Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Computational Fluid Dynamics (3)
- Ablative Materials (2)
- Aircraft Design (2)
- Bending Moment (2)
- Computational Methods (2)
-
- Lift Coefficient (2)
- Thermal Protection System (2)
- Thickness to Chord Ratio (2)
- Wingtip Device (2)
- Ablation (1)
- Acoustics (1)
- Aerodynamic (1)
- Aerodynamic Properties (1)
- Aeroelasticity (1)
- Aerostructural optimisation (1)
- Aerothermodynamics (1)
- Aircraft Configurations (1)
- Aircraft system identification (1)
- Airplane safety (1)
- Artificial Compressibility Method (1)
- Backward Euler Method (1)
- Band Model (1)
- Blended Wing Body (1)
- Carbon fiber-reinforced plastic composite (1)
- Charring (1)
- Compressibility (1)
- Control theory; semi-active control; vibration; wind turbines; multiple hazards; clean energy; smart structures; optimization; damper (1)
- Critical Mach Number (1)
- Deposition (1)
- EKF (1)
- Publication
Articles 1 - 21 of 21
Full-Text Articles in Mechanical Engineering
Numerical Investigation On The Effect Of Spectral Radiative Heat Transfer Within An Ablative Material, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin
Numerical Investigation On The Effect Of Spectral Radiative Heat Transfer Within An Ablative Material, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin
Mechanical Engineering Faculty Publications
The spectral radiative heat flux could impact the material response. In order to evaluate it, a coupling scheme between KATS - MR and P1 approximation model of radiation transfer equation (RTE) is constructed and used. A Band model is developed that divides the spectral domain into small bands of unequal widths. Two verification studies are conducted: one by comparing the simulation computed by the Band model with pure conduction results and the other by comparing with similar models of RTE. The comparative results from the verification studies indicate that the Band model is computationally efficient and can be used to …
Impact Of Surface And Pore Characteristics On Fatigue Life Of Laser Powder Bed Fusion Ti–6al–4v Alloy Described By Neural Network Models, Seunghyun Moon, Ruimin Ma, Ross Attardo, Charles Tomonto, Mark Nordin, Paul Wheelock, Michael Glavicic, Maxwell Layman, Richard Billo, Tengfei Luo
Impact Of Surface And Pore Characteristics On Fatigue Life Of Laser Powder Bed Fusion Ti–6al–4v Alloy Described By Neural Network Models, Seunghyun Moon, Ruimin Ma, Ross Attardo, Charles Tomonto, Mark Nordin, Paul Wheelock, Michael Glavicic, Maxwell Layman, Richard Billo, Tengfei Luo
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this study, the effects of surface roughness and pore characteristics on fatigue lives of laser powder bed fusion (LPBF) Ti–6Al–4V parts were investigated. The 197 fatigue bars were printed using the same laser power but with varied scanning speeds. These actions led to variations in the geometries of microscale pores, and such variations were characterized using micro-computed tomography. To generate differences in surface roughness in fatigue bars, half of the samples were grit-blasted and the other half were machined. Fatigue behaviors were analyzed with respect to surface roughness and statistics of the pores. For the grit-blasted samples, the contour …
Exploring Dft+U Parameter Space With A Bayesian Calibration Assisted By Markov Chain Monte Carlo Sampling, Pedram Tavadze, Reese Boucher, Guillermo Avendaño-Franco, Keenan X. Kocan, Sobhit Singh, Viviana Dovale-Farelo, Wilfredo Ibarra-Hernández, Matthew B. Johnson, David S. Mebane, Aldo H. Romero
Exploring Dft+U Parameter Space With A Bayesian Calibration Assisted By Markov Chain Monte Carlo Sampling, Pedram Tavadze, Reese Boucher, Guillermo Avendaño-Franco, Keenan X. Kocan, Sobhit Singh, Viviana Dovale-Farelo, Wilfredo Ibarra-Hernández, Matthew B. Johnson, David S. Mebane, Aldo H. Romero
Faculty & Staff Scholarship
The density-functional theory is widely used to predict the physical properties of materials. However, it usually fails for strongly correlated materials. A popular solution is to use the Hubbard correction to treat strongly correlated electronic states. Unfortunately, the values of the Hubbard U and J parameters are initially unknown, and they can vary from one material to another. In this semi-empirical study, we explore the U and J parameter space of a group of iron-based compounds to simultaneously improve the prediction of physical properties (volume, magnetic moment, and bandgap). We used a Bayesian calibration assisted by Markov chain Monte Carlo …
Graphene Flake Self-Assembly Enhancement Via Stretchable Platforms And External Mechanical Stimuli, Harrison A. Loh, Claudio Marchi, Luca Magagnin, Konstantinos A. Sierros
Graphene Flake Self-Assembly Enhancement Via Stretchable Platforms And External Mechanical Stimuli, Harrison A. Loh, Claudio Marchi, Luca Magagnin, Konstantinos A. Sierros
Faculty & Staff Scholarship
While the green production and application of 2D functional nanomaterials, such as graphene flakes, in films for stretchable and wearable technologies is a promising platform for advanced technologies, there are still challenges involved in the processing of the deposited material to improve properties such as electrical conductivity. In applications such as wearable biomedical and flexible energy devices, the widely used flexible and stretchable substrate materials are incompatible with high-temperature processing traditionally employed to improve the electrical properties, which necessitates alternative manufacturing approaches and new steps for enhancing the film functionality. We hypothesize that a mechanical stimulus, in the form of …
Thermal Barrier Coating For Carbon Fiber-Reinforced Composite Materials, Heejin Kim, Jungwon Kim, Juhyeong Lee, Min Wook Lee
Thermal Barrier Coating For Carbon Fiber-Reinforced Composite Materials, Heejin Kim, Jungwon Kim, Juhyeong Lee, Min Wook Lee
Mechanical and Aerospace Engineering Faculty Publications
Carbon fiber-reinforced plastic (CFRP) composites are widely employed in lightweight and high performance applications including supercars, aero-vehicles, and space components. However, although carbon fibers are thermally stable, the low thermal endurance of the matrix materials remains a critical problem in terms of the performance of the material. In this study, we proposed a new, Al2O3-based thermal barrier coating (TBC) for the CFRP composites. The TBC comprised α-phase Al2O3 particles with a mean diameter of 9.27 μm. The strong adhesion between the TBC and the CFRP substrate was evaluated using a three point bending …
Comparison Of Theoretical And Multi-Fidelity Optimum Aerostructural Solutions For Wing Design, Jeffrey D. Taylor, Douglas F. Hunsaker
Comparison Of Theoretical And Multi-Fidelity Optimum Aerostructural Solutions For Wing Design, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
As contemporary aerostructural research for aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the …
Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang
Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Coalescence of Two Nanobubbles (NBs) in Water is a Process of Great Importance to Many Industrial Applications. in This Work, We Study the Coalescence of Two Equal-Sized Nitrogen NBs in Water using Molecular Dynamics (MD) Simulations and Continuum-Based Theoretical Analysis. We Vary the NB Diameter from 30 to 50 Nm and Study the Coalescence Characteristics Including the Expansion Speed of the Capillary Bridge between Two Coalescing NBs, the Dynamic Regime of NB Coalescence, the Diameter of Fully Merged NBs, and the Temperature Variation of NBs during the Coalescence Process. for All Cases, We Show the MD Simulation Results Can …
Fully Coupled Internal Radiative Heat Transfer For The 3d Material Response Of Heat Shield, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin
Fully Coupled Internal Radiative Heat Transfer For The 3d Material Response Of Heat Shield, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin
Mechanical Engineering Faculty Publications
The radiative transfer equation (RTE) is strongly coupled to the material response code KATS. A P-1 approximation model of RTE is used to account for radiation heat transfer within the material. First, the verification of the RTE model is performed by comparing the numerical and analytical solutions. Next, the coupling scheme is validated by comparing the temperature profiles of pure conduction and conduction coupled with radiative emission. The validation study is conducted on Marschall et al. cases (radiant heating, arc-jet heating, and space shuttle entry), 3D Block, 2D IsoQ sample, and Stardust Return Capsule. The validation results agree well for …
Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair
Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair
Publications and Research
Lightning strike protection (LSP) have recently been a newly developing field particularly with the emergence of graphene thin film integration into carbon fiber composite structures. This technology has a widespread application in airplanes, wind turbines, and other instruments which are susceptible to frequent lightning strikes. Electrical discharge of the instrument in a safe manner is vital for the safety of the passengers (in the case of flights) as well as the integrity of the aircraft structures because of their specific mechanical and structural properties, which are essential for their functioning. The purpose of the study is to fabricate graphene thin …
Bibliometric Analysis On Artificial Compressibility Method Based Cfd Simulations, Bhavna Hemraj Joshi Miss, Chandrakant R. Sonawane Dr, Priyambada Bada Praharaj Mrs, Anand Kumar Pandey Dr
Bibliometric Analysis On Artificial Compressibility Method Based Cfd Simulations, Bhavna Hemraj Joshi Miss, Chandrakant R. Sonawane Dr, Priyambada Bada Praharaj Mrs, Anand Kumar Pandey Dr
Library Philosophy and Practice (e-journal)
This bibliometric analysis in this paper aims to study the quantitative progress done in the artificial compressibility (AC) method-based CFD simulation and analyze its potential in solving incompressible flow simulations in computational fluid dynamics smoothly. The sector of CFD is enhancing more and more maturely due to advancements in computing architecture, numerical methods, and simulation tools. There have been various attempts to solve the pressure-velocity coupling issue in the Navier-Stokes equation. The artificial compressibility method (ACM), as opposed to pressure-correction methods, solves the incompressible equation in a non-segregated manner. With the introduction of the ACM, the system of the equation …
Low-Fidelity Method For Rapid Aerostructural Optimisation And Design-Space Exploration Of Planar Wings, Jeffrey D. Taylor, Doug F. Hunsaker
Low-Fidelity Method For Rapid Aerostructural Optimisation And Design-Space Exploration Of Planar Wings, Jeffrey D. Taylor, Doug F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
During early phases of wing design, analytic and low-fidelity methods are often used to identify promising design concepts. In many cases, solutions obtained using these methods provide intuition about the design space that is not easily obtained using higher-fidelity methods. This is especially true for aerostructural design. However, many analytic and low-fidelity aerostructural solutions are limited in application to wings with specific planforms and weight distributions. Here, a numerical method for minimising induced drag with structural constraints is presented that uses approximations that apply to unswept planar wings with arbitrary planforms and weight distributions. The method is applied to the …
Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee
Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee
Faculty Publications
During their lifecycle, wind turbines can be subjected to multiple hazard loads, such as high-intensity wind, earthquake, wave, and mechanical unbalance. Excessive vibrations, due to these loads, can have detrimental effects on energy production, structural lifecycle, and the initial cost of wind turbines. Vibration control by various means, such as passive, active, and semi-active control systems provide crucial solutions to these issues. We developed a novel control theory that enables semi-active controller tuning under the complex structural behavior and inherent system nonlinearity. The proposed theory enables the evaluation of semi-active controllers’ performance of multi-degrees-of-freedom systems, without the need for time-consuming …
On The Applicability Of Continuum Scale Models For Ultrafast Nanoscale Liquid-Vapor Phase Change, Anirban Chandra, Zhi Liang, Assad A. Oberai, Onkar Sahni, Pawel Keblinski
On The Applicability Of Continuum Scale Models For Ultrafast Nanoscale Liquid-Vapor Phase Change, Anirban Chandra, Zhi Liang, Assad A. Oberai, Onkar Sahni, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Continuum Methods Are Efficient in Modeling Multi-Phase Flow at Large Time and Length Scales, However, their Applicability to Nanoscale Systems and Processes is Questionable. When Mean Free Path and Average Time between Atomic Collisions Are Comparable to the Characteristic Length and Time Scales of Interest, the Continuum Hypothesis Approaches its Spatial and Temporal Limit. Here We Discuss the Implications of Modeling Such a Limiting Problem Involving Liquid-Vapor Phase Change using Continuum Equations of Mass, Momentum, and Energy Conservation. Our Results Indicate that, Continuum Conservation Laws Can Correctly Represent the Dynamics of the Specific Problem of Interest Provided Appropriate Constitutive Relations …
Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin
Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin
Mechanical Engineering Faculty Publications
To evaluate the effects of spallation on ablative material, it is necessary to evaluate the mass loss. To do so, a Lagrangian particle trajectory code is used to reconstruct trajectories that match the experimental data for all kinematic parameters. The results from spallation experiments conducted at the NASA HYMETS facility over a wedge sample were used. A data-driven adaptive methodology was used to adapts the ejection parameters until the numerical trajectory matches the experimental data. The preliminary reconstruction results show that the size of the particles seemed to be correlated with the location of the ejection event. The size of …
Sensitivity And Estimation Of Flying-Wing Aerodynamic, Propulsion, And Inertial Parameters Using Simulation, Jaden Thurgood, Douglas F. Hunsaker
Sensitivity And Estimation Of Flying-Wing Aerodynamic, Propulsion, And Inertial Parameters Using Simulation, Jaden Thurgood, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
This paper explores the difficulties of aircraft system identification, specifically parameter estimation, for a rudderless aircraft. A white box method is used in conjunction with a nonlinear six degree-of-freedom aerodynamic model for the equations of motion in order to estimate 33 parameters that govern the aerodynamic, inertial, and propulsion forces within the mathematical model. The analysis is conducted in the time-domain of system identification. Additionally, all the parameters are estimated using a single flight rather than a series of shorter flights dedicated to estimating specific sets of parameters as is typically done. A final flight plan is developed with a …
Characterization Of The Common Research Model Wing For Low-Fidelity Aerostructural Analysis, Jeffrey D. Taylor, Douglas F. Hunsaker
Characterization Of The Common Research Model Wing For Low-Fidelity Aerostructural Analysis, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
A characterization of the Common Research Model (CRM) wing for low-fidelity aerostructural optimization is presented. The geometric and structural properties are based on the CAD geometries and finite-element models for the CRM wing and the undeflected Common Research Model Wing (uCRM). Three approximations are presented for the elastic axis from previously-published studies on wing boxes similar to the uCRM, and approximations of the flexural and torsional rigidity are presented from a previously-published study using the uCRM wing. The characterization presented in this paper is intended to be used within low-fidelity aerostructural analysis tools to facilitate rapid design optimization and exploratory …
Comparison Of Theoretical And High-Fidelity Aerostructural Solutions, Jeffrey D. Taylor, Douglas F. Hunsaker
Comparison Of Theoretical And High-Fidelity Aerostructural Solutions, Jeffrey D. Taylor, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
As contemporary aerostructural research in aircraft design trends toward high-fidelity computational methods, aerostructural solutions based on theory are often neglected or forgotten. In fact, in many modern aerostructural wing optimization studies, the elliptic lift distribution is used as a benchmark in place of theoretical aerostructural solutions with more appropriate constraints. In this paper, we review several theoretical aerostructural solutions that could be used as benchmark cases for wing design studies, and we compare them to high-fidelity solutions with similar constraints. Solutions are presented for studies with 1) constraints related to the wing integrated bending moment, 2) constraints related to the …
Simulation And Modeling Of Hypersonic Turbulent Boundary Layers Subject To Adverse Pressure Gradients Due To Concave Streamline Curvature, Gary L. Nicholson, Junji Huang, Lian Duan, Meelan M. Choudhari
Simulation And Modeling Of Hypersonic Turbulent Boundary Layers Subject To Adverse Pressure Gradients Due To Concave Streamline Curvature, Gary L. Nicholson, Junji Huang, Lian Duan, Meelan M. Choudhari
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Direct numerical simulations (DNS) of adverse-pressure-gradient turbulent boundary layers over a planar concave wall are presented for a nominal freestream Mach number of 5, with the objective of assessing the limitations of the currently available Reynolds-averaged Navier-Stokes (RANS) models. The wall geometry and flow conditions of the DNS are representative of the experimental data for a Mach 4.9 turbulent boundary layer that was tested on a two-dimensional planar concave wall model in the high-speed blow-down wind tunnel located at the National Aerothermochemistry Laboratory at Texas A&M University (TAMU). The DNS was validated against the experimental results of TAMU for the …
Fluid-Wall Interactions In Pseudopotential Lattice Boltzmann Models, Cheng Peng, Luis F. Ayala, Orlando M. Ayala
Fluid-Wall Interactions In Pseudopotential Lattice Boltzmann Models, Cheng Peng, Luis F. Ayala, Orlando M. Ayala
Engineering Technology Faculty Publications
Designing proper fluid-wall interaction forces to achieve proper wetting conditions is an important area of interest in pseudopotential lattice Boltzmann models. In this paper, we propose a modified fluid-wall interaction force that applies for pseudopotential models of both single-component fluids and partially miscible multicomponent fluids, such as hydrocarbon mixtures. A reliable correlation that predicts the resulting liquid contact angle on a flat solid surface is also proposed. This correlation works well over a wide variety of pseudopotential lattice Boltzmann models and thermodynamic conditions.
Non-Equilibrium Behavior Of Large-Scale Axial Vortex Cores, Robert L. Ash, Irfan R. Zardadkhan
Non-Equilibrium Behavior Of Large-Scale Axial Vortex Cores, Robert L. Ash, Irfan R. Zardadkhan
Mechanical & Aerospace Engineering Faculty Publications
A logical basis for incorporating pressure non-equilibrium and turbulent eddy viscosity in an incompressible vortex model is presented. The infrasonic acoustic source implied in our earlier work has been examined. Finally, this non-equilibrium turbulent vortex core is shown to dissipate mechanical energy more slowly than a Burgers vortex, helping us to explain the persistence of axial vortices in nature. Recent molecular dynamics simulations replicate aspects of this non-equilibrium pressure behavior.
Evaluation Of Murrell’S Ekf-Based Attitude Estimation Algorithm For Exploiting Multiple Attitude Sensor Configurations, Sharanabasaweshwara Asundi, Norman Fitz-Coy, Haniph Latchman
Evaluation Of Murrell’S Ekf-Based Attitude Estimation Algorithm For Exploiting Multiple Attitude Sensor Configurations, Sharanabasaweshwara Asundi, Norman Fitz-Coy, Haniph Latchman
Mechanical & Aerospace Engineering Faculty Publications
Pico- and nano-satellites, due to their form factor and size, are limited in accommodating multiple or redundant attitude sensors. For such satellites, Murrell's implementation of the extended Kalman filter (EKF) can be exploited to accommodate multiple sensor configurations from a set of non redundant attitude sensors. The paper describes such an implementation involving a sun sensor suite and a magnetometer as attitude sensors. The implementation exploits Murrell's EKF to enable three sensor configurations, which can be operationally commanded, for satellite attitude estimation. Among the three attitude estimation schemes, (i) sun sensor suite and magnetometer, (ii) magnetic field vector and its …