Development of a hybrid global optimization algorithm and its application to helicopter rotor structural optimization

Download

index.pdf

Date

2019

Author

Bilen, Muhammed Emre

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

494
views

214
downloads

Helicopters are notorious for their high vibration levels and the rotor system are the main contributors to the problem. The rotor vibrations can be minimized by optimizing the rotor structure, which require time-consuming high-fidelity solution for vibration predictions. To solve this problem, an effective and efficient global search algorithm called Explorer-Settler Optimization algorithm is developed by combining the advantageous aspects of Particle Swarm Optimization and Nelder-Mead Optimization algorithms. It is shown that the developed algorithm performs superior when compared to other popular search algorithms in terms of search space exploration with minimum number of objective function calls. Moreover, to reduce the rotor optimization times, surrogate-based models are implemented for rotor blade structural property predictions. Data transformation techniques are evaluated and applied to minimize prediction errors. For the reduction of rotor vibrations, two main approaches are implemented namely, frequency separation approach (FSA) and direct vibration reduction approach (DVRA). Along with vibration reduction, both approaches aim to minimize rotor blade mass while satisfying various dynamic and static constraints. However, FSA attempts to achieve minimum vibrations by separating the natural frequencies of the rotor blades from excitation frequencies to avoid resonances; whereas, DVRA directly targets vibration amplitudes. A four-bladed rotor is optimized using both approaches and the performances of them are compared against each other. The results indicate that DVRA performs better in vibration reduction while FSA provides lighter rotor blades.

Subject Keywords

Rotors (Helicopters)., Helicopter rotor optimization, global optimization algorithm, surrogate-based modeling, vibration reduction, structural optimization.

URI

http://etd.lib.metu.edu.tr/upload/12623309/index.pdf
https://hdl.handle.net/11511/43467

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Integration of parameter sensitivity to structural optimization of helicopter rotors for minimum vibration Bilen, Muhammed Emre; Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (CRC, New York , 2020-10-01) Helicopters are notorious for their high vibration levels and the rotor systems are the main contributors to the problem. Rotor vibrations can be minimized by optimizing the rotor structure. However, the result of the optimization might require precise manufacturing of the rotor with tight tolerances leading to increased production cost and time. Moreover, due to loose manufacturing tolerances or wear from usage, the rotor might present higher vibrations during operation if the rotor vibration is sensitive ...
Integration of Parameter Sensitivity to Structural Optimization of Helicopter Rotors for Minimum Vibration Bilen, Muhammed Emre; Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (CRC, New York , 2020-10-01) Helicopters are notorious for their high vibration levels and the rotor systems are the main contributors to the problem. Rotor vibrations can be minimized by optimizing the rotor structure. However, the result of the optimization might require precise manufacturing of the rotor with tight tolerances leading to increased production cost and time. Moreover, due to loose manufacturing tolerances or wear from usage, the rotor might present higher vibrations during operation if the rotor vibration is sensitive ...
Evaluation of Surrogate-Based Modeling Methods for the Optimization of Helicopter Rotor Structures for Minimum Vibration Bilen, Muhammed Emre; Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (null; 2019-11-02) Helicopters are notorious for their high vibration levels and the rotors are the main contributors. At preliminary stages, it is essential to design the rotors to achieve minimum vibration amplitudes, which is generally realized by using optimization routines. The optimization of a helicopter rotor for minimum vibrations requires repeated high-fidelity solutions, which lead to high computational times. Moreover, since the rotor optimization problem contains many local minima by its nature, the optimization ...
Optimal trajectory generation and tracking for a helicopter in tail rotor failure Arslan, Yusuf Onur; Yavrucuk, İlkay; Department of Aerospace Engineering (2022-8-23) Tail rotor failure is the main reason for a variety of helicopter accidents throughout aviation history. It is troublesome to control and navigate the helicopter to a predefined landing point with a non-functioning tail rotor especially if the number of available landing sites is limited. The objective of this thesis is to generate flight trajectories for a helicopter with a failed tail rotor and to track the trajectories by a controller. In this work, the generic helicopter model in FLIGHTLAB software is u...
Experimental Investigation of New Indices of Broken Rotor Bar in Induction Motor Oumaamar, M. E. K.; Razik, H.; Rezzoug, A.; Chemali, H.; Khezzar, A. (2011-09-10) Most of rotor related faults in three-phase induction motors are due to broken rotor bars and end-ring defects. Nowadays Inductions motors are more frequently used with inverters which make the diagnosis process more complicated. Furthermore, some manufacturers of induction machines mount converters (i.e. rectifier and inverter) directly onto the machine, which makes the stator current unattainable for diagnosis. In order to overcome these drawbacks, the authors propose to analyze new motor fault signatures...

Citation Formats

M. E. Bilen, “Development of a hybrid global optimization algorithm and its application to helicopter rotor structural optimization,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Mechanical Engineering., Middle East Technical University, 2019.