Development of a rotating blade finite element with an application to the analysis of helicopter rotor systems

1987 ◽  
Author(s):  
PATRICK MAGARI ◽  
LOUIS SHULTZ
Keyword(s):  
Finite Element ◽  
Helicopter Rotor ◽  
Rotor Systems ◽  
Rotating Blade

scholarly journals ACTIVE TWIST OF MODEL ROTOR BLADES WITH D-SPAR DESIGN

Transport ◽  
2007 ◽  
Vol 22 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Andrejs Kovalovs ◽  
Evgeny Barkanov ◽  
Sergejs Gluhihs
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Rotor Blade ◽  
Element Model ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
3D Finite Element ◽  
3D Finite Element Model ◽  
Helicopter Rotor Blade ◽  
Active Twist

The design methodology based on the planning of experiments and response surface technique has been developed for an optimum placement of Macro Fiber Composite (MFC) actuators in the helicopter rotor blades. The baseline helicopter rotor blade consists of D‐spar made of UD GFRP, skin made of +450/‐450 GFRP, foam core, MFC actuators placement on the skin and balance weight. 3D finite element model of the rotor blade has been built by ANSYS, where the rotor blade skin and spar “moustaches” are modeled by the linear layered structural shell elements SHELL99, and the spar and foam ‐ by 3D 20‐node structural solid elements SOLID 186. The thermal analyses of 3D finite element model have been developed to investigate an active twist of the helicopter rotor blade. Strain analogy between piezoelectric strains and thermally induced strains is used to model piezoelectric effects. The optimisation results have been obtained for design solutions, connected with the application of active materials, and checked by the finite element calculations.

QUANTITATIVE IDENTIFICATION OF ROTOR CRACKS BASED ON FINITE ELEMENT OF B-SPLINE WAVELET ON THE INTERVAL

2009 ◽  
Vol 07 (04) ◽  
pp. 443-457 ◽  
Author(s):  
XUEFENG CHEN ◽  
BING LI ◽  
JIAWEI XIANG ◽  
ZHENGJIA HE
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Beam Element ◽  
Rotational Inertia ◽  
Spline Wavelet ◽  
B Spline ◽  
Rotor Systems ◽  
Crack Location ◽  
Contour Lines ◽  
Quantitative Identification

Based on finite element of B-spline wavelet on the interval (BSWI), the quantitative identification method of transverse crack for rotor systems was studied. The new model of BSWI Rayleigh–Euler rotary beam element considering gyroscopic effect and rotational inertia was constructed to solve the first three natural frequencies of the cracked rotor with high precision, and the first three frequencies solution surfaces of normalized crack location and size were obtained by using surface-fitting technique. Then the first three metrical natural frequencies were employed as inputs of the solution curve surfaces. The intersection of the three frequencies contour lines predicted the normalized crack location and size. The numerical and experimental examples were given to verify the validity of the beam element for crack quantitative identification in rotor systems. The new method can be applied to prognosis and quantitative diagnosis of cracks in the rotor system.

Effects of Free Damping Layers on Harmonic Response of Rotating Blades

1989 ◽  
Author(s):  
T. H. Young ◽  
T. N. Shiau ◽  
S. H. Chiu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Loss Factor ◽  
Harmonic Excitation ◽  
The Finite Element Method ◽  
Harmonic Response ◽  
Rotating Blades ◽  
Rotating Blade ◽  
Triangular Elements

This paper studies the forced vibration of a rotating blade with free damping layers to harmonic excitation by means of the finite element method. The damping layers are made of viscoelastic material with complex elastic modulus, and the excitation may be either distributed or concentrated. Triangular elements with totally 15 d.o.f. are used to allow for a great variety of shapes and boundary conditions. The effects of various parameters, such as loss factor, storage modulus and thickness of damping layers, are investigated. The results show that the vibration amplitudes near resonances can be significantly reduced by the free damping layers.

Numeric Analysis for Resonant Frequency of Rotating Blade

2009 ◽  
Vol 16-19 ◽  
pp. 1365-1369
Author(s):  
Di Zhao ◽  
Ke Qin Ding ◽  
Xin Chun Shang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Resonant Frequency ◽  
Room Temperature ◽  
Vibration Characteristics ◽  
Resonance Analysis ◽  
Working Temperature ◽  
Rotating Blade ◽  
Dynamic Frequency

The paper implements numeric computation to analyze free vibration characteristics of rotating blade by the means of finite element method. The effects of rotate speed and temperature on the resonant frequency of blades are considered. The static frequency and the dynamic frequency under working speed for the room temperature and working temperature are calculated, and the various modes are obtained. The resonance analysis is given by Campbell graph in which shows the distribution of resonant points for resonant frequency and rotate speed under the different excitation.

Effects of blade configuration parameters on helicopter rotor structural dynamics and whirl tower loads

2016 ◽  
Vol 120 (1224) ◽  
pp. 271-290 ◽  
Author(s):  
M. Rohin Kumar ◽  
C. Venkatesan
Keyword(s):  
Structural Dynamics ◽  
Dynamic Characteristics ◽  
Geometric Parameters ◽  
Helicopter Rotor ◽  
Mode Shapes ◽  
Structural Dynamic ◽  
Rotating Blade ◽  
Structural Dynamic Characteristics ◽  
Straight Portion ◽  
General Geometry

ABSTRACTThe influence of the blade geometric parameters on the structural dynamic characteristics, response and loads of a helicopter rotor under hover condition in a whirl tower was investigated. A general geometry was considered for the rotor blade which included configuration parameters like root offset, torque offset, pre-twist, pre-cone, pre-droop, pre-sweep, tip-sweep and tip-anhedral. The option of placing concentrated masses at any location on the blade was also included. Natural frequencies and the corresponding mode shapes of the rotating blade were obtained by solving the linear, undamped structural dynamics model in the finite element domain. For calculating the response and loads on the rotor, the complete aeroelastic equation was solved in modal space. Aerodynamic models used in the aeroelastic loads calculations were Peters-He dynamic wake theory for inflow and themodifiedONERA dynamic stall theory for airloads calculations. From the study, the blade structural dynamic characteristics are found to be sensitive to variation in blade geometric parameters. Tip-sweep was found to have significant effects on root oscillatory moments. The moments at the tip junction with the straight portion of the blade were found to be substantially affected by tip-sweep and tip-anhedral.

Design of composite helicopter rotor blades to meet given cross-sectional properties

2005 ◽  
Vol 109 (1100) ◽  
pp. 471-475 ◽  
Author(s):  
S. L. Lemanski ◽  
P. M. Weaver ◽  
G. F. J. Hill
Keyword(s):  
Finite Element ◽  
Objective Function ◽  
Helicopter Rotor ◽  
Design Parameters ◽  
Stochastic Methods ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design Variables ◽  
Non Linear ◽  
Optimisation Methods

Abstract This paper examines the design of a composite helicopter rotor blade to meet given cross-sectional properties. As with many real-world problems, the choice of objective and design variables can lead to a problem with a non-linear and/or non-convex objective function, which would require the use of stochastic optimisation methods to find an optimum. Since the objective function is evaluated from the results of a finite element analysis of the cross section, the computational expense of using stochastic methods would be prohibitive. It is shown that by choosing appropriate simplified design variables, the problem becomes convex with respect to those design variables. This allows deterministic optimisation methods to be used, which is considerably more computationally efficient than stochastic methods. It is also shown that the design variables can be chosen such that the response of each individual cross-sectional property can be closely modelled by a linear approximation, even though the response of a single objective function to many design parameters is non-linear. The design problem may therefore be reformulated into a number of simultaneous linear equations that are easily solved by matrix methods, thus allowing an optimum to be located with the minimum number of computationally expensive finite element analyses.

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