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MAE Colloquium - Autumn 2015

The Aerospace Engineering Colloquium (AE 598) is a required course that satisfies the professional development component of the Master of Aerospace Engineering (MAE). MAE students are required to complete nine (9) credits of colloquium participation to satisfy the degree requirements. However, all members of the UW community are welcome to attend and participate.

Topics may include current research and advances in aerospace technology as well as other themes relevant to the professional development of aerospace engineers. To earn credit for this course, students must complete a required set of writing assignments.

Download Course Description, Grading, and Assignment Details (pdf)

Autumn 2015

Mondays, 4:00 - 5:00 pm
216 Loew Hall

Faculty Coordinator: Prof. Antonino Ferrante

Current Week's Information

October 5

Trace as the Sun of Our Composites Universe

Composite materials and structures are often hampered by complexity and man-made rules. As a result, composites are not used optimally. Since the discovery of trace in 2014, a new order is emerging. Trace now shines light on nearly all aspects of composites technology. It provides not only the one and only one data that defines universal laminates for all CFRP but also rationalizes design by scaling not possible without it. Instead of the traditional strength pyramid with thousands of coupons two tests of X and X’ with Ex would be sufficient to generate a unit circle failure envelope and thus the ultimate strength of all laminates for all CFRP materials. A material-independent design can be done and the best material for the design can be selected based on its weight savings over aluminum ranked by trace. This is a generalized netting analysis that is easy to understand, makes common sense, and simple to use. Additional features include bi-angle C-Ply tape that would replace unitape to gain layup speed in many folds. Also with homogenization, one-by-one ply drop is simple and flexible, and optimization for thickness tapering becomes rational and direct, and can be engineered for manufacturing. A bi-axially loaded panel as a generic design with universal laminates will be presented to illustrate its tapered profile and layup pattern for relative cost and weight savings based on the values of trace for 15 common CFRP materials.

Presentation Slides (pdf)


October 12


Predicting Failure of Textile Composites: Quasibrittle Fracture Mechanics and Meso-Scale Computational Modeling Applied to Car Crashworthiness

Thanks to their outstanding specific mechanical properties including stiffness, strength and intra-laminar and inter-laminar fracture toughness, textile composites represent a rapidly emerging, cost‐effective technology for the manufacturing of large mechanical and aerospace structures. However, in order to take advantage of the outstanding characteristics of these materials, understanding their damage and fracturing behavior across multiple scales, from micro to macro, is quintessential. The first part of the talk aims at discussing the main challenges for the extensive application of textile composites in large mechanical and aerospace structures. The second part of the lecture demonstrates how the foregoing issues can be addressed effectively.

Presentation Slides (pdf)
Suggested Readings:
(1) Salviato M. Ashari S.E., Cusatis G. Spectral Stiffness Microplane Model for Quasibrittle Textile Composites, (Under review in Composite Structures. Draft available at: arXiv:1509.02501).
(2) Bažant Z.P, Planas J., Fracture and Size Effect in Concrete and Other Quasibrittle materials, CRC Press, (1998).


October 19


No Class Meeting Today


October 26


No Class Meeting Today


November 2


Building Professional Capital: Thoughts for Career Satisfaction

People have heard of the “mid-life crisis,” but what about the “mid-career crisis?” After the economic downturn of the late 2000’s, many people were unprepared to make a forced transition in their professional careers. Learn how you can be in control of your career by understanding your “professional capital” and, if you are considering a career change, how to make a smooth transition with a series of planned steps.

Presentation Slides (pdf)


November 9


Relevance of Steady Planar ZND Model to Unsteady Cellular Detonations

The ZND theory is a one-dimensional and steady model to describe the progression of chemical reactions occurring in detonations. Though plausible, such idealized flow structures have never been detected in experiments. The detonations have always been found to be multi-dimensional and unsteady. Therefore, the relevance of the ZND theory has been regarded as uncertain at best, and highly questionable at worst. A recent study on spinning detonations by Kurosaka & Tsuboi (J. Fluid.Mech.,vol. 756, 2014, pp.728- 757), however, suggested that there might be some underlying connection between the ZND theory and multi-dimensional flow structures. The present paper examines this prospect for two-dimensional cellular detonations. We performed numerical simulations using adaptive mesh refinement for shock capturing and a multiple-step chemical mechanism to reproduce the cellular pattern observed in experiments. Since the ZND theory tracks the detonation progress of a given fluid particle, we follow particles released from the shock front. The profi les of the particle properties such as velocity, pressure, temperature, and species mass fraction, when plotted along the particle trajectories, are found to cluster around the corresponding ZND values, which in turn match with the transverse averages of the particle properties. The reason for their agreement is the positional change of the particle relative to the fluctuating shock front. The results lend support to the relevance of the ZND model as representing the transverse average of unsteady, regular cellular detonations.

Presentation Slides (pdf)


November 16


Energy-Aware Unmanned Aircraft Systems: Enabling Persistent Atmospheric Sampling

The energy-aware airborne dynamic, data-driven application system (EA-DDDAS) performs persistent sampling in complex atmospheric conditions by exploiting wind energy using the dynamic data-driven application system paradigm. The main challenge for future airborne sampling missions is operation with tight integration of physical and computational resources over wireless communication networks, in complex atmospheric conditions. The physical resources considered here include sensor platforms, particularly mobile Doppler radar and unmanned aircraft, the complex conditions in which they operate, and the region of interest. Autonomous operation requires distributed computational effort connected by layered wireless communication. Onboard decision-making and coordination algorithms can be enhanced by atmospheric models that assimilate input from physics-based models and wind fields derived from multiple sources. These models are generally too complex to be run onboard the aircraft, so they need to be executed in ground vehicles in the field, and connected over broadband or other wireless links back to the field. Finally, the wind field environment drives strong interaction between the computational and physical systems, both as a challenge to autonomous path planning algorithms and as a novel energy source that can be exploited to improve system range and endurance. This seminar will describe a collaborative effort to implementation a complete EA-DDDAS. Results will be presented from previous field deployments of unmanned aircraft to show the evolution of the EA-DDDAS concept, and from recent deployments validating the EA-DDDAS.

Presentation Slides (pdf)


November 23


Relevance of Steady Planar ZND Model to Unsteady Cellular Detonations

  • Armand Awad
    PhD Candidate, William E. Boeing Department of Aeronautics & Astronautics, Univeristy of Washington, Seattle

In flight and orbital mechanics, problems are naturally nonlinear and are often plagued by the presence of small parameters which introduce nonlinearities and increase the order of the system. In this talk, I show how the intuitive concept of multiple timescales can be used to understand these systems and make their analysis tractable. These concepts will be illustrated through problems in orbital mechanics and distributed robotics.

Presentation Slides (pdf)


November 30


Relevance of Steady Planar ZND Model to Unsteady Cellular Detonations

  • William Olbricht
    Program Director, Particulate and Multiphase Processes, NSF

The National Science Foundation (NSF) is an independent federal agency with an annual budget of $7.3 billion that supports 24% of federally supported basic research at the nation’s colleges and universities. This seminar will describe ongoing programs and special initiatives at NSF that support engineering research and education, especially in fluid dynamics and related fields. Potential sources of funding for faculty and students and their colleagues in industry will be discussed. Recent trends in engineering research supported by the Foundation will be illustrated.

William Olbricht is currently serving as a program manager in the Chemical, Bioengineering, Environmental and Transport Systems (CBET) division in NSF’s Engineering Directorate. He is also a faculty member in the School of Chemical and Biomolecular Engineering at Cornell University in Ithaca, NY. His research involves the application of fluid dynamics to problems in physiology. For the last decade, he has focused on the development and translation of microfabricated devices to improve drug delivery to the brain for the treatment of glioblastoma and other neurological disorders.

Presentation Slides (pdf)


December 7


Turbulence Prediction in Aeronautics and Neighboring Fields

  • Philippe Spalart, Ph.D.
    Senior Technical Fellow, The Boeing Company.

Turbulence prediction in real life is considered, beginning with the orders of magnitude involved, and the nature and paradoxes of Reynolds averaging and the (RANS) turbulence models based on it. It is argued again that regions of massive separation greatly benefit from Large-Eddy Simulation, as opposed to RANS modeling, which is the core idea of Detached-Eddy Simulation. The competition between RANS and LES is revisited, especially given the trend for Moore's Law to weaken considerably in this decade, and probably permanently. We find that a pure LES treatment of a full-size aerospace system will be out of reach for most of this century, due to large areas of thin boundary layer. However, LES will be initiated inside the attached boundary layer, motivated by the thought that even flow modules such as a shock-boundary-layer interaction will defeat RANS models when high accuracy is required. This involves creating synthetic "LES content" in the boundary layer. Thus, the treatment of the future is an extension of DES, with the region entrusted to RANS gradually shrinking as computing power rises.

Philippe Spalart studied Math and Engineering in Paris, and obtained an Aerospace PhD at Stanford/NASA-Ames in 1982. Still at Ames, he then conducted DNS of transitional and turbulent boundary layers. After moving to Boeing in 1990, he created the Spalart-Allmaras one-equation RANS model. He wrote a review article and co-holds a patent on airplane trailing vortices. In 1997 he proposed the Detached-Eddy Simulation approach, blending RANS and LES to address separated flows at high Reynolds numbers at a manageable cost. Recent work includes RANS modeling, jet and airframe noise, and theoretical contributions in classical aerodynamics.

Presentation Slides (pdf)