In this paper, we introduce a vibration based method using changes in frequencies to detect delamination damage in composite beams. The basis of the present detection method is to first determine how changes in natural frequencies are related to the location and severity of delamination damage and then use this information to solve the inverse problem of predicting the delamination characteristics from measured frequency changes. To study the forward problem, a theoretical model of composite beams with delaminations is built to obtain the natural frequencies as a function of delamination sizes and locations. The inverse detection of delamination is realized using a graphical method, which makes use of frequency changes in multiple modes to assess the damage characteristics. The efficiency and accuracy of the present method are validated using experimental results reported in literature
