Download or read book Global local Analysis and Design Optimization of a Composite Tilt rotor Wing Box Structure written by Timothy Michael Clements and published by . This book was released on 1997 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Higher Order Composite Theory for Analysis and Design of High Speed Tilt Rotor Blades written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: A higher-order theory is developed to model composite box beams with arbitrary wall thicknesses. The theory, based on a refined displacement field, represents a three-dimensional model which approximates the elasticity solution. Therefore, the cross-sectional properties are not reduced to one-dimensional beam parameters. Both inplane and out-of-plane warping are automatically included in the formulation. The model accurately captures the transverse shear stresses through the thickness of each wall while satisfying all stress-free boundary conditions. Several numerical results are presented to validate the present theory. The developed theory is then used to model the load carrying member of a tilt-rotor blade which has thick-walled sections. The composite structural analysis is coupled with an aerodynamic analysis to compute the aeroelastic stability of the blade. Finally, a multidisciplinary optimization procedure is developed to improve the aerodynamic, structural and aeroelastic performance of the tilt-rotor aircraft. The Kreisselmeier-Steinhauser function is used to formulate the multiobjective function problem and a hybrid approximate analysis is used to reduce the computational effort. The optimum results are compared with the baseline values and show significant improvements in the overall performance of the tilt-rotor blade. McCarthy, Thomas Robert Ames Research Center TILT ROTOR AIRCRAFT; THREE DIMENSIONAL MODELS; MULTIDISCIPLINARY DESIGN OPTIMIZATION; ROTARY WINGS; COMPOSITE STRUCTURES; MATHEMATICAL MODELS; AERODYNAMIC LOADS; AEROELASTICITY; BOX BEAMS; TRANSVERSE LOADS; THICK WALLS; STRUCTURAL ANALYSIS; PROPELLER BLADES; SHEAR STRESS; ELASTIC PROPERTIES; STRESS-STRAIN RELATIONSHIPS; RESONANT FREQUENCIES; HIGH SPEED...

Download or read book Whirl Flutter of Turboprop Aircraft Structures written by Jiří Čečrdle and published by Elsevier. This book was released on 2023-01-13 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whirl Flutter of Turboprop Aircraft Structures, Second Edition explores the whirl flutter phenomenon, including theoretical, practical, analytical and experimental aspects of the matter. Sections provide a general overview regarding aeroelasticity, discussions on the physical principle and the occurrence of whirl flutter in aerospace practice, and experimental research conducted, especially from the 60s. Other chapters delve into analytical methods such as basic and advanced linear models, non-linear and CFD based methods, certification issues including regulation requirements, a description of possible certification approaches, and several examples of aircraft certification from aerospace. Finally, a database of relevant books, reports and papers is provided. This updated and expanded second edition covers new chapters including both analytical and experimental aspects of the subject matter. - Provides complex information on turboprop aircraft whirl flutter phenomenon - Presents both theoretical and practical (certification related) issues - Includes experimental research as well as analytical models (basic and advanced) of matter - Includes both early-performed works and recent developments - Contains a listing of relevant books and reports

Download or read book Design Optimization of a Composite Wing Box for High altitude Long endurance Aircraft written by Philip T. Arévalo and published by . This book was released on 2014 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: A design optimization process is developed to define the wing box structure for High-Altitude Long-Endurance Aircraft (HALE). The goal of this study is to determine the best tradeoff between mass and rigidity of a HALE aircraft wing structure. A preliminary composite laminate structural design procedure is described which uses a NASTRAN-based Finite Element Analysis (FEA), and the Hierachical Evolutionary Engineering Design System (HEEDS) MDO software to define a locus of acceptable, optimized wing box design definitions.

Download or read book Design of a Wing Box Structure for the Civil Tilt rotor Transport Aircraft written by Steven Lee Brunson and published by . This book was released on 1995 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Global local Technique for Analysis and Optimization of Composite Aircraft Structures written by Haribaskar Kalyanasundaram and published by . This book was released on 2000 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preliminary Structural Design Optimization of an Aircraft Wing box written by Sridhar Chintapalli and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural weight has always been important in aircraft manufacturing industry. Considering that a large number of candidate material and geometric shapes are available early in the design cycle, preliminary design optimization of skin-stringer panels used to build an aircraft wing is required to obtain the best preliminary structure before the final design phase. The design of skin-stringer panels forms an important and major portion of the wing-box design. The lift generated by the wings opposes the weight of the aircraft, and thus generates bending. Depending on their location, stiffened panels that make up the wings are therefore mainly loaded in compression and tension. Upper skin-stringer panels are typically subjected to compressive load while the lower panels are subjected to tensile load. The ability to resist the compressive load is assessed through a stability study to compute the critical buckling load of the stiffened panel while the ability to withstand the tensile load is evaluated by the Damage Tolerance Analysis. Optimization routines have been developed for the design of upper and lower wing panels. The main objective here is to design a stable wing-box structure more rapidly and automatically in the most economical manner having adequate strength and stability. These optimization routines are tested on a wing section defined at a specific span wise location of a DLR-F6 aircraft. Repeating the design process at different stations along the wing span completes the preliminary design of aircraft wing-box.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Equivalent Plate Analysis of Aircraft Wing Box Structures with General Planform Geometry written by and published by . This book was released on 1986 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of an All composite Wing for a Small UAV Platform Imside the Development Process of FEA and Optimization Software for Composite Structures written by Marc Jiménez Fernández and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is the first movement of the design of an all composite UAV wing, helping a group of aeronautics engineering students, to increase the technologic level of its. To do that, the means and technology from CIMNE Company are used, specially a current main line of investigation in the center, the FEMCOM project. This work is included in the development of new finite element methods for analysis and optimal design of structures with composite materials. After the introduction of the motivations and the student group, it's presented the initial construction technique of the D-box, the seed for the idea of building an entire wing made of composite material, and a test for the methodology to follow when simulating aeronautic composite structures using CIMNE's FEA software COMPack. There are exposed the main requirements that the new structure must fulfill. Besides the global idea of enhance the use of composite materials in the wing structure, it is established the need of increase the wing structural strength and maintain the specific mass, and also, to make it more easy to be constructed by non-professional technicians. Later is presented a general picture of composite structures used in aeronautic applications. How and why the composite parts are being used in aircraft structures, and defining the advantages and benefits of using composites instead ordinary materials. The method to transform the old D-box structure made by a single layer of composite and balsa wood into an all-composite wing is planned. The final structure was defined after a decision process, started by a brainstorming, followed by a detailed evaluation of the more valid concepts, keeping in mind the main objectives. The E model specimen is chosen and the wing structure is named EV structure. After the decision of the structural morphology of the wing, the materials that will effectively form the composite parts as fibers, matrix, foams and such are decided. The decision is made after the study of the materials that are commonly used to manufacture composites structures, including a brief introduction to fiber science, woven fabrics theory and the main aspects of resin chemistry. After this the decision of the materials that will be use to simulate and construct the EV model is made, the materials are dividend in skin and core, and some special considerations of which material fits more to each part are explained, based on the general requirements of the structure and on the features of each material. After this, it's possible to establish the first parameters of the structure and start to virtually construct and test the designed wing, by doing a Finite Element Analysis and the posterior optimization of the EV model of all composite wing. After introducing a brief part of COMPack theory and know-how, a trial load state is applied into the EV model in order to run the first introductory simulations. The first results obtained from the preliminary models served to initiate the optimization process. After a brief presentation of the optimization 16 module, a trial problem will be presented and run in order to establish optimization guidelines, and optimize the initial structure. The optimized models, named series 40's are analyzed and finally a definitive structure configuration is defined. This structure is loaded with the full load set established by the Trencalòs Team for their future plane that will compete in the Trencalòs Team. The results of the simulation showed that the main reinforce structures (carbon tube and the carbon band on the skin) the main part of the stress, still far away of its yielding limit. Due to the method of load application, the PS foam core was damaged when increased the nominal load to 126%. The composite structure takes without any major problem the stress caused by the load set defined, but the foam is sensitive to load concentrations. This fact will be important in order to establish future lines in work. Later on, there is a discussion of the aspects related to the economic issues of this work, as a stage of the development process of CIMNE's FEMCOM project, based in the implementation of analysis and optimization tools and software for composites structures. The cost of this work will be estimated in 52.842 €, considering all the human and technical resources that actually took part and collaborated in a active way to develop the program and get the results here presented. In addition, it's offered the cost that represent to perform a study design or optimization of an composite part or model, in order to quantify the price of the service that CIMNE could offer after the development of this software and the possible launch into the market. Finally, it is explained the future lines of investigation established after the end of this work. Details of how this work will be carried on inside CIMNE are given, considering the problems and conclusions exposed. About COMPACK software one of the main aspects is to improve the method of defining internal loads, specially twist and bending moments to avoid artificial stress concentration zones. The implementation of a module able to apply pressure value directly to a FEM mesh is also defined as a very useful tool, as well as the need of a user manual for COMPack, which was started last month of February. Observing the good results obtained, the construction of the physic EV model is planned for this spring. In order to experimentally test the structure and compare the obtained results. The EV model is planned to take part of the new plane of the Trencalòs Team, which will compete in the next Air Cargo Challenge 2011 that will take place in Stuttgart next 12th of August.

Download or read book Benchmark Composite Wing Design Including Joint Analysis and Optimization written by Robert G. Albers and published by . This book was released on 2014 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: A composite wing panel software package, named WING Joint OpTimization and Analysis (WINGJOTA) featuring bolted joint analysis, is created and presented in this research. Three areas of focus were the development of an analytic composite bolted joint analysis suitable for fast evaluation; a more realistic wing design than what has been considered in the open literature; and the application of two optimization algorithms for composite wing design. Optimization results from 14 wing load cases applied to a composite wing panel with joints are presented. The composite bolted joint analysis consists of an elasticity solution that provides the stress state at a characteristic distance away from the bolt holes. The stresses at the characteristic distance are compared to a failure criterion on a ply-by-ply basis that not only determines first ply failure but also the failure mode. The loads in the multi-fastener joints used in this study were determined by an iterative scheme that provides the bearing-bypass loads to the elasticity analysis. A preliminary design of a composite subsonic transport wing was developed, based around a mid-size, twin-aisle aircraft. The benchmark design includes the leading and trailing edge structures and the center box inside the fuselage. Wing masses were included as point loads, and fuel loads were incorporated as distributed loads. The side-of-body boundary condition was modeled using high stiffness springs, and the aerodynamic loads were applied using an approximate point load scheme. The entire wing structure was modeled using the finite element code ANSYS to provide the internal loads needed as boundary conditions for the wing panel analyzed by WINGJOTA. The software package WINGJOTA combines the composite bolted joint analysis, a composite plate finite element analysis, a wing aeroelastic cycle, and two optimization algorithms to form the basis of a computer code for analysis and optimization. Both the Improving Hit-and-Run (IHR) and the Multi-Particle Simulated Annealing (MPSA) algorithms were coded and used as the optimization routines in WINGJOTA. It was found that MPSA was able to find panel designs with lighter weights than IHR; however, the computation time was longer.

Download or read book Structural Modeling and Optimization of a Joined wing Configuration of a High altiude i e Altitude Long endurance HALE Aircraft written by Valentina B. Kaloyanova and published by . This book was released on 2009 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions, such as telecommunication relay, environmental sensing and military reconnaissance. HALE missions require a light vehicle flying at low speed in the stratosphere at altitudes of 60,000-80,000 ft, with a continuous loiter time of up to several days. To provide high lift and low drag at these high altitudes, where the air density is low, the wing area should be increased, i.e., high-aspect-ratio wings are necessary. Due to its large span and lightweight, the wing structure is very flexible. To reduce the structural deformation, and increase the total lift in a long-spanned wing, a sensorcraft model with a joined-wing configuration, proposed by AFRL, is employed. The joined-wing encompasses a forward wing, which is swept back with a positive dihedral angle, and connected with an aft wing, which is swept forward. The joined-wing design combines structural strength, high aerodynamic performance and efficiency. The results of the simulation of the complex, three-dimensional flow past the joined-wing of a HALE aircraft are used as an input for the structural analysis. The Reynolds-Averaged Navier-Stokes (RANS)-based flow solver, COBALT, provided detailed flow results for altitudes 30,000 ft and 60,000 ft for the cases with M=0.4 and [alpha] = 0°, M = 0.6 and [alpha] = 0°, and M = 0.6 and [alpha] = 12°. The surface static pressure from the flow analyses comprises the load transferred to the structural models developed in this study. To date in the existing studies, only simplified structural models have been examined. In the present work, a semi-monocoque structural model is developed. All stringers, skin panels, ribs and spars are represented by appropriate elements in a finite-element model. Also, the model accounts for the fuel weight and sensorcraft antennae housed within the wings. Linear and nonlinear static analyses under the aerodynamic load are performed. Design optimization is performed to achieve a fully stressed design. The shell elements thickness and stringers cross-sectional area are properly resized to obtain a structure that meets the allowable stress in each element and is minimum weight. In addition to the stress constraints, deflection constraints are also imposed in the design optimization. As the joined-wing structure is prone to buckling, after the design optimization is complete linear and nonlinear bucking analyses are performed to study the global joined-wing structural instability, the load magnitude at which it is expected to occur, and the buckling mode. As this design and analysis study is aimed towards developing a realistic structural representation of the innovative joined-wing configuration, in addition to the global, or upper-level optimization, a local level design optimization is performed as well. At the lower (local) level detailed models of wing structural panels are used to compute more complex failure modes and to design details not included in the upper (global) level model. Proper coordination between local skin-stringer panel models and the global joined-wing model prevents inconsistency between the global and local level models.

Download or read book Innovative Local Global Methods for Aircraft Structural Design written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global-local design of large structures presents a great challenge to structural designers to coordinate the optimization of major structural components (wing or fuselage) with optimization of individual panel details. Moreover, the continuity of the adjacent designs in terms of their geometric and material variables presents a serious manufacturing difficulty for the large structure. The research developed methodology, computational infrastructure and algorithms with sound theoretical basis to extend industrial ad hoc approaches to the global-local design and blending of local designs. We proposed a two-level optimization approach employing genetic algorithms tailored to panel design on the lower level. Genetic algorithms involving both continuous and discrete design variables were developed for the design of composite structures. Response surface approximations to optimized panel failure loads are then used for the upper level wing or fuselage optimization. In addition, metrics for measuring continuity between adjacent panels were developed and incorporated in the optimization procedure.

Download or read book Aerostructural Analysis and Design Optimization of Composite Aircraft written by Graeme James Kennedy and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Global and Local Stress Analyses of McDonnell Douglas Stitched RFI Composite Wing Stub Box written by John T. Wang and published by . This book was released on 1996 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains results of structural analyses performed in support of the NASA structural testing of an all-composite stitched/RFI (resin film infusion) wing stub box. McDonnell Douglas Aerospace Company designed and fabricated the wing stub box. The analyses used a global/local approach. The global model contains the entire test article. It includes the all-composite stub box, a metallic load-transition box and a metallic wing-tip extension box. The two metallic boxes are connected to the inboard and outboard ends of the composite wing stub box, respectively. The load-transition box was attached to a steel and concrete vertical reaction structure and a load was applied at the tip of the extension box to bend the wing stub box upward. The local model contains an upper cover region surrounding three stringer runouts. In that region, a large nonlinear deformation was identified by the global analyses. A more detailed mesh was used for the local model to obtain more accurate analysis results near stringer runouts. Numerous analysis results such as deformed shapes, displacements at selected locations, and strains at critical locations are included in this report.