Page 329 - Mechanics of Microelectromechanical Systems
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316 Chapter 5
Figure 5.49 Stability-related conditions: (a) Stable; (b) Neutral equilibrium; (c) Unstable
Figure 5.50 Finite element model showing out-of-the-plane buckling of a thin column
Figure 5.51 Buckling of a thin ring: (a) Undeformed; (b) Finite element model of the out-
of-the-plane deformed shape
A perturbation will displace the ball, as shown in Fig. 5.49 (a), but the stable-
equilibrium position (denoted by SE) will be regained after the perturbation
ceases. In the case of Fig. 5.49 (b), any position is one of equilibrium, for
instance the ball will move from one equilibrium position to a
subsequent one after the perturbation ends, and therefore this situation is
one of neutral equilibrium (NE). On the contrary, when a perturbation is
