Detection of Crack in a Simple Unswept Wing Using Free Vibration Analysis


The present research is concerned with an investigation of the vibration characteristics of a cracked wing structure. Finite element method has been used to formulate the free vibration analysis. Ansys v9.0 program as a mathematical tool was used in implementation the analysis and extract the results. Effect of several parameters such as (effect of crack ratio, crack location, and crack inclination angle) on the natural frequencies and mode shapes were studied. The results indicate that the natural frequencies are affected in the presence of a crack; but it doesn’t give an indication to the crack location. While, using mode shape is a powerful tool to detect the crack and its magnitude along the wing’s length. The crack inclination angle is investigated to show its effect on the crack identification where relatively little error may appear if crack angle wasn’t normal to the wing axis. Also the presence of the crack may cause to transform and exchange the modes between each other depending on the crack location and its magnitude.