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Articles 1 - 30 of 812
Full-Text Articles in Aerospace Engineering
Crushing Behavior Of Crash Boxes With Hybrid Honeycomb–Auxetic Fillers: Effects Of Architecture, Geometry, And Material Behaviors, A. Yudhanto, A. Jusuf, L. D. Lumanauw, M. Falyanzhuri, A. Afdhal
Crushing Behavior Of Crash Boxes With Hybrid Honeycomb–Auxetic Fillers: Effects Of Architecture, Geometry, And Material Behaviors, A. Yudhanto, A. Jusuf, L. D. Lumanauw, M. Falyanzhuri, A. Afdhal
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Additively manufactured (AM) fillers provide new opportunities to tailor the crushing response and energy absorption of thin-walled metallic crash boxes. This study presents a combined experimental–numerical investigation of hexagonal AA6063-T4 crash boxes filled with architected structures, i.e., honeycomb, auxetic-reentrant, and hybrid honeycomb–auxetic topology. The hybrid configuration, which integrates cells with positive and negative Poisson's ratios, triggers coordinated mechanisms (that enhance folding behavior and collapse control) unattainable via single topology. Quasi-static axial compression tests were conducted to characterize force–displacement curves, deformation mechanisms, energy absorption (EA), and specific energy absorption (SEA). Finite element models developed in the explicit solver LS-DYNA were employed …
Optimizing Ball‐Milled Composites For Fast Energy Release Under Shock Compression, Siva Valluri, Edward Dreizin, Dana Dlott
Optimizing Ball‐Milled Composites For Fast Energy Release Under Shock Compression, Siva Valluri, Edward Dreizin, Dana Dlott
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Microparticle additives containing both Al fuel and oxidizer, fabricated by arrested reactive milling (ARM), could potentially increase the power of energetic materials such as HMX because they contain premixed fuel and oxidizer. Optimizing shock reactivity requires exploring a vast parametric space encompassing composition, milling parameters that govern microstructural features such as intraparticle voids and fuel-oxidizer mixing, and the resulting inhomogeneous shock reactivity of individual particles. To present our approach, we used a model composition 8Al⋅3CuO, previously optimized for combustion. We milled powders and prescreened different prepared batches using differential scanning calorimetry (DSC) to rule out batches with significant pre-reaction. Then …
Tailoring Crushing Responses Of Hexagonal Crash Box Filled With Additively Manufactured Lattice Structures By Assessing The Influence Of Material Parameters, L. D. Lumanauw, A. Jusuf, M. H. Jarwadi, L. Gunawan, T. Sebaey, A. Yudhanto
Tailoring Crushing Responses Of Hexagonal Crash Box Filled With Additively Manufactured Lattice Structures By Assessing The Influence Of Material Parameters, L. D. Lumanauw, A. Jusuf, M. H. Jarwadi, L. Gunawan, T. Sebaey, A. Yudhanto
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Hexagonal crash boxes offer superior crashworthiness compared to other cross-sectional geometries, and their performance can be further enhanced by integrating additively manufactured lattice fillers. This study investigates the quasi-static crushing behavior of hexagonal crash boxes filled with hexagonal close-packed (HCP) lattice structures fabricated via stereolithography (SLA). Finite element models developed in ABAQUS/Explicit, validated against quasi-static compression experiments, show discrepancies below 5%, indicating that polymeric lattice fillers provide modest performance gains, achieving a crushing force efficiency (CFE) of 20%–25%. Replacing polymeric lattices with metallic fillers, namely 316L stainless steel and Ti–6Al–4V titanium alloy, substantially increases energy absorption, with Ti–6Al–4V delivering the …
A Comparative Evaluation Of Experimentally Validated Finite Element Modeling Strategies To Simulate Compression-After-Impact Behavior Of Multidirectional Cfrp Laminates With Barely Visible Impact Damage, Niildiip Chandraa, Vinh Tung Le, Arief Yudhanto, Abhendra K. Singh, Douglas E. Smith
A Comparative Evaluation Of Experimentally Validated Finite Element Modeling Strategies To Simulate Compression-After-Impact Behavior Of Multidirectional Cfrp Laminates With Barely Visible Impact Damage, Niildiip Chandraa, Vinh Tung Le, Arief Yudhanto, Abhendra K. Singh, Douglas E. Smith
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Abstract The finite element-based approaches to predict compression-after-impact (CAI) performance of carbon fiber reinforced polymer (CFRP) subject to a low-velocity impact rely on assumptions about compressive failure mechanisms within the barely visible impact damage (BVID). Comprehensive evaluations of finite element (FE) models concerning accuracy, efficiency, and validity with respect to experimental tests are limited. This study explores several finite element-based approaches developed in ABAQUS Explicit to predict the residual strength and related compressive failure mechanisms of multidirectional CFRP laminates. Drop-weight impact experiments followed by CAI tests employing 3D Digital Image Correlation (DIC) were used to validate our FE models by …
Nascent Titanium-/Silicon-Containing Particle Formation In Corona-Discharge-Assisted Combustion, Chanakya Bagya Ramesh, Frank Daoru Han, Yang Wang
Nascent Titanium-/Silicon-Containing Particle Formation In Corona-Discharge-Assisted Combustion, Chanakya Bagya Ramesh, Frank Daoru Han, Yang Wang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Adding plasmas to a flame has been shown to introduce high concentrations of charges, ions, and radicals to the said flame. This technique of adding plasma to a flame is called plasma-assisted combustion (PAC), and this addition has been shown to make a flame more stable and efficient. At the same time, PAC has also been shown to alter particle formation during combustion. Here, we investigate the effect of a high-frequency (∼21 kHz) alternating current (AC) corona discharge on particle formation and growth in a premixed flame, especially at the initial stages (with particle sizes below 10 nm). We first …
Tracking Continuous Non-Differentiable Trajectories In Euler–Lagrange Systems With Continuous Dynamics, Nilay Kant
Tracking Continuous Non-Differentiable Trajectories In Euler–Lagrange Systems With Continuous Dynamics, Nilay Kant
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Tracking controllers for Euler–Lagrange systems are designed under the assumption that reference trajectories are continuous, and at least twice differentiable with respect to time. However, this assumption precludes several use cases, such as when a robot end-effector must track a path with corners at constant speed. This paper introduces the control design for tracking continuous but non-differentiable trajectories in fully actuated Euler–Lagrange systems that have continuous-time dynamics. The proposed controller combines a continuous feedback law with impulsive inputs, that are intermittently applied at the instants of non-differentiability. A Lyapunov stability analysis establishes global exponential convergence of the tracking error to …
Evaluation Of The Effect Of Vibration On Signal Reflection In Coaxial Cable Connectors For Vibration Sensing In Aircraft Structures And Systems, Saidanvar Esanjonovich Valiev, Anthony C. Okafor, Jeremiah J. Rittenhouse, Daniel S. Stutts, Jie Huang
Evaluation Of The Effect Of Vibration On Signal Reflection In Coaxial Cable Connectors For Vibration Sensing In Aircraft Structures And Systems, Saidanvar Esanjonovich Valiev, Anthony C. Okafor, Jeremiah J. Rittenhouse, Daniel S. Stutts, Jie Huang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper investigates the effects of vibration on signal reflection (S11) in aerospace data transmission line (ADTL) and commercial data transmission line (DTL) connectors for their alternative use as vibration sensors. The impact of vibration on the S11 signal was investigated on five ADTL and four DTL connectors at six vibration frequencies (20 Hz, 40 Hz, 80 Hz, 160 Hz, 320 Hz, and 640 Hz) and four vibration accelerations (0.5G, 1 G, 2 G, and 4G). The experiment was conducted using a split-plot design with a cable type assigned as the main-plot factor, with vibration frequency and acceleration as subplot …
Applying Direct Numerical Simulations To Investigate Wave Forcing Against A Vertical Wall, Hunter Boswell, Frank D. Han, Gaurav Savant, Guirong Yan, Wouter Mostert
Applying Direct Numerical Simulations To Investigate Wave Forcing Against A Vertical Wall, Hunter Boswell, Frank D. Han, Gaurav Savant, Guirong Yan, Wouter Mostert
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Current engineering standards lack the ability to predict the peak impact forces of breaking waves impinging directly upon coastal structures. In this study solitary waves impacting vertical and tapered walls are investigated. To capture the detailed physics of the wave profile that impacts the wall, two-dimensional direct numerical simulations are applied to model the wave traveling over a simplified bathymetry consisting of an initially uniform depth, followed by a uniform beach ramp and then terminating in a uniform depth inshore region and vertical wall. Such an approach can simulate wave runup on land and then the impact with the vertical …
Generative Artificial Intelligence In Aircraft Design Optimization, Xiaosong Du
Generative Artificial Intelligence In Aircraft Design Optimization, Xiaosong Du
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Aircraft design optimization is essential for improving aircraft performance (such as reduced fuel consumption and lowered noise), which leads to more efficient, sustainable, and affordable aircraft. Conventional aircraft design adopts physics-based simulation models, but iteratively evaluating simulation models is computationally intensive, or even practically impossible. Meanwhile, artificial intelligence (AI) emerges as a revolutionary game changer in the modern engineering industry, including aircraft design optimization. Generative AI (genAI), one of the groundbreaking AI methods, has been advancing aircraft design optimization from various aspects, including intelligent parameterization, predictive modeling, training facilitation, and constraints handling. However, there is a lack of a review …
A Large Thermal Vacuum (Tvac) Facility To Simulate Cryogenic Space Environments, Emmanuel Kofi Asuako Wie-Addo, Lucas Alexander Scott, Frank Daoru Han
A Large Thermal Vacuum (Tvac) Facility To Simulate Cryogenic Space Environments, Emmanuel Kofi Asuako Wie-Addo, Lucas Alexander Scott, Frank Daoru Han
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This work reports the upgrade of a 10-ft (3.0 m) long x 6-ft (1.8 m) diameter vacuum facility as part of ongoing efforts to address some of the technology gaps in NASA's Moon to Mars mission architecture, which include systems to survive and operate through extended periods in extreme environments. Consequently, a removable thermal shroud has been fabricated and installed to facilitate the simulation of extreme cryogenic conditions. The cooling rates of the shroud and a surrogate test article, using liquid nitrogen as the coolant are analyzed and documented under varying vacuum environments during cryogenic testing. The attainable vacuum level …
A Combined Tomographic Particle Image Velocimetry And Numerical Simulation Approach For Supersonic Wind Tunnel Calibration, Joshua Gary, Josiah Mcdermott, Kyle Worden, Serhat Hosder, Davide Viganò
A Combined Tomographic Particle Image Velocimetry And Numerical Simulation Approach For Supersonic Wind Tunnel Calibration, Joshua Gary, Josiah Mcdermott, Kyle Worden, Serhat Hosder, Davide Viganò
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Supersonic wind tunnels remain essential tools for high-speed aerodynamics research, yet the characterization of their free-stream conditions remains technically challenging and lacks standardized criteria for defining "good" flow quality. While traditional calibration methods rely on intrusive probes, recent advances in optical diagnostics offer new opportunities for non-intrusive characterization. In this work, we demonstrate a novel use of Tomographic Particle Image Velocimetry (Tomo-PIV), combined with numerical simulations, as a methodology for supersonic wind tunnel calibration. The approach is applied to the recently upgraded Missouri S&T Supersonic Wind Tunnel, where Tomo-PIV measurements reveal uniform flow with low angularity and low turbulent noise …
Physics-Constrained Generative Adversarial Networks For Dimensionality Reduction In Optimization, Samuel Sisk, Xiaosong Du
Physics-Constrained Generative Adversarial Networks For Dimensionality Reduction In Optimization, Samuel Sisk, Xiaosong Du
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electric vertical takeoff and landing (eVTOL) aircraft make a unique form of urban air mobility due to their low noise, zero emission, and precision control. To maximize efficiency, high-fidelity simulation-based multidisciplinary design optimization discovers the optimal balance among subsystems within an eVTOL. However, conventional multidisciplinary design optimization is computationally intensive due to excessive high-fidelity model evaluations. Moreover, complex nonlinear constraints deteriorate optimization efficiency and convergence. While surrogate models enable efficient design optimization, surrogate modeling suffers in large-scale applications and surrogate-based optimization still has to deal with nonlinear constraints. To address these challenges, the authors' previous work proposed physics-constrained generative adversarial …
Tomo-Piv Study Of Baseline Flow Structures Behind A Strut Injector, Josiah Mcdermott, Connor Bell, Davide Viganò
Tomo-Piv Study Of Baseline Flow Structures Behind A Strut Injector, Josiah Mcdermott, Connor Bell, Davide Viganò
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Stabilizing combustion in scramjet engines is a formidable challenge due to the small-time scales afforded for air-fuel mixing. Numerous studies in this area have demonstrated the potential of strut-style platforms for fuel injection and mixing enhancement, which remains an active area of research. In the Aerodynamics Research Laboratory at Missouri S&T, a strut-style injector system has recently been installed. In this study, we characterize the baseline flow structures behind this platform absent fuel injection. The wake generated by a strut itself has an appreciable impact on the resulting air-fuel mixing, which motivates its characterization. In future studies, this characterization will …
Optimal Takeoff Trajectory Prediction Of Electric Drones Based On A Fully Automated Optimal Experimental Design Method, Jiachen Wang, Dheeraj Paramkusham, Xiaosong Du
Optimal Takeoff Trajectory Prediction Of Electric Drones Based On A Fully Automated Optimal Experimental Design Method, Jiachen Wang, Dheeraj Paramkusham, Xiaosong Du
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electric vertical takeoff and landing (eVTOL) aircraft is attracting great interest as a viable solution to promote urban aerial mobility with promising flexibility as well as emission reductions. However, the low specific energy of the current battery is still a strong constraint on the range and endurance of eVTOL flights, especially considering the significant power demands during the takeoff process. Engineering design optimization permits promising solutions for the minimum takeoff energy consumption but can be computationally intensive due to iteratively evaluating simulation models. Surrogate-based design optimization is efficient but still relies on optimization iterations which prohibit real-time decision-making. To fill …
Multiphysics Modeling Of Melt Pool Dynamics And Powder Bed Stability In Lpbf Of Inconel 718 For A Circular Cavity, Nayan Pundhir, Oluwapelumi O. Adejumo, Kumbla Chandrashekhara, Joseph W. Newkirk, Heath Misak, Cesar Ortiz Rios
Multiphysics Modeling Of Melt Pool Dynamics And Powder Bed Stability In Lpbf Of Inconel 718 For A Circular Cavity, Nayan Pundhir, Oluwapelumi O. Adejumo, Kumbla Chandrashekhara, Joseph W. Newkirk, Heath Misak, Cesar Ortiz Rios
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser powder bed fusion (LPBF) is a metal additive manufacturing process in which a concentrated laser beam selectively melts successive powder layers to fabricate components. Final part quality is highly sensitive to process parameters such as hatch spacing, powder bed density, laser power, and scanning speed. In this study, a computational fluid dynamics model employing discrete element method has been developed in FLOW-3D to simulate LPBF of Inconel 718. The modeled powder bed incorporates particle size distribution data obtained from scanning electron microscopy and is evaluated for single-layer, single-track deposition over a circular cavity. The model captured melt pool dynamics …
Distributed Vibration Sensing For Identification Of Loose Connectors In Coaxial Data Transmission Lines, Saidanvar Esanjonovich Valiev, Anthony C. Okafor, Jeremiah J. Rittenhouse, Jie Huang, Daniel S. Stutts
Distributed Vibration Sensing For Identification Of Loose Connectors In Coaxial Data Transmission Lines, Saidanvar Esanjonovich Valiev, Anthony C. Okafor, Jeremiah J. Rittenhouse, Jie Huang, Daniel S. Stutts
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This study investigates the effect of vibration-induced loose connections on signal reflection (S11) for loose connection identification in aerospace coaxial cables using distributed sensing approach, which is effective in filtering the noise and identifying minor discontinuities. In this approach, a sliding gated window is applied to S11 signal, a fast Fourier transform is performed over the gated windows, cross-correlation is computed between the baseline and vibration-affected signals, and the standard deviation is mapped along the cable length. Sinewave signals from 9 kHz to 5 GHz were swept through cables with vibrating connectors under three conditions: fully tightened, loosened by 180°, …
Nonlinear Control Of A Ciws-Style 2-Dof Turret, Ryan Baur, Ethan Wang, Nilay Kant
Nonlinear Control Of A Ciws-Style 2-Dof Turret, Ryan Baur, Ethan Wang, Nilay Kant
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper develops and compares multiple control strategies for a two-degree-of-freedom CIWS (Close-In Weapon System)-style turret tracking rapidly maneuvering airborne targets. A simplified nonlinear manipulator model with realistic actuator torque limits is used as the plant. Five controllers are implemented: a baseline PID (Proportional-Integral-Derivative) controller, a feedforward PID, a Kalman-filter-assisted PID, and two feedback-linearized designs using PID and LQR (Linear-Quadratic-Regulator)-based surrogate dynamics. Controller performance is evaluated on increasingly aggressive three-dimensional target trajectories under varying sensor noise. Results show that PID-family controllers achieve competitive tracking accuracy while remaining torque-efficient and largely unsaturated. Feedback-linearized controllers improve tracking accuracy only when sufficient actuator …
Design, Construction, And Initial Testing Of A Oxy-Acetylene Testing Facility, Blake Bowman, Davide Viganò
Design, Construction, And Initial Testing Of A Oxy-Acetylene Testing Facility, Blake Bowman, Davide Viganò
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Thermal Protection Systems (TPS) are critical for atmospheric re-entry and hypersonic flight vehicles, yet ground-based evaluation of TPS materials remains challenging due to the cost, complexity, and limited availability of large arc-jet and inductively coupled plasma (ICP) facilities. Oxy-acetylene testing provides a low-cost and accessible alternative for preliminary material screening, sensor development, and fundamental studies of material response under high heat-flux conditions. This paper presents the design, construction, and initial validation of the High-Enthalpy Acetylene Testing (HEAT) facility at Missouri University of Science and Technology. The facility incorporates a modular experimental architecture, independently controlled oxygen and acetylene mass-flow systems, and …
Tomo-Piv Study Of A Parallel Two-Dimensional Jet In Supersonic Flow, Josiah Mcdermott, Connor Bell, Davide Vigano
Tomo-Piv Study Of A Parallel Two-Dimensional Jet In Supersonic Flow, Josiah Mcdermott, Connor Bell, Davide Vigano
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Stabilizing combustion in supersonic flows is a formidable challenge due to the small time scales afforded for air-fuel mixing. Numerous studies in this area have demonstrated the potential of strut-style platforms for fuel injection and mixing enhancement, which remains an active area of research. In the Aerodynamics Research Laboratory at Missouri S&T, a strut-style injector system has recently been installed. In this study, we characterize the flow structures behind this platform in a range of injection pressures and corresponding mass flux ratios. The wake generated by a strut and injection plume, even absent combustion or mixing enhancement geometry, has an …
Supersonic Wind Tunnel Free Stream Turbulence Characterization Using 2-Point Focused Laser Differential Interferometry, Joseph Villarreal, Joshua Gary, Davide Vigano
Supersonic Wind Tunnel Free Stream Turbulence Characterization Using 2-Point Focused Laser Differential Interferometry, Joseph Villarreal, Joshua Gary, Davide Vigano
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Non-intrusive laser-based diagnostics, such as Two-Point Focused Laser Differential Interfer-ometry (2-FLDI), play a crucial role in modern aerodynamic research by enabling simultaneous measurements of density and velocity in compressible flows. A 2-FLDI system has been developed and implemented for the Missouri S&T Supersonic Wind Tunnel to characterize free stream turbulence fluctuations and free stream convective velocity. Design choices that enabled the 2-FLDI to overcome low turbulence to measure free stream velocity are detailed. The free stream velocity measurements are validated against previous particle image velocimetry data, showing good agreement. Analysis of normalized velocities and density-based turbulence intensities found that the …
2-Point Focused Laser Differential Interferometry Measurements Of A Parallel Jet In Supersonic Flow, Joshua Gary, Joseph Villarreal, Davide Vigano
2-Point Focused Laser Differential Interferometry Measurements Of A Parallel Jet In Supersonic Flow, Joshua Gary, Joseph Villarreal, Davide Vigano
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Turbulence in compressible flows plays a central role in applications such as air-fuel mixing in supersonic combustors and is significantly more complex than incompressible turbulence due to the presence of fluctuating thermodynamic quantities. As such, models like the Strong Reynolds Analogy (SRA) are used to relate these quantities. However, SRA validity has been examined primarily in boundary-layer flows. In this work, a newly developed Two-Point Focused Laser Differential Interferometry (2-FLDI) system is implemented in a two-dimensional parallel supersonic jet. The diagnostic is described in detail, including optical alignment procedures, calibration methods, and data analysis techniques. Measurements acquired at multiple streamwise …
Anisotropic Second-Harmonic Ince-Gaussian Beam Generation Using Nbobr2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao
Anisotropic Second-Harmonic Ince-Gaussian Beam Generation Using Nbobr2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Ince-Gaussian (IG) modes are a complete and orthogonal set of solutions to the paraxial wave equation in elliptic coordinates representing a continuous transition between Hermite-Gaussian modes and Laguerre-Gaussian modes. Chip-scale platforms to generate IG beams have great significance for various applications, including optical trapping and micromanipulation of particles, optical communication, and quantum optics. On the other hand, materials with high optical anisotropy are crucial for building polarization-sensitive optical devices. In this context, niobium oxide dihalides are a new class of ferroelectric materials exhibiting strong, tailorable, and highly anisotropic second-harmonic generation responses. Here, we report the generation of highly anisotropic second-harmonic …
Upconversion Photoluminescence In Wsse Alloy Monolayer Under Uniaxial Tensile Strain, Shrawan Roy, Jie Gao, Xiaodong Yang
Upconversion Photoluminescence In Wsse Alloy Monolayer Under Uniaxial Tensile Strain, Shrawan Roy, Jie Gao, Xiaodong Yang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The optical responses of monolayer transition metal dichalcogenides (1L-TMDs) can be tuned effectively by using mechanical strain. In this work, the tuning of upconversion photoluminescence (UPL) emission in 1L-WSSe alloy by applying uniaxial tensile strain is investigated. When the uniaxial tensile strain is changed from 0 % to 1.02 %, the peak position of UPL emission has a redshift of around 25.6 nm, and the UPL intensity goes up with an exponential function of the applied strain as the upconversion energy difference is varied from −197 meV to −131 meV. The sublinear power dependence for UPL emission in 1L-WSSe alloy …
Performance Evaluation Of Thick Carbon Fiber-Reinforced Laminates Manufactured Using Six-Magnetron Microwave System, Nayan Pundhir, Sourav Bolar, Kumbla Chandrashekhara, Kristen Donnell, Jim Lua, Kalyan Shrestha, Rui Li
Performance Evaluation Of Thick Carbon Fiber-Reinforced Laminates Manufactured Using Six-Magnetron Microwave System, Nayan Pundhir, Sourav Bolar, Kumbla Chandrashekhara, Kristen Donnell, Jim Lua, Kalyan Shrestha, Rui Li
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Microwave curing is a fast, energy-efficient, and a viable alternative to conventional thermal curing processes. It has been widely adopted for processing carbon fiber-reinforced polymer composites because the high electrical conductivity of carbon fibers enables strong microwave coupling. In this study, IM7/Cycom 5320-1 unidirectional prepreg has been used to fabricate 64-layer laminated composites. Symmetric cross-ply ([0°/90°]16S) and a quasi-isotropic ([45°/90°/−45°/0°]8S) layup have been investigated. A custom-built six-magnetron microwave applicator and an autoclave were employed to manufacture the composite panels. Degree of cure of the manufactured laminates was evaluated via differential scanning calorimetry. Interfacial bonding and porosity of the microwave-cured laminates …
Tunable Phase-Change Metasurfaces Coupled With Mid-Infrared Molecular Vibrations, Haotian Tang, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao
Tunable Phase-Change Metasurfaces Coupled With Mid-Infrared Molecular Vibrations, Haotian Tang, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Chiral optical meta surfaces have emerged as a promising platform in coupling with molecular vibrational fingerprints through the enhanced light-matter interaction under different circularly polarized light illumination. This work reports the mode coupling between the mid-infrared phonon vibrations of polymethyl methacrylate (PMMA) molecules, and the thermally tunable chiral meta surfaces based on the phase-change material Ge₂Sb₂Te₅ (GST-225). Phase-change chiral meta surfaces with high circular dichroism (CD) in absorption and tunable plasmonic resonance in the frequency range of 48-56 THz are demonstrated, which covers the phonon vibrational frequency of PMMA molecules at 52 THz. The mode splitting features are observed in …
Powder Bed Fusion Of Stainless Steel 304l-Nbc Nanocomposite Produced By Ball Milling Method Using A Laser Beam, Khalid Hussain Solangi, Junaid Iqbal Bhatti, Irfan Ali Tunio, Imdad Ali Memon, Temoor Abbas Larik, Lianyi Chen
Powder Bed Fusion Of Stainless Steel 304l-Nbc Nanocomposite Produced By Ball Milling Method Using A Laser Beam, Khalid Hussain Solangi, Junaid Iqbal Bhatti, Irfan Ali Tunio, Imdad Ali Memon, Temoor Abbas Larik, Lianyi Chen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Metal powders with uniformly dispersed nanoparticles, suitable shape, and size for additive manufacturing (AM) processes are highly demanded. However, it is difficult to manufacture metal matrix nanocomposite powders (MMNCs) with uniform dispersion of nanoparticles, optimized shape, and size. This study used high-energy ball milling to disperse NbC nanoparticles with an average length of 400 nm (ex-situ reinforcement) in a Stainless Steel (SS) 304 L matrix. In detail, SS304L-5wt% NbC powders were ball-milled from 4 to 10 h. The results showed that the milled powder particles experienced significant cold-welding during the milling time of 4–6 h, with a wide size distribution. …
Effect Of Thermal History On The Fracture And Fatigue Behaviors Of Semi-Crystalline Polymers Prepared Via Material Extrusion Additive Manufacturing, Ava M. Lea, Khaled Matalgah, Arief Yudhanto, Trevor J. Fleck
Effect Of Thermal History On The Fracture And Fatigue Behaviors Of Semi-Crystalline Polymers Prepared Via Material Extrusion Additive Manufacturing, Ava M. Lea, Khaled Matalgah, Arief Yudhanto, Trevor J. Fleck
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Material extrusion (MEX) additive manufacturing (AM) is transforming the design and production of complex structures, providing reliable on-demand components. However, the effect of thermal history on the resultant microstructure and damage tolerance of MEX-AM materials is not fully understood. This research investigates the critical role of interfacial thermal history, which is dependent on processing conditions, in determining the fracture and fatigue behaviors of semi-crystalline polymers, as exemplified by polyamide-6 (PA-6). Utilizing infrared thermography, the thermal history, and its dependence on nozzle temperature of extruded PA-6, was investigated. Quasi-static and cyclic tests of compact tension specimens were used to evaluate fracture …
Multiphase Iterative Algorithm For Mixed-Integer Optimal Control, Chaoying Pei, Sixiong You, Yu Di, Ran Dai
Multiphase Iterative Algorithm For Mixed-Integer Optimal Control, Chaoying Pei, Sixiong You, Yu Di, Ran Dai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Mixed-integer optimal control problems (MIOCPs) frequently arise in the domain of optimal control problems (OCPs) when decisions including integer variables are involved. However, existing state-of-the-art approaches for solving MIOCPs are often plagued by drawbacks such as high computational costs, low precision, and compromised optimality. In this study, we propose a novel multiphase scheme coupled with an iterative second-order cone programming (SOCP) algorithm to efficiently and effectively address these challenges in MIOCPs. In the first phase, we relax the discrete decision constraints and account for the terminal state constraints and certain path constraints by introducing them as penalty terms in the …
Experiment-Based Superposition Thermal Modeling Of Laser Powder Bed Fusion, Cody S. Lough, Tao Liu, Robert G. Landers, Douglas A. Bristow, James A. Drallmeier, Ben Brown, Edward C. Kinzel
Experiment-Based Superposition Thermal Modeling Of Laser Powder Bed Fusion, Cody S. Lough, Tao Liu, Robert G. Landers, Douglas A. Bristow, James A. Drallmeier, Ben Brown, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Parts experience significant local thermal variations during the Laser Powder Bed Fusion (LPBF) metal Additive Manufacturing (AM) process, providing a potential source of defects. Near real-time thermal predictions can enable better process planning and facilitate corrections on subsequent layers to enable the engineering of laser parameter and scan path combinations that avoid defect inducing scenarios. This paper considers an experiment-based Discrete Green's Function (DGF) thermal model for temperature field prediction in LPBF. An analytical framework is developed and used to calculate an experimental DGF (i.e., powder bed's single pulse temperature response) from spatiotemporal Short-Wave Infrared (SWIR) camera data. The extracted …
Circular Dichroism In Achiral Metasurfaces Induced By Spatially Selective Coupling With Molecules, Baojuan Han, Xiaodong Yang, Jie Gao
Circular Dichroism In Achiral Metasurfaces Induced By Spatially Selective Coupling With Molecules, Baojuan Han, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Achiral metasurfaces with near-field optical chirality have attracted great attention in molecular sensing and chiral emission control. Here, the circular dichroism (CD) response of an achiral metasurface induced by spatially selective coupling with polymethyl methacrylate (PMMA) molecules is demonstrated. A designed achiral metasurface with a V-shaped resonator exhibits large optical chirality with a strongly dissymmetric distribution under circular polarization. By introducing a PMMA molecule layer on top of the metasurface, which covers the area with large optical chirality, CD in absorption of 0.38 and a dissymmetric factor of optical chirality gc of 0.16 are obtained. Furthermore, an analysis of the …