Structural optimization of composite helicopter rotor blades

Işık, Alperen Ayberk
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 single spanwise ply-drop-off. Constraints of the structural optimization are defined as maximum strain in the critical sections of the blade in the functional region, relative distances between the feathering axis, mass center, shear center and the neutral axis and natural frequency limits. Optimization is performed in a stepwise fashion for the hover condition and the sectional analysis of the blade is performed by Variational Asymptotic Beam Section (VABS) method. Loads and natural frequencies of the blade are calculated by the multibody simulation tool Dymore. The initial sectional blade loads calculated by Dymore are kept constant and they are not updated in any design iteration during the optimization process. For the optimized blade properties, blade tuning is done by lumped mass attachment to the blade and the sectional blade loads are calculated again by Dymore and another optimization is performed again by keeping the sectional loads as constant in any design iteration of optimization process. Load calculation, blade tuning and optimization cycle is repeated until the sectional loads calculated by Dymore do not change within a prescribed tolerance to complete full blade optimization. With this approach, the time consuming sectional load calculation process by Dymore is eliminated. The results of the study showed that 16.55% mass reduction could be achieved in the functional region of the blade with respect to the baseline design.


Structural optimization of composite and aluminum horizontal tail plane of a helicopter
Arpacıoğlu, Bertan; Kayran, Altan; Department of Aerospace Engineering (2019)
This thesis presents structural optimization studies of aluminum and composite material horizontal tail plane structure of a helicopter by using MSC.NASTRAN optimization capabilities. Structural design process starts from conceptual design phase, and structural layout design is performed by using CATIA. In the preliminary design phase, study focuses on minimum weight optimization with multiple design variables and similar constraints for both materials. Aerodynamic load calculation is performed using ANSYS ...
Farsadi, Touraj; Şener, Özgün; Kayran, Altan (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...
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...
Structural and aeroelastic analyses of a composite tactical unmanned air vehicle
Özöztürk, Sedat; Kayran, Altan; Tamer, Aykut; Department of Aerospace Engineering (2011)
In this thesis, computational aerodynamics, structural and aeroelastic analyses of the composite tactical unmanned air vehicle which is designed and manufactured in the Department of Aerospace Engineering are performed. Verification of the structural integrity of the air vehicle is shown at the minimum maneuvering and the dive speeds at the static limit loads which are calculated by the computational aerodynamics analysis of the full aircraft model. In the current work, aerodynamic loads are re-calculated f...
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...
Citation Formats
A. A. Işık, “Structural optimization of composite helicopter rotor blades,” M.S. - Master of Science, Middle East Technical University, 2018.