| Air Vehicle Integration and Technology Research (AVIATR). Delivery Order 0023: Predictive Capability for Hypersonic Structural Response and Life Prediction: Phase 2 - Detailed Design of Hypersonic Cruise Vehicle Hot-Structure |
May 2012 |
203 pages |
| Authors:
Brian Zuchowski; LOCKHEED MARTIN AERONAUTICS CO PALMDALE CA
|
 | Structural design of hypersonic vehicles requires additional considerations and effort, relative to conventional subsonic and low-supersonic aircraft, because of the wide Mach number range and the associated heating effects at high Mach numbers. At high temperatures, conventional structural materials, such as metals, suffer from reduced strength, reduced stiffness, increased creep, increased oxidation, increased thermal stresses, and other detrimental effects that impact structural design; many of these effects are of limited ... |
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| Air Vehicle Integration and Technology Research (AVIATR). Task Order 0023: Predictive Capability for Hypersonic Structural Response and Life Prediction: Phase 2 - Detailed Design of Hypersonic Cruise Vehicle Hot-Structure |
Feb 2012 |
758 pages |
| Authors:
Rob Quiroz; Jon Embler; Rich Jacobs; George Tzong; Salvatore Liguore; BOEING CO HUNTINGTON BEACH CA
|
| Four panels from a representative Mach 7 hypersonic cruise vehicle were designed and analyzed with state-of-the-art standard methods and tools to verify structural response and life predictive capabilities. Several modifications were made to the Technology Experiment Vehicle (TX-V) to refine the structure and create a Mach 7 closed-concept configuration with an all-metallic, high-temperature airframe. Structural loads and environments from the TX-V were then used to size and design the four ... |
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| Fluid-Structure Interaction Evaluation of F-16 Limit Cycle Oscillations |
09 Jan 2012 |
11 pages |
| Authors:
Jason A Lechniak; Keerti K Bhamidipati; AIR FORCE FLIGHT TEST CENTER EDWARDS AFB CA
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| Application of high-fidelity computational science and engineering (CSE) tools provide better data for decisions to enhance weapon systems acquisition, testing, and support. Fluid structure interaction (FSI) simulation is being evaluated to quantify aero-structural dynamic mechanisms that bound F-16 limit cycle oscillations (LCO). The intent of the research objectives is to provide a better understanding of flight-test aero-structural observations through the utilization of CSE tools. Validation of results provided by CSE ... |
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| Massive Spontaneous Retroperitoneal Hemorrhage Induced by Enoxaparin and Subsequent Abdominal Compartment Syndrome Requiring Surgical Decompression: A Case Report and Literature Review |
Aug 2011 |
6 pages |
| Authors:
Benjamin Quartey; Jeffrey Nelson; NATIONAL NAVAL MEDICAL CENTER BETHESDA MD
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| Spontaneous retroperitoneal hemorrhage from the use of enoxaparin is very rare but can be fatal. Although most cases are treated by conservative means, there may be a role for surgical intervention. We present the case of a 77-year-old man who developed a large retroperitoneal hemorrhage during treatment for pulmonary embolism and atrial flutter with enoxaparin in which supportive measures failed and necessitated surgical correction. This case adds to the growing ... |
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| Flutter Instability of a Fluid-Conveying Fluid-Immersed Pipe Affixed to a Rigid Body |
Jan 2011 |
12 pages |
| Authors:
Aren Hellum; Ranjan Mukherjee; Andrew J Hull; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| A set of simplified boundary conditions for a flexible beam connected to a rigid body at one end and free at the other end is presented and applied to the case of a fluid-conveying, fluid-immersed pipe. These boundary conditions represent an analytically tractable approximation to those of a submersible which uses a combination of jet action and flutter instability induced tail motion to produce thrust. The boundary conditions are made ... |
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| Continuous Dynamic Simulation of Nonlinear Aerodynamics/Nonlinear Structure Interaction (NANSI) for Morphing Vehicles |
31 Mar 2010 |
290 pages |
| Authors:
Ping-Chih Chen; ZONA TECHNOLOGY INC SCOTTSDALE AZ
|
| In this report, we present the ZONA team's effort for this Phase II project. The ZONA team is made up of ZONA Technology. Inc. (ZONA), Arizona State University (Research Institute), and Professor Feng Liu (Consultant). The objective for this project was to develop a nonlinear aerodynamic and nonlinear structural interaction (NANSI) methodology as an expedient aeroelastic tool to handle continuous dynamic motion of morphing vehicles/wings from incompressible/subsonic to transonic flight ... |
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| Aeroelastic Optimization of Sounding Rocket Fins |
Jun-2009 |
106 pages |
| Authors:
Simmons; Joseph R III; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This research effort develops a multidisciplinary design tool to optimize sounding rocket fin geometries that minimize the mass of the fins while maintaining aerodynamic performance. This research grew out of a design problem experienced by the US Air Force Academy's Falcon LAUNCH program. The Falcon LAUNCH program is a senior design capstone project during which Air Force Academy cadets design, build and fly a sounding rocket over the course of ... |
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| Stochastic Nonlinear Aeroelasticity |
Jan-2009 |
41 pages |
| Authors:
Philip S Beran; Ned J Lindsley; Jose Camberos; Mohammad Kurdi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| This report documents the culmination of in-house work in the area of uncertainty quantification and probabilistic techniques for aeroelasticity. The work was divided into different project areas, including: accurate analysis of limit-cycle oscillations for simple aeroelastic systems with variability; probabilistic prediction of flutter in systems with distributed variability (random fields); optimization of nonlinear dynamic systems (deterministic with intent to transition to risk-quantified optimization), and incorporation of sensitivities into probabilistic analyses. ... |
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| Morphing Aircraft Structures: Research in AFRL/RB |
01-Sep-2008 |
35 pages |
| Authors:
Gregory W Reich; Shiv Joshi; Jayanth Kudva; Geoffrey J Frank; Franklin E Eastep; Bryan Cannon; Matthew P Snyder; Brian Sanders; Jason C Bowman; Terrence Weisshaar; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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| This report reviews research in several different areas related to morphing aircraft structures undertaken in AFRL/RBSA. The first is an aeroelastic analysis of a folding-wing vehicle to determine the flutter boundaries of the wing at different fold angles. The second is the development of a simulation tool to study both the flight stability of a morphing vehicle during the morphing process, and the kinematic stability of the morphing mechanism subject ... |
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| Insect Flight: Computation and Biomimetic Design |
31 MAY 2008 |
8 pages |
| Authors:
Z. J. Wang; CORNELL UNIV ITHACA NY DEPT OF THEORETICAL AND APPLIED MECHANICS
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| Our research has focused on understanding fundamental mechanisms of unsteady aerodynamics in flapping flight. In particular we have focused on dragonfly flight and passive flight of fluttering and tumbling plates in fluid. We use computations, theoretical analyses, and tabletop experiments to unravel the essential mechanisms in these systems. They have yielded new insights into the unsteady aerodynamics and energetics of flapping flight. These new insights offer lessons on designs of ... |
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| Nonlinear Stochastic Flutter of a Cantilever Wing with Joint Relaxation and Random Loading |
21 FEB 2008 |
152 pages |
| Authors:
Raouf A. Ibrahim; Ronald F. Gibson; WAYNE STATE UNIV DETROIT MI DEPT OF MECHANICAL ENGINEERING SCIENCES
|
| The research project has generated a number of problems addressing the uncertainties and relaxation problems in aeroelastic structures. Specifically, three main problems that are of important concern to the aerospace industry and the Air Force technology have been addressed. These are: (1) The influence of structure uncertainties of the flutter of an aircraft wing. (2) Stabilization of wing flutter via parametric excitation. (3) Influence ofjoint relaxation on the flutter of ... |
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| Computational Nonlinear Aeroelasticity |
JAN 2008 |
9 pages |
| Authors:
Philip S. Beran; Richard D. Snyder; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| This report documents the culmination of in-house work in the area of computational modeling techniques for aeroelasticity. At the project onset, emphasis was given to the challenge of predicting flutter points for aircraft in the transonic regime. Methods based on bifurcation theory and reduced order modeling were developed and tested. This work helped to shape the activity of the aeroelastic community, and an international workshop in the subject area to ... |
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| Design Processes and Criteria for the X-51A Flight Vehicle Airframe |
01 NOV 2007 |
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| Authors:
Jeffrey Lane; BOEING CO HUNTINGTON BEACH CA INTEGRATED DEFENSE SYSTEMS
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 | Flight vehicle airframes in today's advanced flight systems are required to optimally integrate a variety of multi-functional requirements to maximize effectiveness with acceptable risk. The X-51A airframe design process and criteria draw upon decades of successful design of both manned and unmanned flight vehicles for production and experimental intent. This paper summarizes the X-51A vehicle mission requirements, system design, design processes used for airframe synthesis, design safety factors, success criteria ... |
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| Reduced Order Modeling for Aero-Elastic Simulations |
JUL 2006 |
11 pages |
| Authors:
Mark Balas; WYOMING UNIV LARAMIE DEPT OF ELECTRICAL ENGINEERING
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| Control of systems described by large-order models typically requires construction and use of reduced order models (ROM's) for the purpose of feedback controller design and implementation. However, controllers based on these ROM's can have deleterious interactions with un-modeled modes, and some sort of stability compensation is needed, such as Residual Mode Filters (RMF's). In this report we summarize our work on exponential closed loop stability using RMF's for Aero-Elastic Simulations. ... |
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| Structural Design of Wing Twist for Pitch Control of Joined Wing Sensor Craft |
MAR 2006 |
117 pages |
| Authors:
III Kimler Fred A.; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This research investigated two aspects of the aft wing structure of a joined wing SensorCraft. First, the efficacy of a novel approach for incorporating wing twist for pitch control was analyzed. This design involved adding a spanwise sliding joint into the wing structure at the lower aft spar of the vehicle's aft wing. Second, the joint section where the forward and aft wings connect and form the outboard wing was ... |
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| Non-Synchronous Vibration of Turbomachinery Airfoils |
MAR 2006 |
75 pages |
| Authors:
Robert E. Kielb; Kenneth C. Hall; Meredith Spiker; Jeffrey P. Thomas; Jr. Pratt Edmund T.; Rhett Jeffries; DUKE UNIV DURHAM NC DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| The goal of this research was to develop a fast computational method to be able to understand non-synchronous vibrations in turbomachinery blades in the design stage. The numerical approach involved the use of a two- and three-dimensional nonlinear Navier- Stokes unsteady harmonic balance method. As an initial demonstration of the method, the flow over a cylinder and a two dimensional airfoil, the 2D C1 case, were investigated and results showed ... |
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| Methodologies for Predicting and Testing the Combat Damage on Flight Envelopes |
FEB 2006 |
7 pages |
| Authors:
Charbel Farhat; STANFORD UNIV CA
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| Survivability of an aircraft in combat is achieved by not getting hit, or withstanding the effects of suffered hits. To assess the latter aspect of survivability of a given military aircraft, live-fire tests are performed on its wings. However, these tests may fail to provide accurate and complete vulnerability assessments, because the static and quasi-static ground loading techniques they currently rely on do not replicate the loads encountered during flight. ... |
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| Extend MANPADS M&S Capabilities to Include Energetic Materials, Fragmentation Effects, and Wing Flutter Response |
31 DEC 2005 |
100 pages |
| Authors:
Ronald L. Hinrichsen; Monty A. Moshier; Brian D. Choules; RHAMM TECHNOLOGIES LLC BELLBROOK OH
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| The purpose of this effort is to create an analytical physics based aircraft-MANPADS model capability that includes impact, detonation, penetration, and wing flutter response. This work extends an existing body-on-body missile model to include energetic materials, fragmentation effects and wing flutter response due to dynamic air loads. The detonation of the high explosive within the missile, as well as the expansion of the surrounding fluids, was modeled in the Eulerian ... |
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| Dynamic Aeroelastic Analysis of Wing/Store Configurations |
DEC 2005 |
124 pages |
| Authors:
Gregory H. Parker; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Limit-cycle oscillation, or LCO, is an aeroelastic phenomenon characterized by limited amplitude, self-sustaining oscillations produced by fluid-structure interactions. In order to study this phenomenon, code was developed to interface a modal structural model with a commercial computational fluid dynamics program. LCO was simulated for a rectangular wing, referred to as the Goland+ wing. It was determined that the aerodynamic nonlinearity responsible for LCO in the Goland+ wing was the combination ... |
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| Dynamic Aeroelastic Analysis of Wing/Store Configurations |
DEC 2005 |
124 pages |
| Authors:
Gregory H. Parker; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Limit-cycle oscillation, or LCO, is an aeroelastic phenomenon characterized by limited amplitude, self-sustaining oscillations produced by fluid-structure interactions. In order to study this phenomenon, code was developed to interface a modal structural model with a commercial computational fluid dynamics program. LCO was simulated for a rectangular wing, referred to as the Goland+ wing. It was determined that the aerodynamic nonlinearity responsible for LCO in the Goland+ wing was the combination ... |
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| Turbine Engine Research Center (TERC) Data System Enhancement and Test Article Evaluation. Delivery Order 0002: TERC Aeromechanical Characterization |
JUN 2005 |
375 pages |
| Authors:
Pamela S. Teets; Walter O'brien; Vince Capece; Choon Tan; BATTELLE DAYTON OPERATIONS OH
|
| Battelle has supported the Air Force Compressor Research Facility from May 13, 2003 through June 30, 2005 under this Delivery Order. Under this Delivery Order, aeromechanical characterization research was performed in conjunction with testing performed in the Turbine Engine Research Center (TERC). This research involved data analysis to identify new behavior, verify codes and model simulating aeromechanical behavior, and perform aeromechanical test and evaluation of hardware undergoing testing in the ... |
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| Research and Development of a Scaled Joined-Wing Flight Vehicle |
APR 2005 |
25 pages |
| Authors:
Afzal Suleman; INSTITUTO SUPERIOR TECNICO LISBON (PORTUGAL) DEPT OF MECHANICAL ENGINEERING
|
| This report results from a contract tasking Instituto Superior Tecnico as follows: The Grantee will investigate the aeroelastic performance of the joined-wing concept. Dr. Suleman and his research team have proposed to investigate the aeroelastic performance of the joined-wing concept by analyzing, designing, manufacturing, and wind tunnel testing aeroelastically scaled models. The first step will include designing a test assembly to conduct aeroelastic flutter and gust response tests. A fairly ... |
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| Validation Tools of Nonlinearities Associated With Aeroelastic Phenomena |
15 NOV 2004 |
4 pages |
| Authors:
Muhammad R. Hajj; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS
|
| The work performed under Grant # F49620-03-l-0206 included the analysis of a unique database on the hard flutter of a Flexible Semispan Model of a High Speed Civil Transport model. The experiments were performed in the Langley Transonic Dynamic Tunnel. These experiments are unique in terms of the model scaling and characteristics, the range of Mach number and dynamic pressure and the observed phenomena. To date, the analysis of the ... |
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| Uncertainties and Relaxation of Boundary Conditions of Aeroelastic Panels |
08 NOV 2004 |
34 pages |
| Authors:
Raouf A. Ibrahim; WAYNE STATE UNIV DETROIT MI DEPT OF MECHANICAL ENGINEERING SCIENCES
|
| The influence of boundary condition relaxation on two-dimensional panel flutter is studied in the presence of in-plane loading. The boundary value problem of the panel involves time-dependent boundary conditions that are converted into autonomous form using a special coordinate transformation. Galerkin's method is used to discretize the panel partial differential equation into six nonlinear ordinary differential equations representing the first six modes. The influence of boundary condition relaxation on the ... |
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| Expanding a Flutter Envelope Using Data From Accelerating Flight: Application to the F-16 Fighter Aircraft |
2004 |
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| Authors:
Charles A. Harris; AIR FORCE FLIGHT TEST CENTER EDWARDS AFB CA
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| Due to the destructive nature of flutter, flutter testing is a mandatory requirement for certification of both civilian and military aircraft. However, along with the complexity of newer aircraft, the time and cost associated with flutter testing has increased dramatically. Considering that many of the test techniques and analysis methods used to perform flutter testing date back to the 1950s and 1960's it may be time to take a fresh ... |
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| Limit Cycle Oscillations and Nonlinear Aeroelastic Wing Response: Reduced Order Aerodynamic Models |
31 DEC 2003 |
24 pages |
| Authors:
Earl H. Dowell; Kenneth C. Hall; DUKE UNIV DURHAM NC DEPT OF MECHANICALENGINEERING AND MATERIALS SCIENCE
|
| To develop an eigenmode or proper orthogonal decomposition (POD) modal representation of unsteady aerodynamic forces on oscillating flexible airfoils and wings and thereby reduce the size and cost of mathematical models for such forces by several orders of magnitude. Building on earlier work for two-dimensional inviscid flows, we seek to extend our models to. three- dimensional flows with viscous effects included. Also a novel form of the harmonic balance (HB) ... |
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| Innovative Manufacturing and Structural Analysis of Composite Isogrid Structures for Space Applications |
DEC 2003 |
92 pages |
| Authors:
Hassan Mahfuz; Derrick Dean; Shaik Jeelani; Mohammed Baseer; Gamaleldin Mohamed; TUSKEGEE UNIV AL
|
| The search for lightweight and highly efficient structural components is a continuing process. Reducing the structural weight and improving the load carrying capabilities of these structures will allow designers to add additional capabilities while reducing cost. The basic functions of aerospace structures are to transmit and sustain the applied loads, provide a basic shape and to protect the payload. Shell stiffened structures have been used for many years to fulfill ... |
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| Nonlinear Reduced-Order Modeling of Limit Cycle Oscillations of Aircraft Wings and Wing/Store |
DEC 2003 |
148 pages |
| Authors:
P. C. Chen; Danny D. Liu; Xiaowei Geo; Kenneth C. Hall; Earl H. Dowell; ZONA TECHNOLOGY INC SCOTTSDALE AZ
|
| Significant progress has been made by the ZONA-Duke team in Phase II of our work. A novel and computationally efficient method for calculating transonic limit cycle oscillations (LCO), flutter and other nonlinear aeroelastic phenomena has been developed. To solve the general 3D Euler and Reynolds Averaging Navier-Stokes( Eulen/RANS) equation, a Harmonic Balance(HB) method formulated in the frequency domain in combination with a proper ormogonal decomposition (POD) technique and reduced order ... |
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| Constructive Nonlinear Control |
30 SEP 2003 |
9 pages |
| Authors:
Petar V. Kokotovic; CALIFORNIA UNIV SANTA BARBARA CENTER FOR CONTROL ENGINEERING AND COMPUTATION
|
| During this grant period, we have enhanced robustness of our designs and thus increased their ability to accommodate disturbances and unmodeled dynamics. We have also broadened the class of systems to which these methods are applicable. In a different direction, we have developed structure specific methods to analyze boundedness properties of systems with "stiffening" nonlinearities, as in micro-electromechanical probes. A major advance has been made on difficult output feedback problem ... |
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| Theoretical Prediction of Limit Cycle Oscillations in Support of Flight Flutter Testing |
31 AUG 2003 |
24 pages |
| Authors:
Earl H. Dowell; Kenneth C. Hall; DUKE UNIV DURHAM NC DEPT OF MECHANICALENGINEERING AND MATERIALS SCIENCE
|
| Using a novel harmonic balance method and a state of the art computational fluid dynamics (CFD) model, limit cycle oscillations have been calculated for a conventional and supercritical airfoil as well as the F-16 wing. The latter result is the first of its kind. |
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| Aerospace Turbomachinery Flow Physics |
AUG 2003 |
152 pages |
| Authors:
Choon S. Tan; MASSACHUSETTS INST OF TECH CAMBRIDGE GAS TURBINE LAB
|
| This document constitutes the final report on a multi-investigator research program on "Aerospace Turbo machinery Flow Physics". The research program encompasses the following four technical areas: (1) Flutter clearance in aircraft engine compressors (2) Physics of coolant/main flow interactions in advanced aircraft/rocket turbines (3) Tip clearance flow effects in axial and centrifugal turbomachines (4) Use of an active rotor to delineate parametric dependence of aerodynamic damping A common theme that ... |
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| Dynamics and Control of Nonlinear Fluid-Structure Interaction |
JUL 2003 |
16 pages |
| Authors:
Earl H. Dowell; Robert L. Clark Jr.; Lawrence N. Virgin; DUKE UNIV DURHAM NC DEPT OF MECHANICALENGINEERING AND MATERIALS SCIENCE
|
| Experimental and theoretical studies of the nonlinear dynamics and control of aeroelastic systems including airfoils and wings have been conducted. Nonlinear geometric stiffness and freeplay have been considered specifically and good theoretical / experimental correlation obtained. Active control systems have been designed, built and tested to increase flutter speed and reduce limit cycle oscillations (LCO). Our most recent work includes theoretical studies of aerodynamic nonlinearities in the transonic range and ... |
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| Multidisciplinary Optimization of an Aircraft Wing/Tip Store in the Transonic Regime |
JUL 2003 |
38 pages |
| Authors:
Srinivasan Janardhan; Ramana V. Grandhi; WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING
|
| In this research, a multidisciplinary optimization procedure is described to delay the occurrence of store-induced flutter of an aircraft wing/ tip store configuration. A preliminary design procedure was developed to enhance the performance characteristics of an aircraft wing model in the transonic Mach number regime. A wing/tip store configuration with the store center of gravity (c.g.) located at the 50% aerodynamic tip chord was chosen for structural optimization. The aircraft ... |
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| Computational Mechanics Approach for Multidisciplinary Nonlinear Sensitivity Analysis |
30 JUN 2003 |
8 pages |
| Authors:
Ramana V. Grandhi; WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING
|
| The primary objective of this research work was to develop preliminary designs of aircraft wing/store configurations to achieve improved flutter performance in the transonic regime. In this research work, a methodology was developed to incorporate the nonlinearities associated with the wing and store in transonic regime into the multidisciplinary environment. Investigated the aeroelastic effects of the wing with and without the inclusion of store aerodynamics. The tip store configurations and ... |
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| A Three-Dimensional Flutter Theory For Rotor Blades With Trailing-Edge Flaps |
JUN 2003 |
237 pages |
| Authors:
Mark A. Couch; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This dissertation develops the equations of motion for the structural and aerodynamic forces and moments of a rotor blade with a trailing-edge flap using eight degrees of freedom. Lagrange's equation is applied using normal modes to find the flutter frequency and speed similar to the classic fixed-wing method developed by Smilg and Wasserman. However, rotary-wing concerns are addressed including different freestream velocities along the blade (variation of reduced frequency along ... |
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| The Aeroelastic Effects of Transverse Shear Deformation on Composite Wings in Various Speed Flow Regimes |
02 MAY 2003 |
70 pages |
| Authors:
Michael Oliver; NAVAL ACADEMY ANNAPOLIS MD DEPT OF AEROSPACE ENGINEERING
|
| This project analyzes the effect of transverse shear deformation upon the aeroelastic response of composite wings in high speed flow regimes. Previously, models were developed to predict the aeroelastic characteristics of classical materials in high speed flow. However, these studies ignored transverse shear by assuming an infinite modulus of rigidity. This assumption underestimates transverse flexibility by ignoring the transfer of loads through the wing thickness. By assuming a finite modulus ... |
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| Dynamic Aeroelastic Instabilities of an Aircraft Wing with Underwing Store in Transonic Regime |
MAY 2003 |
31 pages |
| Authors:
Chakradhar Byreddy; Ramana V. Grandhi; Philip Beran; ADVANCED STRATEGIC AND TACTICAL INFRARED EXPENDABLES OFFICE WRIGHT-PATTERSONAFB OH
|
| The research used the Transonic Small Disturbance (TSD) theory to better understand the dynamic aeroelastic phenomena and factors that affect the onset of flutter and store induced Limit-Cycle Oscillations (LCO) in the transonic regime. Several parametric studies of the flutter and LCO of an aircraft wing with underwing store in the transonic regime were conducted, as well as an investigation of the effect of inclusion of store aerodynamics on the ... |
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| UAV Aeroelastic Control Using Redundant Micro-Actuators |
03 MAR 2003 |
15 pages |
| Authors:
Ilan Kroo; Fritz Prinz; John Eaton; STANFORD UNIV CA
|
| The investigation of trailing edge micro-actuators for aeroelastic control of uninhabited air vehicles (UAVs) has ranged from examining the fundamental aerodynamic effects to demonstrating flutter suppression of a flexible wing. The applicability of aerodynamic prediction methods including CFD and panel methods has been studied. Several generations of actuator concepts have been developed and characterized. Wind tunnel experiments have been completed on a rigid wing to determine the aerodynamic performance of ... |
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| Nonlinear Transonic Flutter Prediction for F-16 Stores Configuration Clearance |
MAR 2003 |
180 pages |
| Authors:
Raymond G. Toth; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Limit cycle oscillation (LCO) has been an issue for the F-16 since its operational deployment. Configuration validation requires large investments in time and resources due to the very specific and stringent guidelines used during flight test to ensure the aircraft does not encounter classical flutter or excessive LCO. A new approach, incorporating inherent nonlinearities that drive LCO is investigated using the Transonic Equivalent Strip method to account for wing thickness ... |
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| The Dependence of Store-Induced Limit-Cycle Oscillation Predictions on Modelling Fidelity |
MAR 2003 |
22 pages |
| Authors:
P. S. Beran; N. S. Khot; F. E. Eastep; R. D. Snyder; J. V. Zweber; AIR FORCE RESEARCH LAB WRIGHT-PATTERSONAFB OH MULTIDISCIPLINARY TECHNOLOGIESCENTER
|
| Store-induced limit-cycle oscillation of a rectangular wing with tip store in transonic flow is simulated using a variety of mathematical models for the flow field: transonic small-disturbance theory (with and without inclusion of store aerodynamics) and transonic small-disturbance theory with interactive boundary layer (without inclusion of store aerodynamics). For the conditions investigated, limit-cycle oscillations are observed to occur as a result of a subcritical Hopf bifurcation, and are obtained at ... |
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| Developpements numeriques recents realises en aeroelasticite chez Dassault Aviation pour la conception des avions de combat modernes et des avions d'affaires |
MAR 2003 |
12 pages |
| Authors:
E. Garrigues; Th. Percheron; DASSAULT AVIATION SAINT-CLOUD (FRANCE)
|
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| Unsteady Aerodynamics & Aeromechanics of Multi-Stage Turbomachinery Blading |
30 NOV 2002 |
200 pages |
| Authors:
Sanford Fleeter; PURDUE RESEARCH FOUNDATION LAFAYETTE IN
|
| An integrated experiment-theory approach included collaboration between Pratt & Whitney, Duke University, and Purdue University. A benchmark- standard multistage transonic research compressor was developed by modifying the Purdue High-Speed Axial Compressor to feature new IGV and stator rows representative of modern high pressure compressors. A quantitative understanding and predictive capability for multi-stage blade row forced response was developed by analytically and experimentally investigating the fundamental flow phenomena. Experiments at Purdue ... |
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| Unsteady Aerodynamics & Aeormechanics of Multi-Stage Turbomachinery Blading |
30 NOV 2002 |
200 pages |
| Authors:
Sanford Fleeter; PURDUE UNIV LAFAYETTE IN SCHOOL OF MECHANICAL ENGINEERING
|
| The overall research objective was to develop the technology needed to predict accurately significant blade row forced response in a multistage environment, thereby providing accurate predictions of HCF in turbine engine blade rows. Specific objectives included: development of a benchmark standard multistage transonic research compressor; providing a quantitative understanding and predictive capability for multi-stage blade row forced response; investigating techniques to control the flow induced vibrations; considering the issue of ... |
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| Aero-Structural Coupling and Sensitivity of a Joined-Wing SensorCraft |
05 NOV 2002 |
27 pages |
| Authors:
Jennifer Schwartz; Robert Canfield; Maxwell Blair; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
|
| This presentation presents information on the Joined-Wing SensorCraft, including a history of the Joined Wing, SensorCraft background, configuration issues, parametric modeling and design method, aerodynamic panel model (i.e., PanAir and FlightLoads), structural finite element model, related studies, and conclusion. The Lockheed Martin new aircraft concept of the Joined Wing is intended to reduce drag, improve stability, strengthen the wing, and prevent flutter. The Air Force's requirement is for an unmanned ... |
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| Limit Cycle Oscillations (LCO) and Nonlinear Aeroelastic Response: Reduced Order Models |
01 NOV 2001 |
13 pages |
| Authors:
Earl H. Dowell; DUKE UNIV DURHAM NC DEPT OF MECHANICALENGINEERING AND MATERIALS SCIENCE
|
| Unsteady aerodynamic computational models for aeroelastic phenomena such as flutter and limit cycle oscillations are complex and high dimensional. Under this grant, reduced order models are being developed that offer increased physical insight and greatly reduced computational cost. Transonic flows are emphasized because of their practical importance and significant technical challenge. |
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| Predicting the Nonlinear Response of Aerospace Structures Using Aeroelastic NS Solutions on Deforming Meshes |
NOV 2001 |
174 pages |
| Authors:
R. P. Selvam; ZU-Qing Qu; Qun Zheng; Uday K. Roy; ARKANSAS UNIV FAYETTEVILLE COMPUTATIONAL MECHANICS LAB
|
| With the resurgent interest in flight vehicles such as the High-Speed Civil Transport (HSCT), the X-33 Advanced Technology Demonstrator, the Reusable Launch Vehicle (RLV), the Joint Strike Fighter (JSF) and the X-38 Spacecraft using a lifting-body concept that will Operate at supersonic/hypersonic Mach numbers, the need for panel flutter analysis has received broad acknowledgement. The linear and nonlinear analysis of the panel flutter has been studied extensive during the past ... |
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| Simulation of the Transient Aeroelastic Response of a Realistic Aircraft Configuration During Three-Dimensional High G Maneuvers |
OCT 2001 |
13 pages |
| Authors:
Charbel Farhat; COLORADO UNIV AT BOULDER DEPT OF AEROSPACE ENGINEERING SCIENCES
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| Our long-term objective has been the development of a high-fidelity and high-performance simulation capability for predicting and optimizing the dynamic aeroelastic response of a fighter during three-dimensional high-G maneuvers in subsonic, transonic, and supersonic airstreams. Our focus has been on Air Force problems involving a modern fighter or bomber, and relevant to new approaches for flutter testing, mitigation of limit-cycle (LCO) and pilot induced (P1O) oscillations, as well as performance ... |
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| Mechanical Systems, Structures and Materials (MSSM) |
JUN 2001 |
6 pages |
| Authors:
Otto Sensburg; DAIMLER CHRYSLER AEROSPACE MUNICH (GERMANY) MILITARY AIRCRAFT
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| Active Control Technology (ACT) was introduced in the seventies together with fly by wire and Control Configured Vehicle (CCV)-Technology 1. Several technologies that are now available and widely used for aircraft are: * Artificial longitudinal and lateral stability * Manoeuver load control * Vibration suppression (-leading to flutter suppression) * Gust load Alleviation The advent of smart adaptive structures, where distributed control with distributed actuators is applied even further increased ... |
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| Aeroelastic Leveraging and Control through Adaptive Structures |
15 JAN 2001 |
140 pages |
| Authors:
Robert L. Clark; DUKE UNIV DURHAM NC
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| The primary objective of the proposed program is to develop and design a distributed actuation methodology for wing warping in UCAVs aimed at: (1) control of higher-order flutter modes, (2) increased maneuverability, and (3) reduced radar signature. Specific milestones achieved during the funded phase of the program include: (1) Completed design and testing of high aspect ratio wing model in Duke University Wind Tunnel to correlate computer model used to ... |
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| Nonlinear Dynamics and Control of Wings and Panels |
26 DEC 2000 |
7 pages |
| Authors:
Earl H. Dowell; Robert L. Clark Jr.; Lawrence N. Virgin; DUKE UNIV DURHAM NC DEPT OF MECHANICALENGINEERING AND MATERIALS SCIENCE
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| This is the Final Report of AFOSR Grant F49620-97-1-O414. The objective of this study was to develop a more fundamental understanding of the causes and modifications of limit cycle oscillations and other dynamic and control phenomena arising from nonlinear effects in aeroelastic systems. A combined experimental-theoretical study was pursued to validate and improve our physical understanding and mathematical models for design and analysis to enable flight of aircraft safely and ... |
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Reports by Keyword(s)
FLUTTER
