3 edition of **Identification of XV-15 aeroelastic modes using frequency-domain methods** found in the catalog.

Identification of XV-15 aeroelastic modes using frequency-domain methods

C. W. Acree

- 139 Want to read
- 16 Currently reading

Published
**1989**
by National Aeronautics and Space Administration, Ames Research Center, US Army Aviation Systems Command, Aviation Research and Technology Activity, For sale by the National Technical Information Service in Moffett Field, Calif, [Springfield, Va
.

Written in English

- Tilt rotor aircraft -- Testing.,
- Aeroelasticity.,
- Curve fitting.,
- Resonant frequencies.,
- Tilting rotors.,
- Vibration damping.,
- XV-15 aircraft.

**Edition Notes**

Other titles | Identification of XV 15 aeroelastic modes using frequency-domain methods. |

Statement | C.W. Acree, Jr., Mark B. Tischler. |

Series | NASA technical memorandum -- 101021., USAAVSCOM conference publication -- 89-A-001. |

Contributions | Tischler, Mark B. 1957-, Ames Research Center., United States. Army Aviation Research and Technology Activity. |

The Physical Object | |
---|---|

Format | Microform |

Pagination | 26 p. |

Number of Pages | 26 |

ID Numbers | |

Open Library | OL18257106M |

Flutter analysis of structures is usually done in frequency domain. Alternately, time-domain methods have been suggested. Both approaches require the identification of aeroelastic parameters (e.g., flutter derivatives in frequency domain and Rational function coefficients or Indicial functions in time domain). For frequency-domainCited by: 5. • Using Fourier analysis, any force time signal F h (t) can be transformed to the frequency domain and written as: F 0 (ω)ejωt • The signal that is of particular interest here is the impulse. Its Fourier Transform is F 0 (ω)=1! If we set F 0 (ω) = 1 and then calculate q 0 File Size: 2MB.

The current calculation power of computers permits the aeroelastic analysis of long-span bridges using time domain methods. These methods solve the differential equations set for the dynamic analysis by means of step by step integration, taking into account the fluid structure interaction of the wind aeroelastic by: 1. NONLINEAR AEROELASTIC REDUCED ORDER MODELS USING MODAL COORDINATES which are related to the n degrees of freedom q i through Eq It is important to notice that the velocity is re-lated to both linear and dual modes. At large dis-placements, the contribution from the dual modes to the kinetic energy is essential to keep the ac-curacy of ICE.

The present work describes the development of a novel aeroelastic code that combines a three‐dimensional viscous–inviscid interactive method, method for interactive rotor aerodynamic simulations (MIRAS), with the structural dynamics model used in the aeroelastic code by: 8. Chapter1: FundamentalsofAeroelasticAnalysis • IntroductiontoAeroelasticAnalysisandDesign • AerodynamicDataInputandGeneration • AerodynamicTheories.

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Frequency and damping values are also compared with new predictions by two different programs, CAMRAD and ASAP. INTRODUCTION Distinctive features of the XV- 15 Tilt Rotor arc the large wing-tip pylons which house the engines, transmissions and pivoting mechanisms for each rotor (Fig.

The XV Tilt-Rotor wing has six major aeroelastic modes that are close in frequency. To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency. Using Frequency-Domain Methods to Identify XV Aeroelastic Modes The XV Tilt-Rotor wing has six major aeroelastic modes that are close in frequency.

To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were by: 1. Get this from a library.

Identification of XV aeroelastic modes using frequency-domain methods. [C W Acree; Mark B Tischler; Ames Research Center.; United States. Army Aviation Research and Technology Activity.]. The XV Tilt-Rotor wing has six major aeroelastic modes that are close in frequency.

To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were installed. The resulting structural data were analyzed in the frequency domain (Fourier-transformed) with cross-spectral and transfer-function methods.

Modal frequencies. The XV Tilt-Rotor wing has six major aeroelastic modes that are close in frequency. To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were installed.

The resulting structural data were analyzed in the frequency domain (Fourier transformed) with cross spectral and transfer function methods. Get this from a library.

Using frequency-domain methods to identify XV aeroelastic modes. [C W Acree; Mark B Identification of XV-15 aeroelastic modes using frequency-domain methods book United States. Army Aviation Research and. Flight modes of the XV tilt-rotor research aircraft. (a) "Airp/ane," (b) "l'i/t-rotor," (c) "Helicopter." 1.

The generation of a more reliable data base of XV wing/pylon aeroelastic modes forthe original metal blades and new steel hubs 2. the incentive for a thorough reevaluation of XV aeroelastics using the latest flight-test and modal identification techniques.

The major wing modes were excited with flaperon frequency sweeps. The XV tilt-rotor wing has six major aeroelastic modes that are close in frequency. To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were installed.

The resulting structural data were analyzed in the frequency domain (Fourier transformed). (0 NASA Technical Memorandum USAAVSCOM Technical Report A- 17 Using Frequency-Domain I Methods to Identify XV Aeroelastic Modes C. Acree, Jr. and Mark B. Tischler II November DTICELIECTFI.D I ' W& Gatm I US ARMY AVIATIN S SYSTEMS COMMAND National Aeronautics and O AVIATION RESEARCH AND Space Administration TECHNOLOGY ACTIVITY R8.

Identification of XV aeroelastic modes using frequency-domain methods. The resulting structural data were analyzed in the frequency domain (Fourier transformed) with cross spectral and transfer function methods. Modal frequencies and damping were determined by performing curve fits to transfer function magnitude and phase data and to Author: Jr.

Cecil W. Acree and Mark B. Tischler. and the symmetric winglet lateral (SWL) mode is a bending of the winglets with additional bending and torsion in the wings.

The main structural modes that are of interest to the research effort are the SW1B and SW1T modes. (a) (b) (c) (d) Figure 2. Longitudinal in-vacuo mode shapes for the XA (FEM conﬁgurationversion _dev, They share research interests in system identification, signal processing, and measurement techniques.

They are the coauthors of a software package with a user-friendly graphical user interface called Frequency Domain System Identification Toolbox for Matlab(r), which covers the methods discussed in this book. For local method, a straightforward approach of generating LTI model from the flight data is to identify a system model using mature system identification algorithms, 18, 19 Direct application of these methods to aeroelastic systems rarely produces an accurate reduced-order model.

One of the difficulties is that the flight data are typically Cited by: Stability analysis in frequency domain. The stability analysis in the frequency domain is performed according to the procedure described in Section Since the present goal is the comparison with the time-domain simulations of the full structure, a high-dimensional modal subspace is adopted by considering the first fifty natural modes Cited by: [8] Acree C.

and Tischler M. B., “ Identification of XV Aeroelastic Modes Using Frequency-Domain Methods,” NASA TMFeb. Google Scholar [9] Acree C.

W., “ An Improved CAMRAD Model for Aeroelastic Stability Analysis of the XV with Advanced Technology Blades,” NASA TMFeb. Google ScholarCited by: 5. System identification from measured flight test data was conducted using the XA aeroelastic demonstrator to identify a longitudinal flight dynamics model that included the short period, first symmetric wing bending, and first symmetric wing torsion modes.

Orthogonal phase-optimized multisines were used to simultaneously excite multiple control effectors while a flight control system was by: 1. Peeters et al. () presented modern frequency-domain modal parameter estimation methods applied to in-flight aeroelastic response data measurements of a large aircraft.

Data acquired from applied sine sweep excitation and natural turbulence excitations were available during short-time by: 4. System identification-based aeroelastic modelling for wing flutter. Aircraft Engineering and Aerospace Technology, Vol. 90, No. 2 Three-Dimensional Aeroelastic Solutions via the Nonlinear Frequency-Domain Method.

Invariant aeroelastic by:. Determining XV Aeroelastic Modes from Flight Data with Frequency-Domain Methods c. W. Acree, Jr. and Mark B. Tischler (~ASA-TP) DETERMINING XV-lS N AEROElASTIC MODES FROM FLIGHT DATA WITH FREQUENCY-DOMAIN METHODS (NASA) 68 P Unclas HI/OS Abstract: An iterative, CFD-based approach for aeroelastic computations in the frequency domain is presented.

The method relies on a linearized formulation of the aeroelastic problem and a fixed-point iteration approach and enables the computation of the eigenproperties of each of the wet aeroelastic Cited by: 1.Frequency Domain Based on Computational Fluid Dynamics David Amsallem1, Daniel Neumann2, Youngsoo Choi3, Charbel Farhat4 Stanford University, Stanford, CAUSA An iterative, CFD-based approach for aeroelastic computations in the frequency domain is presented.

The method relies on a linearized formulation of the aeroelas.