Detection of the Crack in Cantilever Structures Using Fuzzy Gaussian Inference Technique.

Detection of the cracks in beam structures using the fuzzy Gaussian inference technique has been investigated in this paper. The fuzzy-logic controller used in the present investigation consists of six input parameters and two output parameters. The input parameters to the fuzzy controller are the relative divergence of the first three natural frequencies and first three mode shapes in dimensionless forms. The output parameters of the fuzzy controller are the relative crack depth and relative crack location in dimensionless forms. To derive the fuzzy rules for the controller, theoretical expressions have been developed considering four parameters such as natural frequencies, mode shapes, crack depths, and crack locations. The strain-energy release rate has been used for calculating the local stiffnesses of the beam for a mode-I type of the crack. Several boundary conditions are outlined that take into account the crack location. Required fuzzy rules are derived for the fuzzy Gaussian controller. The experimental setup has been fabricated in the laboratory 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 with the real results. [ABSTRACT FROM AUTHOR]