Experimental Study of Crack Identification in Thick Beams with a Cracked Beam Element Model

Abstract

Model-based crack identification in beam-like structures has been a classic problem. The authors have recently developed a framework to identify crack damage in beams based on a cracked beam element model, which stems from the local flexibility and fracture mechanics principles. This paper presents an experimental study on the cracked beam element model for crack damage identification in a physical testing environment. Five solid beam specimens were prepared with different numbers of cracks, and they were subjected to a modal testing and analysis procedure to extract the natural frequencies and mode shapes. The extracted modal data were then compared with the predicted counterparts using the cracked beam element model to verify the accuracy of the model. The extracted modal data were also employed to inversely identify the cracks with the cracked beam element model through a model updating procedure. Results indicate that all the cracks can be identified correctly with accurate crack depth and location information. To enhance the modal dataset for FE model updating, the so-called 'artificial boundary condition' (ABC) technique has also been applied on the test beams, and the incorporation of such frequencies proves to enhance the identification of cracks from the FE model updating.

Damage Detection of Laminated Rubber Bearings Based on the Antiresonance Frequencies of Periodic Structure and Its Sensitivity Analysis

“…In addition, as the total number of natural frequencies is always limited in high-quality measurements [20], the available modal data that can be used in damage detection is usually incomplete. Natural frequencies and mode shapes are clearly inadequate in damage identification; thus, antiresonance frequencies have been applied to the finite element model updating and damage identification of structures [21][22][23][24][25][26][27]. Dilena [22] found that the appropriate use of natural frequencies and antiresonance frequencies could avoid the nonuniqueness of the damage location problem, which occurs in symmetrical beams when only frequency data are employed.…”

“…Sinou [25] detected the breathing crack of a pipeline beam based on the antiresonances of higher-order frequency response functions (FRFs). In an experimental study on the crack identification of thick beams, Hou [26] proved that the incorporation of antiresonance frequencies could enhance the modal dataset in finite element model updating. Another study involving model updating found that antiresonance frequencies could be used as an alternative of natural frequencies and mode shapes [27].…”

Damped vibration analysis of cracked Timoshenko beams with restrained end conditions

“…Apart from these studies, Thalapil et al [17] investigated the crack which is parallel to the longitudinal direction of the beam. In addition to these analytical studies, some experimental works were also carried out by Nahvi and Jabbari [18], Hou and Lu [19]. Altunisik et al [20] compared experimental results with analytical results.…”

Optimal Method for Identification of Cracks in Different Beams using Fuzzy with Elephant Based Neural Network

“…As indicated by the reaction of the structure in various stages, parameters responsible for structural damage are picked as the system input vector, structural damage stages are selected as output vector, and the preparation test set is set up through the feature extraction [13]. In a numerical reenactment study in which the genuine impact of the crack on the dynamic properties of the beam was reenacted by a precise solid finite component model permitting unequivocal portrayal of the cracks and after that contrasted with the forecasts utilizing the cracked beam component [14,15]. Be that as it may, if different damage situations are seen from the distance along the beam, Artificial Neural Network will be utilized to additionally affirm the areas damaged and additionally to evaluate damage severities in all areas.…”