FREE VIBRATION ANALYSIS OF UNIFORM AND ASYMMETRIC COMPOSITE PRETWISTED ROTATING THIN WALLED BEAM

2017-11-09
Composite pretwisted rotating thin walled beams (TWB) can be used as the structural model for composite helicopter and wind turbine blades for the study of aeroelastic response of the blades. In the present study, semi-analytical solution is performed for the free vibration analysis of uniform and asymmetric composite pretwisted rotating TWB. The approximation of the Green-Lagrange strain tensor is adopted to derive the strain field of the system. The Euler Lagrange governing equations of the dynamic system and the related boundary conditions are derived via Hamilton's principle. In order to solve the governing set of equations, the Extended Galerkin's Method (EGM) is employed. For this purpose, the structural variables are separated in space and time and the assumed mode shapes are defined to satisfy the essential boundary conditions. For the purpose of validating the TWB model developed, the commercial finite element analysis tool, MSC Nastran is used to compare the results of modal analysis obtained by the present structural model with the finite element solution. With the results obtained in this paper, it is aimed to ascertain the effect of various coupling in circumferentially asymmetric stiffness (CAS) and circumferentially uniform stiffness CUS configurations, pretwist, angular velocity and fibre orientation, on the natural frequencies and the mode shapes of the rotating thin-walled composite beams. The results are expected to propose better predictions of the vibrational behavior of thin walled structures in general, and in the design of rotor blades of turbomachinery, rotorcraft and wind turbine systems, in particular.
ASME International Mechanical Engineering Congress and Exposition

Suggestions

Delamination-Debond Behaviour of Composite T-Joints in Wind Turbine Blades
Gulasik, H.; Çöker, Demirkan (2014-06-20)
Wind turbine industry utilizes composite materials in turbine blade structural designs because of their high strength/stiffness to weight ratio. T-joint is one of the design configurations of composite wind turbine blades. T-joints consist of a skin panel and a stiffener co-bonded or co-cured together with a filler material between them. T-joints are prone to delaminations between skin/stiffener plies and debonds between skin-stiffener-filler interfaces. In this study, delamination/debond behavior of a co-b...
Nonlinear vibration analysis of bladed disks with dry friction dampers
Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (2006-08-22)
in this work, a new model is proposed for the vibration analysis of turbine blades with dry friction dampers. The aim of the study is to develop a multiblade model that is accurate and yet easy to be analyzed so that it can be used efficiently in the design of friction dampers. The suggested nonlinear model for a bladed disk assembly includes all the blades with blade to blade and/or blade to cover plate dry friction dampers. An important feature of the model is that both macro-slip and micro-slip models ar...
Structural optimization of composite helicopter rotor blades
Işık, Alperen Ayberk; Kayran, Altan; Department of Aerospace Engineering (2018)
Structural optimization of a helicopter rotor blade with uniform aerodynamic surface and twist at the functional region is performed for weight minimization subject to various constraints relevant to helicopter rotor blades. The genetic algorithm based optimization is performed only for the functional region of the blade. Design variables are taken as the number of unidirectional S-glass layers in the spar cap, position of the spar web with respect to the leading edge, nose mass diameter and position of the...
Computer-aided design of horizontal-axis wind turbine blades
Duran, Serhat; Albayrak, Kahraman; Department of Mechanical Engineering (2005)
Designing horizontal-axis wind turbine (HAWT) blades to achieve satisfactory levels of performance starts with knowledge of the aerodynamic forces acting on the blades. In this thesis, HAWT blade design is studied from the aspect of aerodynamic view and the basic principles of the aerodynamic behaviors of HAWTs are investigated. Blade-element momentum theory (BEM) known as also strip theory, which is the current mainstay of aerodynamic design and analysis of HAWT blades, is used for HAWT blade design in thi...
Multibody simulation of helicopter rotor with structural flexibility
Özturan, Bali İhsan; Kayran, Altan; Department of Aerospace Engineering (2019)
Most of the multibody simulation tools used for modeling helicopter rotor use beam models of the blade and the rigid rotor hub. Stress recovery in the blade and in the hub are then performed by means of cross-sectional analysis tools or finite element analysis tools. In this study, multibody model of a helicopter main rotor is established using three dimensional flexible models of the blade and the rotor hub, and multibody simulations of the rotor are performed for the hover and the forward flight load case...
Citation Formats
T. Farsadi, Ö. Şener, and A. Kayran, “FREE VIBRATION ANALYSIS OF UNIFORM AND ASYMMETRIC COMPOSITE PRETWISTED ROTATING THIN WALLED BEAM,” presented at the ASME International Mechanical Engineering Congress and Exposition, Tampa, FL, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55004.