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Monday, August 10, 2020 | History

1 edition of Coupled rotor/airframe vibration analysis found in the catalog.

Coupled rotor/airframe vibration analysis

Coupled rotor/airframe vibration analysis

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  • 12 Currently reading

Published by National Aeronautics and Space Administration, Scientific and Technical Information Branch, For sale by the National Technical Information Service] in Washington, D.C, [Springfield, Va .
Written in English

    Subjects:
  • Rotors -- Dynamics.,
  • Rotors -- Vibration.,
  • Rotors (Helicopters),
  • Airframes.

  • Edition Notes

    StatementRobert Sopher ... [et al.] ; prepared for Structures Laboratory, AVRADCOM Research and Technology Laboratories, and NASA Langley Research Center.
    SeriesNASA contractor report -- 3582., NASA contractor report -- NASA CR-3582.
    ContributionsSopher, Robert., Langley Research Center., Army Research and Technology Laboratories (U.S.). Structures Laboratory., United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch., United Technologies Corporation. Sikorsky Aircraft Division.
    The Physical Object
    Paginationix, 195 p. :
    Number of Pages195
    ID Numbers
    Open LibraryOL15266142M

    This paper explores the model for the analysis of two misaligned Jeffcott rotors flexibly-coupled through a Hooke’s joint. The aim is to present a transmission on non-linear shafts-coupling model subjected to elastic deformation. The model provides some insight into the transmission motion on misaligned rotor-system under the influences of unbalance and helps to understand the . -Cross-Coupled Forces are, in the simplest of terms, negative damping. Cross-Coupled stiffness is a force that acts tangential to the orbit, perpendicular to the principle stiffness and opposite to the damping, see Figure 1. These forces are a result of energy being ‘fed’ into the system and act to destabilize the rotor. Cross-coupled.

    AH-1G Flight Vibration Correlation Using Nastran and The C81 Rotor/Airframe Coupled Analysis R.V. Dompka, J.J. Corrigan, Bell Helicopter Textron, Inc June 2, Your Path: Home > AH-1G Flight Vibration Correlation Using Nastran and The C81 Rotor/Airframe Coupled Analysis.   This paper investigates the vibration mode structure of three-dimensional, cyclically symmetric centrifugal pendulum vibration absorber (CPVA) systems. The rotor in the system has two translational, one rotational, and two tilting degrees of freedom.

    The Third Revised And Enlarged Edition Of The Book Presents An In-Depth Study Of The Dynamic Behaviour Of Rotating And Reciprocating Machinery. It Evolved Out Of Lectures Delivered At Different Universities Over The Last Two Decades. The Book Deals With Torsional And Bending Vibrations Of Rotors, Stability Aspects, Balancing And Condition Monitoring/5(6). The coupled lateral-torsional vibration of a geared rotor-bearing system is studied. Natural frequencies and corresponding mode shapes, and whirl frequencies under different spin .


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Coupled rotor/airframe vibration analysis Download PDF EPUB FB2

Coupled rotor/airframe vibration analysis. Washington, D.C.: National Aeronautics and Space Administration, Scientific and Technical Information Branch ; [Springfield, Va.: For sale by the National Technical Information Service], (OCoLC) Material Type: Government publication, National government publication: Document Type: Book.

This report describes a Coupled Rotor/Airframe Vibration Analysis which was developed as a design tool for predicting helicopter vibrations, and a research tool to quantify the effects of structural properties, aerodynamic interactions and vibration reduction devices on vehicle vibration levels.

A comprehensive vibration analysis of a coupled rotor/fuselage system is carried out using detailed 3-D finite element models of the AH-1G airframe from the DAMVIBS program. Predicted vibration results are compared with operational load survey flight test data of the AH-1G by: A comprehensive vibration analysis of a coupled rotor/fuselage system is carried out using detailed 3-D finite element models of the AH-1G airframe from the DAMVIBS program.

Predicted vibration. Coupled Rotor-Fuselage Analysis with Finite Motions Using Component Mode Synthesis Journal of the American Helicopter Society, Vol. 49, No. 2 Vibration Prediction for Rotor System with Faults Using Coupled Rotor-Fuselage ModelCited by: If the problem originates in the rotor (unbalance or oil whirl, for instance), obtain shaft vibration data with either a shaft stick or a proximity probe.

Loaded, coupled, full voltage, With a solid knowledge of motor fundamentals and vibration analysis, you can usually identify areas of concern well before they lead to a failure. In tail rotor pitch-flap instability, the flapping and lagging motions are coupled.

There is coalescence of the flap, lag, and torsion mode frequencies in tail rotor pitch-flap-lag instability. This chapter closes with a discussion on coupled rotor blade and airframe instabilities, which include ground resonance and air resonance.

Coupled rotor/airframe vibration analysis book It opens with the dynamics of oil film bearings and their influences on unbalance, vibration resonance and the stability of rotor whirl motion.

Subsequently, the book introduces readers to vibration diagnosis techniques for traditional ball bearings and active vibration control from magnetic bearings. An advancing blade concept rotorcraft includes an airframe and a pylon assembly subject to vibration.

The pylon assembly includes a dual rotor system having coaxially disposed top and bottom rotor assemblies that counter rotate relative to one another. The advancing blade concept rotorcraft includes a vibration isolation system including at least one pylon link coupled to the airframe.

Abstract. In helicopters, a high vibration level of the airframe occurs due to higher harmonic aerodynamic loads acting on the rotor blades.

However, when the airfoil shape is adaptive, the aerodynamic loads can be affected to reduce vibration and moreover, the airfoil shape can be adjusted to the periodically changing flow conditions to increase aerodynamic efficiency. Building on the previous volume “Vibrations of Rotating Machinery - Volume 1.

Basic Rotordynamics: Introduction to Practical Vibration Analysis,” this book is intended for all practical designers and. This report describes a Coupled Rotor/Airframe Vibration Analysis which was developed as a design tool for predicting helicopter vibrations, and a research tool to quantify the effects of structural properties, aerodynamic interactions and vibration reduction devices on vehicle vibration levels.

The analysis consists of a Base Program utilizing. A comprehensive vibration analysis of a coupled rotor/fuselage system is carried out using detailed 3-D finite element models of the AH-1G airframe from the DAMVIBS program. ix SUMMARY This report describes a Coupled Rotor/Airframe Vibration Analysis which was developed as a design tool for predicting helicopter vibrations, and a research tool to quantify the effects of struc- tural properties, aerodynamic interactions and vibration reduction devices on vehicle vibration levels.

Coupled rotor/airframe vibration analysis / By Robert. Sopher, United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch., United Technologies Corporation.

Sikorsky Aircraft Division., Army Research and Technology Laboratories (U.S.). Abstract: This paper studies the Jeffcott cracked rotor based on level set, considering the oil film oscillation effects on crack rotor, building the stiffness matrix of the cracked rotor in the fixed coordinate system and the moving coordinate, deriving the nonlinear differential equations of coupled vibration of a cracked rotor, and analysis of its dynamic characteristic combined.

Rotordynamics, also known as rotor dynamics, is a specialized branch of applied mechanics concerned with the behavior and diagnosis of rotating structures. It is commonly used to analyze the behavior of structures ranging from jet engines and steam turbines to auto engines and computer disk its most basic level, rotor dynamics is concerned with one or more.

Part I: Primer on Rotor Vibration Vibration Concepts and Methods One-Degree-of-Freedom Model Multi-DOF Models Modes, Excitation, and Stability of Multi-DOF Models Lateral Rotor Vibration Analysis Models Simple Linear Models Formulations for RDA Software Insights into Linear LRVs Nonlinear Effects in Rotor Dynamical Systems Torsional Rotor Vibration Analysis Models Rotor.

Blade Tracking and Vibration Analysis: rotor alignment rotor tracking static and dynamic balance vibratin types and reduction ground resonance Transmissions: gear boxes; main and tail rotors clutches; free wheel and rotor brakes tail rotor drive shafts, flexible couplings, bearings, vibration dampers, bearing hangers Airframe Structures.

element modeling methods are coupled to comprehensive rotor analysis codes in a new way and improved internal load and stress predi ctions result. Methodology The new method to calculate high frequency airframe loads and stresses uses global/local techniques typically applied to static loads analysis, modified for use with dynamic analysis models.

earized rotor model should be as good for coupled rotor-airframe vibration analysis as the underlying nonlinear model, and representing the airframe by harmonic forced responses is recommended for airframe structural design work.

INTRODUCTION Helicopters are prone to vibrations arising from the cyclic nature of the rotor. The basic idea of aircraft vibration analysis is to locate the heavy spot and place a counter-weight on the opposite side to balance out the imbalance. Learn More ACES Systems manufactures several analyzers designed to measure vibration in your aircraft and mathematically compute the best place to install counterweights on your propeller or rotor.Helicopter and tilt-rotor dynamics, coupled rotor/fuselage vibrations R.

Blackwell. Dynamics refresher (natural frequencies and forced response) Articulated rotor dynamics (flap, lag, torsion, etc.) Types of rotors; Isolated rotor stability; Coupled rotor airframe stability; Aircraft vibration; Vibration control approaches; Design support and.