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X-WR-CALDESC:Events for Department of Aerospace Engineering
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TZID:Asia/Kolkata
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TZOFFSETFROM:+0530
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DTSTART:20240101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20240627T153000
DTEND;TZID=Asia/Kolkata:20240627T163000
DTSTAMP:20261021T094902
CREATED:20240627T053941Z
LAST-MODIFIED:20240803T060152Z
UID:10000010-1719502200-1719505800@aero.iisc.ac.in
SUMMARY:[MTech(Res) Colloquium] Sub-mesoscale modeling of woven fabrics using VAM-based geometrically-exact beam model
DESCRIPTION:In this work\, a sub-mesoscale model of a woven fabric is developed using finite element methods. The yarns are modeled as beam elements that move freely in space and undergo large deformations and rotations. The geometrically-exact beam theory (GEBT) used to model composite beams of arbitrary cross sections is considered to model the yarns. The variational asymptotic method (VAM) offers the advantage of modeling beams of arbitrary cross sections. A surface-to-surface contact model is developed\, considering that the contact occurs at a point on the surface. The robustness of the contact model is tested by designing a patch test. The mesoscale model is validated using experimental results of biaxial tests performed on a plain glass weave woven fabric. The biaxial simulation is performed by varying the number of yarns in the mesoscale model to study the behavior of the model and demonstrate a representative volume element (RVE). The yarns are made up of fibers twisted together. An isotropic model is an approximation that works well on the mesoscale\, but a more general model is needed to include fiber-level information. Most microscale models use technologically expensive micro-CT scans. There are powerful homogenization techniques\, such as variational asymptotic homogenization (VAH)\, that can be leveraged to develop homogenized properties of the yarn by including fiber-level information. The use of VAH includes more physics into the model with minimal effort. A novel alternative model to a woven fabric is developed using VAM to include microscale information. The tools like cross-sectional analysis\, GEBT\, and VAH are used to study the behavior of woven fabrics with different coatings. The model can be extended by introducing friction between yarns in the contact. Further\, the uncertainty in the input parameters can be quantified by propagating the uncertainty through the system using uncertainty quantification (UQ) techniques. \n  \n\nSpeaker: R ADHITHYA
URL:https://aero.iisc.ac.in/event/mtechres-colloquium-sub-mesoscale-modeling-of-woven-fabrics-using-vam-based-geometrically-exact-beam-model/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2024/04/Thesis-Colloquium-Defence.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20240614T160000
DTEND;TZID=Asia/Kolkata:20240614T170000
DTSTAMP:20261021T094902
CREATED:20240614T061338Z
LAST-MODIFIED:20240803T061531Z
UID:10000015-1718380800-1718384400@aero.iisc.ac.in
SUMMARY:Design and characterization of periodic scatterers for noise insulation
DESCRIPTION:The array of periodic scatterers is known as sonic crystal at present and sonic crystal is the most cost-effective solution for a “noise barrier” because of its acoustic attenuation due to size\, geometry\, and periodic arrangement of scatterers. Porous materials that are commonly used for sound absorption have poor sound insulation capability. In this work\, rigid scatterers are installed periodically inside porous materials to improve their transmission loss (TL) with the Bragg diffraction. The Delany-Bazley impedance model is used to model the porous material and the transfer matrix method is adopted to calculate the TL of the mixed structure in a duct. Simulation results with a different number of scatterers and porous materials with different airflow resistivity show that the TL of porous materials can be increased significantly with periodically arranged scatterers. The decoupled analysis reveals that the TL of the mixed structure is larger than the sum of the TL of individual components in most frequency bands\, except that around the first Bragg resonance frequency. Afterwards\, the insertion loss (IL) of two types of finite size structures constructed by installing two parallel porous sheets within rows of periodic scatterers is investigated in free field. Next\, the free field insertion loss (IL) and echo reduction (ER) are calculated for finite size periodic scatterers via time domain simulations in a room environment where the walls of the room are acoustically reflective. A spectrally dense short pulse is used as a sound source and the time domain pulse separation technique is devised to calculate the IL and ER of finite size periodic scatterers. The key discovery of the research is that the calculated IL and ER of periodic cylindrical scatterers in a room environment agree to results obtained from the free field simulations which are also imitable experimentally. Next\, the experiments are conducted in a room environment with periodic cylindrical scatterers. A loudspeaker is used as a sound source. The signal synthesis technique is demonstrated to generate the desired short pulse from a loudspeaker for measurement in given environment followed by measurements which agree to simulation results. \n  \nSpeaker: Dr. Dibya Prakash Jena \nBiography: Dr. Dibya Prakash Jena is an expert in artificial metamaterials\, condition monitoring\, and acoustics\, vibration and noise control having wide experience in industry and academia. He has been awarded the DIN Young Visiting Fellowship 2022 and the Honorary Research Fellow of the University of Technology Sydney. He has over 32 journal publications\, 4 patents\, 2 book chapters and 12 conference publications.
URL:https://aero.iisc.ac.in/event/design-and-characterization-of-periodic-scatterers-for-noise-insulation/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2024/04/AE-Seminar.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20240313T073000
DTEND;TZID=Asia/Kolkata:20240313T203000
DTSTAMP:20261021T094902
CREATED:20240312T225849Z
LAST-MODIFIED:20240803T053029Z
UID:10000003-1710315000-1710361800@aero.iisc.ac.in
SUMMARY:[PhD Colloquium] Asymptotic Modelling of Carbon Nanotube (CNT) and CNT-reinforced composite structures using strain gradient formulations
DESCRIPTION:Carbon nanotubes (CNTs) have garnered attention for their remarkable mechanical\, thermal\, and electrical properties\, making them valuable in various applications. CNTs are particularly advantageous in aerospace structures as reinforcements in polymer matrix composites\, enhancing structural strength while reducing weight. Furthermore\, they offer the potential for multifunctionality\, integrating structural\, thermal\, and electrical functionalities within components like wings. However\, accurately modelling CNT behaviour poses challenges\, especially considering their application in larger-scale aerospace structures. While accurate\, molecular dynamics and molecular structural mechanics are computationally intensive and limited in length scale. In this context\, the present research proposes reduced-order continuum structural models using the Variational Asymptotic Method (VAM) to study CNT and its composite structures while incorporating length scale effects using strain-gradient formulations. \nUsing VAM\, single-walled CNTs (SWCNTs) were first analysed by considering them as straight\, hollow\, circular tubes in a local continuum framework. This tube model accounts for the geometrically nonlinear behaviour of standalone CNT when subjected to bending and buckling loads. Cross-sectional ovalisation leading to nonlinear bending and buckling behaviour has been studied. Combined loading cases of bending and compression and torsion and compression and bending and torsion have been examined. The study aims to provide insights into the 3-D nonlinear deformation behaviour of SWCNTs\, offering a more efficient approach for evaluating CNTs in aerospace composite applications. \nIn the next step\, recognising the significance of the structure’s small size (such as used in MEMS\, NEMS\, and sensors)\, the non-classical theories\, such as the Modified Strain Gradient Theory\, which account for the size effect in the material\, have been employed to develop a pioneering beam and plate models tailored for CNT-reinforced composite structures. Emphasising the critical nature of size effects\, characterised by length scale parameters\, this study delves into the nuances of the length scale effects in nanoscale structures. To develop the asymptotically-correct strain-gradient beam model\, a prismatic beam with a rectangular cross section has been considered to derive zeroth-order and subsequent higher-order models while capturing the strain-gradient effects. Notably\, this work is the first application of non-classical theories in developing VAM-based beam models. Different orders for length scale parameters have been considered\, and the validity of each choice is scrutinised\, followed by guidance on the appropriate choice of the length scale parameters. \nFollowing the development of the strain-gradient beam model\, a modified strain gradient theory-based plate model has also been developed using VAM\, which is again a first-of-its-kind work in the context of VAM and reduced-order structural models. Using the variational methods\, fourth-order ordinary differential equations were obtained for the non-classical case\, and similarly\, an additional set of boundary conditions (non-classical) were also derived. The warping solutions and the plate stiffnesses are obtained by solving these governing differential equations and boundary conditions. It was noted that the material length scale parameters appear only in the bending and twist stiffness terms. Further\, the classical results can be derived by setting the material length scale parameters as zero. Zeroth- and first-order approximations have been derived\, followed by detailed validation of the results with literature for bending and buckling load cases. Parametric studies involving variations in thickness and plate width have been conducted to assess their influence on mechanical behaviour. The developed plate model is then applied to CNT-reinforced composites\, and their bending and buckling studies have been carried out. The parametric studies have also considered evaluating all influencing parameters like CNT volume fraction\, material length scale parameter\, plate thickness and width. \n  \nSpeaker: Renuka Sahu
URL:https://aero.iisc.ac.in/event/asymptotic-modelling-of-carbon-nanotube-cnt-and-cnt-reinforced-composite-structures-using-strain-gradient-formulations/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:Thesis Colloquium / Defence
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2024/04/Thesis-Colloquium-Defence.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20240304T200000
DTEND;TZID=Asia/Kolkata:20240304T213000
DTSTAMP:20261021T094902
CREATED:20240324T084614Z
LAST-MODIFIED:20240802T165719Z
UID:10000002-1709582400-1709587800@aero.iisc.ac.in
SUMMARY:Nonequilibrium reacting flows: First principles based modeling for chemical kinetics and hydrodynamics
DESCRIPTION:Predicting state of the gas hitting vehicles flying at hypersonic speeds (Mach ~5) is challenging and is an exciting area of research. Hypersonic flows create shock waves\, which compress and heat the surrounding gas to high-temperatures\, nearly thousands of Kelvins. At these high temperatures\, air molecules (nitrogen and oxygen) dissociate into atomic species. Predicting the extent of dissociation and recombination of atomic species is important since the state of the gas near the vehicle surface determines heating rates and gas-surface chemistry that damages the heat shield. Since experiments in ground test facilities do not mimic such extreme flight conditions\, numerical simulation plays an important role. Predictive numerical simulations require accurate reaction chemistry models. Computational models developed thus far range from simple empirical models fit to limited experimental data to models with millions of input parameters that track individual quantized energy state transitions. The level of model fidelity required for accurate engineering analysis remains an open question of active research. Models coupling internal energy and dissociation chemistry tend to be developed at either the kinetic scale or the continuum scale. In this work\, we develop new nonequilibrium models for shock heated flows that are analytically consistent between kinetic and continuum scales and are based on recent ab-initio data\, applicable to large-scale CFD and direct simulation Monte Catlo (DSMC) simulations. \nNonequilibrium Hydrodynamics: The Navier-Stokes equations\, typically employed even at strong non-equilibrium conditions\, wherein thermodynamic fluxes such as stresses and heat flux vector are based on linear irreversible thermodynamics\, not be accurate in multiscale and multiphysics scenarios encountered in hypersonic flows. Similarly\, the Navier-Stokes equations are known to breakdown in rarefied (low density) gas flows. Therefore\, a new formalism is proposed to circumvent these issues\, which can also benefit\, hybrid methods that can combine continuum description using the Navier-Stokes equations and microscopic description\, necessary for efficient high-fidelity numerical simulations. Other wide range of physics problems such as nano-scale flows\, plasma physics modeling\, and general complex gas flows can also benefit from the proposed new non-equilibrium hydrodynamic formalism. \n  \nSpeaker: Dr. Narendra Singh \nBiography: Dr. Narendra Singh graduated with a PhD (and MS) in Aerospace Engineering (with minor in Mathematics and Chemistry) from University of Minnesota. Narendra obtained his undergraduate degree (with Honors) in MechE from IIT Bombay. In his doctoral thesis\, Narendra developed chemical kinetics models for DSMC and CFD using first principles-based approach. In addition\, Narendra (along with Prof.Agrawal) has developed higher order equations for rarefied and strong nonequilibrium flows\, known as O-13 and O-Burnett equations\, where O ‘refers’ to Onsager due to the consistency of equations with Onsager’s reciprocity principle. Narendra Singh did his 2 years postdoc in MechE at Stanford\, where his research spanned particle-laden flows\, carbon sequestration\, and ultrafast chemistry at SLAC. Currently\, he is a postdoc research associate at Center for Hypersonic\, UIUC\, and developing reduced order models for chemical kinetics. \n 
URL:https://aero.iisc.ac.in/event/nonequilibrium-reacting-flows-first-principles-based-modeling-for-chemical-kinetics-and-hydrodynamics/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2024/04/AE-Seminar.jpg
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20240205T140000
DTEND;TZID=Asia/Kolkata:20240205T150000
DTSTAMP:20261021T094902
CREATED:20240324T082740Z
LAST-MODIFIED:20240803T052011Z
UID:10000001-1707141600-1707145200@aero.iisc.ac.in
SUMMARY:Innovations in Aerospace Systems – Current Research (including Artificial Intelligence) and Future Challenges
DESCRIPTION:Aircraft and spacecraft are highly complex systems\, comprising various subsystems such as flight control\, propulsion\, and power. These subsystems feature Multiple Input & Multiple Output (MIMO) configurations and exhibit highly nonlinear characteristics. Over recent years\, there has been a growing demand for aerospace systems with improved performance\, fault tolerance\, and enhanced autonomous capabilities. This presentation explores how fault diagnosis\, prognosis and artificial intelligence can address these requirements. It delves into model-based\, data-driven (artificial intelligence)\, and hybrid approaches\, which have been proposed for fault diagnosis and prognosis. Furthermore\, the author has proposed novel methods to meet these evolving demands. These innovative techniques\, including the Covariance-based adaptive unscented Kalman filter (CAUKF)\, Binary grid covariance adaptive Kalman filter (GAUKF)\, Reinforced Unscented Kalman Filter (an integration of UKF and Reinforcement Learning techniques)\, and Growing Neural Networks (GNN)\, hold promise for aerospace system enhancement. The presentation will feature case studies illustrating the application of these methods in spacecraft attitude and orbit control systems\, as well as aircraft engines. By examining the latest advancements and methodologies\, attendees will gain insights into the pivotal role these techniques play in enhancing aerospace system reliability and efficiency\, ultimately addressing current research challenges and shaping the trajectory of future aerospace systems. \n  \nSpeaker: Prof. Krishna Dev Kumar \nBiography: Dr. Krishna D. Kumar is a Professor of Aerospace Engineering and Director of Artificial Intelligence for Aerospace Systems (AIAS) Laboratory at Toronto Metropolitan University\, Canada. Additionally\, he is the Founder and President of iSAC Systems Inc\,  a leader inArtificial Intelligence (AI)\, Internet-of-Things (IoT)\, and Smart Systems since 2010. Prof. Kumar has made outstanding contributions with major impact in the areas of spacecraft dynamics and control\, fault diagnosis and prognosis\, artificial intelligence\, and predictive analytics with over 250 publications including 5 books\, 14 intellectual properties\, and four patents. His AI and IoT products have been deployed across diverse industries\, including aerospace\, transportation\, and waste management. His illustrious career boasts several remarkable achievements\, including the development of AI-powered predictive analytics for the NASA Kepler Spacecraft and Aircraft Engines\, the world’s first 100-gram miniature satellite\, and the world’s first miniature IoT monitoring systems for Bombardier Trains\, and Safran Aircraft Landing gears.  Prof. Kumar’s exemplary contributions to the field have been widely recognized with numerous national and international awards\, including the prestigious Canada Research Chair Award\, Ontario Early Researcher Award\, Associate Fellow of American Aeronautics and Astronautics\, Japan Society for the Promotion of Science Fellow\, Japan Science and Technology Agency Fellow\, Member of the International Academy of Astronautics in France\, the Sarwan Sahota Ryerson Distinguished Scholar Award\, and the Eminent Alumnus Award from Veer Surendra Sai University of Technology\, Sambalpur\, India. Furthermore\, Prof. Kumar is the Co-Editor of Acta Astronautica and Transactions of the Japan Society for Aeronautical and Space Sciences.
URL:https://aero.iisc.ac.in/event/innovations-in-aerospace-systems-current-research-including-artificial-intelligence-and-future-challenges/
LOCATION:STC Seminar Hall\, Dept. of Aerospace Engineering
CATEGORIES:AE Seminar
ATTACH;FMTTYPE=image/jpeg:https://aero.iisc.ac.in/wp-content/uploads/2024/04/AE-Seminar.jpg
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