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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 …
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 …