The design of structural health monitoring (SHM) systems usually involves the selection of actuators and sensors, defining their positions on the structure, and post-processing output signals. The definition of the characteristics of the excitation signals before investigating the structural condition is also an important task to be considered to establish a damage detection process. In this context, the present article introduces an approach to determine the optimal parameters to detect symmetric damage in plates when considering perpendicular incidence of flexural waves in the damage. Circular piezoelectric transducers are applied to create and measure the waves. Optimal frequencies to detect the damage, create and measure the flexural waves are observed, which are described in terms of the properties of damage and the piezoelectric transducers, and these frequencies must be close to guarantee good damage detectability. Experimental tests are carried out by considering a rectangular aluminum plate with circular piezoelectric transducers coupled to its surface. Experimental results demonstrate the proposed approach, and the results show that it contributes to establishing more efficient SHM systems.
Detecting incipient damage in structures is an important challenge for the engineering community. The design of structural health monitoring (SHM) systems usually involves strategic definition of the excitation signal, selecting the best frequencies to avoid false alarms. In this sense, the present article introduces an approach to determine the optimal frequencies for asymmetrical damage detection in plates considering perpendicular incidence of longitudinal and flexural waves incoming in the damage. Numerical simulations are carried out by considering an aluminum plate, and the results show that the approach contributes to the establishment of more efficient SHM systems.
Frequency domain modeling has been developed to different engineering applications. In particular, the Spectral Element method (SEM) has been discussed in literature mainly for vibration control design and structural health monitoring once it allows to study unlimited range of frequencies. However, although different authors discuss classical control techniques like PID for SEM formulations there is a limited number of works involving modern control theory based on state space representation. In this context, this work introduces a new approach that allows to use feedback techniques in vibration control design based on SEM. The formulation is presented and numerical simulations are performed using the Timoshenko beam model with two PZT patch bonded. The PZT transducer effects are included too. Results show vibrations reductions of the first three modes of a campled-clamped beam and the proposed approach offers promise to control design using SEM.
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