Mechanical Engineering Commons^™

Retraction Notice To "Hydrogen Recovery, Cleaning, Compression, Storage, Dispensing, Distribution System And End-Uses On The University Campus From Combined Heat, Hydrogen And Power System" [International Journal Of Hydrogen Energy 39 (2014) 647-653], Tarek A. Hamad, Abdulhakim A. Agll, Yousif M. Hamad, Sushrut Bapat, Mathew Thomas, Kevin B. Martin, John W. Sheffield

Engineering Management and Systems Engineering Faculty Research & Creative Works

This article has been retracted: please see Elsevier policy on Article Correction, Retraction and Removal (https://www.elsevier.com/about/policies-and-standards/article-withdrawal). This article has been retracted at the request of the Editor.

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 …

Percolation-Induced Thermo-Rheological Transitions In Biobased Graphene Nanoplatelet Nanofluids, Abiodun A. Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Biobased lubricants with thermally responsive rheology are increasingly needed for high-efficiency mechanical systems. Graphene nanoplatelet (GnP) nanofluids in vegetable oils are promising candidates, yet their percolation-driven thermo-rheological transitions remain insufficiently understood. In particular, the coupled concentration–temperature landscape controlling network-mediated flow transitions has not previously been established. Here, surfactant-free GnP nanofluids were prepared in high-oleic soybean oil (HOSO) at concentrations of 0.025–2.15% v/v (ϕ), and their rheological response was mapped between 25°C and 80 °C under steady-shear and oscillatory conditions. Below the percolation threshold (ɸ ≤ 0.1% v/v), the nanofluids exhibit near-Newtonian behavior, moderate reversible viscosity enhancement, and classical Arrhenius-type temperature …

A Transfer-Learning And Continuous Optimization-Based Framework For Predicting Heat Treatment-Dependent Mechanical Properties Of Ded-Processed Low-Alloy Steels, Atiqur Rahman, Sung Heng Wu, Ranjit Joy, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Directed energy deposition (DED) of low-alloy steels involves strongly coupled effects among alloy composition, solidification behavior, and post-deposition heat treatment, making mechanical property prediction difficult when target-domain data are limited. This study develops a transfer-learning and continuous optimization framework for predicting heat treatment-dependent yield strength (YS), ultimate tensile strength (UTS), hardness (HV), and as-solidified phase fractions of martensite, ferrite, and austenite in DED-processed low-alloy steels. A CALPHAD-based dataset was generated for 125 low-alloy steel compositions. A multilayer perceptron (MLP) surrogate was first trained as a baseline model, then fine-tuned through transfer learning and progressively updated as staged continuous optimization; the …

3d Semi-Analytical Thermo-Elasto-Plastic Model For Additive Manufacturing, Tao Liu, Ming C. Leu, Edward C. Kinzel, Chinedum Okwudire

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In additive manufacturing (AM), stress field drives distortion and warping and promotes delamination and cracking. Fast, accurate stress prediction is therefore essential for AM process planning and control, including real-time adaptive control, AM digital twins, data-driven and physics-driven workflows. However, spot-wise thermo-elasto-plastic finite element method (FEM) are often too slow for design iteration or real time use. Existing semi-analytical thermo-elasto-plastic approaches achieve high speed but are largely limited to 2D. In this paper, a full 3D semi-analytical thermo-elasto-plastic model for AM is built. The method uses a spot-wise analytical thermal field as the load and computes displacements and stresses via …

Magnetic Field-Induced Transformation In Polycrystalline Ni2mnal Heusler Type Magnetic Shape Memory Alloy, Choji J. Daches, Joseph W. Newkirk, Mario Buchely, Laura N. Bartlett

Materials Science and Engineering Faculty Research & Creative Works

The martensitic and magnetic transformations, as well as the mechanical properties, of Ni₂MnAl alloys in as-cast (AC) and heat-treated (HT) conditions were investigated. Magnetic-field-induced strain was evaluated via magnetostriction, with reversible strains of 0.14% and 0.2% achieved in the martensitic phase at 2 K for the AC and HT alloys, respectively. Transformation temperatures and Curie temperatures were determined under constant applied magnetic field, revealing that γ-phase inclusions in the AC microstructure suppress antiferromagnetic domain response, yielding a lower magnetization (∼8.4 emu g⁻¹) compared to the HT alloy (∼13.4 emu g⁻¹). Both alloys exhibited hysteretic behavior in the martensitic state and …

A Carbon Fiber-Based Self-Sensing Approach For Monitoring Damage Evolution In Coal Pillars, Shan Ning, Weibing Zhu, Jie Gao, Wei Qin, Guang Xu, Jingmin Xu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Under long-term high stress and dynamic disturbances, damage accumulation within underground coal masses can induce sudden instability, posing a considerable threat to coal mine safety. Real-time acquisition of coal damage information is essential for disaster prevention and control. This study proposes a coal damage and fracturing monitoring approach based on a carbon fiber composite mortar (CFCM) coating. By applying the CFCM coating to coal specimen surfaces and monitoring resistance changes, the dynamic evolution of damage can be tracked. The study combines experimental mechanical loading, continuous electrical resistance monitoring and acoustic emission recording with detailed numerical modelling to comprehensively evaluate sensing …

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 …

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 …

Liquid-Phase Chemical Melting Deposition For Anchored Nanoparticle–Nanofiber Architectures, Hiep Pham, Kiernan O'Boyle, Gracie Boyer, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We report chemical melting deposition (CMD), a manufacturing strategy designed to overcome the low mass loading and weak interfacial bonding inherent to vapor-based synthesis. Unlike conventional vapor routes, CMD leverages a transient liquid-phase transfer (TLPT) mechanism driven by the differential thermal degradation of carrier fibers to transfer and anchor nanoparticles directly onto target fibers. This process thermodynamically drives the wetting and interfacial fusion of nanoparticles, establishing a liquid-phase contact pathway that enables markedly higher active material loading. To validate the structural resilience of this fused architecture against extreme volumetric stress, we utilized lead oxide (PbO) as a model system, which …

Effect Of Environmental Conditions On Fracture Of Composite Materials And Thin Films, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Environmental conditions, i.e., temperature and moisture, affect mechanical properties of materials, including composites. In this paper, we concentrate on one of the aspects of the effect of environment on fracture in a composite lamina. The paper demonstrates an analytical approach to account for the effect of the changes in environment on the strain energy release rate of composite materials and thin films. These analytically determined strain energy release rates should be compared to fracture toughness to predict the susceptibility of the material to fracture. Numerical examples are presented for several polymeric and metal matrix composites using available experimental data for …

A Federated Learning Framework For Data-Sovereign Predictive Maintenance In Distributed Smart Manufacturing, Md Sazol Ahmmed, Sriram Praneeth Isanaka, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Featured Application: The proposed federated learning framework can be applied in distributed smart manufacturing environments where multiple factories or production facilities collaboratively develop predictive maintenance models without sharing sensitive operational data. This approach is particularly useful for industrial networks involving geographically distributed plants, contract manufacturing partners, and multi-site production systems where data sovereignty and avoidance of raw data sharing are critical. Predictive maintenance enables early detection of machine failures and reduces unexpected production downtime. However, conventional approaches typically rely on centralized data collection and model training which introduce challenges related to data sovereignty, communication overhead and data ownership. To address …

Using Machine-Learning-Based Process Map To Guide Evaluation Of Inconel 625 Mechanical Properties In Laser Foil Printing, Yu Hsiang Wang, Sung Heng Wu, Hung Chu Chiang, Pen Ning Yu, Chia Hung Hung, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Inconel 625 is widely studied in powder-based additive manufacturing, but its processing characteristics and mechanical performance in foil-feedstock laser foil printing (LFP) remain largely unexplored. In this study, a gradient boosting regression (GBR)-based process map was developed for LFP of Inconel 625 using 32 single-track experiments. The GBR model achieved R² values of 0.859 and 0.793 and mean absolute errors of 22.25 μm and 19.83 μm for melt-pool depth and width, respectively, outperforming second- and third-order polynomial regressions in capturing nonlinear melt-pool responses and distinguishing lack-of-fusion, conduction, and keyhole regimes. Three conduction-mode conditions with target depth-to-foil thickness ratios (D/T) …

Validity Of The Schrage Equation In Prediction Of Evaporation Rate Of Liquid N-Dodecane In High-Pressure Nitrogen Gas: A Molecular Dynamics Study, Wazih Tausif, Jordan Hartfield, Md Amin Haque, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Evaporation of liquid fuel in a high-pressure air is a process that critically influences fuel–air mixing in advanced propulsion systems. In this work, we use molecular dynamics (MD) simulations to study the validity and accuracy of the Schrage equation in quantifying the evaporation and condensation rates of n-dodecane (a diesel surrogate) in air (approximated as N2 gas) with gas pressure varying from 0 atm to above the critical pressure of n-dodecane. The MD simulation results show that the evaporation coefficient (αe) is higher than the condensation coefficient (αc) at the evaporating n-dodecane surface and is lower than αc at the …

Machine Vision For In Situ Measurement And Control Of Wire Stickout In Lwded Process, Braden Mclain, Remy Mathenia, Todd Sparks, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work presents a machine-vision–based measurement and control framework for laser wire directed energy deposition (LWDED) processes. A visible-light camera system is used to capture meltpool images, from which a novel vision algorithm extracts the wire–meltpool interface location. By utilizing a camera that is rigidly mounted to the deposition head, the vision algorithm provides a relative measurement of the distance between the nozzle tip and the workpiece, also referred to as wire stickout. A proportional-derivative (PD) control strategy is implemented using the measured stickout as feedback to adjust deposition feedrate. Results show that the control system successfully compensates for improper …

Quantitative Phase-Field Modeling Of Nonequilibrium Microstructural Evolution In Rapid Solidification For Additive Manufacturing, Leiji Li, Fei Xiao, Ying Zhou, Xiaorong Cai, Chongfeng Zhang, Jinzhong Gao, Xiaopeng Shen, Tianchi Zhu, Sihan Wang, Yijia Gu, Xuejun Jin

Materials Science and Engineering Faculty Research & Creative Works

Fusion-based metal additive manufacturing (AM) relies on layer-by-layer deposition and rapid solidification, where the material transitions swiftly from liquid to solid. A key phenomenon during this process is solute trapping, a nonequilibrium effect governed by a velocity-dependent partition coefficient, which critically influences microstructure kinetics, morphology, and phase formation. In this study, we employ a recently proposed quantitative phase field (PF) model to systematically explore solute trapping, solute drag, and their impacts on pattern formation during rapid solidification at AM-relevant velocities, in both one and two dimensions. Our simulations reveal a growth mode transition from planar to cellular to dendritic, and …

Simulating Thermal Diffusion Through Image-Derived Microstructures Of Ceramic Matrix Composites, Matik Heskin

Miners Solving for Tomorrow Research Conference

Thermal energy transport in materials can be effectively modeled using finite element software such as COMSOL. Experimentally measured or NIST–JANAF thermal conductivity data can be used to represent material behavior within these simulations. For heterogeneous or composite materials, effective properties are often approximated using rule-of-mixtures calculations. However, this overlooks the nuanced effects caused by complex microstructural geometry. To address this limitation, imaging and coding tools such as MATLAB can be used to process scanning electron microscopy (SEM) images. By thresholding the images to distinguish constituent materials, a representative mesh can be generated and imported into an FEM program. This approach …

Human Intention Prediction Using Cnn And Lstm Networks In Physical Human–Robot Interactions, Khosro Ghorbani Zadeh

Miners Solving for Tomorrow Research Conference

Advances in robotics and artificial intelligence have increased expectations for interactive robots in eldercare and assistive applications. A key challenge in creating safe and effective systems is accurately recognizing human intent and translating it into meaningful commands for robots to follow. Traditional physics-based models often fail to fully represent human force interactions due to their dynamic nature, while neural networks provide a promising alternative for predicting force-movement intentions. Multi-layer perceptrons (MLPs) show potential, however, they struggle with temporal dependencies and generalization. Long Short-Term Memory (LSTM) networks and Convolutional Neural Networks (CNNs) help address these limitations. This study compares these architectures …

Ballistic Trajectories From Triangular Libration Points To Moon, Collin Gentry

Miners Solving for Tomorrow Research Conference

As stable points in the Earth-Moon system, the triangular libration points, L4 and L5, have many advantageous properties for space exploration. Ballistic trajectories at varying delta-Vs and impulse angles are computed and propagated from the libration points, and trajectories that arrive at the lunar surface are investigated. Preliminary conclusions are drawn about the accessibility of the lunar surface from the triangular libration points, and the implications for mission design are discussed. These trajectories present an alternative means of accessing the Moon, expanding the viability of the triangular points for missions and offering additional options for the use of cisular space.

Additive Manufacturing Of Ti-Ni Based Ternary Shape Memory Alloys, Yitao Chen, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metal additive manufacturing has become a powerful tool to develop customized metal alloys and to discover more advanced properties for novel extended applications. Ti-Ni based shape memory alloy is a group of intriguing smart functional materials, and adding a small amount of a third element can promote and induce more attractive functions. Due to the difficulty in traditional processing and the unique feature of material flexibility of in-situ alloying in additive manufacturing processes, not only Ti-Ni binary shape memory alloys but also Ti-Ni-X ternary shape memory alloys can be developed, manufactured, and investigated in-depth by additive manufacturing. This paper provides …

Understanding Human Arm Stiffness Modulation In Overground Phri: The Roles Of Kinematics, Perturbation, And Trunk Sway, Mohsen Mohammadi Beirami, Sambad Regmi, Devin Michael Burns, Yun Seong Song

Psychological Science Faculty Research & Creative Works

This study examines human arm kinematics during overground physical human-robot interaction (pHRI). Previous work showed humans adjust arm stiffness with changing trajectory uncertainty, but the roles of arm kinematics and muscle activation remained unclear. Building on a preliminary study, we analyzed arm movements with more participants (10 individuals) to achieve more reliable findings and examined two potential influences that arose in the preliminary study: the robot's perturbation effect (a brief hand push) and left-to-right trunk sway. Using a linear mixed-effects model, we evaluated the effects of participant, block, and trajectory condition on arm angles. Results showed minimal kinematic contribution to …

Hybrid Sensing For Near-Earth Space Domain Awareness: Leveraging Space-Based Assets For Augmenting Optical Ground Observations, Smriti Nandan Paul, Hang Woon Lee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Because of recent advancements in space technologies, easier and more economical access to space, and an increase in commercial interests, the near-Earth space environment has witnessed an exploding number of objects being put into orbit. In particular, the low Earth orbit (LEO) region is at an increased risk of orbital collisions from large satellite constellation projects. Thus, monitoring LEO objects for space domain awareness and space traffic management has become increasingly imperative. In this paper, we use the concept of limited-CDF (cumulative distribution function) surface and mutual information for designing sensor tasking algorithms focusing on regular observation of known catalog …

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 …

An Improved United-Atom Potential For Molecular Dynamics Simulation Of Saturated Properties Of N-Alkanes, Wazih Tausif, Jordan Hartfield, Alex George, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multiple united-atom (UA) potential models have been developed in the literature to reproduce experimental saturated properties of n-alkanes using Monte Carlo simulations. When these UA potentials are employed in molecular dynamics (MD) simulations, MD simulations often give relatively poor predictions of saturated properties of n-alkanes, particularly the saturated vapor densities, due to the challenges in accurate calculation of long-range intermolecular forces beyond the cutoff distance in an inhomogeneous system. In this work, a new set of UA Lennard-Jones (LJ) interaction parameters for n-alkanes is proposed to reproduce the saturated properties, including saturated liquid and vapor densities (ρ_f and ρ …

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 For Extrusion-Based Additive Manufacturing: Generation Of Guidelines For Ceramics With Comparison To Thermoplastics, Hollis Hervey Waites

Masters Theses

"Design for Additive Manufacturing (DfAM) has made much progress for polymer material extrusion processes (MEX-P), like Fused Deposition Modeling (FDM), but very little progress for ceramic MEX processes (MEX-C) like Direct Ink Writing (DIW). This thesis leverages MEX-P design guidelines to create an initial set of design guidelines for DIW. FDM and DIW processes and material properties are compared, and the effect of these factors on the differences in rules is discussed. Five design guidelines are identified as applying to all MEX. For three of these, an exact limit for DIW of alumina is studied: minimum corner radius in the …

Castrip Process Technology: Non-Grain Oriented (Ngo) Si Steels Extension And Carbide-Free Bainitic (Cfb) For Flat Products, Naram Naidu Meesala

Masters Theses

"This research explores the development of advanced steel grades manufactured through Castrip® twin-roll thin strip casting technology, with particular attention to non-grain-oriented electrical Si-Steels (NGOES) and carbide-free bainitic (CFB) steels. The Castrip® process offers a near-net-shape route for producing thin steel strips, which greatly decreases the number of processing stages, lowers energy demand, and reduces carbon dioxide emissions when compared with traditional steel production methods.

In the NGOES part of the study, several industrial Fe–Si steel compositions were cold rolled to final thicknesses ranging from 0.35 mm to 0.15 mm. These materials were then exposed to short-duration continuous annealing at …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

Fabrication And Characterization Of A High Strength Novel Aluminum Alloy For Implementation With Directed Energy Deposition, Rachel Boillat-Newport

Doctoral Dissertations

"Additive manufacturing (AM) is of significant interest due to the ability to fabricate 3D components layer-by-layer. Compared with traditional manufacturing methods, AM allows for the direct fabrication of complex, intricate parts without the need for extensive machining, reducing manufacturing time and tooling costs and minimizing material waste. Aluminum alloys are highly desired for implementation via AM due to their high strength-to-weight ratios; however, there are several challenges that complicate the situation and hinder the use of aluminum alloys. One of the most challenging issues is that the desired high-strength alloys are not compatible with AM processing methods. A method to …

Manufacturing And Performance Evaluation Of Carbon/Epoxy Laminated Composites Cured Using Single- And Six-Magnetron Microwave Applications, Nayan Pundhir

Doctoral Dissertations

Microwave curing is fast, energy-efficient, and a viable alternative to conventional thermal curing processes. It has been widely adopted for processing carbon fiber-reinforced polymer (CFRP) composites because the high electrical conductivity of carbon fibers enables strong microwave coupling, leading to rapid volumetric heating and reduced energy consumption. The aim of this study is to investigate the use of microwave curing for manufacturing CFRP composites. IM7/Cycom 5320-1 unidirectional prepreg was utilized to fabricate laminated composites in two thickness ranges: 16-layer laminates (2.5 mm thickness) and 64-layer laminates (9.2 mm thickness). Two lay-up configurations were examined: symmetric cross-ply and quasi-isotropic. Different curing …