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Because of the special material properties, the direct pie-
zoelectric effect and the converse piezoelectric effect, piezo-
electric material can be used as sensors or actuators. The con-
cept of using a network of piezoelectric sensors and actuators
to form a self-monitoring and self-controlling "smart system"
has recently drawn considerable interest. Consider a composite
plate containing piezoceramics on both upper and bottom
surface. Based on the piezoelectricity with consideration for
the coupling between the strain field and the electric field, a
finite element formulation is developed. An eight-node three-
dimensional brick element is used, and three- dimensional
incompatible modes are introduced to take into ac- count the
bending behavior of the structure. This study uses this code to
analyze the response of the structure subjected to different
boudary conditions and loading conditions. As the sensor
electrical output is known, an inverse method is imple- mented
to determine the voltage that should be applied to the actuator
to reduce the deflection to a minimum. This study in- cludes
different optimization method in the inverse analysis, and
provides a model of direct control. The results of this study
show that the deflections resul- ting from thermal loading
could be reduced from the inverse analysis. An active control
algorithm could be obtained based on enough analytical data.
The optimum voltage of actuator is easy to determine from the
control algorithm.
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