The overwhelming majority of MDO work reported in the literature is based on a monolithic MDO approach referred to as the All-At-Once (AAO) architecture. Various monolithic MDO architectures are derived from the AAO approach. They include the Simultaneous Optimization and Design (SAND), the Individual Discipline Feasible (IDF) and the Multidisciplinary Feasible (MDF) architecture among others. The main characteristic of the AAO approach is that all of the optimization decisions are made at the system level.

This presentation reviews some of these methodologies and explores the development and applicability of an alternative MDO method, utilizing decomposition-based optimization schemes. Decomposition-based strategies involve nesting all subsystem (or discipline-level) independent optimizations within a system-level optimizer. The system-level optimizer makes all system-level decisions and the subsystem-level optimizers solve for all parameters local to each discipline while holding system-level parameters fixed. The discipline-level optimizations are performed completely during each iteration of the system-level optimization so these approaches are said to be bi-level, nested optimizations. These methods take advantage of the typical division of expertise and information between disciplines during the design phase, and reduces the number of variables at the system level, thus making the optimization effort more efficient. There are three distinct classes of bi-level methods: concurrent subspace optimization, collaborative optimization (CO), and bi-level integrated system synthesis.

Short Bio: Dr. Hamid Hefazi joined Florida Institute of Technology (FIT) in Fall 2013, as a Professor of Aerospace Engineering and the Mechanical and Aerospace Engineering Department head. Prior to joining Florida Tech, Professor Hefazi served as the MAE department chair at California State University, Long Beach (CSULB) for twelve years. Professor Hefazi received his Ph.D. degree in Aerospace Engineering from the University of Southern California in 1985. He has been involved in a broad range of teaching and research activities in fluid mechanics, including geophysical fluid mechanics and computational fluid dynamics (CFD), with emphasis on the computation of transonic flows over complex geometries. His more recent research works have been on the application of CFD in turbomachinery, aerodynamic design optimization, aeroacoustics, hydrodynamics, and advanced optimization methods. He has forty-seven papers in various publications, and four book chapters including co-authoring the "Aircraft Design" chapter of the Springer International Handbook of Mechanical Engineering. Dr. Hefazi has been the Principal Investigator for more than one-hundred externally funded research projects totaling over $10.6 million, including projects sponsored by the National Science Foundation, the Office of Naval Research and the Boeing Company. He has organized several national conferences, taught several short courses for industry and given many invited lectures and talks for aerospace companies. Dr. Hefazi has extensively worked as a consultant for wind-energy companies and the Prada 2000 and 2003 America's Cup Challenges in the areas of keel hull and sail performance for race boats.