Measurement of rotational FRFs in isotropic beams and plates using piezoceramic bimorphs including genetic algorithm optimization

In this work, an attractive low cost approach for accurate measurement of angular motions is presented. A recently proposed technique using PZT transducers seems quite interesting since it uses bimorph piezoceramic patches to measure the structure's local curvature through the measurement of the electric potential induced by the extension and compression of the patch's top and bottom stripes, respectively. From this curvature, rotation can be obtained directly by several interpolation techniques (single polynomial, mode shapes basis). Finite element models for the dynamic analysis were proposed to evaluate bimorphs patches applied to the measurement of angular degrees of freedom for one-dimensional structures, like a beam, and for two-dimensional structures, like a plate. Theoretical modeling of the vibration incorporating piezoelectric bimorph sensor is presented and equations governing the dynamics of beam and plate are derived for isotropic structures. Numerical results are compared with experimental data considering a cantilever beam. Also, in this work, a genetic algorithm was used as an adaptive heuristic search algorithm for optimal placement and sizing of the bimorph sensor.