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Ahn, Junghyun. "Integrated analysis procedure of aerospace composite structure." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43106.
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Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2008.Includes bibliographical references (p. 50).
The emergence of composite material application in major commercial aircraft design, represented by the Boeing 787 and Airbus A350-XWB, signals a new era in the aerospace industry. The high stiffness to weight ratio of continuous fiber composites (CFC) makes CFCs one of the most important materials to be introduced in modern aircraft industry. In addition to inherent strength (per given weight) of CFCs, they also offer the unusual opportunity to design the structure and material concurrently. The directional properties (and the ability to change these properties through the design process) of composite materials can be used in aeroelastically tailored wings, the fuselage and other critical areas. Due to the longer lifecycle (25-30 years) of a commercial airliner and the tools and processes developed for the airplane of previous product development cycles, new technology often ends up being deployed less effectively because of the mismatch in the technical potential (what can be done) vs. design tools and processes (what was done before). Tools and processes need to be current to take advantage of latest technology, and this thesis will describe one possible approach in primary composite structural design area using integrated structural analysis
by Junghyun Ahn.
S.M.
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Key, Ross A. "Automated manufacturing processes for secondary structure aerospace composites." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33572/.
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As projected manufacturing rates for commercial aircraft increase to levels of multiple ship sets per day from individual manufacturing facilities, GE Aviation have expressed the need for a shift in composites secondary structure manufacturing philosophy. Traditional manufacturing processes tend to be touch labour intensive and hence costly. The manual placement of large numbers of individual ply profiles, lengthy debulking operations and complex cure cycles, result in excessive component lead times and manufacturing costs. As a result, direct labour cost is a major factor in the total economies of production processes. The implementation of industrial robotics has proved highly successful in automotive manufacturing, and various methods for automating individual aspects of the composites manufacturing process have been suggested. Technical cost modelling has been used to anticipate the production costs of a prototype secondary structure component, as supplied by GE Aviation, through direct simulation of the existing manufacturing process. This work has clearly highlighted the potential for cost and cycle time reductions if process automation can be successfully introduced. Observation of the existing manufacturing process has allowed three alternative manufacturing scenarios to be considered with respect to cost-effectiveness and feasibility, whilst highlighting long term cost benefits. Investigations have been undertaken to identify and evaluate alternative material and processing methodologies ranging from resin infused woven dry fabrics to UD prepreg tape and tow. In addition, candidate processing routes have been systematically evaluated using design of experiments techniques, which focussed on assessing the feasibility and technology readiness of robotic deposition and consolidation methodologies, including pick and place and debulking. Process automation in these areas has the potential for total component cost and cycle time reductions in the order of 2.8 to 21.6 and 0.6 to 63.4 per cent respectively. The quasi-static mechanical testing of a range of face sheet materials has provided a performance assessment based on tensile, compressive and shear properties and laminate Vf. Findings suggest that materials offering increased suitability for automation typically have reduced mechanical performance when compared to candidate prepregs; tensile modulus and strength reductions of 5 and 34 per cent were reported when comparing a 6k woven 2X2 twill fabric and equivalent prepreg respectively. Furthermore, 26 and 4 per cent reductions in tensile modulus and 38 and 40 per cent reductions in tensile strength were observed for 179 and 318gsm UD NCF, when compared with a candidate UD prepreg. Data has also been presented on the effect of varying the traditional consolidation frequency and methodology. While earlier findings suggest that debulking has little effect on the laminate tensile modulus; ply compaction level varies considerably. Furthermore, it has been shown that on-the-fly consolidation, using a robotically mounted, roller-based end effector has the advantages of mechanical performance retention, cycle time reduction and repeatable laminate post cure thickness. In addition, when compared with candidate woven and UD prepreg laminates manufactured using the traditional vacuum bagging approach; equivalent tensile modulus, strength and fibre volume fraction have been observed and with less variability. Handling characteristics inherent to vacuum and needle grippers, including pickup performance, defined as the pickup or holding force required to overcome fabric weight, shear force performance; the maximum force that can be exerted on the fabric before the onset of slip, and the accuracy with which non-rigid-materials (NRMs) can be handled, have also been considered. The achievable positional accuracy of robotically pick and placed prepreg plies greatly exceeds that of dry fabrics in all cases and with less variability, irrespective of the gripping mechanism used. Vacuum grippers exhibit more uniform positional error and increased positional accuracy when handling dry fabrics, whilst needle grippers outperformed the vacuum alternative when handling prepregs, irrespective of form. Robotic pick and place solutions offer low variability in ply positional error with a guaranteed placement accuracy of ±0.8mm and ±2.3mm for prepregs and dry fabrics respectively. Characterisation of the gap type defect and butt and overlapping joining methodologies has provided a performance trend based on ply positional error. Quasi-static mechanical testing has revealed that laminates with equivalent tensile modulus to an un-spliced control could be achieved. However, significant reductions in the tensile strength and an increase in overall laminate thickness and thickness variation highlighted the negative effect of ply splicing on laminate performance. However, it has been shown that a robotic placement accuracy of ±0.8mm gives rise to acceptable tensile strength reductions in candidate prepreg laminates. The up-scaling of laminate level robotic manipulators has been discussed and addressed in conjunction with the commissioning of a flexible robotic manufacturing cell, facilitating the manufacture of full-scale secondary structure aerospace components. Comparisons have been made between a benchmark prepreg panel, manufactured using traditional manual methods and alternative dry fabric and prepreg panels manufactured using increased levels of process automation. In each case, manufacturing feasibility, mechanical performance and component geometric accuracy have been assessed. It has been shown that there are significant advantages to be gained from the implementation of robotic automation within the traditional manufacturing process. Component cost and cycle time reductions, coupled with the processing and performance advantages and increased suitability to automation of woven dry fibre materials are clear. Findings which support a key driver of this project, which seeks to justify alternative dry fabrics as a viable alternative to traditional prepreg broadgoods for the manufacture of secondary structure aerospace components.
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Hu, Zhuopei. "Finite Element Modeling of Aerospace Materials and Structure." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1344224158.
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Zheng, LiangKan 1972. "Fluid-structure coupling for aeroelastic computations in the time domain using low fidelity structural models." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99127.
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Flutter analysis plays an important role in the design and development of aircraft wings because of the information it provides regarding the flight envelope of the aircraft. With the coupling of the flow and structural solver, the flutter boundary of wings can be evaluated in the time domain. This study: First, computes the aeroelastic response for a typical sweptback wing section model by coupling a flow solver and a two degree of freedom structural equation of motion solver to predict the flutter boundary of an airfoil at different Mach numbers. The results agree well with previous numerical results, and the transonic-dip phenomenon can be observed. Second, a new coupling approach is introduced to conservatively transfer the load and displacement between the flow solver and the structural solver for 3-D flow. By coupling the flow solver and a low fidelity finite element structural model, the flutter point of AGARD wing 445.6 at Mach number 0.499 is computed. The flutter point agrees well with experimental results and previous numerical results.
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Seddon, Caroline Michelle. "Modelling transient dynamic fluid-structure interaction in aerospace applications." Thesis, University of Salford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492434.
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Although significant progress has been made in the study of dynamic loading of aircraft structures, several areas have been identified that require further research. In particular, attention is drawn to problems involving transient, dynamic fluid-structure interaction, where fluids play an important role, heavily influencing the response of the structure to the applied dynamic load. In this work the use of existing numerical modelling techniques for the evaluation of such problems is investigated.
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Bhatti, Wasim. "Mechanical integration of a PEM fuel cell for a multifunctional aerospace structure." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/21513.
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A multifunctional structural polymer electrolyte membrane (PEM) fuel cell was designed, developed and manufactured. The structural fuel cell was designed to represent the rear rib section of an aircraft wing. Custom membrane electrode assemblies (MEA s) were manufactured in house. Each MEA had an active area of 25cm2.The platinum loading on each electrode (anode and cathode) was 0.5mg/cm2. Sandwiched between the electrodes was a Nafion 212 electrolyte membrane. Additional components of the structural fuel included metallic bipolar plates and end plates. Initially all the components were manufactured from aluminium in order for the structural fuel cell to closely represent an aircraft wing rib. However due to corrosion problems the bipolar plate had to be manufactured from marine grade 361L stainless steel with a protective coating system. A number of different protective coating systems were tried with wood nickel strike, followed by a 5μm intermediate coat of silver and a 2μm gold top coat being the most successful. Full fuel cell experimental setup was developed which included balance of plant, data acquisition and control unit, and a mechanical loading assembly. Loads were applied to the structural fuel cells tip to achieve a static deflection of ±7mm and dynamic deflections of ±3mm, ±5mm, and ±7mm. Static and dynamic torsion induced 1° to 5° of twist to the structural fuel cell tip. Polarisation curves were produced for each load case. Finite element analysis was used to determine the structural fuel cell displacement, and stress/strain over the range of mechanical loads. The structural fuel cells peak power performance dropped 3.9% from 5.5 watts to 5.3 watts during static bending and 2% from 6.2 watts to 6.1 watts during static torsion. During dynamic bending (2000 cycles) the structural fuel cell peak power performance dropped 11% from 6.7 watts to 6 watts (3mm deflection at 190N), 23% from 6.3 watts to 4.8 watts (5mm deflection at 270N), and 41% from 7.2 watts to 5 watts (7mm deflection at 350N). During dynamic torsion (2000 cycles) the structural fuel cell peak power performance dropped 16% from 6 watts to 5.1 watt (3° of torsional loading), and 30% from 6.4 watts to 4.3 watts (5° of torsional loading). The simulated (finite element modelling) displacement of -6.6mm (At maximum bending load of 364.95N) was within 9% of the actual measured displacement of -7.2mm at 364.95N. Furthermore the majority of the simulated strain values were within 10% of the actual measured strain for the structural fuel cell.
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Palsule, Sanjay. "Structure and properties of aerospace molecular composites : third generation polymers." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1388.
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Khataee, Amin. "Structure and properties of some Ti-Al-Ru alloys." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46915.
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Liang, Lijun. "Experimental investigation of an aeroelastic structure with continuous nonlinear stiffness." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80123.
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An experimental investigation is presented for the aeroelastic response of a two-degree-of-freedom airfoil positioned in an incompressible flow. In particular, the effects of cubic structural nonlinearities in the pitch degree-of-freedom are considered. These nonlinearities are introduced via a specially designed pitch cam, which permits different degrees of nonlinearity, as well as a linear system, to be obtained.Several linear and nonlinear system tests are presented, and the results compared and analyzed. The effects of linear plunge stiffness on the stability of the aeroelastic system are discussed, and the nonlinear system response is studied for different degrees of cubic nonlinearity in pitch.
In several nonlinear system tests, limit cycle oscillations (LCO) are observed when the air speed is above the linear flutter speed. The effects of airfoil initial conditions and air speeds on the LCO amplitude, frequency, and convergence rate are studied.
The effective linear flutter speed is predicted using the so-called "flutter-margin" method for both the linear and nonlinear cases. The prediction results for the nonlinear cases are compared with those for the linear cases and with the actual flutter speed.
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Ozsoy, Serhan. "Vibration Induced Stress And Accelerated Life Analyses Of An Aerospace Structure." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12606966/index.pdf.
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Fatigue failure of metallic structures operating under dynamic loading is a
common occurrence in engineering applications. It is difficult to estimate the
response of complicated systems analytically, due to structure’
s dynamic characteristics and varying loadings. Therefore, experimental, numerical or a combination of both methods are used for fatigue evaluations. Fatigue failure can occur on systems and platforms as well as components to be mounted on the platform. In this thesis, a helicopter&
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s Missile Warning Sensor - Cowling assembly is analyzed. Analytical, numerical and experimental approaches are used wherever necessary to perform stress and fatigue analyses. Operational flight tests are used for obtaining the loading history at the analyzed location by using sensors. Operational vibration profiles are created by synthesizing the data (LMS Mission Synthesis). Numerical fatigue analysis of the assembly is done for determining the natural modes and the critical locations on the assembly by using a finite element model (MSC Fatigue). In addition, numerical multiaxial PSD analysis is performed for relating the experimental results (Ansys). Residual stresses due to riveting are determined (MSC Marc) and included in experimental analysis as mean stresses. Bolt analysis is performed analytically (Hexagon) for keeping the v assembly stresses in safe levels while mounting the experimental prototype to the test fixture. Fatigue tests for determining the accelerated life parameters are done by an electromagnetic shaker and stress data is collected. Afterwards, fatigue test is performed for determining whether the assembly satisfies the required operational life. Resonance test is performed at the frequency in which the critical location is at resonance, since there was no failure observed after fatigue testing. A failure is obtained during resonance test. At the end of the study, an analytical equation is brought up which relates accelerated life test durations with equivalent alternating stresses. Therefore, optimization of the accelerated life test duration can be done, especially in military applications, by avoiding the maximum stress level to reach or exceed the yield limit.
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Beji, Faycel Ben Hedi. "Buckling Analysis of Composite Stiffened Panels and Shells in Aerospace Structure." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/81620.
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Stiffeners attached to composite panels and shells may significantly increase the overall buckling load of the resultant stiffened structure. Initially, an extensive literature review was conducted over the past ten years of published work wherein research was conducted on grid stiffened composite structures and stiffened panels, due to their applications in weight sensitive structures. Failure modes identified in the literature had been addressed and divided into a few categories including: buckling of the skin between stiffeners, stiffener crippling and overall buckling. Different methods have been used to predict those failures. These different methods can be divided into two main categories, the smeared stiffener method and the discrete stiffener method. Both of these methods were used and compared in this thesis. First, a buckling analysis was conducted for the case of a grid stiffened composite pressure vessel. Second, a buckling analysis was conducted under the compressive load on the composite stiffened panels for the case of one, two and three longitudinal stiffeners and then, using different parameters, stiffened panels under combined compressive and shear load for the case of one longitudinal centric stiffener and one longitudinal eccentric stiffener, two stiffeners and three stiffeners.Master of Science
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Vestlund, Oscar. "Aerodynamics and Structure of a Large UAV." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-38562.
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This thesis investigates what design of a large UAV performing VTOL using only electrical motors is the most viable in terms of extending its range. Because it uses batteries for power, its powered time is limited, posing the need for a way of extending its flight time. By using a tiltwing design, its vertical flight time is cut at the same time as it will be able to perform as a glider, increasing its range drastically. To achieve the best lift-to-drag ratio, the high-lift F3B RG15-airfoil was chosen, giving the UAV a lift-to-drag ratio of 36,48, and a maximum range per descend glide of approximately 25,5 kilometers. The fuselage will be a simple, aerodynamic body just big enough to hold the batteries and the load while giving the wing the ability to tilt without interfering with the rotors. The material used in this thesis comes from a company which produces high-strength carbon fiber tubes and rods as well as a 3k twill weave carbon fiber prepreg for the skin, making the structure as light and strong as possible. The result is an aircraft with a structural weight of 56,6 kilograms that is strong enough to lift with a combined weight of 495 kilograms and at the same time perform a safe glide flight.
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Bingham, Christopher Malcolm. "Application of variable structure control methods to actuator nonlinearities in aerospace systems." Thesis, Cranfield University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358823.
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Roy, Steven. "Mechanical modeling and testing of a composite helicopter structure made by resin transfer moulding." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40829.
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The design and mechanical performance of a helicopter horizontal stabilizer slat made by resin transfer moulding (RTM) can be evaluated with finite element analysis (FEA). To verify the validity of the assumptions used in the modelling of the slat structure, static mechanical tests were performed on prototype slats which were half of the full-size length. The slat complex boundary conditions were simplified to make static mechanical testing possible. Two fixtures were designed and built to introduce simplified loads in specimens with two different bracket configurations: a full and a half bracket. A finite element (FE) model of the specimens was made with shell elements and the finite element solution was compared with the experimental results. In most cases, comparison between the finite element analysis solution and experimental results showed good agreement in terms of structure stiffness, strength, strain and damage location. It is believed that out-of-plane stresses should be considered to improve the finite element solution accuracy.Le design et la performance mécanique d’un bec de bord d’attaque de stabilisateur horizontal d’hélicoptère fabriqué par moulage par injection sur renfort (« resin transfer moulding ») peuvent être évalués par des analyses par éléments finis. Pour vérifier la validité des hypothèses utilisées dans la modélisation du bec de bord d’attaque, des essais mécaniques ont été effectués sur des prototypes demi-longueurs. Les conditions frontières complexes ont été simplifiées pour rendre les essais mécaniques possibles. Deux gabarits ont été conçus et construits pour introduire les chargements simplifiés dans les pièces d’essai possédant deux configurations de support: un support complet et un demi-support. Un modèle par éléments finis des pièces d’essai a été réalisé avec des éléments de type membrane et la solution est comparée avec les résultats expérimentaux. Dans la plupart des cas, la comparaison entre la solution par éléments finis et les résultats expérimentaux coïncide concernant la rigidité de la structure, la résistance, l’allongement et la localisation de l’endommagement. Les contraintes hors du plan devraient être considérées pour améliorer la précision de la solution par éléments finis.
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Farinha, Marques Vitor Manuel. "Lead free solders for aerospace applications." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:85707054-bc46-44f3-b9c6-9fd29358ad25.
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The factors controlling the reliability of Pb-free solders when subject to thermomechanical regimes relevant to the harsh aerospace environment have been studied. Ball grid array (BGAs) typical of microelectronic devices have been manufactured in-house and subjected to isothermal ageing and thermal cycling. The BGAs comprised both Cu and Ni-Au metallizations, Pb-free Sn-Ag-Cu 400 and 600μm solder balls, FR4 and Al2O3 boards, and included circuits to measure resistance changes due to damage in the joints during thermal cycling. Microstructural evolution within the solders balls and complex interfacial reactions were studied in all configurations using various types of electron microscopy. The mechanical properties of the different phases formed within solder joints were studied using nanoindentation at room and elevated temperatures up to 175°C for the first time. Intermetallic compounds (IMCs) were stiff, hard and brittle with very low creep rates, while the softer primary Sn, eutectic regions and Cu metallization readily underwent creep. Two-dimensional finite element analysis (FEA) of nanoindentation was used to understand better the physical meaning of nanoindentation creep data. Reliability experiments comprised both thermal cycling and FEA of BGAs. The difference in coefficient of thermal expansion (CTE) in the BGA materials caused interfacial fatigue damage in the solder joints, which was detected primarily at the solder/metallization interface of the outermost, most strained solder joint. Accumulated creep strain per cycle at this interface was evaluated using 3D FEA of the stress-strain state of the BGA and results calibrated against experimental BGA mean lifetimes using the Coffin-Mason relationship. Nanoindentation combined with FEA has been shown to be a viable route for the rapid assessment of creep performance and lifetime in lead-free solders under aerospace thermal cycles.
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Fry, Zachary S. "A LABORATORY SCALE STUDY OF INTUMESCENT COATINGS FOR PROTECTION OF BUILDING STRUCTURE MEMBERS FROM FIRES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1402055149.
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Holder, Justin. "Fluid Structure Interaction in Compressible Flows." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin159584692691518.
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Vishwakarma, R. "The use of inverse methods in determining applied dynamic loads on aerospace structure." Thesis, University of Hertfordshire, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.691048.
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Park, Conrad. "Mechanical Performance and Structure-Property Relations in6061B Aluminum Metal Matrix Composites." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1547842396716777.
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Drury, William David. "An adaptive structure based sensorless position estimator for permanent magnet machines in aerospace applications." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654114.
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The application of the research is towards brushless ac permanent magnet machine drives of the type deployed in aerospace actuation systems. These drives tend to utilise motor designs having concentrated windings with a low slot to pole ratio and thus are not ideal sinusoidal machines. In addition, these machines are often required to operate both below base speed and in the field-weakened region. The proposed sensorless technique, based on two flux models, avoids the need for differentiation in the position and speed estimation, is computationally efficient and is robust to temperature dependent motor parameter variation.
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Korobenko, Artem. "Advanced Fluid--Structure Interaction Techniques in Application to Horizontal and Vertical Axis Wind Turbines." Thesis, University of California, San Diego, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3670451.
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During the last several decades engineers and scientists put significant effort into developing reliable and efficient wind turbines. As a wind power production demands grow, the wind energy research and development need to be enhanced with high-precision methods and tools. These include time-dependent, full-scale, complex-geometry advanced computational simulations at large-scale. Those, computational analysis of wind turbines, including fluid-structure interaction simulations (FSI) at full scale is important for accurate and reliable modeling, as well as blade failure prediction and design optimization.
In current dissertation the FSI framework is applied to most challenging class of problems, such as large scale horizontal axis wind turbines and vertical axis wind turbines. The governing equations for aerodynamics and structural mechanics together with coupled formulation are explained in details. The simulations are performed for different wind turbine designs, operational conditions and validated against field-test and wind tunnel experimental data.
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Bail, Justin L. "Non-desctructive investigation & FEA correlation on an aircraft sandwich composite structure." Akron, OH : University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1196702586.
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Thesis (M.S.)--University of Akron, Dept. of Civil Engineering, 2007."December, 2007." Title from electronic thesis title page (viewed 02/25/2008) Advisor, Wieslaw Binienda; Faculty readers, Craig Menzemer, Robert Goldbert; Department Chair, Wieslaw Binienda; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Bin, Abdullah Nur Azam. "Numerical modelling and interaction of crack and aeroelastic behaviour of composite structure for aerospace applications." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/21462/.
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Aeroelasticity and fracture mechanics are two fields that commonly known will result in a structural failure. However, small attention is given in assessing the structural integrity of any flying object in aerospace application subjected to aerodynamic or aeroelastic loads especially the aircraft wing. The current research in the aircraft industry is focusing on the development of advanced composite wing structure, which there are still not well explored widely. Due to the higher strength of composite materials, a stronger wing could be designed to sustain the aerodynamic loads or any gust turbulence during flying at high altitude. This situation will be severely dangerous in the event of having a crack or damage on the surface of the cruising wing structure. This research aims at investigating the structural integrity of composite plate, either undamaged or with damage (with crack) subjected to the aerodynamic loads. The purpose of this study is to provide a novel numerical modelling in predicting the application of aerodynamic loads, by observing the flight maneuver safety margin including the flutter speed determination. Initially, the flutter speed was computed based on the coupled of finite element method (FEM) for the structural modelling and the doublet lattice method (DLM) in MSC Nastran for the unsteady aerodynamic modelling. Both structural and aerodynamic models were connected by interpolation using spline. In the end, the safety flight envelope for the composite plate was plotted based on the regulations provided by the Federal Aviation Regulations (FAR) 23. The numerical predictions of crack propagations of the damaged composite structure were determined by implementing the extended finite element model (XFEM), subjected to the aerodynamic loads intercorrelated through Fourier Series Function (FSF). Significantly, the aerodynamic loads were predicted by the implementation of gust, which produced the same level of maximum deflection analysed via aero-static analysis. The results show that the fibre orientation of the composite plate contributes significant crack propagations under the cruising aerodynamic loads. The same procedures were repeated to the wing box prototype developed under the joint program of Indonesian Aerospace, National Institute of Aeronautics and Space of Indonesia and Agency for Assessment and Application of Technology of Indonesia. For this work, the wing fracture was investigated by the influence of turbulence, called discrete 'gust loads'. From here, FSF was used to combine the wingtip deflection under the gust load influence, and hence applied XFEM to model the crack propagations. The results show that the crack propagated at the lower-front skin near to the wing root.
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Michaels, Simone Colette. "Development and Assessment of Artificial Manduca sexta Forewings: How Wing Structure Affects Performance." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1446206590.
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He, Yunzheng. "Modeling and Simulation of Tensegrity Structure based on SimMechanics." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592395403390476.
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Hinton, David A. "The organization as a system : structure, process, and human capital considerations in aerospace R&T." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/91790.
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Puttmann, John Paul. "Spatially Targeted Activation of a SMP." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1525166147319011.
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Inman, Jennifer Ann. "Fluorescence imaging study of free and impinging supersonic jets: Jet structure and turbulent transition." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539623513.
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A series of experiments into the behavior of underexpanded jet flows has been conducted at NASA Langley Research Center. This work was conducted in support of the Return to Flight effort following the loss of the Columbia. The tests involved simulating flow through a hypothetical breach in the leading edge of the Space Shuttle Orbiter along its reentry trajectory, with the goal of generating a data set with which other researchers can test and validate computational modeling tools. Two nozzles supplied with high-pressure gas were used to generate axisymmetric underexpanded jets exhausting into a low-pressure chamber. These nozzles had exit Mach numbers of 1 and 2.6. Reynolds numbers based on nozzle exit conditions ranged from about 200 to 35,000, and nozzle exit-to-ambient jet pressure ratios ranged from about 1 to 37. Both free and impinging jets were studied, with impingement distances ranging from 10 to 40 nozzle diameters, and impingement angles of 45??, 60??, and 90??. For the majority of cases, the jet fluid was a mixture of 99.5% nitrogen seeded with 0.5% nitric oxide (NO).;Planar laser-induced fluorescence (PLIF) of NO was used to non-intrusively visualize the flow with a temporal resolution on the order of lets. PLIF images were used to identify and measure the location and size of flow structures. PLIF images were further used to identify unsteady jet behavior in order to quantify the conditions governing the transition to turbulent flow. This dissertation will explain the motivation behind the work, provide details of the laser system and test hardware components, discuss the theoretical aspects of laser-induced fluorescence, give an overview of the spectroscopy of nitric oxide, and summarize the governing fluid mechanical concepts. It will present measurements of the size and location of flow structures, describe the basic mechanisms and origins of unsteady behavior in these flows, and discuss the dependence of such behavior on particular flow structures. Finally, correlations describing the relationship between flow conditions and the degree of flow unsteadiness at a given location along the jet axis will be presented.
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Nwankpa, Uzoma Vincent. "Effectiveness of arc based processes and deposition strategies on additive manufacture structure for naval and aerospace applications." Thesis, Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0010.
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Le processus de fabrication additive par fusion de fil métallique par arc électrique (Wire Arc Additive Manufacturing, WAAM) est devenu un procédé pertinent pour la fabrication de composants de structures complexes, qui étaient très compliqués à réaliser avec les méthodes de fabrication conventionnelles. Différents procédés à base d'arc électriques sont disponibles pour la mise en œuvre de matériaux tels que les alliages de titane ou d'aluminium et les aciers inoxydables, afin de produire des composants de grandes tailles. Néanmoins, il reste à déterminer quel est le meilleur procédé à base d'arc électrique à employer pour un matériau donné. Dans le cadre de cette thèse, plusieurs procédés à base d'arc électrique ont été étudiés pour déterminer s'ils convenaient à la fabrication de structures en acier inoxydable austénitique et en aluminium. Pour ce dernier, les travaux ont porté sur le procédé MIG/MAG de transfert de métal froid (CMT) en raison de son vaste choix de paramètres et de son faible apport de chaleur. Différentes stratégies de dépôt et l'utilisation des procédés TIG, MIG et Plasma ont été étudiés pour le dépôt d'aciers inoxydables austénitique par fabrication additive. Une étude approfondie des paramètres du processus tels que le courant, la vitesse de dévidage du fil et la vitesse de déplacement de la torche a été réalisée. Il a été montré que les propriétés mécaniques de chaque structure déposée par divers procédés à base d'arc satisfaisaient aux propriétés mécaniques requises. De plus, les stratégies de dépôt ont eu un impact plus important sur les propriétés mécaniques. En outre, la précision de la géométrie et le taux de ferrite diminuent en fonction de l'augmentation de l'apport de chaleur. Des études sur l'aluminium ont été menées avec le procédé CMT, une méthodologie de sélection de la meilleure synergie et du meilleur mode CMT pour le dépôt d'un fil prototype a été proposée. En outre, l'impact des stratégies de dépôt et de l'alternance de ces stratégies avec divers modes CMT sur l'atténuation de la propagation des fissures à partir de la base d'un composant WAAM ont été étudiées. Des études détaillées sur l'impact de la rampe des paramètres sur la précision de la géométrie de la paroi mince en aluminium ont été réalisées ainsi que sur la capacité de réaliser des structures suspendues. Enfin, l'étude a montré que le dépôt d'une structure en aluminium sur un support aux propriétés différentes est sujet à des fissures dues à une expansion et une contraction thermique inégales. Ainsi, ces travaux apportent des éléments d'aciers inoxydables austénitique et l'aluminium de paramétrage des procédés WAAM qui peux être significative dans l’objectif de réaliser des composants pour des applications navales et aéronautiquesWire and Arc Additive Manufacturing process is becoming an alternative technique used in manufacturing components of complex structures, which were unimaginable to achieve by conventional manufacturing methods. Various arc-based processes have been applied with titanium, aluminium, steel, and stainless steel to produce large components. Nevertheless, the best arc-based process for any given material of choice is yet to be addressed. In this research, several arc-based processes were investigated for their suitability to manufacture austenitic stainless steel and aluminium structures. However, the latter was confined to be deposited by cold metal transfer process (CMT) due to its high deposition rate and low heat input. Different deposition strategies and the use of gas metal arc, tungsten inert gas and plasma arc as heat sources for the deposition of austenitic stainless steel were investigated. An in-depth investigation of the process parameters such as current, wire feed speed and travel speed were carried out. It was found that the mechanical properties on each structure deposited by various arc-based processes satisfied the required mechanical properties Moreover, deposition strategies had moreimpact on the mechanical properties. Inaddition, the geometry accuracy and ferrite number decrease with respect to increased heat input. Aluminium studies were investigated with CMT process; a methodology to select the best CMT synergy and deposition mode for a prototype wire was proposed. Furthermore, the impact of deposition strategies and alternating these strategies with various CMT modes on mitigating crack propagation from the root of a WAAM component was investigated. Detailed studies on impact of ramping parameters on the aluminium thin wall geometry accuracy were performed. Afterwards the ramping parameters was implemented in the manufacture of suspended aluminium structures on steel support. Finally, the investigation showed that deposition of aluminium structure on a support of dissimilar properties is subject to crack due to uneven thermal expansion and contraction. The results of these research work on austenitic stainless steel and aluminium alloys for WAAM component can be of significance in the naval and aerospace applications
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Chamberlain, Britany L. "Additively-Manufactured Hybrid Rocket Consumable Structure for CubeSat Propulsion." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7285.
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Three-dimensional, additive printing has emerged as an exciting new technology for the design and manufacture of small spacecraft systems. Using 3-D printed thermoplastic materials, hybrid rocket fuel grains can be printed with nearly any cross-sectional shape, and embedded cavities are easily achieved. Applying this technology to print fuel materials directly into a CubeSat frame results in an efficient, cost-effective alternative to existing CubeSat propulsion systems. Different 3-D printed materials and geometries were evaluated for their performance as propellants and as structural elements. Prototype "thrust columns" with embedded fuel ports were printed from a combination of acrylonitrile utadiene styrene (ABS) and VeroClear, a photopolymer substitute for acrylic. Gaseous oxygen was used as the oxidizer for hot-fire testing of prototype thrusters in ambient and vacuum conditions. Hot-fire testing in ambient and vacuum conditions on nine test articles with a combined total of 25 s burn time demonstrated performance repeatability. Vacuum specific impulse was measured at over 167 s and maximum thrust of individual thrust columns at 9.5 N. The expected ΔV to be provided by the four thrust columns of the consumable structure is approximately 37 m/s. With further development and testing, it is expected that the consumable structure has the potential to provide a much-needed propulsive solution within the CubeSat community with further applications for other small satellites.
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Mignee, Juliette L. "Proper Orthogonal Decomposition Applied to a Supersonic Single Flow Jet." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1329935384.
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Khasawneh, Firas Abdallah. "Characterization of drillability of sandwich structure of carbon fiber reinforced epoxy composite over titanium alloy." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/5871.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 13, 2007). Vita. Includes bibliographical references.
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Bail, Justin. "Non-Destructive Investigation & FEA Correlation on an Aircraft Sandwich Composite STructure." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1196702586.
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Brod, Stephen P. 1970. "A testbed for investigating the effect of electrode structure on the performance of a solid oxide electrolysis system." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/291547.
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In-Situ Resource Utilization (ISRU) can reduce the mass launched to low Earth orbit for a Mars Sample Return Mission by as much as 75%. Solid Oxide Electrolysis is a candidate technology for producing oxygen out of carbon dioxide. A testbed was developed to test the effect of electrode structure on electrode performance. The testbed used all metal interconnects. Electrodes of 0.5 microns (applied by evaporative deposition) and 10-12 microns thick (applied by airbrushing) were produced. The disks were tested in argon, oxygen, and carbon dioxide. The thin electrode showed deterioration in both short term and long term tests. The thick electrode showed no deterioration even over a 120 hour test. Oxygen was produced from carbon dioxide for extended durations. The experiments show the thicker electrode is needed for an oxygen production system. The electrode/electrolyte disks withstood normal handling without damage.
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BOLLINO, ARCANGELA. "QUASI STATIC GRAVITY SIGNATURES IN SLOW TECTONIC ZONES: ASSIMILATION OF NOVEL AEROSPACE DATA AND GEOPHYSICAL MODELING." Doctoral thesis, Università degli Studi di Milano, 2023. https://hdl.handle.net/2434/956505.
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The main aim of my Ph.D. research project was to investigate the gravitational signatures of the mechanisms that regulate slow rate tectonic deformation in areas where the earthquakes enucleate. 2D thermo-mechanical numerical models are used to simulate the crust-mantle dynamics; in particular, complexities such as compositional stratification of crust-lithosphere system, mantle hydration, phase changes and degree of plate coupling are investigated, exploring how they affect the gravity field and its rate of change in different tectonic environments.
A strongly integration between modelling, gravitational and GNSS (Global Navigation Satellite System) data has provided valuable constraints to the analysis. In fact, this work is part of the GravSeis-Gravitational Seismology project, an ESA-founded research project whose objective is to establish a theoretical framework for the detection and characterization of earthquake precursors based on the observations of the gravitational field made by satellite. Gravitational Seismology concept expresses the idea that earthquakes are not generated only by surface displacements but are closely connected to deep masses redistribution involved in the subduction systems. This rearrangement generates density anomalies, which in turn are responsible for the Earth's gravity field anomalies.
A first study has been conducted on the Sumatra and Mariana complexes, representative of the two major types of subduction: ocean–continent and ocean–ocean, respectively. In a first phase, a set of numerical tests has been developed, varying three main parameters:
prescribed subduction velocity, prescribed subduction dip angle and degree of plate coupling, exploiting how their variation affect the gravity pattern.
In a second phase, the study of the EIGEN-6C4 gravitational disturbance patterns of the Sumatra and Mariana subductions has been carried out, allowing to strengthen the analysis of the gravitational signature in ocean–continent and ocean–ocean subductions in terms of the physics of the processes occurring during the convergence of the plates. Model predictions show a good agreement with gravity data, both in terms of wavelengths and magnitude of the gravity anomalies measured in the surroundings of the Sumatra and Marina subductions, supporting that the differences in the style of the gravity anomaly observed in the two areas are attributable to the different environments – ocean-ocean or ocean-continental subduction – that drives a significantly different dynamic in the wedge area.
A second study has been carried out developing 2D finite-element thermo-mechanical models, in which the formation of oceanic crust and serpentinite due to the hydration of upwelling mantle peridotite is implemented, to simulate the evolution of the Gulf of Aden from the rift initiation to the development of an active oceanic spreading center.
The thermo-mechanical analysis support the hypothesis that the Gulf of Aden developed as a slow passive rift in thin lithosphere with thick crust and that the variations in features along the passive margins could be related to lateral variations in the amount of H2O in the mantle, which determines the different times of mantle melting.
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Witeof, Zachary. "Exploratory Study on the Design of Combined Aero-Thermo-Structural Experiments in High Speed Flows." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366213825.
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Rinehart, Aidan Walker. "A Characterization of Seal Whisker Morphology and the Effects of Angle of Incidence on Wake Structure." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu1483991011265196.
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Miller, Samuel C. "Fluid-Structure Interaction of a Variable Camber Compliant Wing." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1428575972.
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Magal, Rithvik. "Development and validation of a mathematical model for a monotube automotive damper." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22951/.
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Automotive dampers involve complex flow physics that cannot be fully described by analytical models derived from first principles. Therefore, the development of a mathematical model based on semi-empirical laws that accurately describe the influence of each of the many design features would greatly help the design and optimization of automotive dampers. This thesis aims to develop a computationally efficient mathematical model capable to predicting damper performance with reasonable accuracy.
Lumped parameter mathematical models were developed and implemented using the MATLAB and Simulink environments. In order to solve for the structural dynamics of the shim stack, a force method based analytical model was developed. In order to solve for the internal flow field, fluid structure interaction simulations were necessitated due to the inherent coupling of fluid and structural dynamics.
Fluid-Structure Interaction (FSI) simulations were attempted using an open source setup consisting of OpenFOAM and CalculiX coupled by the preCICE coupling library. Coupled simulations on a trial simplified geometry produced physically consistent results. FSI simulations could not be performed on the real geometry due to lack of time and computational resources. The discharge coefficients were modelled as a linear function on the basis of CFD simulations perfomed on outputs from the force method model.
In order to validate the MATLAB mathematical model, experiments were carried out on a test automotive damper on a suspension dynamometer. The model showed good agreement in with experimental data at low bleed valve openings. The model accuracy was observed decrease for larger bleed valve openings due to unavailability of accurate model coefficients.
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Byrd, Alex W. "Fluid-Structure Interaction Simulations of a Flapping Wing Micro Air Vehicle." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401559891.
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Hart, Peter Bartholomew. "A plm implementation for aerospace systems engineering-conceptual rotorcraft design." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28278.
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The thesis will discuss the Systems Engineering phase of an original Conceptual Design Engineering Methodology for Aerospace Engineering-Vehicle Synthesis. This iterative phase is shown to benefit from digitization of Integrated Product&Process Design (IPPD) activities, through the application of Product Lifecycle Management (PLM) technologies. Requirements analysis through the use of Quality Function Deployment (QFD) and 7 MaP tools is explored as an illustration. A "Requirements Data Manager" (RDM) is used to show the ability to reduce the time and cost to design for both new and legacy/derivative designs. Here the COTS tool Teamcenter Systems Engineering (TCSE) is used as the RDM. The utility of the new methodology is explored through consideration of a legacy RFP based vehicle design proposal and associated aerospace engineering. The 2001 American Helicopter Society (AHS) 18th Student Design Competition RFP is considered as a starting point for the Systems Engineering phase. A Conceptual Design Engineering activity was conducted in 2000/2001 by Graduate students (including the author) in Rotorcraft Engineering at the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology, Atlanta GA. This resulted in the "Kingfisher" vehicle design, an advanced search and rescue rotorcraft capable of performing the "Perfect Storm" mission, from the movie of the same name. The associated requirements, architectures, and work breakdown structure data sets for the Kingfisher are used to relate the capabilities of the proposed Integrated Digital Environment (IDE). The IDE is discussed as a repository for legacy knowledge capture, management, and design template creation. A primary thesis theme is to promote the automation of the up-front conceptual definition of complex systems, specifically aerospace vehicles, while anticipating downstream preliminary and full spectrum lifecycle design activities. The thesis forms a basis for additional discussions of PLM tool integration across the engineering, manufacturing, MRO and EOL lifecycle phases to support business management processes.
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Fernández, Bravo Elena. "Modelling and testing of a solar panel structure for KNATTE (Kinesthetic Node and Autonomous Table-Top Emulator)." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-87200.
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One of the challenges that satellites face is the interaction between control movement and vibration of flexible appendages such as solar arrays and antennas that can negatively affect the performance of the spacecraft. The aim of this thesis is to develop a numerical model of a solar panel structure for KNATTE, a frictionless platform developed by the Onboard Space Systems group at Luleå University of Technology, and develop a control law that reduces the flexible vibration of the solar arrays when attitude control manoeuvres are performed. A set of solar panel structures have been designed and tested, the mathematical model of the multibody system, which consists of KNATTE and two flexible solar panels, has been developed in MATLAB by applying the finite element method. A finite element analysis has been performed in MATLAB to extract the natural frequencies of the system. The model has been numerically verified using a commercial software, and experimentally verified by performing testing on the frictionless vehicle, KNATTE, equipped with the solar panel structures and a number of piezoelectric sensors. Once the model has been verified, a Linear Quadratic Gaussian (LQG) controller has been developed using the results from the finite element model in order to reduce the amplitude of the vibrations of the flexible solar panel structure. The behaviour of the system has been simulated when the spacecraft performs an attitude manoeuvre. The finite element model provides the modal behaviour of the multibody system, obtaining its natural frequencies with low relative error. The LQG controller reduces the amplitude of the vibrations of the flexible solar panel structure.
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Mikol, Collin Everett. "Design, Modeling, and Experimental Testing of a Variable Stiffness Structure for Shape Morphing." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523454926569658.
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Mills, Austin Shelley. "The Structural Suitability of Tensegrity Aircraft Wings." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1590172090108379.
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Knöös, Franzén Ludvig, and Erik Magnusson. "Weight Penalty Methods for Conceptual Aircraft Design." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-175012.
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This report addresses a project conducted at Saab Aeronautics during the spring of 2018. The goal of the project was to investigate aircraft weight estimations in the conceptual design phase. The work was divided into two major parts: finding new weight estimation techniques and implementing an existing technique called the Berry Weight Estimation in to the Pacelab APD software. Several weight estimation techniques were found during an extensive literature review but in the end, only one was chosen for further investigation. The chosen technique was the NASA Wing Weight Build-Up which proposed calculations for wing weights based on aircraft statistics. It contained material data tables for determining so called K-factors that were used to essentially scale the individual wing weight formulas. The data tables did not include K-factors up to a load factor of 9 which was a requirement from Saab. Extrapolations of the material data tables were done to approximate the missing values. The NASA wing weight build-up showed promising results with little deviation from the actual wing weight for a few chosen aircraft. This weight estimation technique was consequently chosen as a worthy candidate for a future implementation in the Pacelab APD software. The task of implementing the Berry Weight Estimation in Pacelab APD was divided into a fuselage- and a wing part. This was done to ease the implementation since it would resemble the original description of the method. The wing and fuselage weights were both calculated in two steps. The first step was to calculate a gross shell weight. This is the weight of an idealized structure without cut-outs or imperfections. The second step was to add so called weight penalties for various components within the wing or fuselage. Typical aircraft components had associating weight penalty functions described in the Berry Weight Estimation. Most of the implemented calculations used Pacelab APD to get involved parameters automatically. However, some of the needed parameters had to be user specified for the implemented Berry Weight Estimation to work. Once the implementation task was finished, several sensitivity studies were made to establish a perception about the involved parameters impact on the Berry Weight Estimation results. The new implementation gave benefits compared with the Berry Weight Estimation in Bex. One of these was the ability to perform extensive trade- and sensitivity studies. The sensitivity studies gave verdicts on the most influencing parameters of the implemented code and guide lines on future improvements of the calculations. These sensitivity studies show, among other things, that is recommended to increase the number of wing and fuselage stations significantly in order to get a converged result for the Berry Weight Estimation.
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Pesich, Justin M. "Steady Aeroelastic Response Prediction and Validation for Automobile Hoods." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1482329426783128.
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Wilmoth, Nathan G. "Determining the Mechanical Properties of Lattice Block Structures." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1366275566.
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Reilly, Daniel Oliver. "Inlet Distortion Effects on the Unsteady Aerodynamics of a Transonic Fan Stage." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1482139741887976.
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Jenett, Benjamin (Benjamin Eric). "Digital material aerospace structures." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101837.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 71-76).
This thesis explores the design, fabrication, and performance of digital materials in aerospace structures in three areas: (1) a morphing wing design that adjusts its form to respond to different behavioral requirements; (2) an automated assembly method for truss column structures; and (3) an analysis of the payload and structural performance requirements of space structure elements made from digital materials. Aerospace structures are among the most difficult to design, engineer, and manufacture. Digital materials are discrete building block parts, reversibly joined, with a discrete set of positions and orientations. Aerospace structures built from digital materials have high performance characteristics that can surpass current technology, while also offering potential for analysis simplification and assembly automation. First, this thesis presents a novel approach for the design, analysis, and manufacturing of composite aerostructures through the use of digital materials. This approach can be used to create morphing wing structures with customizable structural properties, and the simplified composite fabrication strategy results in rapid manufacturing time with future potential for automation. The presented approach combines aircraft structure with morphing technology to accomplish tuned global deformation with a single degree of freedom actuator. Guidelines are proposed to design a digital material morphing wing, a prototype is manufactured and assembled, and preliminary experimental wind tunnel testing is conducted. Seconds, automatic deployment of structures has been a focus of much academic and industrial work on infrastructure applications and robotics in general. This thesis presents a robotic truss assembler designed for space applications - the Space Robot Universal Truss System (SpRoUTS) - that reversibly assembles a truss column from a feedstock of flat-packed components, by folding the sides of each component up and locking onto the assembled structure. The thesis describes the design and implementation of the robot and shows that an assembled truss compares favorably with prior truss deployment systems. Thirds, space structures are limited by launch shroud mass and volume constraints. Digital material space structures can be reversibly assembled on orbit by autonomous relative robots using discrete, incremental parts. This will enable the on-orbit assembly of larger space structures than currently possible. The engineering of these structures, from macro scale to discrete part scale, is presented. Comparison with traditional structural elements is shown and favorable mechanical performance as well as the ability to efficiently transport the material in a medium to heavy launch vehicle. In summary, this thesis contributes the methodology and evaluation of novel applications of digital materials in aerospace structures.
by Benjamin Jenett.
S.M.
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Villalva, Gómez Rodrigo. "Structure, Stability and Emissions of Lean Direct Injection Combustion, including a Novel Multi-Point LDI System for NOx Reduction." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384427714.
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