Smart Detection of Damage in a Cracked Cantilever Beam Using Artificial Intelligence

Abstract

Increasing attention is being given to the detection of damage in structures. For this purpose different newer techniques are being used. In this paper a defect in a cantilever beam in the form of a transverse crack, is investigated using smart techniques such as Fuzzy Logic 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 outlined which take into account the crack location. Several fuzzy rules are derived and the Fuzzy controller has been designed accordingly. The experimental setup has been developed for verifying the robustness of the developed fuzzy controller. The developed fuzzy controller can predict the location and depth of the crack in close proximity to actual results.