Exploring vibration based method for crack detection in turbine blade

In case of a low pressure steam turbine the crack like flaws due to low cycle fatigue (LCF) is one of the main reasons for its premature failure as reported by various researchers. Non destructive testing (NDT) methods like dye penetrate, magnetic particle induction, acoustic, ultrasonic etc. are used for detection of crack which are very costly and time consuming task. Also vicinity of the fault has to be known beforehand and area has to be readily accessible. Since last two decades lot of research has been done in using vibration analysis to detect crack in beams by using modal parameters like natural frequency, mode shape, damping etc. In this research work an attempt is made to extend vibration characteristic based method for detection of crack in turbine blade. The finite element method is used with development of stiffness matrix for cracked element from the theory of linear elastic fracture mechanics.