Modal Analysis And Life Prediction Of Turbine Blade

With more and more power units making and putting into production, it's very important to provide the correct dynamic (static) state parameter to improve the blades design and analyze life prediction of the blades for safe operation.Modal analysis is a experimental and analytic technique to analyze the dynamic performance of machines, establish the dynamic models and optimize the parameters. It's very powerful in the research fields of space and aviation, now, in the vibration performance research of turbine parts it's also very useful. Weibull distribution is one of the extensively used continuous distribution to analyze the life distribution of fatigue failure, it's very practical in the description of blades' life distribution of Power Plant. By using Weibull distribution, it's very fast and easy to estimate the natural parameters, and the result gained is available.Cracked blade of low pressure cylinder of domestic 300MW turbine in Huang Pu power plant is analyzed in this paper, on the basis of the vibration and dynamic signal collecting system constructed, the real reason of blade crack is found from the repeated measurement and analysis of the blade in lab and crack character of blade, which is very meaningful to safe operation; Different stage self-oscillation frequency and mode are gained by finite element calculation of blade's main mode using ANSYS software. It is clear that repeated measurement and analysis of the blade in lab and finite element calculation results are matched well in main self-oscillation frequency and mode, which prove that experiment dates are convinced and reliable. Proved with corresponding experiments, the influencing factors of the blade modal experiment are presented and analyzed. At last, life prediction of the blade is estimated and analyzed by using Weibull distribution.