ABSTRACT:The objective of this paper is to update its readers the various vibration based Crack/damage diagnosis techniques presented by various researchers for a cracked structures. These methods use "finite element analysis techniques, together with experimental results, to detect damage in a fibre reinforced composites, laminated composites and non composite structures for its vibration analysis. Damage in structure alters its dynamic characteristics. It results in reduction of natural frequencies and changes in mode shapes, stiffness of the beam. An analysis of these changes makes it possible to determine the position and depth of cracks.