A layered shell containing patches of piezoelectric fibers and interdigitated electrodes: Finite element modeling and experimental validation

The work gives a theoretical and experimental contribution to the problem of smart materials connected to double curved flexible shells. In the theoretical part the finite element modeling of a double curved flexible shell with a piezoelectric fiber patch with interdigitated electrodes (IDEs) is presented. The developed element is based on a purely mechanical eight-node isoparametric layered element for a double curved shell, utilizing first-order shear deformation theory. The electromechanical coupling of piezoelectric material is added to all elements, but can also be excluded by setting the piezoelectric material properties to zero. The electrical field applied via the IDEs is aligned with the piezoelectric fibers, and hence the direct d33 piezoelectric constant is utilized for the electromechanical coupling. The dynamic performance of a shell with a microfiber composite (MFC) patch is investigated using frequency response functions (FRFs) obtained via external impact test as well as internal random signal excitation using the MCF patch as an actuator. The experiments are used to validate the numerical results. Good agreement between theory and experiments is obtained in a large frequency range. Discrepancies and insights into optimal modeling frequency range and non-linear behavior are discussed.