Abstract
To improve the reliability and the thermal efficiency of LP end blades of steam turbine, new standard series of LP end blades have been developed. The new LP end blades are characterized by the ISB (Integral Shroud Blade) structure, where the blades are continuously coupled by blade untwist due to centrifugal force. One of the most important technologies to design the ISB structure with high reliability is the analysis method of resonant stress of the blade. This paper presents the analysis method of the resonant stress of the ISB structure, which is caused by the lower engine order excitation force and the stage interaction force. The measured and calculated resonant stresses are compared to show the validity of the prediction method of the resonant stress.
