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- Aerodynamics (2)
- MAVs (2)
- ABS (1)
- Additive Manufacturing (1)
- Al 2195 (1)
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- Al 2219 (1)
- Al Heat Treatment (1)
- Biomimetic artificial insect-sized wing (1)
- Buckling (1)
- Crane fly (1)
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- Equivalent Structural Stress (1)
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- Friction Stir Welding (1)
- Helicopter vibration, Control, Linear quadratic regulator, Rotating beam (1)
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- Master S-N Curve (1)
- Photolithography (1)
- Postbuckling (1)
- Size Effect (1)
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Articles 1 - 6 of 6
Full-Text Articles in Structures and Materials
Active Vibration Control Of Helicopter Rotor Blade By Using A Linear Quadratic Regulator, Md Mosleh Uddin
Active Vibration Control Of Helicopter Rotor Blade By Using A Linear Quadratic Regulator, Md Mosleh Uddin
University of New Orleans Theses and Dissertations
Active vibration control is a widely implemented method for the helicopter vibration control. Due to the significant progress in microelectronics, this technique outperforms the traditional passive control technique due to weight penalty and lack of adaptability for the changing flight conditions. In this thesis, an optimal controller is designed to attenuate the rotor blade vibration. The mathematical model of the triply coupled vibration of the rotating cantilever beam is used to develop the state-space model of an isolated rotor blade. The required natural frequencies are determined by the modified Galerkin method and only the principal aerodynamic forces acting on the …
Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds, Matthew Champagne
Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds, Matthew Champagne
University of New Orleans Theses and Dissertations
To evaluate potential uses for friction stir welding in additive manufacturing, two separate parts were fabricated, one of 2195-T84 and the other 2219-T87, utilizing fixed pin techniques and additive lap welds. The parts were cut into samples, artificially aged and subjected to Rockwell hardness (HRB), Vickers hardness, micrographic photography, and metallographic imaging on both pre- and post- heat treatment. Additionally, tensile testing was performed on the heat-treated samples. A comparisons of test results showed a minimal increase in the yield strength of the 2195-T84 samples compared to as-welded tensile results obtained from a previous project. The ultimate tensile strength was …
Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio
Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio
University of New Orleans Theses and Dissertations
The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite …
Modal Characterization And Structural Dynamic Response Of A Crane Fly Forewing, Jose E. Rubio
Modal Characterization And Structural Dynamic Response Of A Crane Fly Forewing, Jose E. Rubio
University of New Orleans Theses and Dissertations
This study describes a method for conducting the structural dynamic analysis of a crane fly (family Tipulidae) forewing under different airflow conditions. Wing geometry is captured via micro-computed tomography scanning. A finite element model of the forewing is developed from the reconstructed model of the scan. The finite element model is validated by comparing the natural frequencies of an elliptical membrane with similar dimensions of the crane fly forewing to its analytical solution. Furthermore, a simulation of the fluid-structure interaction of the forewing under different airflows is performed by coupling the finite element model of the wing with a …
Buckling, Postbuckling And Imperfection Sensitivity Analysis Of Different Type Of Cylindrical Shells By Hui's Postbuckling Method, Hailan Xu
University of New Orleans Theses and Dissertations
Hui and Chen (1986) were the first to show that the well-known Koiter’s General Theory of Elastic Stability of 1945 can be significantly improved by evaluating the postbuckling b coefficient at the actual applied load, rather than at the classical buckling load. Such improvement method was demonstrated to be (1) very simple to apply with no tedious algebra, (2) significant reduction in imperfection sensitivity and (3) although it is still asymptotically valid, there exists a significant extension of the range of validity involving larger imperfection amplitudes. Strictly speaking, Koiter’s theory of 1945 is valid only for vanishingly small imperfection amplitudes. …
Fatigue Testing And Data Analysis Of Welded Steel Cruciform Joints, Alina Shrestha
Fatigue Testing And Data Analysis Of Welded Steel Cruciform Joints, Alina Shrestha
University of New Orleans Theses and Dissertations
In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate …