Deflection-Based Structural Loads Estimation from the Active Aeroelastic Wing F/A-18 Aircraft PDF Download
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Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781723718212
Category : Science
Languages : en
Pages : 28
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Book Description
Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. This technique was examined using a reliable strain and structural deformation measurement system. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.Lizotte, Andrew M. and Lokos, William A.Armstrong Flight Research CenterAEROELASTICITY; DEFLECTION; WINGS; F-18 AIRCRAFT; AERODYNAMIC LOADS; BENDING MOMENTS; FEASIBILITY ANALYSIS; STRAIN GAGES; CIRCUITS; POTENTIOMETERS (INSTRUMENTS); WING ROOTS; ROOT-MEAN-SQUARE ERRORS; GROUND TESTS
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781723718212
Category : Science
Languages : en
Pages : 28
Get Book Here
Book Description
Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. This technique was examined using a reliable strain and structural deformation measurement system. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.Lizotte, Andrew M. and Lokos, William A.Armstrong Flight Research CenterAEROELASTICITY; DEFLECTION; WINGS; F-18 AIRCRAFT; AERODYNAMIC LOADS; BENDING MOMENTS; FEASIBILITY ANALYSIS; STRAIN GAGES; CIRCUITS; POTENTIOMETERS (INSTRUMENTS); WING ROOTS; ROOT-MEAN-SQUARE ERRORS; GROUND TESTS
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 20
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Book Description
This report describes strain-gage calibration loading through the application of known loads of the Active Aeroelastic Wing F/A-18 airplane. The primary goal of this test is to produce a database suitable for deriving load equations for left and right wing root and fold shear; bending moment; torque; and all eight wing control-surface hinge moments. A secondary goal is to produce a database of wing deflections mesured by string potentiometers and the onboard flight deflection measurement system. Another goal is to produce strain-gage data through both the laboratory data acquisition system and the onboard aircraft data system as a check of the aircraft system. Thirty-two hydraulic jacks have applied loads through whiffletrees to 104 tension-compression load pads bonded to the lower wing surfaces. The load pads covered approximately 60 percent of the lower wing surface.
Author: Candida D. Olney
Publisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 30
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Book Description
A limited evaluation of the F/A-18 baseline loads model was performed on the Systems Research Aircraft at NASA Dryden Flight Research Center (Edwards, California). Boeing developed the F/A-18 loads model using a linear aeroelastic analysis in conjunction with a flight simulator to determine loads at discrete locations on the aircraft. This experiment was designed so that analysis of doublets could be used to establish aircraft aerodynamic and loads response at 20 flight conditions. Instrumentation on the right outboard leading edge flap, left airleron, and left stabilator measured the hinge moment so that comparisons could be made between in-flight-measured hinge moments and loads model-predicted values at these locations. Comparisons showed that the difference between the loads model-predicted and in-flight-measured hinge moments was up to 130 percent of the flight limit load. A stepwise regression technique was used to determine new loads derivatives. These derivatives were placed in the load model, which reduced the error to within 10 percent of the flight limit load. This paper discusses the flight test methodology, a process for determining loads coefficients, and the direct comparisons of predicted and measured hinge moments and loads coefficients.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704
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Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 974
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Book Description
Author: Jan Robert Wright
Publisher: John Wiley & Sons
ISBN: 047085846X
Category : Technology & Engineering
Languages : en
Pages : 559
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Book Description
Aeroelastic phenomena arising from the interaction of aerodynamic, elastic and inertia forces, and the loads resulting from flight / ground manoeuvres and gust / turbulence encounters, have a significant influence upon aircraft design. The prediction of aircraft aeroelastic stability, response and loads requires application of a range of interrelated engineering disciplines. This new textbook introduces the foundations of aeroelasticity and loads for the flexible aircraft, providing an understanding of the main concepts involved and relating them to aircraft behaviour and industrial practice. This book includes the use of simplified mathematical models to demonstrate key aeroelastic and loads phenomena including flutter, divergence, control effectiveness and the response and loads resulting from flight / ground manoeuvres and gust / turbulence encounters. It provides an introduction to some up-to-date methodologies for aeroelastics and loads modelling. It lays emphasis on the strong link between aeroelasticity and loads. It also includes provision of MATLAB and SIMULINK programs for the simplified analyses. It offers an overview of typical industrial practice in meeting certification requirements.
Author: Frederic M. Hoblit
Publisher: AIAA
ISBN: 9781600860607
Category : Airplanes
Languages : en
Pages : 332
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Book Description
Author: Robert C. Nelson
Publisher:
ISBN:
Category : History
Languages : en
Pages : 464
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Book Description
This edition of this this flight stability and controls guide features an unintimidating math level, full coverage of terminology, and expanded discussions of classical to modern control theory and autopilot designs. Extensive examples, problems, and historical notes, make this concise book a vital addition to the engineer's library.
Author: Thomas R. Yechout
Publisher: AIAA
ISBN: 9781600860782
Category : Aerodynamics
Languages : en
Pages : 666
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Book Description
Based on a 15-year successful approach to teaching aircraft flight mechanics at the US Air Force Academy, this text explains the concepts and derivations of equations for aircraft flight mechanics. It covers aircraft performance, static stability, aircraft dynamics stability and feedback control.
Author: North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Structures and Materials Panel. Meeting
Publisher:
ISBN: 9789283600374
Category : Airplanes
Languages : en
Pages : 190
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Book Description
