An analytical model of cracked composite shell is developed to study the characteristics of the natural vibration of composite aircraft wing in relation to crack position and orientations. Also, the analysis incorporates the effect of stacking sequence of the composite lamina and volume fraction of fiber to matrix response to natural vibration. The composite wing is modeled as a shell using ANSYS software. The local flexibility approach based on linear fracture mechanics is used to model the crack and a local compliance matrix at the crack location is derived. Changes in natural frequencies and mode shapes of the cracked shell are investigated. The spectrum of the natural frequency reduction, along with observations on the mode shape changes indicated by this model, used to detect the crack location for on-line structural health monitoring SHM).
