Influence of Manufacturing Tolerances on Vibration Frequencies of Turbine Blade

High Cycle Fatigue is one of most common mechanism of turbine blade failures. The reason are vibrations, which cause cyclic displacements and though that also variable stresses and strains. The most dangerous are excitation frequencies around resonances - that can cause failure in a very short time. About 70 years of jet engine development and more than one century of steam turbine history, was not enough to fully eliminate that problem. This paper shows an influence of manufacturing tolerances and accuracy of manufacturing technology on blade frequencies. Additionally, few methods for avoiding resonances have been presented and its implementation effort have been compared.