Page 325 - Mechanics of Microelectromechanical Systems

312 Chapter 5
in Fig. 5.44. Find the deformed position at the free end defined by,
and by using the large-displacement theory and compare it with the
results given by the small-displacement theory when the force F increases
from to Consider that Young’s modulus is 130 GPa.

Solution:
The tip angle is found by solving Eq. (5.135) for the large-
displacement theory and Fig. 5.45 (a) is the plot of this angle against the
force, whereas Fig. 5.45 (b) shows the angle when calculated by means of
the small-deflection hypotheses, according to which:

Figure 5.45 Tip rotation angle according to the: (a) large-displacement theory; (b) small-
displacement theory

It can be noticed that the predictions of the small-displacement theory are
always higher than the ones of the large-displacement model, and for large
values of the force F the difference in results is more than 250%.