AE Research Publications
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Item Exploration of general aviation aircraft ride comfort related to turbulence(American Institute of Aeronautics and Astronautics Inc, AIAA, 2023) Kliment, Linda K.; Rokhsaz, Kamran; Rafi, MelvinPilot-reported ride quality has been examined and its limitations have been emphasized. Turbulence and load factor intensity have been examined as alternatives for reporting ride quality. The absence of a unified quantitative connection between the two and ride quality has been highlighted through simulation and comparison of the results with recommended levels of each. The possibility of the jerk as a third indicator of ride quality has been introduced. The actual inflight recorded data from two general aviation aircraft has been used to examine this parameter. It has been demonstrated that the load factor alone is not a sufficient indicator for ride quality. It is recommended that a combination of the jerk and load factor may be a better metric for this purpose. © 2023, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Item Sustainable multifunctionality: Bio-inspired printing of nanocellulose aerogel acoustical materials(John Wiley and Sons Inc, 2024) Yang, Guang; Lomte, Amulya; Sharma, Bhisham N.; Lei, Shuting; Lin, DongThe 3D freeze printing (3DFP) of nanocellulose aerogels are demonstrated with large-scale aligned pore orientations as a sustainable alternative to current acoustical materials. In contrast with the unidirectional pore network orientations obtained from current 3DFP techniques, a bidirectional orientation is achieved by using an inhomogeneous printing substrate to alter the thermal gradient within the print volume. The microstructural morphology shows that bidirectional printing results in a 2D pore orientation, with comparatively thinner pore walls and larger pore widths. Acoustic measurements reveal that altering the pore network characteristics significantly affects the acoustical behavior of the printed CNC aerogels; the wider pores allow the bidirectional CNC aerogels to provide higher sound absorption performance at lower frequencies than the unidirectional samples. Notably, both 3D Freeze printed CNC aerogels provide substantially higher sound transmission loss performance as compared to current acoustical materials. The unidirectional pore structure results in CNC aerogels with higher stiffness and improved energy absorption performance, with both 3D freeze printed CNC aerogels outperforming other CNC aerogel materials in their stiffness-to-density ratios. The ability to simultaneously control their pore orientation and macrostructural geometry paves the way for printing complex shaped CNC aerogel structures for multifunctional noise control applications.Item Application of sensor fusion for attitude estimation of an aircraft in approach phase(American Institute of Aeronautics and Astronautics Inc, AIAA, 2024) Kartikeyan, Balaji C.; Steck, James E.; Johnson, Noah; Ahmadabadi, Zahra N.Prior work by the authors was a first step towards development of aircraft-based guidance and navigation sensors to reduce the decision height of a Localizer Performance with Vertical (LPV) approach from 200ft to 0 ft. They developed a vision-based parameter estimation algorithm which performed well when tested in a simulation environment. The current work will improve on this using sensor and information fusion algorithms that combine data from vision, and simulated Inertial Measurement Unit (IMU) in X-plane for position estimation. © 2024 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.Item Effects of manufacturing defects on composite seat pans at static and dynamic strain rates(American Institute of Aeronautics and Astronautics Inc, AIAA, 2024) Bhasin, Akhil; Maichan, Tanat; Gomez, Luis M.; Olivares, Gerardo; Keshavanarayana, Suresh R.The use of composite materials in aircraft primary seat structures has increased and requires additional standards to maintain the current level of aircraft seat safety. The presence of manufacturing defects or service damage could undermine the load-carrying capabilities of these structures at dynamic loading rates. In the current work, the effects of out-of-plane fiber waviness/wrinkle on representative aircraft seatpans has been investigated. The seatpans are tested at both quasi-static and elevated strain rates. The performance of seatpans with defects is compared against pristine seatpans. All the experiments were conducted using a high-rate test frame and were supported with high-speed Digital Image Correlation (DIC). A comparison of load, displacement, strain, and strain rate at failure between different configurations is reported. © 2024 by Akhil Bhasin, NIAR AVET.Item Designing hybrid aerogel-3D printed absorbers for simultaneous low frequency and broadband noise control(Elsevier Ltd, 2024) Xue, Yutong; Nobles, Laura Paige; Sharma, Bhisham N.; Bolton, J. StuartRecent studies have demonstrated that granular aerogels with sub-50 ?m particles surpass conventional acoustic materials like glass fibers and polyurethane foams in low-frequency sound absorption. However, incorporating such granular materials within practical structural solutions remains a challenge. In this study, we use additive manufacturing to overcome this challenge by designing a modular geometry that allows us to encapsulate such granular materials within a 3D printed scaffold. Using the 3D printed porous scaffold provides the added benefits of tunability and durability. Further, we introduce a design methodology and software tool to facilitate the efficient design of such hybrid sound absorbers. The proposed method uses the Johnson-Champoux-Allard model, Biot theory, and the transfer matrix method to model the acoustical behavior of hybrid absorber designs that use layered granular aerogels and 3D printed bulk absorbers. The tool can also be used to inversely characterize the acoustic bulk properties of such materials. We validate the design concept and tool by comparing the model predictions with experimental measurements. Finally, we outline strategies for designing hybrid absorbers that can provide application specific low-frequency and broadband absorption performance within specific frequency ranges, while considering engineering constraints on their total mass and depth. © 2024 The Author(s)