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Aerospace Engineering

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2023

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Articles 1 - 30 of 53

Full-Text Articles in Mechanical Engineering

Experimental And Modelling Of Lightning Damage To Carbon Fibre-Reinforced Composites Under Swept Stroke, Chengzhao Kuang, Kunkun Fu, Juhyeong Lee, Huixin Zhu, Qizhen Shi, Xiaoyu Cui Dec 2023

Experimental And Modelling Of Lightning Damage To Carbon Fibre-Reinforced Composites Under Swept Stroke, Chengzhao Kuang, Kunkun Fu, Juhyeong Lee, Huixin Zhu, Qizhen Shi, Xiaoyu Cui

Mechanical and Aerospace Engineering Faculty Publications

Lightning swept stroke creates multiple lightning attachments along an aircraft in flight. This introduces distinct structural damage compared to that from a single-point lightning current injection test in laboratory. This study presents both experimental and numerical studies on lightning damage in carbon fibre-reinforced polymer (CFRP) composites under swept stroke. Coupled electrical–thermal finite element (FE) models were proposed to predict lightning damage to CFRP composites under single-point current injection and swept stroke, respectively. A lightning swept stroke testing method was proposed by embedding a copper wire inside the composites to simulate multiple lightning attachments on the composites. The FE-predicted damage from …

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Effects Of Simultaneous Co2 Addition To The Fuel And Oxidizer Streams On Soot Formation In Co-Flow Diffusion Ethylene Flame, Yu Yang, Shu Zheng, Yuzhen He, Hao Liu, Ran Sui, Qiang Lu Dec 2023

Effects Of Simultaneous Co2 Addition To The Fuel And Oxidizer Streams On Soot Formation In Co-Flow Diffusion Ethylene Flame, Yu Yang, Shu Zheng, Yuzhen He, Hao Liu, Ran Sui, Qiang Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Soot formation in a co-flow diffusion ethylene flame with the addition of CO2 to the fuel (the CO2-F), oxidizer (the CO2-O), and fuel/oxidizer (the CO2-F/O) streams was numerically and experimentally investigated in this study. The effects of different CO2 addition ways on soot inception, soot condensation, H-abstraction-C2H2-addition (HACA) and oxidation by O2/OH processes, were quantitatively analyzed by introducing the integrated reaction rates over the whole computational domain. The simulated and experimental results showed that the CO2-F/O was the most effective in inhibiting soot formation …

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Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen Dec 2023

Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen

Honors Theses

Formula SAE is a multifaceted competition that involves student teams designing and competing with an open-wheel style race car. There are 5 different dynamic events included in the competition. Each event requires a unique aerodynamic setup to have the best performance possible. This design project focuses on a drag reduction system (DRS) that will improve aerodynamic performance, resulting in faster lap times and increased competitiveness. Key features include a direct electronic actuation mechanism that will allow the rear wing to be adjusted during a race. The benefits of the DRS system, include increased speed, improved handling, and greater fuel efficiency …

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The Role Of Atomic Layer Deposited Coatings On Lithium-Ion Transport: A Comprehensive Study, Yufang He, Hiep Pham, Xinhua Liang, Jonghyun Park Dec 2023

The Role Of Atomic Layer Deposited Coatings On Lithium-Ion Transport: A Comprehensive Study, Yufang He, Hiep Pham, Xinhua Liang, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Use of Ultrathin Film Coatings Prepared through Atomic Layer Deposition (ALD) Has Become Widespread for Improving Lithium-Ion Diffusivity of Active Particles, Which Plays a Crucial Role in Determining the Rate Capability of Lithium-Ion Batteries (LIBs). in This Study, the Impact of ALD Coating Thickness on Ionic Diffusivity in CeO2-Coated LiMn2O4 (LMO) Cathode Particles is Comprehensively Investigated through First-Principles Calculations by Focusing on the Trade-Offs between the Physical Properties of the Film and its Impact on the Diffusivity of Ions. Our Findings Indicate that Several Physical Factors Affect the Diffusivity of the Coating, Including the Crystal-Amorphous Structure that Depends on …

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Molecular Dynamics Simulations Of The Spontaneous Deformation And Auxetics Behavior During Tensile Test Of A Nematic Liquid Crystal Elastomer Model, Haoran Wang, Nanang Mahardika Nov 2023

Molecular Dynamics Simulations Of The Spontaneous Deformation And Auxetics Behavior During Tensile Test Of A Nematic Liquid Crystal Elastomer Model, Haoran Wang, Nanang Mahardika

Browse all Datasets

Nematic liquid crystal elastomers (LCEs) are advanced materials known for their shape-changing capability in response to external stimuli such as heat, light and electromagnetic fields. This makes them excellent candidates for applications like soft robotics and energy harvesting. While studies on their physical behavior have shed light on the complex nonlinear mechanics of LCEs, investigations through all-atom molecular dynamics (MD) simulations remain an underutilized avenue compared to experimental and theoretical analyses. This limited use is primarily due to the lack of well-established frameworks for conducting high-fidelity atomistic simulations of LCEs. To bridge this gap, we introduce an all-atom MD simulation …

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Searching For Unknown Material Properties For Am Simulations, Aaron Flood, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou Nov 2023

Searching For Unknown Material Properties For Am Simulations, Aaron Flood, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing (AM) simulations are effective for materials that are well characterized and published; however, for newer or proprietary materials, they cannot provide accurate results due to the lack of knowledge of the material properties. This work demonstrates the process of the application of mathematical search algorithms to develop an optimized material dataset which results in accurate simulations for the laser directed energy deposition (DED) process. This was performed by first using a well-characterized material, Ti-64, to show the error in the predicted melt pool was accurate, and the error was found to be less than two resolution steps. Then, …

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Towards A Virtual Test Framework To Predict Residual Compressive Strength After Lightning Strikes, Scott L.J. Millen, Xiaodong Xu, Juhyeong Lee, Suparno Mukhopadhyay, Michael R. Wisnom, Adrian Murphy Nov 2023

Towards A Virtual Test Framework To Predict Residual Compressive Strength After Lightning Strikes, Scott L.J. Millen, Xiaodong Xu, Juhyeong Lee, Suparno Mukhopadhyay, Michael R. Wisnom, Adrian Murphy

Mechanical and Aerospace Engineering Faculty Publications

A novel integrated modelling framework is proposed as a set of coupled virtual tests to predict the residual compressive strength of carbon/epoxy composites after a lightning strike. Sequentially-coupled thermal-electric and thermo-mechanical models were combined with Compression After Lightning Strike (CAL) analyses, considering both thermal and mechanical lightning strike damage. The predicted lightning damage was validated using experimental images and X-ray Computed Tomography. Delamination and ply degradation information were mapped to a compression model, with a maximum stress criterion, using python scripts. Experimental data, in which artificial lightning strike and compression testing were performed, was used to assess the predictive capabilities …

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On Quantifying Uncertainty In Lightning Strike Damage Of Composite Laminates: A Hybrid Stochastic Framework Of Coupled Transient Thermal-Electrical Simulations, R. S. Chahar, J. Lee, T. Mukhopadhyay Nov 2023

On Quantifying Uncertainty In Lightning Strike Damage Of Composite Laminates: A Hybrid Stochastic Framework Of Coupled Transient Thermal-Electrical Simulations, R. S. Chahar, J. Lee, T. Mukhopadhyay

Mechanical and Aerospace Engineering Faculty Publications

Lightning strike damage can severely affect the thermo-mechanical performance of composite laminates. It is essential to quantify the effect of lightning strikes considering the inevitable influence of material and geometric uncertainties for ensuring the operational safety of aircraft. This paper presents an efficient support vector machine (SVM)-based surrogate approach coupled with computationally intensive transient thermal-electrical finite element simulations to quantify the uncertainty in lightning strike damage. The uncertainty in epoxy matrix thermal damage and electrical responses of unprotected carbon/epoxy composite laminates is probabilistically quantified considering the stochasticity in temperature-dependent multi-physical material properties and ply orientations. Further, the SVM models are …

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Hardware-In-The-Loop Reaction Wheel Testbed With Camera Vision, Abigail Romero, Harvey Perkins, Stephen Kwok-Choon Oct 2023

Hardware-In-The-Loop Reaction Wheel Testbed With Camera Vision, Abigail Romero, Harvey Perkins, Stephen Kwok-Choon

College of Engineering Summer Undergraduate Research Program

Reaction wheels are widely used in aerospace systems as a method of attitude control. This research was focused on the design, development, and testing of a hardware-in-the-loop reaction wheel testbed that can be used for research and teaching applications related to satellite navigation and control. This project successfully utilized commercial off-the-shelf components to develop a reaction wheel capable of controlling the orientation of a freely rotating platform, as well as tracking objects using computer vision.

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The Investigation Of A Likely Scenario For Natural Tornado Genesis And Evolution From An Initial Instability Profile, Alexios Nicolas Philippou, Kakkattukuzhy M. Isaac Oct 2023

The Investigation Of A Likely Scenario For Natural Tornado Genesis And Evolution From An Initial Instability Profile, Alexios Nicolas Philippou, Kakkattukuzhy M. Isaac

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A likely mechanism for the little-understood tornado genesis is proposed and its numerical implementation is presented. The Burgers-Rott vortex with its axis in the vertical direction is introduced as an instability mechanism, and the flow field then evolves under the influence of the atmospheric pressure, temperature and density variations with altitude. Buoyancy effects are implemented using the Boussinesq model. Results are presented and discussed for a set of conditions including mesh type and size, different turbulence models, and a few different boundary conditions. Post-processed results of the transient simulations including animations contain a wealth of information to help analyze tornado …

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Stochastic Modeling Of Physical Drag Coefficient – Its Impact On Orbit Prediction And Space Traffic Management, Smriti Nandan Paul, Phillip Logan Sheridan, Richard J. Licata, Piyush M. Mehta Aug 2023

Stochastic Modeling Of Physical Drag Coefficient – Its Impact On Orbit Prediction And Space Traffic Management, Smriti Nandan Paul, Phillip Logan Sheridan, Richard J. Licata, Piyush M. Mehta

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ambitious satellite constellation projects by commercial entities and the ease of access to space in recent times have led to a dramatic proliferation of low-Earth space traffic. It jeopardizes space safety and long-term sustainability, necessitating better space domain awareness (SDA). Correct modeling of uncertainties in force models and orbital states, among other things, is an essential part of SDA. For objects in the low-Earth orbit (LEO) region, the uncertainty in the orbital dynamics mainly emanate from limited knowledge of the atmospheric drag-related parameters and variables. In this paper, which extends the work by Paul et al. (2021), we develop a …

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In-Situ Lock-In Thermographic Measurement Of Powder Layer Thermal Diffusivity And Thickness In Laser Powder Bed Fusion, Tao Liu, Edward C. Kinzel, Ming-Chuan Leu Jul 2023

In-Situ Lock-In Thermographic Measurement Of Powder Layer Thermal Diffusivity And Thickness In Laser Powder Bed Fusion, Tao Liu, Edward C. Kinzel, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The thermal transport properties of the powder layer play a crucial role in the process of laser powder bed fusion (LPBF). This paper introduces an in-situ measurement method utilizing active lock-in infrared thermography (LIT) to determine the thermal diffusivity and thickness of the powder layer. The proposed method exhibits great potential for accurate powder property and thickness measurements and real-time process monitoring. In this lock-in thermographic technique, the LPBF laser beam is directed through an optical diffuser and modulated into a square thermal wave. This thermal wave serves as an active heat source to heat the surface of the powder …

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High-Temperature Phonon-Assisted Upconversion Photoluminescence Of Monolayer Wse2, Fengkai Meng, Xiaodong Yang, Jie Gao Jul 2023

High-Temperature Phonon-Assisted Upconversion Photoluminescence Of Monolayer Wse2, Fengkai Meng, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Phonon-assisted up conversion photoluminescence (UPL) is an anti-Stokes process emitting photons of energy higher than the excitation photons, with up conversion energy gain provided by optical phonons. Atomically thin transition metal dichalcogenides provide a promising platform for exploring the phonon-assisted UPL process due to their strong phonon-exciton interactions. Here, high-temperature phonon-assisted UPL process in monolayer WSe2 is investigated, aiming to understand the role of phonon population and the number of phonons involved in the UPL process at elevated temperatures. It is demonstrated that the integrated intensity of UPL emission significantly increases by two orders of magnitude as the temperature rises …

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Kinetic Particle Simulations Of Plasma Charging At Lunar Craters Under Severe Conditions, David Lund, Xiaoming He, Daoru Frank Han Jul 2023

Kinetic Particle Simulations Of Plasma Charging At Lunar Craters Under Severe Conditions, David Lund, Xiaoming He, Daoru Frank Han

Mathematics and Statistics Faculty Research & Creative Works

This paper presents fully kinetic particle simulations of plasma charging at lunar craters with the presence of lunar lander modules using the recently developed Parallel Immersed-Finite-Element Particle-in-Cell (PIFE-PIC) code. The computation model explicitly includes the lunar regolith layer on top of the lunar bedrock, taking into account the regolith layer thickness and permittivity as well as the lunar lander module in the simulation domain, resolving a nontrivial surface terrain or lunar lander configuration. Simulations were carried out to study the lunar surface and lunar lander module charging near craters at the lunar terminator region under mean and severe plasma environments. …

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The Plastics Collection Reference Packet, Special Collections Research Center Jul 2023

The Plastics Collection Reference Packet, Special Collections Research Center

Special Collections Research Center

This reference packet is an informational tool to support further research into the history of plastics—whether interested in companies, individuals within the plastics industry's history, historical plastics materials, essays, and more. All content featured within this packet was previously published on the former plastics.syr.edu website as part of a Syracuse University Libraries and Special Collections Research Center (SCRC) partnership established in 2007 with the Plastics Pioneers Association (PPA)—an association of plastics industry professionals interested in preserving the plastics industry's past.

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Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly Jun 2023

Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly

Faculty Publications

In the pursuit of student success, it is essential to acknowledge that a singular teaching style does not universally cater to all students. The educator's crucial role lies in creating an optimal learning environment that fosters students' endeavors to excel. This endeavor transcends mere classroom success or employment prospects, encompassing a broader impact on societal well-being. An experiential learning approach, where students actively engage in practical tasks, emerges as the most effective mode of instruction. Integrating project-based learning activities into the curriculum holds immense potential for enhancing student learning. Additionally, the utilization of analysis software tools like FTool and STAAD …

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Decomposition Of The Wall-Heat Flux Of Compressible Boundary Layers, Dongdong Xu, Pierre Ricco, Lian Duan Jun 2023

Decomposition Of The Wall-Heat Flux Of Compressible Boundary Layers, Dongdong Xu, Pierre Ricco, Lian Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We use the method developed by Elnahhas and Johnson ["On the enhancement of boundary layer skin friction by turbulence: An angular momentum approach," J. Fluid Mech. 940, A36 (2022)] and Xu et al. ["Decomposition of the skin-friction coefficient of compressible boundary layers," Phys. Fluids 35, 035107 (2023)] for the decomposition of the skin-friction coefficient to integrate the mean temperature equation for high-Reynolds-number compressible boundary layers and arrive at an identity for the decomposition of the wall-heat flux. The physical interpretation of the identity and the limitations of this approach are discussed. We perform an integration on the mean temperature equation …

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Multiscale Damage Modelling Of Notched And Un-Notched 3d Woven Composites With Randomly Distributed Manufacturing Defects, S.Z.H. Shah, Juhyeong Lee, P.S.M. Megat-Yusoff, Syed Zahid Hussain, T. Sharif, R.S. Choudhry May 2023

Multiscale Damage Modelling Of Notched And Un-Notched 3d Woven Composites With Randomly Distributed Manufacturing Defects, S.Z.H. Shah, Juhyeong Lee, P.S.M. Megat-Yusoff, Syed Zahid Hussain, T. Sharif, R.S. Choudhry

Mechanical and Aerospace Engineering Faculty Publications

This work proposes a stochastic multiscale computational framework for damage modelling in 3D woven composite laminates, by considering the random distribution of manufacturing-induced imperfections. The proposed method is demonstrated to be accurate, while being simple to implement and requiring modest computational resources. In this approach, a limited number of cross-sectional views obtained from micro-computed tomography (µCT) are used to obtain the stochastic distribution of two key manufacturing-induced defects, namely waviness and voids. This distribution is fed into a multiscale progressive damage model to predict the damage response of three-dimensional (3D) orthogonal woven composites. The accuracy of the proposed model was …

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Multifunctional Additive Manufacturing And Multiphysics Numerical Investigations Of Carbon Fiber Structural Battery Composite Using A Drop-On-Demand Method With In-Situ Consolidation, Xiangyang Dong, Yuekun Chen May 2023

Multifunctional Additive Manufacturing And Multiphysics Numerical Investigations Of Carbon Fiber Structural Battery Composite Using A Drop-On-Demand Method With In-Situ Consolidation, Xiangyang Dong, Yuekun Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lightweight Carbon Fiber Structural Battery Composite Has Great Potential in Increasing Structural Energy Storage Efficiency for Multifunctional Applications. However, It is Still Challenging to Design Carbon Fiber Multifunctional Composite Due to Lack of Proper Manufacturing Methods. in This Study, an Integrated Multifunctional Design and Fabrication Approach is Developed by Combining a Drop-On-Demand Additive Manufacturing Method with a Multiphysics Numerical Model to Guide the Development of the New Multifunctional Composite. through Deposition with In-Situ Consolidation, the Function and Thickness of Each Carbon Fiber Layer as Well as its Fiber Volume Fraction Are Accurately Controlled. Decreasing Layer Thickness Improves Flexural Properties. the …

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Characterizing Energy Dissipation Of Shallow-Water Wave Breaking In A Storm Surge, Hunter Boswell, Guirong Grace Yan, Wouter Mostert May 2023

Characterizing Energy Dissipation Of Shallow-Water Wave Breaking In A Storm Surge, Hunter Boswell, Guirong Grace Yan, Wouter Mostert

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

While understanding breaking waves is crucial for the development of parametrizations used in ocean wave modeling for both deep and shallow water, the complete process of wave breaking is not well understood. Here we present direct numerical simulations of two-dimensional solitary waves that shoal and break on a uniform beach in shallow water, with the presence of storm surge represented by an inshore region. The storm surge depth, beach slope, and wave amplitude are varied to study the dependence of energy dissipation in the breaker on wave and bathymetric parameters. We classify wave breaker types and find a separation between …

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Effects Of Tempering Temperature On Gas Turbine Fan Cases, Seth Utter Apr 2023

Effects Of Tempering Temperature On Gas Turbine Fan Cases, Seth Utter

Honors Scholar Theses

The project aimed to investigate the effects of tempering temperature on metals used for gas turbine engine fan cases as a major relevant concern is containing blades in during blade-out events. There are three ways to accomplish this: using a thicker metal, incorporating different materials into the case, or heat treating the metal. This project focused on the third solution: reviewing the impact toughness and hardness of fractured samples and their equivalent ductile-to-brittle transition shear faces. Given its availability, 1045 steel, as opposed to aerospace grade metals, was used for in-house testing. The data obtained from these experiments were then …

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Experimental And Numerical Studies Of Slurry-Based Coextrusion Deposition Of Continuous Carbon Fiber Micro-Batteries To Additively Manufacture 3d Structural Battery Composites, Aditya R. Thakur, Xiangyang Dong Apr 2023

Experimental And Numerical Studies Of Slurry-Based Coextrusion Deposition Of Continuous Carbon Fiber Micro-Batteries To Additively Manufacture 3d Structural Battery Composites, Aditya R. Thakur, Xiangyang Dong

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Carbon Fiber Structural Battery Composites Have Recently Attracted Growing Interests Due to their Potentials of Simultaneously Carrying Mechanical Loads and Storing Electrical Energy for Lightweight Application. in This Study, We Present a Slurry-Based Coextrusion Deposition Method to Additively Manufacture 3D Structural Battery Composites from Carbon Fiber Micro-Batteries. Cathode Slurry is Coextruded Together with Solid Polymer Electrolyte-Coated Carbon Fibers in a Single Deposition. a Network of Carbon Fiber Micro-Batteries is Achieved within the Fabricated Structural Battery Composites. Electrochemical Tests Show a Stable Charge-Discharge Performance Up to 100 Cycles. the Rheological Behavior of the Cathode Slurry is Found to Govern the Coextrusion …

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Sharprazor: Automatic Removal Of Hair And Ruler Marks From Dermoscopy Images, Reda Kasmi, Jason Hagerty, Reagan Harris Young, Norsang Lama, Januka Nepal, Jessica Miinch, William V. Stoecker, R. Joe Stanley Apr 2023

Sharprazor: Automatic Removal Of Hair And Ruler Marks From Dermoscopy Images, Reda Kasmi, Jason Hagerty, Reagan Harris Young, Norsang Lama, Januka Nepal, Jessica Miinch, William V. Stoecker, R. Joe Stanley

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Background: The removal of hair and ruler marks is critical in handcrafted image analysis of dermoscopic skin lesions. No other dermoscopic artifacts cause more problems in segmentation and structure detection. Purpose: The aim of the work is to detect both white and black hair, artifacts and finally inpaint correctly the image. Method: We introduce a new algorithm: SharpRazor, to detect hair and ruler marks and remove them from the image. Our multiple-filter approach detects hairs of varying widths within varying backgrounds, while avoiding detection of vessels and bubbles. The proposed algorithm utilizes grayscale plane modification, hair enhancement, segmentation using tri-directional …

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Advanced Ensemble Modeling Method For Space Object State Prediction Accounting For Uncertainty In Atmospheric Density, Smriti Nandan Paul, Richard J. Licata, Piyush M. Mehta Mar 2023

Advanced Ensemble Modeling Method For Space Object State Prediction Accounting For Uncertainty In Atmospheric Density, Smriti Nandan Paul, Richard J. Licata, Piyush M. Mehta

Mechanical and Aerospace Engineering Faculty Research & Creative Works

For objects in the low Earth orbit region, uncertainty in atmospheric density estimation is an important source of orbit prediction error, which is critical for space traffic management activities such as the satellite conjunction analysis. This paper investigates the evolution of orbit error distribution in the presence of atmospheric density uncertainties, which are modeled using probabilistic machine learning techniques. The recently proposed "HASDM-ML," "CHAMP-ML," and "MSIS-UQ" machine learning models for density estimation (Licata and Mehta, 2022b; Licata et al., 2022b) are used in this work. The investigation is convoluted because of the spatial and temporal correlation of the atmospheric density …

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Microscale Modelling Of Lightning Damage In Fibre-Reinforced Composites, Scott L. J. Millen, Juhyeong Lee Mar 2023

Microscale Modelling Of Lightning Damage In Fibre-Reinforced Composites, Scott L. J. Millen, Juhyeong Lee

Mechanical and Aerospace Engineering Faculty Publications

In this work, three-dimensional (3D) finite element simulations were undertaken to study the effects of lightning strikes on the microscale behaviour of continuous fibre-reinforced composite materials and to predict and understand complex lightning damage mechanisms. This approach is different from the conventional mesoscale or macroscale level of analysis, that predicts the overall lightning damage in composite laminates, thus providing better understanding of lightning-induced thermo-mechanical damage at a fundamental level. Micromechanical representative volume element (RVE) models of a UD composite laminate were created with circular carbon fibres randomly distributed in an epoxy matrix. The effects of various grounding conditions (one-, two-, …

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Decomposition Of The Skin-Friction Coefficient Of Compressible Boundary Layers, Dongdong Xu, Pierre Ricco, Lian Duan Mar 2023

Decomposition Of The Skin-Friction Coefficient Of Compressible Boundary Layers, Dongdong Xu, Pierre Ricco, Lian Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We derive an integral formula for the skin-friction coefficient of compressible boundary layers by extending the formula of Elnahhas and Johnson ["On the enhancement of boundary layer skin friction by turbulence: An angular momentum approach, "J. Fluid Mech. 940, A36 (2022)] for incompressible boundary layers. The skin-friction coefficient is decomposed into the sum of the contributions of the laminar coefficient, the change of the dynamic viscosity with the temperature, the Favre-Reynolds stresses, and the mean flow. This decomposition is applied to numerical data for laminar and turbulent boundary layers, and the role of each term on the wall-shear stress is …

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Simulation Of Natural Tornado Genesis And Evolution From An Initial Instability Profile, Kakkattukuzhy M. Issac Feb 2023

Simulation Of Natural Tornado Genesis And Evolution From An Initial Instability Profile, Kakkattukuzhy M. Issac

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A likely mechanism for the little-understood tornado genesis is proposed and its numerical implementation is presented. The Burgers-Rott vortex with its axis in the vertical direction is introduced as an instability mechanism, and the flow field then evolves under the influence of the atmospheric pressure, temperature and density variations with altitude. Buoyancy effects are implemented using the Boussinesq model. Results are presented and discussed for a set of conditions including mesh type and size, different turbulence models, and a few different boundary conditions. Post-processed results of the transient simulations including animations contain a wealth of information to help analyze tornado …

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Synthesizing Ti–Ni Alloy Composite Coating On Ti–6al–4v Surface From Laser Surface Modification, Yitao Chen, Joseph William Newkirk, Frank W. Liou Feb 2023

Synthesizing Ti–Ni Alloy Composite Coating On Ti–6al–4v Surface From Laser Surface Modification, Yitao Chen, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In This Work, a Ni-Alloy Deloro-22 Was Laser-Deposited on a Ti–6Al–4V Bar Substrate with Multiple Sets of Laser Processing Parameters. the Purpose Was to Apply Laser Surface Modification to Synthesize Different Combinations of Ductile TiNi and Hard Ti2Ni Intermetallic Phases on the Surface of Ti–6Al–4V in Order to Obtain Adjustable Surface Properties. Scanning Electron Microscopy, Energy Dispersion Spectroscopy, and X-Ray Diffraction Were Applied to Reveal the Deposited Surface Microstructure and Phase. the Effect of Processing Parameters on the Resultant Compositions of TiNi and Ti2Ni Was Discussed. the Hardness of the Deposition Was Evaluated, and Comparisons with …

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Selection Of Solidification Pathway In Rapid Solidification Processes, Nima Najafizadeh, Men G. Chu, Yijia Gu Feb 2023

Selection Of Solidification Pathway In Rapid Solidification Processes, Nima Najafizadeh, Men G. Chu, Yijia Gu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Solidification Processing of Alloys Enables the Formation of Exotic Nonequilibrium Microstructures. However, the Interrelationship between the Processing Parameters and the Resulting Microstructure is Yet to Be Fully Understood. in Melt Spinning (MS) and Additive Manufacturing (AM) of Rapidly Solidified Alloys, Opposite Microstructure Development Sequences Were Observed. a Fine-To-Coarse Microstructural Transition is Typically Observed in Melt-Spun Ribbons, Whereas Melt Pools in AM Exhibit a Coarse-To-Fine Transition. in This Paper, the Microstructural Evolutions during These Two Processes Are Investigated using Phase-Field Modeling. the Variation of All Key Variables of the Solid-Liquid Interface (Temperature, Composition, and Velocity) throughout the Entire Rapid Solidification …

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Glass-Based Biodegradable Pressure Sensor Toward Biomechanical Monitoring With A Controllable Lifetime, Devdatt Chattopadhyay, Jonghyun Park, Chang-Soo Kim Feb 2023

Glass-Based Biodegradable Pressure Sensor Toward Biomechanical Monitoring With A Controllable Lifetime, Devdatt Chattopadhyay, Jonghyun Park, Chang-Soo Kim

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A New Class of Potentially Implantable Solid-State Sensors is Demonstrated Utilizing Biodegradable Glass as the Main Structural Material. the Device Behavior is Manipulated Via Chemical Decomposition, and Then Physically Disintegrated in a Controlled Manner. It is based on the Capacitive Sensing Mechanism, Comprising an Elastic Insulator between Two Borate-Rich Glass Substrates. This Mesoscale Pressure Sensor is Characterized by a Range of Pressure of Up to 14 MPa in a Phosphate Buffer Solution Environment. the Sensor Exhibits Good Sensitivity and Reversibility Responding to Compressive Pressures and Remains Fully Functional Before a Desired, Sudden Failure Caused by Dissolution. the Operational Lifetime Can …

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