A cooling system for s.m.a. (shape memory alloy)based on the use of peltier cells

The aim of this thesis has been the study and the implementation of an innovative cooling system for S.M.A. (Shape Memory Alloy) material by using a Peltier cell. This system has demonstrated a consistent cooling time reduction during the application and so that the solution adopted has confirmed that it can be used for a better operability of the S.M.A. material during the cooling phase. After an accurate selection of possible cooling system to be adopted on these materials the better choice in terms of efficiency and energy consumption reduction has converged on Peltier cell design development. In this context for our research three investigation have been conducted. The first one has concerned an analytic investigation in order to understand the phenomenology and the terms involved during the heat exchange. After this study a numerical investigation through a Finite Element approach by commercial software has been carried out. Also an experimental investigation has been conducted, at the CIRA Smart Structure Laboratory, in order to verify the results obtained by the numerical prediction. The set-up with the Peltier cell used as heater and cooler of the S.M.A. has confirmed the soundness of the solution adopted. Finally, a correlation between numerical and experimental results have been presented demonstrating the validity of the obtained results through the developed investigations. This system, composed of Peltier cell has confirmed also an energy consumption reduction because the cell has been used for heating and cooling phase without additional system as resistive system (Joule effect). This project shall be also industrial involvement in a new cost cut down point of vie

Design and analysis of a low cost, deployable unmanned aerial vehicle for environmental surveillance

Capstone Project submitted to the Department of Engineering, Ashesi University in partial fulfillment of the requirements for the award of Bachelor of Science degree in Mechanical Engineering, May 2021Surveillance aircraft require long flight endurance and range to perform their task fully. An aircraft's flight endurance can be increased by lowering the aircraft's weight and increasing the UAV's wingspan. However, the challenges that arise with a long wingspan are increased weight and costs due to the addition of materials to the wing. Most importantly, it results in large volumes that take much storage space resulting in difficulties in storing and deploying multiple UAVs. This project discusses the design and analysis of a low-cost micro-UAV with collapsible wings made from lightweight, flexible fabric. The UAV designed in this paper weighs less than 300g and flies at an altitude of 200m and a flight endurance of approximately 45 minutes. Size optimisation was done in guidance with the mission and design requirements. Flight endurance baseline was established by deriving a mathematical endurance model together with power sizing. The shape of the UAV was defined using configuration selection. This was followed by 3D modelling of parts and were assembled using SolidWorks software. To wrap the design, an XFLR5 software was used to analyse and select aerofoils and analyse the UAV's aerodynamic performance, Cl, Cd and Cl/Cd. The coefficient of lift of the aircraft when cruising is 0.455. Results from XFLR5 were compared with the analytically predicted values. Lastly, structural analysis (Finite Element Analysis (FEA)) was performed numerically (using SolidWorks) to determine the structural performance of the wing hinge to avoid failures due to static and fatigue torsional stresses. The critical point on the hinge had 0.74% damage and a safety factor of 2.258, showing that the hinge is unlikely to fail. Keywords: UAV Design, Aerofoil, XFLR5, Flight EnduranceAshesi Universit

Druckaktuierte zelluläre Strukturen

The herein presented investigations address the implementation of a holistic design process for Pressure-Actuated Cellular Structures (PACS) and include their realization and characterization. Similar to the motion of nastic plants, the actuation principle of these biologically inspired shape-variable structures bases on the controlled expansion of pressurized volumes. The advantages of fluidic actuation are combined with an adaptive single-curved structure that deforms continuously and with controllable stiffness between predefined states of shape. Benfits from the utilization of such a structure are expected within the fields of aeronautical, automobile, power and civil engineering. The identification of open issues, the development and the validation of design methods, as well as the evaluation of the performance of the concept of PACS are realized in consideration of the global system. A holistic solution for the design of PACS is successfully implemented and allows for the profound investigation on an experimental basis. The foundation for the evaluation and utilization of such shape-variable structures is thus laid.Die nachfolgenden Untersuchungen befassen sich mit der Entwicklung eines ganzheitlichen Entwurfsprozesses für Druckaktuierte Zelluläre Strukturen (PACS, engl.: Pressure-Actuated Cellular Structures), sowie deren Realisierung und Charakterisierung. Ähnlich dem Vorbild nastischer Pflanzen, basiert das Antriebsprinzip dieser biologisch inspirierten formvariablen Strukturen auf der Ausdehnung druckbeaufschlagter Volumina. Die Vorzüge fluidischer Aktuierung lassen sich dabei auf eine einfach gekrümmte Struktur übertragen, welche sich stufenlos und mit kontrollierbarer Steifigkeit zwischen spezifizierbaren Formzuständen deformieren lässt. Potentiale aus der Nutzung einer solchen Struktur ergeben sich unter anderem für die Bereiche Luftfahrt, Automobil- und Energietechnik sowie Bauwesen. Die Identifikation offener Problemfelder, die Entwicklung und Validierung von Entwurfsmethoden, sowie die Bewertung der Leistungsfähigkeit des Konzeptes der PACS erfolgen in dieser Arbeit über eine ganzheitliche Systembetrachtung. Das Konzept der PACS kann durch den Aufbau eines ganzheitlichen Entwurfsprozesses erstmals fundiert und auf experimenteller Basis untersucht werden. Die Grundlagen zur Bewertung und Nutzung solcher formvariabler Strukturen sind damit geschaffen

Near stall unsteady flow responses to morphing flap deflections

The unsteady flow characteristics and responses of an NACA 0012 airfoil fitted with a bio-inspired morphing trailing edge flap (TEF) at near-stall angles of attack (AoA) undergoing downward deflections are investigated at a Reynolds number of 0.62 × 106 near stall. An unsteady geometric parametrization and a dynamic meshing scheme are used to drive the morphing motion. The objective is to determine the susceptibility of near-stall flow to a morphing actuation and the viability of rapid downward flap deflection as a control mechanism, including its effect on transient forces and flow field unsteadiness. The dynamic flow responses to downward deflections are studied for a range of morphing frequencies (at a fixed large amplitude), using a high-fidelity, hybrid RANS-LES model. The time histories of the lift and drag coefficient responses exhibit a proportional relationship between the morphing frequency and the slope of response at which these quantities evolve. Interestingly, an overshoot in the drag coefficient is captured, even in quasi-static conditions, however this is not seen in the lift coefficient. Qualitative analysis confirms that an airfoil in near stall conditions is receptive to morphing TEF deflections, and that some similarities triggering the stall exist between downward morphing TEFs and rapid ramp-up type pitching motions

Simplified Dynamic Models for Modern Flying Vehicles

This dissertation contributes to the definition of minimum–complexity approaches that allows for representing realistic effects typical of modern fixed- and rotary-wing configurations, limiting as much as possible increase in order and overall complexity of the dynamic model of the class of aerial vehicles considered. In particular, the thesis deals with (1) the development of a novel low–order mathematical model for including structural deformation effects in the analysis of response to control inputs of flexible aircraft; (2) the derivation of a simplified models for unsteady aerodynamic effects, with an application to helicopter main rotor; (3) modeling and assessment of the maneuvering potential for a novel quadrotor configuration with tilting rotors. A mixed Newtonian–Lagrangian approach is proposed for the derivation of flexible aircraft equations of motion, where Lagrange equations are used for flexible degrees of freedom, discretized by means of Gal¨erkin method, whereas the evolution of transport degrees of freedom (position and attitude variables) is obtained by means of Newton second law and generalized Euler equation. A strong link with conventional rigid aircraft equations of motion is maintained, that allows highlighting those terms less relevant for aircraft response. When negligible, these terms are removed and a minimum complexity flexible aircraft model is derived, suitable for real–time simulation and control law synthesis. Similarly, unsteady aerodynamic effects over a rotating blade are modeled by means of an available approach, namely the ONERA dynamic stall model. Some reasonable simplifying assumptions based on the comparison of simulation results with a quasi–static aerodynamic model are then derived and a minimum complexity, 6 degree–of–freedom helicopter model is proposed which takes into account the issues related to retreating blade stall. Finally, an existing inverse simulation algorithm is applied for the first time to the determination of the control laws for tracking desired maneuvers by means of an unconventional quad-rotor configuration featuring four tilting rotors. This novel configuration allow access to an extended maneuver envelope and ad hoc instruments are needed for assessing its maneuvering potential. For all the considered problems, the approaches developed are demonstrated by means of numerical results, applied to a particular class of modern fixed- or rotary-wing aircraft, but the possibility of extending the results to different classes of vehicles is also highlighted

Air Force Institute of Technology Research Report 2019

This Research Report presents the FY19 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document

High-Fidelity Aerostructural Design Optimization of Transport Aircraft with Continuous Morphing Trailing Edge Technology

Adaptive morphing trailing edge technology offers the potential to decrease the fuel burn of transonic commercial transport aircraft by allowing wings to dynamically adjust to changing flight conditions. Current configurations allow flap and aileron droop; however, this approach provides limited degrees of freedom and increased drag produced by gaps in the wing’s surface. Leading members in the aeronautics community including NASA, AFRL, Boeing, and a number of academic institutions have extensively researched morphing technology for its potential to improve aircraft efficiency. With modern computational tools it is possible to accurately and efficiently model aircraft configurations in order to quantify the efficiency improvements offered by mor- phing technology. Coupled high-fidelity aerodynamic and structural solvers provide the capability to model and thoroughly understand the nuanced trade-offs involved in aircraft design. This capability is important for a detailed study of the capabilities of morphing trailing edge technology. Gradient-based multidisciplinary design opti- mization provides the ability to efficiently traverse design spaces and optimize the trade-offs associated with the design. This thesis presents a number of optimization studies comparing optimized config- urations with and without morphing trailing edge devices. The baseline configuration used throughout this work is the NASA Common Research Model. The first opti- mization comparison considers the optimal fuel burn predicted by the Breguet range equation at a single cruise point. This initial singlepoint optimization comparison demonstrated a limited fuel burn savings of less than 1%. Given the effectiveness of the passive aeroelastic tailoring in the optimized non-morphing wing, the singlepoint optimization offered limited potential for morphing technology to provide any bene- fit. To provide a more appropriate comparison, a number of multipoint optimizations were performed. With a 3-point stencil, the morphing wing burned 2.53% less fuel than its optimized non-morphing counterpart. Expanding further to a 7-point stencil, the morphing wing used 5.04% less fuel. Additional studies demonstrate that the size of the morphing device can be reduced without sizable performance reductions, and that as aircraft wings’ aspect ratios increase, the effectiveness of morphing trailing edge devices increases. The final set of studies in this thesis consider mission analy- sis, including climb, multi-altitude cruise, and descent. These mission analyses were performed with a number of surrogate models, trained with O(100) optimizations. These optimizations demonstrated fuel burn reductions as large as 5% at off-design conditions. The fuel burn predicted by the mission analysis was up to 2.7% lower for the morphing wing compared to the conventional configuration.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/140858/1/daburdet_1.pd

Air Force Institute of Technology Research Report 2012

This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physics

Air Force Institute of Technology Research Report 2020

This Research Report presents the FY20 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document