Fault Detection of Cracked Cantilever Beam Sing Smart Technique

Abstract

Over the years damage detection in structures is being given prior attention. For this purpose different newer techniques are being used so far. In this investigation defect in cantilever beam in the form of a transverse crack is being investigated using smart Technique like Fuzzy Logic. Gaussian membership functions are used for the Fuzzy Controller. The input parameters to the Fuzzy Controller are relative divergence of first three natural frequencies and the output parameters of the Fuzzy Controller are relative crack depth and relative crack location in dimensionless forms. For deriving the fuzzy rules for the controller; theoretical expressions have been developed considering three parameters such as; natural frequencies, crack depths and crack locations. Strain energy release rate has been used for calculating the local stiffnesses of the beam. The local stiffnesses of the beam are dependent on the crack depth. Different boundary conditions are being outlined which take into account the crack location. Several fuzzy rules are derived and the Fuzzy controller has been designed accordingly. Experimental setup has been developed for verifying the robustness of the developed fuzzy controller. Finite Element Analysis is performed on the single and double cracked cantilever beam to obtain the modal natural frequencies. The proposed approach is verified by comparing the results obtained from the numerical analysis and the developed experimental set-up. And it was observed that the Fuzzy Controller can predict the location and depth of the crack in a close proximity as par with the actual results.