In this paper, the structural mode shapes extracted from the finite element model of a simply supported reinforced concrete beam are employed for damage identification using different types of wavelets. To start with, the parity of signals, wavelets, and their convolution, that is, wavelet transform properties, are verified. In light of the mathematical modeling complexity of modal frequency, which relates to the localization and quantification of damage in the reinforced concrete beam, the maximum curves based on multiresolution wavelet transform coefficient differences and the corresponding theoretical assumptions are described and analyzed. It is concluded that the maximum curve reaches a peak value at a specific scale for a specific case, based upon which, a new mode shape based algorithm and damage index are proposed for damage identification. The accuracy of localization as well as the sensitivity of quantification is further discussed.

A three-nodded beam finite element is developed for the analysis of compositelaminated beams with distributed piezoelectric sensor/actuator layers. The mechanical part of the proposed element is based on the refined sinus model. This element does not require shear correction factor and ensures continuity conditions for displacements, transverse shear stresses as well as boundary conditions on the upper and lower surfaces of the beam. This conforming finite element is totally free of shear locking, and the number of mechanical unknowns is independent of the number of layers. For each piezoelectric layer, a high-order electrical potential field is considered. The virtual work principle leads to a derivation that could include dynamic analysis. However, in this study, only static problems have been considered. Comparison of numerical results obtained from this formulation with previous works shows that the present finite element is suitable for predicting fully coupled behaviors of both thick and thin smart-laminated beams under mechanical and electrical loadings.

No abstract

No abstract

The harmonic displacement response of a beam is utilized as the input signal function in wavelet analysis. Sudden changes in the spatial variation of transformed response identify the location of damages and defects. The damage incurred causes a change in the stiffness or mass of the beam. This causes a localized singularity which can be identified by a wavelet analysis of the displacement response. In this article, it is shown that using harmonic response is superior to the static deflection response and this approach is more effective in the presence of noise and more sensitive to the versatility of the applied harmonic loads.