Monitoramento da Integridade Estrutural de uma laje de concreto utilizando transformadas de wavelet

Abstract

This paper describes the methodology to locate the damage area on the concrete slab structure. The damaged structure is numerically simulated using the Finite Element Method (FEM). The vertical displacement signal has obtained is using for location of the damage area position employing the Discrete Wavelet Transform (DWT). The mother wavelets studied were: Daubechies, Symlets and ReverseBior. The damage on the slab is numerically simulated as one stiffness reduction in the concrete and the displacement signal obtained from the static analysis is interpolated and then amplified by means of the Tikhonov regularization. The finite element is quadrilateral with corner nodes only and each node has six degrees of freedom per node, i.e. three translations and three rotations. The calibration of Tikhonov regularization parameters b_j is important to amplify and smooth the perturbations of wavelet coefficients graphs. In addition, all the mother wavelets available in this paper have being able to identify the damage. Results suggest when the damage reduces the concrete modulus of elasticity more than 20% it is only necessary the knowledge of signal of damage structure to detect the damaged area position. For the smaller damage values it is required to know the different between the displacement signals about the undamaged and damaged structure.