ROOT AND GROOVE CONTACT ANALYSIS FOR STEAM-TURBINE BLADES

The reliability of the rotating blades is the most important factor in improving the reliability of steam turbines. The peak stress of the blade root and the disc groove which support the large centrifugal force of the blade should be analyzed accurately in order to assure the mechanical strength for both steady and vibratory stresses. The three-dimensional finite-element method is applied to the peak stress analysis considering slippage at the contact surface between the blade root and the disc groove. Nonlinear calculation is usually carried out to deal with the slippage effect. In this paper the appropriate methods to calculate the accurate local peak stress of the blade root and the disc groove are discussed, including nonlinear and linear analysis.