Identification of Multiple Cracks in Composite Laminated Beams Using Perturbation to Dynamic Equilibrium

Abstract

Identification of cracks in beam-type components is significant to ensure the safety of structures. Among the approaches relying on mode shapes, the concept of transverse pseudo-force (TPF) has been well proved for single and multiple crack identification in beams made of isotropic materials; however, there is a noticeable gap between the concept of TPF and its applications in composite laminated beams. To fill this gap, an enhanced TPF approach that relies on perturbation to dynamic equilibrium is proposed for the identification of multiple cracks in composite laminated beams. Starting from the transverse equation of motion, this study formulates the TPF in a composite laminated beam for the identification of multiple cracks. The capability of the approach is numerically verified using the FE method. The applicability of the approach is experimentally validated on a carbon fiber-reinforced polymer laminated beam with three cracks, the mode shapes of which are acquired through non-contact vibration measurement using a scanning laser vibrometer. In particular, a statistic manner is utilized to enable the approach to be feasible to real scenarios in the absence of material and structural information; besides, an integrating scheme is utilized to enable the approach to be capable of identifying cracks even in the vicinity of nodes of mode shapes.

Numerical Simulation of the Bearing Capacity of Variotropic Short Concrete Beams Reinforced with Polymer Composite Reinforcing Bars

“…Of course, such tasks should be approached in a comprehensive manner, and building elements made of heavy concrete with various reinforcing elements should be evaluated as a system operating in conditions of a certain synergy [ 24 , 25 , 26 , 27 , 28 , 29 ]. Such synergy, as we have already established earlier, can be complex reinforcement, namely, fiber plus reinforcing bars, improved concrete characteristics due to their nanomodification or the same fiber reinforcement with fibers [ 30 , 31 , 32 , 33 , 34 ]. However, in addition to the above methods, it is also promising to create so-called differentiated building elements, particularly in their cross section [ 35 , 36 , 37 , 38 , 39 , 40 ].…”

Wavelet and Lipschitz exponent based damage identification method for beams using mode shapes

“…In this study, the notch is considered always in the open state so that the structural response can reflect the effect of damage. At the location of damage, the induced abnormality in the displacement field (both static deflections and mode shapes) will result in a local peak value of wavelet coefficients [2][3][4][5][6][7]. Common methods to determine the location of these local peaks include the use of a 2D color map [2,3,8] or the use of combined wavelet coefficients through different scales [9,10].…”

“…Kumar and Singh [8] compares the use of 100, 200, and 1000 measurement points for the application of CWT for damage detection and indicates that the accuracy of the results is affected significantly. Hence, numerical studies on this topic consider usually a high number of measurement points and the experimental studies are conducted with measuring systems that can obtain a dense measurement grid, such as laser scanning [7,11] and photogrammetry measuring system [1,8,[12][13][14]. In Table 1, the number of samples in some relevant research studies are listed.…”