• Title/Summary/Keyword: Composite Blade

Search Result 263, Processing Time 0.027 seconds

Aeroelastic Stability Analysis of Hingeless Rotor Blades with Composite Flexures

  • Kim, Seung-Jo;Kim, Ki-Tae;Jung, Sung-Nam
    • Journal of Mechanical Science and Technology
    • /
    • v.16 no.4
    • /
    • pp.512-521
    • /
    • 2002
  • The flap-lag-torsion coupled aeroelastic behavior of a hingeless rotor blade with composite flexures in hovering flight has been investigated by using the finite element method. The quasisteady strip theory with dynamic inflow effects is used to obtain the aerodynamic loads acting on the blade. The governing differential equations of motion undergoing moderately large displacements and rotations are derived using the Hamilton's principle. The flexures used in the present model are composed of two composite plates which are rigidly attached together. The lead-lag flexure is located inboard of the flap flexure. A mixed warping model that combines the St. Versant torsion and the Vlasov torsion is developed to describe the twist behavior of the composite flexure. Numerical simulations are carried out to correlate the present results with experimental test data and also to identify the effects of structural couplings of the composite flexures on the aeroelastic stability of the blade. The prediction results agree well with other experimental data. The effects of elastic couplings such as pitch-flap, pitch-lag, and flap-lag couplings on the stability behavior of the composite blades are also investigated.

Resonant fatigue testing of composite rotor blades (공진현상을 이용한 복합재 블레이드의 피로시험)

  • Kee, Youngjung;Lee, Sangwon;Park, Seonkyu
    • Journal of Aerospace System Engineering
    • /
    • v.4 no.2
    • /
    • pp.21-25
    • /
    • 2010
  • Fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. However, it is very difficult to apply conventional fatigue test loads in short period. Therefore, accelerating test speed and facilitating spectrum load realization are required. In this study, we have developed a fatigue testing method that uses a resonance of simply supported beam type blade specimen. This test consists in exciting the blade specimen with a frequency that corresponds to its natural frequency. In that case, the test specimen similar to a beam fixed between two pivot points starts vibrating and is significantly deformed. Resonant fatigue tests were performed by changing exciting vertical amplitude and frequency, and S-N curves of each composite materials were successfully obtained.

  • PDF

Resonant Fatigue Testing of Full-Scale Composite Helicopter Blades (공진현상을 이용한 실물 복합재 헬리콥터 블레이드의 피로수명 평가)

  • Kee, Young-Jung;Kim, Tae-Joo;Kim, Seung-Ho
    • Aerospace Engineering and Technology
    • /
    • v.9 no.2
    • /
    • pp.1-7
    • /
    • 2010
  • Fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. However, it is very difficult to apply conventional fatigue test loads in short period. Therefore, accelerating test speed and facilitating spectrum load realization are required. In this study, we have developed a fatigue testing method that uses a resonance of simply supported beam type blade specimen. This test consists in exciting the blade specimen with a frequency that corresponds to its natural frequency. In that case, the test specimen similar to a beam fixed between two pivot points starts vibrating and is significantly deformed. Resonant fatigue tests were performed by changing exciting vertical amplitude and frequency, and S-N curves of each composite materials were successfully obtained.

Improved Equivalent Beam Element Modeling Technique for Large Scale Wind-Turbine Composite Blade (대형 풍력발전용 복합재료 블레이드의 개선된 등가 모델링 기법)

  • Kim, Dong-Hyun;Park, Hyo-Geun;Kim, Dong-Man
    • The KSFM Journal of Fluid Machinery
    • /
    • v.11 no.4
    • /
    • pp.32-37
    • /
    • 2008
  • In this study, we have introduced an improved equivalent modeling technique for large scale composite wind-turbine blade. Conventional or general equivalent modeling procedure may give critical error in the analysis results because of geometric coupling effects. For the analyses of structural vibration and aeroelastic problems, the accuracy of equivalent structural models is very important since it can have high numerical efficiency and various practical applications. Three-dimensional realistic composite wind-turbine blade model is practically considered for numerical study. In order to validate the effect of the mass and the stiffness of the equivalent beam model, comparison study based on the natural vibration analysis has been conducted, and the accuracy levels of the conventional and modified equivalent modeling techniques are presented.

Thermally-Induced Vibration Control of Rotating Composite Thin-Walled Blade (회전하는 복합재 블레이드의 열진동 해석 및 제어)

  • Jung, Hoe-Do;Na, Sung-Soo;Kwak, Mun-Kyu;Heo, Seok
    • Proceedings of the KSME Conference
    • /
    • 2003.11a
    • /
    • pp.1696-1701
    • /
    • 2003
  • This paper deals with a vibration control analysis of a rotating composite blade, modeled as a tapered thinwalled beam induced by heat flux. The displayed results reveal that the thermally induced vibration yields a detrimental repercussions upon their dynamic responses. The blade consists of host graphite epoxy laminate with surface and spanwise distributed transversely isotropic (PZT-4) sensors and actuators. The controller is implemented via the negative velocity and displacement feedback control methodology, which prove to overcome the deleterious effect associated with the thermally induced vibration. The structure is modeled as a composite thin-walled beam incorporating a number of nonclassical features such as transverse shear, secondary warping, anisotropy of constituent materials, and rotary inertias.

  • PDF

Structural Design for 2kW Class Wind Turbine Blade by using Design of Experiment (실험계획법을 이용한 2kW급 풍력발전용 블레이드에 대한 구조설계)

  • Lee, Seung-Pyo;Kang, Ki-Weon;Chang, Se-Myong;Lee, Jang-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.20 no.1
    • /
    • pp.28-33
    • /
    • 2011
  • In this paper, structural design for 2kW class composite blade is performed by using design of experiment(DOE). A full factorial design is applied to meet the design specifications at the manufacturing process. The analysis of variance(ANOVA) is made in order to determine the significance of effects in an analysis. Structural analysis by using of commercial software ABAQUS is performed to compute the displacement and safety factor of filament wound composite blade. The results show that the proposed method is suitable to analyze the factors at the design of wind turbine blade.

Equivalent Structural Modeling of Wind Turbine Rotor Blade (풍력발전기 로터 블레이드의 등가 구조모델 수립)

  • Park, Young-Geun;Hwang, Jai-Hyuk;Kim, Seok-Woo;Jang, Moon-Seok;Bae, Jae-Sung
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.14 no.4
    • /
    • pp.11-16
    • /
    • 2006
  • The wind turbine rotor blade is faced with various aeroelastic problem as rotor blades become bigger and lighter by the use the composite material. The aeroelastic analysis of a wind turbine rotor blade requires its aerodynamic model and structural model. For effective aeroelastic analysis, it is required the simple and effective structural model of the blade. In the present study, we introduce the effective equivalent structural modeling of the blade for aeroelastic analysis. The equivalent beam model of the composite blade based on its 3D finite element model is established. The free vibration analysis shows that the equivalent beam model of the blade is equivalent to its 3D finite element model.

  • PDF

A Study on the Helicopter Composite Blade Impact Loads (헬리콥터 복합재 블레이드 충돌하중 연구)

  • Lee, Hyun-Cheol;Jeon, Boo-Il;Moon, Jang-Soo;Yee, Seok-June
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.2
    • /
    • pp.181-186
    • /
    • 2009
  • The objective of this study is ensuring safety of cabin when the blade impacts into a obstacle by verifying safety of the rotor mast and the transmission using impact loads calculated from the simulation. The rotor mast shall not fail and the transmission shall not be displaced into occupiable space when the main rotor composite blade impact into a 8 inch rigid cylinder in diameter on the outer 10% of the blade at operational rotor speed. To calculate the reaction loads at the spherical bearing and lead-lag damper, blade impact analysis was performed with FE model consist of composite blade, tree(or rigid cylinder) using elastic-plastic with damage material and several contact surfaces which were created to describe a progress of actual failure. Also, the reaction loads were investigated in change of blade rotation speed and pitch angle.

ANALYSIS OF A LAMINATED COMPOSITE WIND TURBINE BLADE CHARACTERISTICS THROUGH MATHEMATICAL APPROACH

  • CHOI, YOUNG-DO;GO, JAEGWI;KIM, SEOKCHAN
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.23 no.4
    • /
    • pp.367-380
    • /
    • 2019
  • A 1kW-class horizontal axis wind turbine (HAWT) rotor blade is taken into account to investigate elastic characteristics in 2-D. The elastic blade field is composed of symmetric cross-ply laminated composite material. Blade element momentum theory is applied to obtain the boundary conditions pressuring the blade, and the plane stress elasticity problem is formulated in terms of two displacement parameters with mixed boundary conditions. For the elastic characteristics a fair of differential equations are derived based on the elastic theory. The domain is divided by triangular and rectangular elements due to the complexity of the blade configuration, and a finite element method is developed for the governing equations to search approximate solutions. The results describe that the elastic behavior is deeply influenced by the layered angle of the middle laminate and the stability of the blade can be improved by controlling the layered angle of laminates, which can be evaluated by the mathematical approach.

One-Dimensional Beam Modeling of a Composite Rotor Blade (복합재 블레이드의 1차원 보 모델링)

  • Lee, Min-Woo;Bae, Jae-Sung;Lee, Soo-Yong;Lee, Seok-Joon;Jeon, Boo-Il
    • Journal of Aerospace System Engineering
    • /
    • v.2 no.1
    • /
    • pp.7-12
    • /
    • 2008
  • The three-dimensional finite element modeling of a composite rotor blade is very hard and requires much computation effort. The efficient method to model a composite beam is necessary for the dynamic and aeroelastic analyses of rotor blades. In this study, the beam modeling method of a composite rotor blade is studied using VABS. The computer program, VABS (Variational Asymptotic Beam Section Analysis), uses the variational asymptotic method to split a 3-D nonlinear elasticity problem into 2-D cross-sectional analysis and 1-D nonlinear beam problem. The VABS can produce the sectional stiffness coefficients of composite rotor blades with various cross section and initial twist/curvatures, and recover the original 3-D distribution of displacement/strain/stress fields. The results of various cross section beams show that VABS gives us the accurate results comparared to commercial codes and does not need much computation effort. It can be concluded that VABS provides the efficient method to establish the FE model of a composite rotor blade.

  • PDF