Numerical Analysis of Crack Propagation and Life Estimation of Curtis Stage Blade of a Steam Turbine

During the operation of a turbomachine the parts most exposed to the alternative forces are the blades. The Curtis stage blades are then subjected to high alternative loads which may cause forced vibrations and these may fracture and fatigue the blades, affecting the integrity of the machine and causing its consequential shut down. In this paper the numerical analysis of crack propagation in Curtis stage blade subject to forced vibrations is presented. A finite element model of the Curtis stage blade was constructed. The natural frequencies, the steady and dynamic stresses were calculated according to life estimation. The stresses due to forced vibration were estimated using the alternative forces based in computed numerical fluid dynamics from a previous study.Copyright © 2007 by ASME