Day :
- Fluid Mechanics, Aerodynamics, Design and Modelling of Aircraft and Helicopter Engines
Chair
Mark N. Callender
Middle Tennessee State University, USA
Session Introduction
George Bye
Bye Aerospace, CO, USA
Title: Electric-powered Flight Training: Disruptive Ops-Costs; Practical Pilot Training
Biography:
George E. Bye, Founder and CEO of Bye Aerospace, is an aviation influencer, innovator and pioneer. He has two decades of experience as an aerospace entrepreneur, engineer, and executive, balancing engineering services with internal development and research of advanced concepts. George has developed several aircraft designs, including a 14-foot wing span solar-electric hybrid UAV, Silent Falcon, now in production. He also conceived the eFlyer and StratoAirNet designs and authored articles for industry journals, textbooks and publications. George holds a B.S. in Engineering from the University of Washington, and is an ATP rated pilot with over 4,000 flying hours.
Abstract:
The primary challenges for flight training to address the global commercial pilot shortage include cost, noise, emissions, and the age of training aircraft (over fifty years old). For the past ten years, Bye Aerospace has been developing electric-powered aircraft, during which time battery-powered technology, electric motors, solar cells, and software that manages electric propulsion systems have advanced significantly. Flight endurance can now be measured in hours, rather than minutes. Efficient light-weight electric motors and controllers are combined with lithium-ion batteries whose cells are configured in packs, which can be recharged quickly and efficiently. The second element is a sleek, light carbon fiber structure, low-drag fuselage with efficient long-wing (high aspect ratio) advanced aerodynamics. Bye Aerospace is combining these elements to develop the two-seat eFlyer 2 aircraft, which will be certified under Federal Aviation Regulations (FAR) Part 23, day-night visual flight rules (VFR), and later instrument flight rules (IFR) with a target gross weight of 2,000 pounds. The eFlyer 2’s advanced aerodynamics result in a high-performance aircraft that will not compromise performance, given a projected max speed of 135 knots and climb rate of over 1,000 feet per minute.
Steven Y. Liang
Georgia Institute of Technology, Atlanta, GA 30332, USA
Title: Computational Mechanics of Metal Additive Manufacturing
Biography:
Steven Y. Liang holds a 1987 Ph.D. in Mechanical Engineering from University of California at Berkeley, and was Georgia Tech’s founding Director of Precision Machining Research Consortium and Director of Manufacturing Education Program and has been Morris M. Bryan, Jr. Professor for Advanced Manufacturing Systems. Dr. Liang's technical interests lie in advanced manufacturing, precision engineering, and materials-centric production, and in these areas he has supervised over 80 post-doctoral studies, Ph.D. dissertations, and M.S. theses and has authored in excess of 400 book chapters, archival journal papers, and professional conference articles. He has delivered more than 60 keynotes and invited seminars at industries, peer institutions, and conferences in over 20 countries on manufacturing science and technology. Dr. Liang served as President of North American Manufacturing Research Institution and Chair of Manufacturing Engineering Division of The American Society of Mechanical Engineers. Dr. Liang is the recipient of Robert B. Douglas Outstanding Young Manufacturing Engineer Award of SME, Ralph R. Teetor Education Award of SAE, Blackall Machine Tool and Gage Award of ASME, Milton C. Shaw Manufacturing Research Medal of ASME, etc. Dr. Liang is a fellow of both ASME and SME.
Abstract:
Recognized as a milestone technology, additive manufacturing (AM) has promised unparalleled part complexity and small-batch cost effectiveness. However the control of AM throughput and build quality has been challenged by the deficiency in process mechanics understanding to support systematic prediction, monitoring, and optimization. a fair amount of experimental observations and numerical FEM studies have been pursued and documented, but they unfortunately suffer from the need of trial-and-errors and the lack of knowledge extendibility. Aiming at a scientific scope and engineering applicability way beyond experimentation and FEM, physics-based analytical modeling flanked on computational mechanics of materials is developed at Georgia Tech and presented herein to quantify the thermodynamics, heat-transfer, and materials thermos-physical behaviors in powder bed and powder feed metal AM. Closed-form solutions have been established for temperature distributions. Subsequently the corresponding thermal stresses, residual stresses, microstructure, build distortion, and mechanical properties are expressed as explicit and algebraic functions of process parameters and powder properties, factoring in the effects of scan strategy, and powder packing. Bounded-medium solutions have been established by folding boundary thermal balance conditions into the traditional semi-infinite medium solutions to compute material responses near build edges without iterations. Extensive experimental validations are also presented. The solutions deliver more penetrating physics of the metal AM process, showing much higher accuracy, and costing less than 1% time of commercial FEM’s, thus promising effective prediction and optimization for first-and-every-print-correct AM.
Tom Hoffman
California Institute of Technology, Pasadena CA
Title: InSight: Revealing the Interior of Mars
Biography:
Tom Hoffman is the project manager of the InSight mission which successfully landed on Mars in November 2018. Tom has been the Project Manager since the proposal phase of InSight in 2011. Prior to his role on InSight, Tom was the Deputy Project Manager for the GRAIL mission, a Discovery mission which gravity mapped the moon. Over the past 30+ years at the Jet Propulsion Laboratory, Tom has worked on several other NASA flight projects including Voyager Operations, Cassini, Stardust, Spirit/Opportunity Mars rovers and several Earth scatterometers, as well as a several technology development efforts.
Abstract:
The InSight mission to Mars was selected as part of the NASA Discovery portfolio in 2012. InSight was launched on May 5, 2018 as the first interplanetary mission from Vandenberg Air Force Base in California and Landed successfully on Mars on November 26, 2018. The project management, Principal Investigator, systems engineering and operations were led primarily by the Jet Propulsion Laboratory. The mission utilized a heritage spacecraft and Lander from Lockheed Martin which had successfully landed on Mars before as the Phoenix mission. Significant changes were made to the Lander structure, power system and Entry, Descent and Landing system to adjust to the different mission parameters. Importantly, InSight is the first solar powered stationary lander designed to last a full Mars year. The main science instruments were contributed by CNES and DLR and were designed to provide the first glimpse into the Martian interior using seismometry, heat flux and geodesy. A particular challenge to InSight was development of the first system to robotically deploy these instruments from a Lander to the surface of another planet. Early results include the first recorded sounds from Mars and indications that the science instruments are performing nominally. This talk will describe these systems, detail some of the unique challenges of the InSight mission, and provide information on some of the early operational results.
Weiqiu Chen
Zhejiang University, Hangzhou 310027, China
Title: Tuning Bandgaps in Soft Phononic Plates by Small Deformation
Biography:
Professor Weiqiu Chen received his BS and PhD degrees from Zhejiang University in 1990 and 1996, respectively. He worked as a postdoctoral research associate at The University of Tokyo during 1997-1999. He was promoted as an associate professor in 1999 and a full professor in 2000. He has engaged himself in mechanics of smart materials/structures and vibration/waves in structures for over twenty years. He has co-authored over 350 peer-reviewed journal articles and three monographs. He now serves as the editorial member/associate editor-in-chief of 12 academic journals including Mechanics of Advanced Materials and Structures, International Journal of Mechanical Sciences, Journal of Thermal Stresses, and Composite Structures.
Abstract:
In this work, a phononic crystal plate made of soft material with resonant units is proposed. Each resonant unit consists of a mass which is connected to the perforated plate by thin beams. Finite element method is employed to study the deformation and the dispersion behavior of such structure when subject to external mechanical loadings. Obvious complete band gaps are found to even exist in the intact structure without any mechanical loading. The evolution of band gaps under stretching is systematically revealed. Results show that remarkable tunability of bandgaps with small pre-stretch or extension is realized when strong resonance appears for some particular modes. The resonance frequency is mainly affected by the mass of the resonator and the stiffness of the connecting beams. In the proposed structure, the stiffness of the connecting beams can be substantially increased under a small pre-stretch. As a result, the resonance frequencies of resonant modes are increased, giving rise to a remarkable modification of the band gaps, while the geometry of the structure is nearly unchanged.