3D modeling of imperfect contact conditions between turbine blades and disk

Imperfect contact conditions occur between turbine blade roots and the rotor disks. This happens because of imperfections in the geometry of the two interlocking parts. Thus it is necessary to include 3-D contact and friction in the nonlinear computation of the stress state. A finite element formulation and solution strategy is developed in this paper. The paper also presents the results of such simulations and quantifies the errors which result if the aforementioned behavior is not considered. The computer implementation of this capability and the tools to create and visualize the 3-D model using an interactive program, BLADE{trademark}, are also described. Examples are chosen to incorporate features such as curvature of the root, multiple hooks, and various types of root geometry, and to emphasize the importance of a three-dimensional simulation. The key results presented here would be of interest to designers, as well as the engineers who are involved with evaluating the safety or remaining life of bladed disks.