(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
,
![](formulas2/image098.gif) |
(27) |
|