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- 주제어 : Linear panel flutter (검색결과 5 건)
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Kailash Dhital(카일라시 디탈),Jae-Hung Han(한재흥),Yoon-Kyu Lee(이윤규) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.4
The present study considers the usage of concentrated force to simulate panel flutter. This idea has been validated for studying the flutter of wing structure in subsonic flow, yet its application in the supersonic region remained to be explored. In that context, a simply supported panel subjected to forces, equivalent to aerodynamic force is used for studying supersonic panel flutter. The distributed aerodynamic force is approximated to few concentrated forces by taking numerical integration. The aeroelastic equation is formulated using classical small-deflection theory and piston theory in linear panel flutter whereas for emulated panel flutter the flutter equation is derived by replacing the pressure due to aerodynamic loading with pressure from concentrated loading. Finally, critical flutter frequency, critical dynamic pressure, and corresponding mode shape are found for emulated panel flutter and compared with linear panel flutter. Two important parameters, the number of concentrated forces and their location are discussed through numerical examples and optimization process respectively. So far, the flutter results acquired in this study are reasonable to explain the feasibility of reproducing panel flutter using concentrated forces.
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Panel Flutter Emulation Using a Few Concentrated Forces
Dhital, Kailash,Han, Jae-Hung The Korean Society for Aeronautical Space Sciences 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
The objective of this paper is to study the feasibility of panel flutter emulation using a few concentrated forces. The concentrated forces are considered to be equivalent to aerodynamic forces. The equivalence is carried out using surface spline method and principle of virtual work. The structural modeling of the plate is based on the classical plate theory and the aerodynamic modeling is based on the piston theory. The present approach differs from the linear panel flutter analysis in scheming the modal aerodynamics forces with unchanged structural properties. The solutions for the flutter problem are obtained numerically using the standard eigenvalue procedure. A few concentrated forces were considered with an optimization effort to decide their optimal locations. The optimization process is based on minimizing the error between the flutter bounds from emulated and linear flutter analysis method. The emulated flutter results for the square plate of four different boundary conditions using six concentrated forces are obtained with minimal error to the reference value. The results demonstrated the workability and viability of using concentrated forces in emulating real panel flutter. In addition, the paper includes the parametric studies of linear panel flutter whose proper literatures are not available.
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Panel Flutter Emulation Using a Few Concentrated Forces
Kailash Dhital,한재흥 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
The objective of this paper is to study the feasibility of panel flutter emulation using a fewconcentrated forces. The concentrated forces are considered to be equivalent to aerodynamic forces. The equivalence is carried out using surface spline method and principle of virtual work. The structural modeling of the plate is based on the classical plate theory and the aerodynamic modeling is based on the piston theory. The present approach differs to the linear panel flutter analysis in scheming the modal aerodynamics forces with unchanged structural properties. The solutions for the flutter problem are obtained numerically using the standard eigenvalue procedure. A few concentrated forces were considered with an optimization effort to decide their optimal locations. The optimization process is based on minimizing the error between the flutter bounds from emulated and linear flutter analysis method. The emulated flutter results for the square plate of four different boundary conditions using six concentrated forces are obtained with minimal error to the reference value. The results demonstrated the workability and viability of using concentrated forces in emulating real panel flutter. In addition, the paper includes the parametric studies of linear panel flutter whose proper literatures are not available.
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열하중을 받는 패널플러터의 궤환 선형화에 의한 비선형제어
문성환(Seonghwan Moon),이광주(Kwangju Lee) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.9
압전재료를 사용한 복합재료 패널의 플러터 억제 방법으로서 비선형 모델을 기반으로 하 는 비선형 제어기법 중의 하나인 궤환 선형화에 의한 제어방법을 소개하였다. 기존의 패널 플러터 제어기에 대한 대부분의 연구들은 선형모델을 기반으로 설계된 선형2차제어기(LQR: Linear Quadratic Regulator)였음에 비해, 본 연구에서 제안한 비선형제어기는 시스템이 갖고 있는 비선형 특성들을 모두 고려해서 설계하였다. 압전 작동기로서는 PZT를 사용하였다. 가상변위의 원리와 4절점 사각형 C¹요소를 사용하여 이산화된 비선형 운동방정식을 유도하였으며 제어기 설계를 위해 모달 변환을 통해 상태공간에서의 비선형 연계-모달 방정식으로 변환하였다. 본 논문에서 제안한 비선형 제어기에 의한 제어 결과와 선형모델을 기반으로 한 LQR 제어결과를 Newmark 수치적분법을 통해 시간영역에서 비교하였다. In this study, a nonlinear control by feedback linearization method, one of nonlinear control schemes based on the nonlinear model, is proposed to suppress the flutter of a supersonic composite panel using piezoelectric materials. Most of the previous panel flutter controllers are the LQR(Linear Quadratic Regulator) which is based on the linear model. A nonlinear feedback linearizing controller proposed in this study considers the nonlinear characteristics of the system model. We use the actuator implemented by piezoceramic PZT. Using the principle of virtual displacements and a finite element discretization with the C¹ conforming four-node rectangular element, we first derive the discretized dynamic equations of motion, which are transformed into a nonlinear coupled-modal equations of motion of state space form. The effectiveness of the proposed method is also compared with the LQR based on the linear model through numerical simulations in the time domain using the Newmark method.
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