Download or read book Robust and Reliability based Aeroelastic Design of Composite Wings written by Carl Scarth and published by . This book was released on 2016 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeroelastic Tailoring of Composite Aircraft Wings with Uncertainty Quantification for Robust and Reliable Design written by Muhammad F. B. Othman 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 A Robust and Reliability based Optimization Framework for Conceptual Aircraft Wing Design written by Ricardo Miguel Paiva and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A robustness and reliability based multidisciplinary analysis and optimization framework for aircraft design is presented. Robust design optimization and Reliability Based Design Optimization are merged into a unifed formulation which streamlines the setup of optimization problems and aims at preventing foreseeable implementation issues in uncertainty based design. Surrogate models are evaluated to circumvent the intensive computations resulting from using direct evaluation in nondeterministic optimization. Three types of models are implemented in the framework: quadratic interpolation, regression Kriging and artificial neural networks. Regression Kriging presents the best compromise between performance and accuracy in deterministic wing design problems. The performance of the simultaneous implementation of robustness and reliability is evaluated using simple analytic problems and more complex wing design problems, revealing that performance benefits can still be achieved while satisfying probabilistic constraints rather than the simpler (and not as computationally intensive) robust constraints. The latter are proven to to be unable to follow a reliability constraint as uncertainty in the input variables increases. The computational effort of the reliability analysis is further reduced through the implementation of a coordinate change in the respective optimization sub-problem. The computational tool developed is a stand alone application and it presents a user-friendly graphical user interface. The multidisciplinary analysis and designoptimization tool includes modules for aerodynamics, structural, aeroelastic and cost analysis, that can be used either individually or coupled.

Download or read book A Robust and Reliability Based Optimization Framework for Conceptual Aircraft Wing Design written by Ricardo Miguel Paiva 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 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 Optimum Design of Composite Wing Structures with Twist Constraint for Aeroelastic Tailoring written by N. S. Khot and published by . This book was released on 1976 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this effort was to develop a method to design a minimum weight, fiber reinforced, composite wing structure with a specific twist constraint. Designing a wing for the desired twist is one of the main objectives in the concept of aeroelastic tailoring. The structure is analyzed by a finite element method and the design variables are modified by using a recurrence relation based on an optimality criteria. To demonstrate the method, a wing structure is designed to have a specific negative or positive twist corresponding to 'wash out' and 'wash in' conditions. The designs satisfy the twist constraint and the strength criteria in all elements. (Author).

Download or read book A Methodology for Robust Structural Design with Application to Active Aeroelastic Wings written by Paul Scott Zink and published by . This book was released on 2001 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Robust Structural Design for Active Aeroelastic Wing with Aerodynamic Uncertainties written by P. Scott Zink and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Integration of a Code for Aeroelastic Design of Conventional and Composite Wings Into ACSYNT an Aircraft Synthesis Program written by and published by . This book was released on 1976 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Multidisciplinary Design Optimization and Its Application in Deep Manned Submersible Design written by Binbin Pan and published by Springer Nature. This book was released on 2020-08-28 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book investigates Reliability-based Multidisciplinary Design Optimization (RBMDO) theory and its application in the design of deep manned submersibles (DMSs). Multidisciplinary Design Optimization (MDO) is an effective design method for large engineering systems like aircraft, warships, and satellites, which require designers and engineers from various disciplines to cooperate with each other. MDO can be used to handle the conflicts that arise between these disciplines, and focuses on the optimal design of the system as a whole. However, it can also push designs to the brink of failure. In order to keep the system balanced, Reliability-based Design (RBD) must be incorporated into MDO. Consequently, new algorithms and methods have to be developed for RBMDO theory. This book provides an essential overview of MDO, RBD, and RBMDO and subsequently introduces key algorithms and methods by means of case analyses. In closing, it introduces readers to the design of DMSs and applies RBMDO methods to the design of the manned hull and the general concept design. The book is intended for all students and researchers who are interested in system design theory, and for engineers working on large, complex engineering systems.

Download or read book Aeroelastic Modelling and Design written by Mohammad Yazdi Harmin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Three related methodologies relating to the modelling and design of aero elastic aircraft structures are considered. In the first study, a procedure for devel9pirig efficient aeroelastic Nonlinear Reduced Order (NROM) Models for aerospace structures containing geometric nonlinearities is described. The structural modelling is based upon a combined modal/FE approach (CMFE) that describes the nonlinear stiffening effects from nonlinear static analyses for a range of prescribed inputs. The prescribed load cases and resultant displacements from the static nonlinear test cases are transformed into modal coordinates using the modal transformation of the underlying linear system. A regression analysis is then performed to curve-fit the sets of nonlinear stiffness force / displacement maps in order to find the unknown nonlinear modal stiffness coefficients. Once the structural NROM has been defined, it is coupled to the Rational Fraction Approximation of the doublet lattice aerodynamic model corresponding to the wing planform. The aeroelastic model can then be used to predict the dynamic aeroelastic behaviour of the defined structure. The methodology is demonstrated on an aeroelastic model of a flexible high aspect ratio wing with the static deflections, limit cycle oscillation (LCO) behaviour and gust response being predicted. To further understand the aeroelastic behaviour of high aspect ratio wings, and to validate the mathematical model, an experimental model is developed. Experimental modal testing was employed to analyze the dynamical behaviour of the structure and the Finite Element (FE) representation updated to bring the model close to the experimental counterpart. The wing was analyzed in both deformed and undeformed shapes. The static and dynamic response of the wing was demonstrated and a comparison made with the numerical model; a good agreement was achieved. In the second study, an Ant Colony Optimisation (ACO) approach is used to maximize the flutter-divergence speed of a simple rectangular composite wing through determination of the best combination of ply orientations. An improved aeroelastic tailoring implementation is proposed based upon a combination of rank based and min-max ant system algorithms, and compared with several different implementations. A statistical investigation is performed on the example aeroelastic tailoring problem in order to investigate the effectiveness and robustness of the approaches. Consideration is also made to the best weightings of the pheromone addition and evaporation parameters. In the third study, innovative metallic wing structural designs are introduced that can be used to influence the bending I torsion coupling behaviour of aircraft wings, leading to the possibility of metallic aeroelastic tailoring. It is intended that the aeroelastic behaviour, such as the flutter I divergence speed or gust loads response, can be influenced in a beneficial way without any increase in weight. Two different approaches are demonstrated: using ribs with varying orientations, and making use of crenellations in the wing skins. The concepts are demonstrated using two simple FE models: a rectangular wing box and a more realistic wing model. In both cases it is shown that bending-torsion coupling can be achieved in metallic structures using both approaches and that this has an encouraging influence on the wing aeroelastic behaviour.

Download or read book Active Aeroelastic Tailoring of High Aspect Ratio Composite Wings written by and published by . This book was released on 2005 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear aeroelastic modeling and the fundamental mechanisms of active aeroelastic tailoring of high-aspect-ratio composite wings for High-altitude Long-endurance (HALE) aircraft is presented. To investigate the effects of distributed anisotropic strain actuation and their synergism with the passive aeroelastic tailored composite structure, a new framework was developed for analysis and design of high aspect ratio active flexible wings. The formulation is capable of modeling the nonlinear large deflection behavior of slender wings and other structural members, 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 HALE wings are long and slender, they can be well modeled as beams 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 nonlinear beam model is constructed. A novel beam representation was developed and it was based entirely on the beam strains, resulting in a computationally efficient low-order model suitable for preliminary structural design and control synthesis. The formulation was then extended to analyze different beam configurations, particularly in the presence of joints and splits. With that, the entire vehicle can be modeled and non-conventional wing configurations such as the joined wing could be analyzed. Finally, different aircraft configurations such as the ones being considered for the new Air Force Sensor Craft vehicle were studied.

Download or read book Optimal Design of a Composite Active Aeroelastic Wing written by Melanie Perera and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary aim of this research was to design a Seamless Aeroelastic Wing (SAW) structure applicable to a lightweight Unmanned Aerial Vehicle (UAV). Therefore the study focused on optimal design of a SAW structure by utilising the maximum aeroelastic beneficial effect. Although similar to the Active Aeroelastic Wing (AAW) and relevant to the Flapless Air Vehicle Integrated Industrial Research (FLAVIIR), the major difference from them is that a SAW will function as an integrated one piece lifting and control surface. It is designed to produce a desirable wing camber for control by deflecting a hinge-less flexible trailing edge (TE) part instead of a traditional control surface. Attention was firstly paid on the design of a hinge-less flexible trailing edge control surface and the actuation mechanism applicable for a light-weight aircraft (UAV). The proposed mechanism in the SAW TE section has two innovative design features: an open sliding TE and a curved beam and disc actuation mechanism. This type of actuated TE section allows for the SAW having a smooth camber change in a desirable shape with minimum control power demand. This design concept has been simulated numerically and its feasibility has been demonstrated by a test model. The wing structure for a small scale UAV is likely to be over designed in terms of strength, stiffness and weight due to manufacturing constraints. For the optimal wing design, the investigation was conducted in two stages. In the first stage, effort was made to design and model an optimised composite wing box for a minimum weight and maximum flutter speed. Both analytical and numerical methods were used for structural stress, vibration and aeroelastic analyses. In the second stage, the study focused on integrating the TE actuation mechanism with the optimised wing box for detailed understanding of the structure. A finite element analysis was conducted to simulate the SAW TE to ensure that structural strength requirements were satisfied. Furthermore, a study was carried out on the structural dynamic behaviour of the SAW TE section under the aerodynamic pressure to demonstrate its dynamic stability. Hence, the outcome of this research shows that a feasible SAW design for a UAV can be achieved.

Download or read book Aerospace America written by and published by . This book was released on 2006 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Engineering Design Reliability Handbook written by Efstratios Nikolaidis and published by CRC Press. This book was released on 2004-12-22 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers in the engineering industry and academia are making important advances on reliability-based design and modeling of uncertainty when data is limited. Non deterministic approaches have enabled industries to save billions by reducing design and warranty costs and by improving quality. Considering the lack of comprehensive and defini