Failure analysis of turbine disc of an aero engine

Finite element analysis of fir-tree region in turbine discs

In this paper, the effect of blade crack on the mode localization of a rotating blade disk is studied. Pretwisted taper beams are used to simulate blades of a blade disk. The crack on the blade can be regarded as a local disorder of this periodically coupled blades system. An application of Hamilton's principle and Galerkin's method is used to formulate the equations of motion of the mistuned system. Effects of pretwisted angle, rotating speed, and crack depth of the blade on the in-plane and off-plane mode localizations of a rotating system are investigated. Numerical results indicate that the increase of rotating speed pretwisted angle, and crack depth coula enhance the localization phenomenon significantly.

Mode Localization of a Cracked Blade Disk

Management of the variability of vibration response levels in mistuned bladed discs using robust design concepts, Part 1: Parameter design

Management of the variability of vibration response levels in mistuned bladed discs using robust design concepts. Part 2

When calculating the resonant response of bladed turbine disks, it has been expedient to assume that all blades on a given disk are identical. This leads to the prediction that all blades experience the same amplitude of displacement and stress when excited by forces harmonically related to the rotor speed. However, it has been shown experimentally that significant variations in these amplitudes occur for different blades on the same disk. These variations arise due to the effects of mistuning, which refers to small differences in blade characteristics. In this paper, effects of mistuning for free-standing blades and integral shroud blades are studied by means of Monte Carlo simulation and sensitivity analysis. It is found that weakly coupled systems with low damping are very sensitive to mistuning. Also, the validity of the lumped model used in this paper is examined by comparing the calculated results with experimental data.

Vibrational Response Analysis of Mistuned Bladed Disk.

Vibrational Response Analysis of Mistuned Bladed Disk

Root and Groove Contact Analysis for Steam Turbine Blades

Recently, in order to improve power plant thermal efficiency, the turbine blade, which is the most important element of the power plant, has been used in severe conditions where high loading is in effect. Therefore, for the purpose of increasing plant reliability, we must establish a precise calculation method and optimal design procedure of the blade, taking its specific characteristics into consideration. In this paper, an effective autotuning technique of the blade's natural frequencies by combining sensitivity analysis with nonlinear programming is presented, and its application is shown. In the blade design, many natural frequencies must be tuned between engine order frequencies, satisfying various constrained conditions which result from such requirements as thermal efficiency and manufacturing. The new optimal technique in this paper is very useful for such blade design because a blade profile having the required natural frequencies can be obtained automatically.

Katsuhisa Fujita

Papers

Vibrational Response Analysis of Mistuned Bladed Disk.

Vibrational Response Analysis of Mistuned Bladed Disk

Root and Groove Contact Analysis for Steam Turbine Blades

Optimal Design of Turbine Blade using Sensitivity Analysis

Optimal Design of Turbine Blade by Sensitivity Analysis.