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Measurement Of Aeroelastic Wing Deflections On A Remotely Piloted Aircraft Using Modal Strain Shapes
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Book Synopsis Measurement of Aeroelastic Wing Deflections on a Remotely Piloted Aircraft Using Modal Strain Shapes by : Stephen Daniel Wilfred Warwick
Download or read book Measurement of Aeroelastic Wing Deflections on a Remotely Piloted Aircraft Using Modal Strain Shapes written by Stephen Daniel Wilfred Warwick and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerospace industry endeavours to improve modern aircraft capabilities in efficiency, endurance, and comfort. One means of achieving these goals is through new enhancements in aerodynamics. Increased wing aspect ratio is an example of further improving efficiency. However, this comes with new challenges including possibly adverse aero-elastic and aero-servo-elastic (ASE) phenomena. New computational methods and tools are emerging and there is a need for experimental data for validation. University of Victoria's Centre for Aerospace Research (UVic CfAR) set out to design a 20kg ASE demonstrator using a remotely piloted aircraft (RPA). This aircraft was designed with the intent of exploring coupling between aero-elastic modes including coupling between the short period aerodynamic mode and the first out-of-plane elastic mode of the wing. This thesis discuses the implementation of instrumentation designed and integrated into the ASE RPA demonstrator to monitor the deformation of the elastic wing in-flight. A strain based measurement technique was selected for integration into the ASE aircraft. This choice was made for several reasons including its reliability regardless of outdoor lighting, relatively lightweight processing requirements for real time applications, and suitable sampling bandwidth. To compute the wing deformation from strain, a method, sometimes referred to as strain pattern analysis (SPA), utilizing linear combinations of reference modal shapes fit against the measured strain, was used. Although this method is not new, to the author's knowledge, it is the first practical application to a reduced scale RPA demonstrator. The deformation measurement system was validated against a series of distributed static load tests on the ground. Distributed load cases along the wing demonstrated good out-of-plane measurement performance. A case where only load is applied near the root of the wing resulted in the largest error in part as the mode shapes generated are less suited to approximate the resulting shape. In general errors in out-of-plane displacement at the end of the flexible wing portion can be expected to be less than 5%. The displacement at the tip of the wing can be as great as 11% for the left wing whereas the right wing is 4.7%. This suggest an asymmetry between the left and right wings requiring specifically tuned FE models for each to achieve best results. Twist angles presented in tests were relatively small for accurate comparison against the reference measurement, which was relatively noisy. Generally, the deformation measurement by SPA technique followed the same twist behaviours as the reference. A twist case, unlikely to be seen in flight, provided some insight into twist measurement robustness. The work presented is merely a small step forward with many opportunities for further research. There is room for improvement of the FE model used to generate the mode shapes in the strain pattern analysis. Initial efforts focused on the flexible spar portion of the wing. With more work improvements could be achieved for the estimation of the rigid wing. Additionally, there was some asymmetry between each wing semi-span, and with some focus on the left wing its results could be improved to at least match that of the right wing. A real-time implementation was not completed and would be particularly interesting for use as feedback for flight control. Study of load alleviation techniques may benefit. Another topic of study is the combination of this method with other measurements, such as accelerometers, to provide improved performance state estimation through sensor fusion.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781723718212 Total Pages :28 pages Book Rating :4.7/5 (182 download)
Book Synopsis Deflection-Based Structural Loads Estimation from the Active Aeroelastic Wing F/A-18 Aircraft by : National Aeronautics and Space Adm Nasa
Download or read book Deflection-Based Structural Loads Estimation from the Active Aeroelastic Wing F/A-18 Aircraft written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-14 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721510016 Total Pages :32 pages Book Rating :4.5/5 (1 download)
Book Synopsis Strain Gage Loads Calibration Testing of the Active Aeroelastic Wing F/a-18 Aircraft by : National Aeronautics and Space Administration (NASA)
Download or read book Strain Gage Loads Calibration Testing of the Active Aeroelastic Wing F/a-18 Aircraft written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 measured 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. A series of 72 load cases has been performed, including single-point, double-point, and distributed load cases. Applied loads have reached 70 percent of the flight limit load. Maximum wingtip deflection has reached nearly 16 in. Lokos, William A. and Olney, Candida D. and Chen, Tony and Crawford, Natalie D. and Stauf, Rick and Reichenbach, Eric Y. and Bessette, Denis (Technical Monitor) Armstrong Flight Research Center NASA/TM-2002-210726, NAS 1.15:210726, H-2490
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781793986948 Total Pages :32 pages Book Rating :4.9/5 (869 download)
Book Synopsis Wing Shape Sensing from Measured Strain by : National Aeronautics and Space Adm Nasa
Download or read book Wing Shape Sensing from Measured Strain written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new two-step theory is investigated for predicting the deflection and slope of an entire structure using strain measurements at discrete locations. In the first step, a measured strain is fitted using a piecewise least-squares curve fitting method together with the cubic spline technique. These fitted strains are integrated twice to obtain deflection data along the fibers. In the second step, computed deflection along the fibers are combined with a finite element model of the structure in order to interpolate and extrapolate the deflection and slope of the entire structure through the use of the System Equivalent Reduction and Expansion Process. The theory is first validated on a computational model, a cantilevered rectangular plate wing. The theory is then applied to test data from a cantilevered swept-plate wing model. Computed results are compared with finite element results, results using another strain-based method, and photogrammetry data. For the computational model under an aeroelastic load, maximum deflection errors in the fore and aft, lateral, and vertical directions are -3.2 percent, 0.28 percent, and 0.09 percent, respectively; and maximum slope errors in roll and pitch directions are 0.28 percent and -3.2 percent, respectively. For the experimental model, deflection results at the tip are shown to be accurate to within 3.8 percent of the photogrammetry data and are accurate to within 2.2 percent in most cases. In general, excellent matching between target and computed values are accomplished in this study. Future refinement of this theory will allow it to monitor the deflection and health of an entire aircraft in real time, allowing for aerodynamic load computation, active flexible motion control, and active induced drag reduction.. Pak, Chan-Gi Armstrong Flight Research Center NASA/TM-2015-218358, DFRC-E-DAA-TN16068
Book Synopsis Unsteady-pressure and Dynamic-deflection Measurements on an Aeroelastic Supercritical Wing by : David A. Seidel
Download or read book Unsteady-pressure and Dynamic-deflection Measurements on an Aeroelastic Supercritical Wing written by David A. Seidel and published by . This book was released on 1991 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of an Aeroelastic Model Technique for Predicting Airplane Buffet Loads by : Perry W. Hanson
Download or read book Evaluation of an Aeroelastic Model Technique for Predicting Airplane Buffet Loads written by Perry W. Hanson and published by . This book was released on 1973 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel technique which makes use of a dynamically scaled aeroelastic model to predict full-scale airplane buffet loads during buffet boundary penetration is evaluated. A 1/8-scale flutter model of a fighter airplane with remotely controllable variable-sweep wings and trimming surfaces was used for the evaluation. The model was flown on a cable-mount system which permitted high lift forces comparable to those in maneuvering flight. Bending moments and accelerations due to buffet were measured on the flutter model and compared with those measured on the full-scale airplane in an independent flight buffet research study. It is concluded that the technique can provide valuable information on airplane buffet load characteristics not available from any other source except flight test.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781719500098 Total Pages :54 pages Book Rating :4.5/5 ( download)
Book Synopsis Deformed Shape Calculation of a Full-Scale Wing Using Fiber Optic Strain Data from a Ground Loads Test by : National Aeronautics and Space Administration (NASA)
Download or read book Deformed Shape Calculation of a Full-Scale Wing Using Fiber Optic Strain Data from a Ground Loads Test written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: A ground loads test of a full-scale wing (175-ft span) was conducted using a fiber optic strain-sensing system to obtain distributed surface strain data. These data were input into previously developed deformed shape equations to calculate the wing s bending and twist deformation. A photogrammetry system measured actual shape deformation. The wing deflections reached 100 percent of the positive design limit load (equivalent to 3 g) and 97 percent of the negative design limit load (equivalent to -1 g). The calculated wing bending results were in excellent agreement with the actual bending; tip deflections were within +/- 2.7 in. (out of 155-in. max deflection) for 91 percent of the load steps. Experimental testing revealed valuable opportunities for improving the deformed shape equations robustness to real world (not perfect) strain data, which previous analytical testing did not detect. These improvements, which include filtering methods developed in this work, minimize errors due to numerical anomalies discovered in the remaining 9 percent of the load steps. As a result, all load steps attained +/- 2.7 in. accuracy. Wing twist results were very sensitive to errors in bending and require further development. A sensitivity analysis and recommendations for fiber implementation practices, along with, effective filtering methods are included Jutte, Christine V. and Ko, William L. and Stephens, Craig A. and Bakalyar, John A. and Richards, W. Lance Armstrong Flight Research Center DEFORMATION; GROUND TESTS; SHAPES; WINGS; FIBER OPTICS; STRAIN DISTRIBUTION; FULL SCALE TESTS; BENDING; DEFLECTION; PHOTOGRAMMETRY; STRAIN MEASUREMENT; BRAGG GRATINGS; STRAIN GAGES
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1992 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1973 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Geometrical and Structural Properties of an Aeroelastic Research Wing (ARW-2) by :
Download or read book Geometrical and Structural Properties of an Aeroelastic Research Wing (ARW-2) written by and published by . This book was released on 1989 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introduction to Aircraft Aeroelasticity and Loads by : Jan Robert Wright
Download or read book Introduction to Aircraft Aeroelasticity and Loads written by Jan Robert Wright and published by John Wiley & Sons. This book was released on 2008-02-28 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Monthly Catalog of United States Government Publications by :
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1971 with total page 1388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monthly Catalog of United States Government Publications, Cumulative Index by : United States. Superintendent of Documents
Download or read book Monthly Catalog of United States Government Publications, Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1976 with total page 1466 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Geometrical and Structural Properties of an Aeroelastic Research Wing (ARW-2) by : Maynard C. Sandford
Download or read book Geometrical and Structural Properties of an Aeroelastic Research Wing (ARW-2) written by Maynard C. Sandford and published by . This book was released on 1989 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introduction to Nonlinear Aeroelasticity by : Grigorios Dimitriadis
Download or read book Introduction to Nonlinear Aeroelasticity written by Grigorios Dimitriadis and published by John Wiley & Sons. This book was released on 2017-03-10 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Nonlinear Aeroelasticity Introduces the latest developments and technologies in the area of nonlinear aeroelasticity Nonlinear aeroelasticity has become an increasingly popular research area in recent years. There have been many driving forces behind this development, increasingly flexible structures, nonlinear control laws, materials with nonlinear characteristics and so on. Introduction to Nonlinear Aeroelasticity covers the theoretical basics in nonlinear aeroelasticity and applies the theory to practical problems. As nonlinear aeroelasticity is a combined topic, necessitating expertise from different areas, the book introduces methodologies from a variety of disciplines such as nonlinear dynamics, bifurcation analysis, unsteady aerodynamics, non-smooth systems and others. The emphasis throughout is on the practical application of the theories and methods, so as to enable the reader to apply their newly acquired knowledge Key features: Covers the major topics in nonlinear aeroelasticity, from the galloping of cables to supersonic panel flutter Discusses nonlinear dynamics, bifurcation analysis, numerical continuation, unsteady aerodynamics and non-smooth systems Considers the practical application of the theories and methods Covers nonlinear dynamics, bifurcation analysis and numerical methods Accompanied by a website hosting Matlab code Introduction to Nonlinear Aeroelasticity is a comprehensive reference for researchers and workers in industry and is also a useful introduction to the subject for graduate and undergraduate students across engineering disciplines.
Book Synopsis Complex Systems: Spanning Control and Computational Cybernetics: Applications by : Peng Shi
Download or read book Complex Systems: Spanning Control and Computational Cybernetics: Applications written by Peng Shi and published by Springer Nature. This book was released on 2022-09-18 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, dedicated to Professor Georgi M. Dimirovski on his anniversary, contains new research directions, challenges, and many relevant applications related to many aspects within the broadly perceived areas of systems and control, including signal analysis and intelligent systems. The project comprises two volumes with papers written by well known and very active researchers and practitioners. The first volume is focused on more foundational aspects related to general issues in systems science and mathematical systems, various problems in control and automation, and the use of computational and artificial intelligence in the context of systems modeling and control. The second volume is concerned with a presentation of relevant applications, notably in robotics, computer networks, telecommunication, fault detection/diagnosis, as well as in biology and medicine, and economic, financial, and social systems too.
Book Synopsis The Finite Element Method and Applications in Engineering Using ANSYS® by : Erdogan Madenci
Download or read book The Finite Element Method and Applications in Engineering Using ANSYS® written by Erdogan Madenci and published by Springer. This book was released on 2015-02-10 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook offers theoretical and practical knowledge of the finite element method. The book equips readers with the skills required to analyze engineering problems using ANSYS®, a commercially available FEA program. Revised and updated, this new edition presents the most current ANSYS® commands and ANSYS® screen shots, as well as modeling steps for each example problem. This self-contained, introductory text minimizes the need for additional reference material by covering both the fundamental topics in finite element methods and advanced topics concerning modeling and analysis. It focuses on the use of ANSYS® through both the Graphics User Interface (GUI) and the ANSYS® Parametric Design Language (APDL). Extensive examples from a range of engineering disciplines are presented in a straightforward, step-by-step fashion. Key topics include: • An introduction to FEM • Fundamentals and analysis capabilities of ANSYS® • Fundamentals of discretization and approximation functions • Modeling techniques and mesh generation in ANSYS® • Weighted residuals and minimum potential energy • Development of macro files • Linear structural analysis • Heat transfer and moisture diffusion • Nonlinear structural problems • Advanced subjects such as submodeling, substructuring, interaction with external files, and modification of ANSYS®-GUI Electronic supplementary material for using ANSYS® can be found at http://link.springer.com/book/10.1007/978-1-4899-7550-8. This convenient online feature, which includes color figures, screen shots and input files for sample problems, allows for regeneration on the reader’s own computer. Students, researchers, and practitioners alike will find this an essential guide to predicting and simulating the physical behavior of complex engineering systems."
