Thermomechanical vibration behaviour of advanced composite rotating blades for high performance gas turbines

Abstract

Rotating blades are one of the most critical components of any gas turbine (GT) engine system. Therefore, enhancement in the performance of the existing blade design is often seen as a way of improving the overall performance of the GT engine systems. Furthermore, blades are designed to bear high temperatures and are often coated with thermal and environmental barrier coatings. Besides this, different-sized engines are fitted with appropriately configured blades, where the material and geometry of rotating blades play a vital role. Some advanced composites such as, ceramic matrix composites (CMC), functionally graded materials (FGM), etc., are being projected as possible solutions to enhance overall efficiency as well as for better durability. Therefore, vibration analysis of these kinds of blades become inevitable to avoid fatigue and resulting catastrophic failure, especially during rotation. In this work, vibration newlineanalysis of GT straight/curved blades bearing different advance composite materials, such as FG-sandwich composites; ceramic/metal/ceramic FGM composites; and CMC with/without newlineCNT reinforcement, is examined under rotation and thermal environment to capture linear/nonlinear frequencies. For this purpose, a robust mathematical model, representing the pretwisted rotating straight/curved blade attached to a hub system, is developed using 2D newlineisoparametric finite element approach. Here, the geometrical nonlinearity is introduced using Green-Lagrange s strain via the higher-order shear deformation theory