ISBN-13: 9781842650097 / Angielski / Twarda / 2000 / 352 str.
This book aims at outlining the steps involved in estimating blade life. The blade life estimation is a multifaceted technology involving free and forced vibrations of blades, damping, aerodynamic and mechanical excitation forces that lead to the determination of steady and dynamic stresses at different critical speeds during the startup and shutdown procedures as well as in the operational speed range. These steps are clearly explained for different variety of blades using special computer codes or commercially available finite element packages. The life of a blade is then determined by using cumulative fatigue damage theories. Both linear and nonlinear theories are considered and examples given. Both low and high cycle fatigue cases are considered. The local stress-strain approach is clearly explained with practical examples for crack initiation life calculations. Linear elastic fracture mechanics principles are then explained that lead to the stress intensity factor methods for crack initiation. Propagation and unstable fracture are described with practical examples to estimate blade life. This book is written to help both the practicing engineer as well as a researcher in the university and laboratory in understanding the various aspects of life estimation. The material provided is useful at both the design stage and diagnostics of blade failures.