Structural dynamics sf stiffened plates with piezoceramic sensors and actuators

A dynamic model of a stiffened plate, developed for the purpose of analyzin g the coupling between piezoceramic transducers and the plate dynamics, is presented. The model is based on Hamilton's principle and discretized with a polynomial expansion of the transverse plate vibration, The effects of ec centric stiffeners, piezoceramic transducers, and point masses located on t he plate are accounted for in the model, To validate the model, the results of numerical simulations are compared with experiments on a rectangular al uminum plate with one eccentric stiffener and simply supported boundary con ditions. The model accurately predicts the first seven natural frequencies and mode shapes of the plate as well as the coupling between piezoceramic t ransducers and the plate vibration. A study of the plate natural frequencie s and transducer coupling over a range of stiffener heights reveals that fo r geometries with slight asymmetries and near repeated eigenvalues the corr esponding mode shapes are very sensitive to small changes in stiffener heig ht, For the structure studied in this work, the sensitivity of the mode sha pes caused the piezoceramic transducer modal strain energy fraction for the fourth mode to increase by 140% with only an 8% increase in stiffener heig ht, Over the same range of stiffener heights, the piezoceramic transducer m odal strain energy fraction for the symmetric structure's fourth mode only changed by 5%.