Analysis of the Effect of Break Edge in Load and Lock Slot of Circumferential Dovetail Disk of Gas Turbine Compressor

Aviation gas turbine compressor disk assemblies are subjected to high thermo-mechanical loads due to rotation, radial loads of blades and thermal gradients. They contain highly stressed three dimensional features like load slot and lock slot. The centrifugal loads of the blades are transferred to the disk through disk dovetail interface. The sharp edges in the load and lock slot features in the hardware are removed by incorporating a blending with small radius. The study involves evaluation of the impact on stresses at critical locations by modeling the blending in finite element (FE) model of circumferential dovetail disks. The impact of this blending on the stresses at critical locations in the load and lock slot and at the disk and blade dovetail interface is analyzed using UG CAD package and the FE analysis package ANSYS. Including this feature in the FE model takes a lot of effort. Hence, the need for considering this blending in the FE model during the design and analysis has to be justified. The above study is conducted on parametric models of fictitious configurations resembling compressor disks to assess whether there is any substantial change in stresses by incorporating blending in the load and lock slot (LLS) features, as the feature sizes vary depending on the engine size and the stage of the disk in the compressor. By analysis comparison is drawn between with and without break edge and concluded that there is not of much variation in stresses by modeling break edge in LLS.