Page 157 - Mechanics of Microelectromechanical Systems
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144 Chapter 3
Figure 3.12 U-spring design with sharp corners
The stiffness is the element of the stiffness matrix (which is the inverse of
the compliance matrix consisting of the elements defined in Eqs. (3.35)
through (3.40)) located on the first row and first column. Similarly, the
stiffness is the element placed on the second row – second column position
of the same stiffness matrix. The definition stiffnesses are simply the inverses
of the corresponding compliances, and
The stiffness about the z-direction is calculated in the definition sense that
has been introduced in the previous chapters and was also mentioned
previously in Eq. (3.30) for instance. Its expression is found by taking the
ratio of a force which is applied at point 1 in Fig. 3.12 about a direction
perpendicular to the plane of the microdevice to the corresponding
displacement namely:
