تحلیل دینامیکی دیسک و پره دارای شراد و تماس اصطکاکی

In this research, a finite element model of a gas turbine's bladed disc with a shroud was developed, incorporating frictional contact and the cyclic symmetry condition for dynamic analysis. The engineering requirements of the design process were also investigated. The developed model accurately calculates dynamic stresses by considering the blade passing frequency and frictional damping in the contact region. A primary challenge in gas turbine engines is the high-cycle fatigue (HCF) failure of turbine blades caused by blade resonance during operation. To prevent failure, increase the damping of vibrations, and enhance stability, researchers and turbomachinery manufacturers use friction dampers such as shrouds and under-platform dampers. These dampers provide an effective method for energy dissipation and natural frequency shift through friction-impact contact. Vibrational analysis of shrouded blades is essential for blade design, dynamic stress prediction, and high-cycle fatigue life determination. The computations in this study comprise three main parts: (1) Creating an efficient reduced-order model using cyclic symmetry, capable of static and dynamic analysis of the assembled disc and blade under aeromechanical forces. (2) Performing a nonlinear static analysis considering centrifugal forces, temperature, and pressure. The friction-impact contact model in this research is based on the Coulomb model and simulates the macro-slip phenomenon. (3) Conducting a free vibration analysis of the disc and blade using cyclic symmetry to extract the Campbell diagram, which is a crucial prerequisite for the design of the disc and blade. (4) Performing a forced-response analysis of the disc and blade under dynamic excitation forces from blade transient flow to determine the dynamic stresses in the blade.