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Articles 1 - 9 of 9
Full-Text Articles in Structures and Materials
Structural Optimization Of A Distributed Actuation System In A Flexible In-Plane Morphing Wing, James T. Westfall
Structural Optimization Of A Distributed Actuation System In A Flexible In-Plane Morphing Wing, James T. Westfall
Theses and Dissertations
Structural weight and efficiency are hurdles for morphing aircraft being realizable on the full-scale level. The optimal distribution and orientation of actuators throughout an in-plane flexible morphing wing structure is investigated. The drive to minimize structural weight causes a wing to be more flexible and the location and orientation of the actuators become more critical as the structure becomes more flexible. NextGen's N-MAS morphing wing is used as a case study. The wing is modeled as a number of unit cells assembled in a scissor-like structure, each comprised of four linkages pinned together and an actuator. The flexible skin of …
Optimization Of Zero Net-Mass Flow Actuators For Aero-Optics Applications, Moira L. Denatale, Jonathan M. Mihaly
Optimization Of Zero Net-Mass Flow Actuators For Aero-Optics Applications, Moira L. Denatale, Jonathan M. Mihaly
Honors Capstone Projects - All
Using experimental methods, zero net-mass flow actuators were optimized to manipulate flow around an airborne laser turret in order to reduce destructive aero-optics effects. Synthetic jets are created by 50 mm and 27 mm piezoelectric disk actuators. Our optimization process involved identifying an actuator’s cavity size, driving frequency, and amplitude to achieve the strongest, most consistent jet possible. The effects of driving a single actuator versus driving two actuators in or out of phase with one another were also investigated. An initial cavity depth was determined using the Helmholtz resonator cavity approximation which estimates the ideal cavity depth for a …
Recent Developments In Smart Adaptive Structures For Solar Sailcraft, Mark Whorton, Young Kim, Jerry Oakley, Olawale Adetona, Lee Keel
Recent Developments In Smart Adaptive Structures For Solar Sailcraft, Mark Whorton, Young Kim, Jerry Oakley, Olawale Adetona, Lee Keel
Information Systems and Engineering Management Research Publications
The "Smart Adaptive Structures for Solar Sailcraft" development activity at MSFC has investigated issues associated with understanding how to model and scale the subsystem and multi-body system dynamics of a gossamer solar sailcraft with the objective of designing sailcraft attitude control systems. This research and development activity addressed three key tasks that leveraged existing facilities and core competencies of MSFC to investigate dynamics and control issues of solar sails. Key aspects of this effort included modeling and testing of a 30 m deployable boom; modeling of the multi-body system dynamics of a gossamer sailcraft; investigation of control-structures interaction for gossamer …
Assessment Of Preliminary Design Approaches For Metallic Stiffened Cylindrical Shell Instability Problems, Vicki Owen Britt
Assessment Of Preliminary Design Approaches For Metallic Stiffened Cylindrical Shell Instability Problems, Vicki Owen Britt
Mechanical & Aerospace Engineering Theses & Dissertations
A preliminary design tool for metallic stiffened fuselage cylindrical panels subjected to longitudinal compression has been developed and validated by comparison to test results. Several methodologies for stiffened panel buckling and failure predictions were examined and evaluated. An appropriate level of analysis fidelity was determined for different failure modes and design details. Results from panel tests conducted to verify analytical methods used to design the Gulfstream V aircraft were presented. The panels were representative of four general skin/stringer configurations on the aircraft. Finite Element analyses and standard analytical methods were used to predict panel failure loads. The accuracy of the …
Effects Of Prior Aging At Elevated Temperature In Air And In Argon Environments On Creep Response Of Pmr-15 Neat Resin, Joseph L. Broeckert
Effects Of Prior Aging At Elevated Temperature In Air And In Argon Environments On Creep Response Of Pmr-15 Neat Resin, Joseph L. Broeckert
Theses and Dissertations
Creep behavior of PMR-15 neat resin, a polyimide thermoset polymer, aged in air or argon gaseous environments at 288 °C for up to 1000 h was evaluated. Creep tests were performed at 288 C at creep stress levels of 20 and 10 MPa. Creep periods of at least 25 h in duration were followed by recovery at zero stress. Weight loss and growth of the oxidation layer were also monitored and correlated with aging time. The aging time in both air and argon environments had a strong influence on the creep and recovery response of PMR-15 neat resin. Samples aged …
Three Dimensional Analysis Of A Composite Repair And The Effect Of Overply Shape Variation On Structural Efficiency, David A. Sutter
Three Dimensional Analysis Of A Composite Repair And The Effect Of Overply Shape Variation On Structural Efficiency, David A. Sutter
Theses and Dissertations
This research characterizes, in the elastic range, a scarf joint with overply using digital image correlation photogrammetry and finite element modeling. Additionally, the effect of varying the overply's geometric profile is examined. Specimens are constructed from AS4/3501-6 prepreg with a [0±45/90]2S layup. A fixture is used to achieve a consistent scarfed hole in each panel. The patch and adhesive (FM 300) are co-cured to the panels using positive pressure, which minimizes repair porosity. Three variations in the overply geometry are used: circular, rooftop-end, and tooth-end. The full strain field in each uni-axially loaded specimen is captured using digital image …
Forest Products Laboratory: Supporting The Nation's Armed Forces With Valuable Wood Research For 90 Years, Christopher D. Risbrudt, Robert J. Ross, Julie J. Blankenburg, Charles A. Nelson
Forest Products Laboratory: Supporting The Nation's Armed Forces With Valuable Wood Research For 90 Years, Christopher D. Risbrudt, Robert J. Ross, Julie J. Blankenburg, Charles A. Nelson
Julie Blankenburg
Founded in 1910 by the U.S. Forest Service to serve as a centralized, national wood research laboratory, the USDA Forest Products Laboratory (FPL) has a long history of providing technical services to other government agencies, including those within the Department of Defense (DoD). A recent search of FPL’s library and correspondence files revealed that approximately 10,000 articles, reports, manuals, other technical publications, and communications have been generated and provided to the DoD since 1910. FPL has provided support on a broad array of technical questions—from designporting materiel to Europe and the South Pacific during World War II to assisting in …
Development Of A Coupled Fluid/Structure Aeroelastic Solver With Applications To Vortex Breakdown-Induced Twin Tail Buffeting, Steven J. Massey
Development Of A Coupled Fluid/Structure Aeroelastic Solver With Applications To Vortex Breakdown-Induced Twin Tail Buffeting, Steven J. Massey
Mechanical & Aerospace Engineering Theses & Dissertations
Simulation of tail buffet is studied for several delta wing-vertical tail configurations. Flow conditions are chosen such that the wing primary-vortex cores experience vortex breakdown and the resulting turbulent wake flow impinges on the vertical tail. The dimensions and material properties of the vertical tails are chosen such that the deflections are large enough to insure interaction with the flow, and the natural frequencies are high enough to facilitate a practical computational solution. This multi-disciplinary problem is solved sequentially for the fluid flow, the elastic deformations and the grid displacements. The flow is simulated by time accurately solving the laminar, …
Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards
Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards
Mechanical & Aerospace Engineering Theses & Dissertations
A research effort has been undertaken to investigate critical aspects of launch vehicle performance as affected by variations in specific launch vehicle parameters. The major portion of the study involves liquid propellant systems. However, since solid propellant systems also play a role in today's launch systems, a representative solid-propellant launch vehicle has also been analyzed. The research undertaken determined that the payload capability of a space launch vehicle, or, conversely, the vehicle total liftoff mass, is highly sensitive to the manner in which the space launch vehicle is staged. The research has led to the development and programming of a …