Page 270 - Mechanics of Microelectromechanical Systems

4. Microtransduction: actuation and sensing 257
Other transduction implementations, especially in microfluidics, utilize
various basic principles such as dielectrophoresis, surface-tension, liquid-
vapor phase change or microbubbles.

Problems

Problem 4.1
A bent beam thermal actuator needs to be able to deliver its mechanical
output around an operation point that lies within a domain bounded by
and Determine the inclination angle satisfying this
condition. Known are also the length l, the cross-sectional area A and the
moment of inertia

Answer:

Problem 4.2
Determine the optimal value of the inclination angle of a bent beam
thermal sensor that will maximize the free displacement for a temperature
increase Known are the coefficient of thermal expansion
the length and the cross-sectional dimensions

Answer:

Problem 4.3
A two-beam polysilicon thermal sensor is defined by the following
geometric parameters: Design the rectangular
cross-section of this sensor (w and t) which will produce a tip rotation
under a temperature increase of The coefficient of thermal
expansion is

Answer:
t can be chosen arbitrarily

Problem 4.4
A geometric envelope of is available for the design of a
thermal actuator of maximum bloc force. In case the cross-section of the
flexible beams is specified decide whether a bent beam
actuator or a two-beam design constitutes the best solution. (Hint: Study the
bloc force ratio).