It appears that for complicated shell structures with piezoelectric components, idealized by the finite element method (FEM), and under stochastic disturbances, a very limited number of active control strategies exists in the literature. In the present investigation, a mixed formulation based three node lower order triangular shell finite element with and without piezoelectric effects has been developed and employed for the modeling of complicated shell structures embedded with piezoelectric components. Its main features are: (i) in every node there are 7 degrees-of-freedom (dof) which include 3 translational, 3 rotational and one piezoelectric dof, (ii) it is free from shear and membrane lockings, and (iii) it can provide correctly the 6 rigid body modes. The stochastic optimal control strategy adopted in the present investigation is the state covariance assignment method of Skelton and associates (1985, 1986, 1987). It provides a direct approach for achieving performance goals stated in terms of the root-mean-square (RMS) values which are common in many engineering system designs. In this presentation, representative computed results are compared with those obtained by the Monte Carlo simulation (MCS). As a caveat it is shown that for a certain combination of performance goals no displacement feedback control is possible. This, in turn, implies that control is achieved by increasing system damping only.
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