Forced vibration problem of a delaminated beam made of fiber metal laminates is studied in this paper. Firstly, a delamination is considered to divide the beam into four sections. The classic beam theory is assumed to dominate each section. The layers on two sides of the delamination are constrained to have the same deflection. This hypothesis approves the conditions of compatibility as well. Consequently, dynamic response of the beam is obtained by the means of differential transform method (DTM). In order to verify the correctness of the results, a model is constructed using commercial software ABAQUS 6.14. A linear spring with constant stiffness takes the effect of contact between delaminated layers into account. The attained semi-analytical outcomes are in great agreement with finite element analysis.
 Ramkumar R. L., Kulkarni S. V., and Pipes R. B., "Free VibrationFrequencies of a Delaminated Beam", Annual Technical ConferenceProceedings34, Reinforced/Composite Institute, Society of Plastics Industry Section22-E, PP 1–5, 1979.
 Wang J. T. S., Liu Y. Y., and Gibby J. A., "Vibration of Split Beams", Journal of Sound and Vibration 84(4), PP491–502, 1982.
 Oveysi H. R., Kharazi M., "Stability Analysis of Composite Plates with Through-the-Width Delamination", Journal of Engineering Mechanics 137(2), PP 87-100, 2011.
 Anastasiadis J. S., and Simitses G. J., "Spring simulated delamination of axially loaded ﬂat laminates", Composite Structures17, PP 67–85, 1991.
 Kargarnovin M. H., Ahmadian M. T. and Jafari-Talookolaei R.A., "Analytical solution for the dynamic analysis of a delaminated composite beam traversed by a moving constant force", Journal of Vibration and Control 0(0), PP 1–14, 2012.
 Rashidifar MA., Rashidifar AA., "Analysis of Vibration of a Pipeline Supported on Elastic Soil Using Differential Transform Method", American Journal of Mechanical Engineering 4, PP 96-102, 2013.