<title>Analysis and design of thin-walled smart structures in industrial applications</title>

Abstract

The utilization of the smart structures technology gains increasing attention in engineering and industrial applications, especially in the wide field of noise and vibration reduction of thin-walled structures. The application of distributed sensors and actuators - e.g. piezoelectric wafer or fiber arrays - directly attached at the structure or laminated into a composite structure results in a highly integrated smart structural system. An optimal exploitation of such facilities of piezoelectric materials requires effective and robust numerical tools for an optimal overall design. In our opinion the finite element approximation based on multi-field thin shell elements provides an excellent method for the simulation and the design of complex smart structures. In the paper a brief introduction in our finite element simulation and design tool is given where the focus is on the recently developed multi-field finite shell elements. These elements have been created on the basis of the classical SemiLoof element family by introducing additional degrees of freedom to approximate the electromechanical coupling. One central point in the design process is the distribution of the active material at the passive base structure to fulfill the design criteria. In the paper a design concept based on controllability and observability indices is presented, which results in an acceptable first design even in complex industrial applications. In connection with a flexible automatic meshing, which generates the overall model for structures with any amount and distribution of active wafers, the overall behavior of a smart structure can be simulated quite accurate. To underline the capability of the design and simulation tool two examples with references to mechanical and automotive applications are discussed.