Download or read book Aeroelastic Tailoring of Composite Wings for Flutter and Divergence Control written by Sirri Oguz and published by . This book was released on 1994 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Improvement of Composite Wings Through Aeroelastic Tailoring and Modern Control written by and published by . This book was released on 1995 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research has been carried out simultaneously on three aspects of aircraft wings performance optimization, as follows: (1) Structural tailoring and modern control of thin-walled model of composite aircraft wings; (2) Structural tailoring of a low-aspect ratio plate model of composite aircraft wings; and (3) Integrated structural design and vibration control by multiobjective optimization. Significant progress has been made on all fronts.

Download or read book Aeroelastic Tailoring with Composites Applied to Forward Swept Wings written by T. J. Hertz and published by . This book was released on 1981 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of aeroelastic tailoring with advanced composites has made forward swept wings a viable configuration option for high performance aircraft. Forward swept wings have an inherent tendency to encounter a static aeroelastic instability called divergence. The extreme weight penalty required to avoid this instability in conventional metallic construction has been the basis for the reluctance of designers to incorporate forward sweep in aircraft. Studies performed for the Flight Dynamics Laboratory and by others independently show that, through the use of aeroelastic tailoring (the design process that makes use of the directional properties of fibrous composite materials in wing skins and orients these materials in optimum directions) with advanced composite material, the aeroelastic behavior of a conventional aft swept wing can be controlled and forward swept wings can be constructed with composites that results in an increase in the divergence speed without a prohibitive increase in weight. This report presents the background and evolution of aeroelastic tailoring as applied to forward swept wings together with a summary of work required to establish an aeroelastic data base for forward swept design.

Download or read book Aeroelastic Tailoring of a Composite Wing with Adaptive Control Surfaces for Optimal Aircraft Performance written by Eduardo Krupa and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeroelastic Tailoring of Woven Cantilevered Glass epoxy Plate like Aircraft Wing written by Dayang Laila Abang Haji Abdul Majid and published by . This book was released on 2008 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of uni-directional composites in aeroelastic tailoring has long been established due to their highly directional properties. However, the use of woven, bi-directional textile composite in this area is practically nil due to their lower strength and stiffness, although this class of material is generally cheaper and more conforming. Therefore, the current work presents a new prospect for this type of material in the aeroelastic tailoring of aircraft wings. The aeroelastic flutter and divergence behaviour of rectangular, woven glass/epoxy cantilevered plates with varying amount of bending and torsion stiffness coupling is investigated in subsonic flow. To do so, a range of tailored plate configurations with various stacking sequence having 6-plies thickness were considered. The ply orientation was varied from -450 to 450 to provide the widest range of negative and positive bend-twist coupling. Test plates without stiffness coupling were first constructed and subjected to static and dynamic testing in order to characterize the elastic and dynamic behaviour of the plate. Secondly, tailored configurations with varying stiffness coupling were fabricated and tested for flutter in wind tunnel tests. Numerical analyses were also conducted using MSc.Nastran structural analysis in conjunction with ZAERO's flutter program to verify the mechanical and dynamic properties as well as predict the occurrence of flutter and divergence. Results from the extensive experimental and computational works had successfully shown that flutter speed can be optimized by tailoring the woven composite laminates. It was found that the torsional stiffness and bend-twist coupling play a major role in the aeroelastic behaviour of the woven laminate as compared to the bending stiffness. The bend-twist flutter that occurred was dominated by the torsion mode, thus explained the significant effect it has on the flutter speed. The numerical calculations predicted a 37% improvement whereas the experimental results are more understated at 29%. This improvement is remarkable considering that the configurations are symmetric. Both agreed well in terms of the optimized configuration that gave the maximum flutter speed. The flutter frequency and flutter mode shape was shown to be highly dependent on the coupled structural modes. In addition, divergence occurred when the plate-like wing is swept forward.

Download or read book Aeroelastic Stability and Performance Characteristics of Aircraft with Advanced Composite Sweptforward Wing Structures written by Terrence A. Weisshaar and published by . This book was released on 1978 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sweptforward metallic wings have not been considered to be a serious design concept for nearly thirty years. The large structural weights necessary to preclude aeroelastic divergence of metallic wing structures are unfavorable when compared to similar sweptback designs, designs that are usually divergence free. The development of fibrous laminated composite materials and the fact that forward swept wings may have superior aerodynamic performance has led to renewed interest in this design. In this report, laminated beam theory, together with aerodynamic strip theory, is used to predict the static aeroelastic divergence characteristics of swept wings. From the results of this theory, it is predicted that, because of elastic coupling between bending and torsional deformation of the wing box, laminated composites may be used to preclude wing divergence for a large range of wing forward sweep angles. Formulas are developed to illustrate the important parameters governing composite wing divergence. Two examples are presented to illustrate the use of these formulas. These examples show that composite forward swept wings have the potential to be feasible, efficient designs.

Download or read book Introduction to Structural Dynamics and Aeroelasticity written by Dewey H. Hodges and published by Cambridge University Press. This book was released on 2014-01-02 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides an introduction to structural dynamics and aeroelasticity, with an emphasis on conventional aircraft. The primary areas considered are structural dynamics, static aeroelasticity, and dynamic aeroelasticity. The structural dynamics material emphasizes vibration, the modal representation, and dynamic response. Aeroelastic phenomena discussed include divergence, aileron reversal, airload redistribution, unsteady aerodynamics, flutter, and elastic tailoring. More than one hundred illustrations and tables help clarify the text, and more than fifty problems enhance student learning. This text meets the need for an up-to-date treatment of structural dynamics and aeroelasticity for advanced undergraduate or beginning graduate aerospace engineering students. Praise from the First Edition "Wonderfully written and full of vital information by two unequalled experts on the subject, this text meets the need for an up-to-date treatment of structural dynamics and aeroelasticity for advanced undergraduate or beginning graduate aerospace engineering students." - Current Engineering Practice "Hodges and Pierce have written this significant publication to fill an important gap in aeronautical engineering education. Highly recommended." - Choice ". . . a welcome addition to the textbooks available to those with interest in aeroelasticity. . . . As a textbook, it serves as an excellent resource for advanced undergraduate and entry-level graduate courses in aeroelasticity. . . . Furthermore, practicing engineers interested in a background in aeroelasticity will find the text to be a friendly primer." - AIAA Bulletin

Download or read book Thin Walled Composite Beams written by Liviu Librescu and published by Springer Science & Business Media. This book was released on 2006-01-15 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation This is the first monograph devoted to the foundation of the theory of composite anisotropic thin-walled beams and to its applications in various problems involving the aeronautical/aerospace, helicopter, naval and mechanical structures. Throughout the theoretical part, an effort was made to provide the treatment of the subject by using the equations of the 3-D elasticity theory. Non-classical effects such as transverse shear, warping constraint, anisotropy of constituent materials yielding the coupling of twist-bending (lateral), bending (transversal)-extension have been included and their implications have been thoroughly analyzed. Thermal effects have been included and in order to be able to circumvent their deleterious effects, functionally graded materials have been considered in their construction. Implications of the application of the tailoring technique and of the active feedback control on free vibration, dynamic response, instability and aeroelasticity of such structures have been amply investigated. Special care was exercised throughout this work to address and validate the adopted solution methodologies and the obtained results against those available in the literature and obtained via numerical or experimental means.

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.

Download or read book Composite Wing Design for Aeroelastic Requirements written by L. A. McCullers and published by . This book was released on 1972 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wing flexibility is an important consideration in the configuration development phase of an aircraft system. the impact of stiffness requirements for flutter, aeroelastic loads, divergence, and control surface effectiveness on the advanced composites compounds this problem in that past experience and "rule-of-thumb" estimates for design are no longer valid; and, when the aerodynamic configurations are driven to maximum payoff, the resulting composite surface is usually stiffness critical.

Download or read book Active Aeroelastic Tailoring of High Aspect Ratio Composite Wings written by and published by . This book was released on 2002 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the proposed work is to study the fundamental mechanisms of active aeroelastic tailoring of high-aspect-ratio composite wings. The emphasis will be on actively exploring structural flexibility to enhance flight performance and reduce structural weight, while controlling aeroelastic instabilities. To investigate the effects of distributed anisotropic strain actuation and their synergism with the passive aeroelastic tailored composite structure, a suitable nonlinear active aeroelastic framework is required. Therefore, an analysis and design tool is being developed for high aspect ratio active flexible wings. The formulation is capable of modeling the nonlinear large deflection behavior of the wings, deformation due to applied voltages on the active plies in the skin of the wing, and the unsteady subsonic aerodynamic forces acting on the wing. Because the wing is long and slender, it can be reasonably well modeled as a beam undergoing three dimensional displacements and rotations. The cross sectional stiffness, inertia, and actuation properties of the wing are calculated along the span, and then a 1-d nonlinear beam model is constructed. This is a novel beam representation that is based on the beam curvatures, resulting in a computationally efficient low-order model suitable for preliminary structural design and control synthesis. Preliminary numerical results are presented in this report.

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1976 with total page 938 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics and Aeroelasticity of Composite Structures written by John Dugundji and published by . This book was released on 1986 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical and experimental investigation was made of the aeroelastic flutter and divergence behavior of graphite/ epoxy forward swept wings with rigid body pitch and plunge freedoms present. A complete, two-sided 30-degree forward swept wing aircraft model was constructed and mounted with low friction bearing in a low speed wind tunnel. Four different ply layup wings could be interchanged on the model, namely, [02/90] s', [15/2/0]s', [30/2/0]s', and [-152/0]s'. Wind tunnel tests on the "free" flying models revealed body freedom flutter, bending torsion flutter, and a support dynamic instability which could be eliminated by proper adjustment of the support stiffness. Good agreement with linear theory was found for the observed instabilities

Download or read book A Demonstration of the Principle of Aeroelastic Tailoring Applied to Forward Swept Wings written by Van C. Sherrer and published by . This book was released on 1982 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principle of aeroelastic tailoring with advanced composite materials to increase the divergence speed of a forward swept wing has been demonstrated through low speed wind tunnel tests. The approach was to perform a low cost, fairly simple wind tunnel test on a variable sweep cantilever wing model. Available analytical methods were used and were shown to accurately predict the divergence speed of both aluminum and composite plate structures in the subsonic speed range. Methods were evaluated for predicting the onset of divergence using subcritical wind tunnel data. Results of the analyses and tests are presented.

Download or read book X 29 Flight research Program written by and published by . This book was released on 1984 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Elements of Structural Optimization written by Raphael T. Haftka and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of structural optimization is still a relatively new field undergoing rapid changes in methods and focus. Until recently there was a severe imbalance between the enormous amount of literature on the subject, and the paucity of applications to practical design problems. This imbalance is being gradually redressed. There is still no shortage of new publications, but there are also exciting applications of the methods of structural optimizations in the automotive, aerospace, civil engineering, machine design and other engineering fields. As a result of the growing pace of applications, research into structural optimization methods is increasingly driven by real-life problems. t-.Jost engineers who design structures employ complex general-purpose software packages for structural analysis. Often they do not have any access to the source program, and even more frequently they have only scant knowledge of the details of the structural analysis algorithms used in this software packages. Therefore the major challenge faced by researchers in structural optimization is to develop methods that are suitable for use with such software packages. Another major challenge is the high computational cost associated with the analysis of many complex real-life problems. In many cases the engineer who has the task of designing a structure cannot afford to analyze it more than a handful of times.

Download or read book Commercial Aircraft Composite Technology written by Ulf Paul Breuer and published by Springer. This book was released on 2016-05-10 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on lectures held at the faculty of mechanical engineering at the Technical University of Kaiserslautern. The focus is on the central theme of societies overall aircraft requirements to specific material requirements and highlights the most important advantages and challenges of carbon fiber reinforced plastics (CFRP) compared to conventional materials. As it is fundamental to decide on the right material at the right place early on the main activities and milestones of the development and certification process and the systematic of defining clear requirements are discussed. The process of material qualification - verifying material requirements is explained in detail. All state-of-the-art composite manufacturing technologies are described, including changes and complemented by examples, and their improvement potential for future applications is discussed. Tangible case studies of high lift and wing structures emphasize the specific advantages and challenges of composite technology. Finally, latest R&D results are discussed, providing possible future solutions for key challenges such as low cost high performance materials, electrical function integration and morphing structures.