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Full-Text Articles in Mechanical Engineering

Decomposed Lifting-Line Predictions And Optimization For Propulsive Efficiency Of Flapping Wings, W. F. Phillips, R. A. Miller, Doug F. Hunsaker Jun 2013

Decomposed Lifting-Line Predictions And Optimization For Propulsive Efficiency Of Flapping Wings, W. F. Phillips, R. A. Miller, Doug F. Hunsaker

Mechanical and Aerospace Engineering Faculty Publications

A decomposed Fourier series solution to Prandtl's classical lifting-line theory is used to predict the lift, induced-thrust, and power coefficients developed by a flapping wing. A significant advantage of this quasi-steady analytical solution over commonly used numerical methods is the utility provided for optimizing wing flapping cycles. The analytical solution involves five time-dependent functions that could all be optimized to maximize thrust, propulsive efficiency, and/or other performance measures. Results show that by optimizing only two of these five functions, propulsive efficiencies exceeding 97% can be obtained. Results are presented for untwisted rectangular wings in pure plunging, rectangular wings with linear …


Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon Jun 2013

Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

In recent years, ductile hybrid FRP (DHFRP) bars have been developed for use as tensile reinforcement. However, initial material costs regain high, and it is difficult to simultaneously meet strength, stiffness, ductility, and reliability demands. In this study, a reliability-based design optimization (RBDO) is conducted to determine minimum cost DHFRP bar configurations while enforcing essential constraints. Applications for bridge decks and building beams are considered, with 2, 3, and 4-material bars. It was found that optimal bar configuration has little variation for the different applications, and that overall optimized bar cost decreased as the number of bar materials increased.