Mechanical Engineering Commons^™

Assessing The Limitations Of Effective Number Of Samples For Finding The Uncertainty Of The Mean Of Correlated Data, Barton L. Smith, Douglas R. Neal, Mark Feero, Geordie Richards

Mechanical and Aerospace Engineering Faculty Publications

The efficacy of recent and classical theories on the uncertainty of the mean of correlated data have been investigated. A variety of very large data sets make it possible to show that, under circumstances that are often too expensive to achieve, the integral time scale can be used to determine the effective number of independent samples, and therefore the uncertainty of the mean. To do so, the data set must be sufficiently large that it may be divided into many records, each of which is many integral time scales long. In this circumstance, all lags of the autocorrelation should be …

Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly

Faculty Publications

In recent years, as a result of significant climate change, stringent windstorms are becoming more frequent than before. Given the threat that windstorms bring to people and property, wind/structural engineering research is imperative to improve the resilience of existing and new infrastructure, for community safety and assets protection. The Windstorm Impact, Science and Engineering (WISE) research program at Louisiana State University (LSU) focuses on creating new knowledge applicable to the mitigation of existing and new infrastructure, to survive and perform optimally under natural hazards. To achieve our research goals, we address two imperious challenges: (i) characterization of realistic wind forces …

Prediction Of Thermal Conductance At Liquid-Gas Interfaces Using Molecular Dynamics Simulations, James Gonzalez, Josue Ortega, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using Molecular Dynamics (MD) Simulations and Theoretical Calculations, We Study Heat Transfer Across Liquid-Gas Interfaces within a Planar Heat Pipe. to Determine the Thermal Conductance (Kapitza Conductance), GK, at the Interface, Two Heat Transfer Mechanisms, Namely, Conduction and Evaporation/condensation Are Considered. in the Case of Interfacial Heat Conduction, Gas Molecules, Particularly Non-Condensable Gas Molecules, Exchange Heat with Liquid Surfaces through Gas-Liquid Collisions, and the Theoretical Expression for GK is Derived from the Kinetic Theory of Gases. for Interfacial Heat Transfer by Evaporation or Condensation, the Theoretical Expression for GK is Derived from the Schrage Relationships. to Assess the Accuracies of …

Fast Prediction Of Thermal Distortion In Metal Powder Bed Fusion Additive Manufacturing: Part 1, A Thermal Circuit Network Model, Hao Peng, Morteza Ghasri-Khouzani, Shan Gong, Ross Attardo, Pierre Ostiguy, Bernice Aboud Gatrell, Joseph Budzinski, Charles Tomonto, Joel Neidig, M. Ravi Shankar, Richard Billo, David B. Go, David Hoelzle

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The additive manufacturing (AM) process metal powder bed fusion (PBF) can quickly produce complex parts with mechanical properties comparable to wrought materials. However, thermal stress accumulated during PBF induces part distortion, potentially yielding parts out of specification and frequently process failure. This manuscript is the first of two companion manuscripts that introduce a computationally efficient distortion and stress prediction algorithm that is designed to drastically reduce compute time when integrated in to a process design optimization routine. In this first manuscript, we introduce a thermal circuit network (TCN) model to estimate the part temperature history during PBF, a major computational …

Fast Prediction Of Thermal Distortion In Metal Powder Bed Fusion Additive Manufacturing: Part 2, A Quasi-Static Thermo-Mechanical Model, Hao Peng, Morteza Ghasri-Khouzani, Shan Gong, Ross Attardo, Pierre Ostiguy, Ronald B. Rogge, Bernice Aboud Gatrell, Joseph Budzinski, Charles Tomonto, Joel Neidig, M. Ravi Shankar, Richard Billo, David B. Go, David Hoelzle

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The additive manufacturing (AM) process metal powder bed fusion (PBF) can quickly produce complex parts with mechanical properties comparable to that of wrought materials. However, thermal stress accumulated during Metal PBF may induce part distortion and even cause failure of the entire process. This manuscript is the second part of two companion manuscripts that collectively present a part-scale simulation method for fast prediction of thermal distortion in Metal PBF. The first part provides a fast prediction of the temperature history in the part via a thermal circuit network (TCN) model. This second part uses the temperature history from the TCN …

Considerations For Atmospheric Measurements With Small Unmanned Aircraft Systems, Jamey D. Jacob, Phillip B. Chilson, Adam L. Houston, Suzanne Weaver Smith

Mechanical Engineering Faculty Publications

This paper discusses results of the CLOUD-MAP (Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics) project dedicated to developing, fielding, and evaluating integrated small unmanned aircraft systems (sUAS) for enhanced atmospheric physics measurements. The project team includes atmospheric scientists, meteorologists, engineers, computer scientists, geographers, and chemists necessary to evaluate the needs and develop the advanced sensing and imaging, robust autonomous navigation, enhanced data communication, and data management capabilities required to use sUAS in atmospheric physics. Annual integrated evaluation of the systems in coordinated field tests are being used to validate sensor performance while integrated into various sUAS platforms. …

Catalytic Augmentation Of An Arc-Ignited Hydrogen Peroxide/Abs Hybrid Rocket System, Stephen A. Whitmore, Christopher J. Martinez

Mechanical and Aerospace Engineering Faculty Publications

The authors have collaborated with an industry partner to develop a prototype upper stage for a dedicated nano-launch vehicle. In addition to providing sufficient impulse for orbit insertion, the unique motor system also provides capability for multiple restarts; allowing operation as an orbital maneuvering thruster. The hybrid motor design uses 85%-90% hydrogen peroxide solution and 3-D printed ABS as propellants. In the original system design the peroxide catalyst bed was completely removed and a patented arc-ignition system thermally ignited the propellants. The thermal ignition system was effective but resulted in a combustion latency of approximately 1-second, reducing overall performance and …

Novel Structural Health Monitoring And Damage Detection Approaches For Composite And Metallic Structures, Shervin Tashakori

FIU Electronic Theses and Dissertations

Mechanical durability of the structures should be continuously monitored during their operation. Structural health monitoring (SHM) techniques are typically used for gathering the information which can be used for evaluating the current condition of a structure regarding the existence, location, and severity of the damage. Damage can occur in a structure after long-term operating under service loads or due to incidents. By detection of these defects at the early stages of their growth and nucleation, it would be possible to not only improve the safety of the structure but also reduce the operating costs. The main goal of this dissertation …

Numerical Assessment Of The Convective Heat Transfer In Rotating Detonation Combustors Using A Reduced-Order Model, James Braun, Jorge Sousa, Guillermo Paniagua

School of Aeronautics and Astronautics Faculty Publications

The pressure gain across a rotating detonation combustor offers an efficiency rise and potential architecture simplification of compact gas turbine engines. However, the combustor walls of the rotating detonation combustor are periodically swept by both detonation and oblique shock waves at several kilohertz, disrupting the boundary layer, resulting in a rather complex convective heat transfer between the fluid and the solid walls. A computationally fast procedure is presented to calculate this extraordinary convective heat flux along the detonation combustor. First, a numerical model combining a two-dimensional method of characteristics approach with a monodimensional reaction model is used to compute the …

Fracture Initiation In A Transversely Isotropic Solid: Transient Three Dimensional Analysis, Louis Milton Brock

Mechanical Engineering Faculty Publications

A transversely isotropic solid is at rest, and contains a semi-infinite, plane crack. The axis of rotational material symmetry lies in the crack plane. Application of normal point forces to each face of the crack causes transient 3D growth. The related problem of discontinuities in displacement and traction that exist on regions that exhibit dynamic similarity is first considered. Analytic results are obtained in integral transform space. These lead to equations of the Wiener–Hopf type for the fracture problem. Analytic solutions are again obtained and, upon inversion, subjected to a dynamic energy release rate criterion that includes kinetic energy. A …

Tutorial: Determination Of Thermal Boundary Resistance By Molecular Dynamics Simulations, Zhi Liang, Ming Hu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Due to the High Surface-To-Volume Ratio of Nanostructured Components in Microelectronics and Other Advanced Devices, the Thermal Resistance at Material Interfaces Can Strongly Affect the overall Thermal Behavior in These Devices. Therefore, the Thermal Boundary Resistance, R, Must Be Taken into Account in the Thermal Analysis of Nanoscale Structures and Devices. This Article is a Tutorial on the Determination of R and the Analysis of Interfacial Thermal Transport Via Molecular Dynamics (MD) Simulations. in Addition to Reviewing the Commonly Used Equilibrium and Non-Equilibrium MD Models for the Determination of R, We Also Discuss Several MD Simulation Methods Which Can Be …

The Water Entry Of Multi-Droplet Streams And Jets, Nathan B. Spiers, Zhao Pan, Jesse Belden, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

Water entry has been studied for over a century, but few studies have focused on multiple droplets impacting on a liquid bath sequentially. We connect multi-droplet streams, jets and solid objects with physical-based scaling arguments that emphasize the intrinsically similar cavities. In particular, the cavities created by the initial impact of both droplet streams and jets on an initially quiescent liquid pool exhibit the same types of cavity seal as hydrophobic spheres at low Bond number, some of which were previously unseen for jets and droplet streams. Low-frequency droplet streams exhibit an additional three new cavity seal types unseen for …

Development Of A Self-Orienting Cubesat Solar Array, Eric Mcgill

Honors Theses

The sponsor of this conceptual design project was the Air Force Institute of Technology (AFIT) at WrightPatterson Air Force Base in Dayton, Ohio. AFIT was striving to give CubeSats more capability to conduct research, reconnaissance, and other functions. One of the major barriers for AFIT to overcome to give CubeSats more capability was the ability of the CubeSat to generate usable power while in orbit. All of AFIT’s CubeSats generated the power needed while in orbit with solar panels that are rigidly mounted to the outside of the craft. AFIT believes that a new design for the solar array used …

Influence Of Reverse Shoulder Implant Positioning On Patient-Specific Muscle Forces: A Simulation Study, Kayla Marie Pariser

Honors Theses

A reverse total shoulder arthroplasty (RTSA) is a common treatment used to stabilize the shoulder and improve range of motion in patients with torn rotator cuff muscles. Shoulder stability relies on the shoulder muscles. With rotator cuff tears, the RTSA enables the deltoid muscle to become the primary stabilizer of the shoulder joint. To improve stability, RTSAs increase the deltoid muscle moment arm and decrease the required torque about the shoulder joint for movement. Currently, there is not standardized, objective method for a surgeon to position an implant on a specific patient. This study is part of a larger, ongoing …

Direct Metal Laser-Sintered Stainless Steel: Comparison Of Microstructure And Hardness Between Different Planes, M. Ghasri-Khouzani, H. Peng, R. Attardo, P. Ostiguy, J. Neidig, R. Billo, D. Hoelzle, M. R. Shankar

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microstructural analysis and micro-hardness measurements were performed on different planes of 316L stainless steel fabricated by direct metal laser sintering (DMLS) technique. A fine cellular network was observed within the steel microstructure, where morphology of most cells changed from columnar on XZ-plane (vertical section) to equiaxed on XY-plane (horizontal section). Correspondingly, morphology of most grains was found to alter from columnar for the XZ-plane to equiaxed in the case of the XY-plane. Moreover, X-ray diffraction (XRD) analysis revealed a fully austenitic structure for both the planes. The average micro-hardness value for the XZ-plane and XY-plane was insignificantly (≈ 3%) different, …

Numerical Simulation Of Heat Transfer And Chemistry In The Wake Behind A Hypersonic Slender Body At Angle Of Attack, Matthew J. Satchell, Jeffrey M. Layng, Robert B. Greendyke

Faculty Publications

The effect of thermal and chemical boundary conditions on the structure and chemical composition of the wake behind a 3D Mach 7 sphere-cone at an angle of attack of 5 degrees and an altitude of roughly 30,000 m is explored. A special emphasis is placed on determining the number density of chemical species which might lead to detection via the electromagnetic spectrum. The use of non-ablating cold-wall, adiabatic, and radiative equilibrium wall boundary conditions are used to simulate extremes in potential thermal protection system designs. Non-ablating, as well as an ablating boundary condition using the “steady-state ablation” assumption to compute …

Les Taux De Rupture De Conduites D’Eau Aux États-Unis Et Au Canada : Une Étude Complète, Steven Folkman

Mechanical and Aerospace Engineering Faculty Publications

La prospérité économique des villes modernes est basée sur un réseau d’infrastructures complexe à la fois en surface et sous la terre. Un élément essentiel pour la santé publique et le bien-être économique est notre eau potable, qui est acheminée jusqu’à notre robinet à travers un réseau complexe de conduites de distribution d’eau souterraines. Étant donné que la plus grande partie de cette infrastructure se trouve sous terre, elle est hors de vue et souvent négligée. Disposer de données empiriques sur des ruptures de conduites d’eau aide les services publics avec leurs processus de prises de décision quant aux réparations …

Molecular Simulation Of Steady-State Evaporation And Condensation In The Presence Of A Non-Condensable Gas, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using Molecular Dynamics Simulations, We Study Evaporation and Condensation of Fluid Ar in the Presence of a Non-Condensable Ne Gas in a Nanochannel. the Evaporation and Condensation Are Driven by the Temperature Difference, ΔTL, between the Evaporating and Condensing Liquid Surfaces. the Steady-State Evaporation and Condensation Fluxes (JMD) Are Also Affected by the Ne Concentration, ΡNe, and the Nanochannel Length. We Find that Across a Wide Range of ΔTL and ΡNe, JMD is in Good Agreement with the Prediction from Stefan's Law and from Schrage Relationships. Furthermore, for ΔTL Less Than ∼20% of the Absolute Average Temperature, We Find that …

Some Insights Into The Migration Of Double Imaginary Roots Under Small Deviation Of Two Parameters, Dina Alina Irofti, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper studies the migration of double imaginary roots of the systems’ characteristic equation when two parameters are subjected to small deviations. The proposed approach covers a wide range of models. Under the least degeneracy assumptions, we found that the local stability crossing curve has a cusp at the point that corresponds to the double root, and it divides the neighborhood of this point into an S-sector and a G-sector. When the parameters move into the G-sector, one of the roots moves to the right halfplane, and the other moves to the left half-plane. When the parameters move into the …

Nano-Graphene Oxide And Vitamin D Delivery, Reza Mahdavi, Mehran Solati-Hashjin, Meisam Omidi, Arash Khojasteh, Fateme Fayyazbakhsh

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the Most Interesting and Recent Insights into Biomimetic Scaffold Nano-Biomaterial is Smart Scaffolding with Targeted Drug Delivery Ability. in Recent Decades, the Use of Graphene-Based Materials, Such as Nano-Graphene Oxide (NGO), as a Drug Carrier with Amphiphilic Properties, Has Attracted Considerable Attention of Scientists and Researchers in This Field. in Addition, One of the Important Global Problems is Increased Vitamin D Deficiency, Particularly in Pregnant and Postmenopausal Women. Therefore, in This Work, by Considering Hydrophobic Properties of Vitamin D, We Attempted to Examine its Loading and Release Both in the Presence of Surfactant and Surfactant-Free NGO-Aqueous Solution. at …

Numerical Algorithm For Wing-Structure Design, Jeffrey D. Taylor, Douglas F. Hunsaker, James J. Joo

Mechanical and Aerospace Engineering Student Publications and Presentations

Low-fidelity aerostructural optimization routines have often focused on determining the optimal spanloads for a given wing configuration. Several analytical approaches have been developed that can predict optimal lift distributions on rectangular wings with a specific payload distribution. However, when applied to wings of arbitrary geometry and payload distribution, these approaches fail. Increasing the utility and accuracy of these analytical methods can result in important benefits during later design phases. In this paper, an iterative algorithm is developed that uses numerical integration to predict the distribution of structural weight required to support the bending moments on a wing with arbitrary geometry …

Evaluating Augmented Reality For Space Telerobotics Training, John Karasinski

Link Foundation Modeling, Simulation and Training Fellowship Reports

Despite the extensive previous research into manual tracking, to the author’s knowledge there exists no study in the literature addressing human performance or workload changes in manual tracking tasks between traditional computer monitors and mobile, augmented reality headsets. The aim of this study was to investigate the effect of several factors on human performance and workload in a three-axis manual tracking task. Recent advances in computing hardware have enabled a new generation of augmented reality stereoscopic devices, such as the Microsoft HoloLens, which have yet to be evaluated in the literature. The Microsoft HoloLens provides depth cues to the user …

Mechanical And Aerospace Engineering, 2017-2018, College Of Engineering And Applied Sciences

Mechanical and Aerospace Engineering News

• Letter from the Chair
• Introducing Dr. Jinseok Kim
• Use of 3D Printing at WMU Helps Borgess Cardiologist Plug Holes in the Heart
• Department of Mechanical and Aerospace Engineering Develops Semi-Virtual Reality Powered Wheelchair Simulator
• The Western Aerospace Launch Initiative (WALI)
• 2017 NSF I-Corps Experience of MAE team
• Matthew Baird's Internship Experiences at JPL and GRC
• More Department News
• Faculty Sabbaticals

Electrostatic Potential And Valence Modulation In La0.7sr0.3mno3 Thin Films, Robbyn Trappen, A. C. Garcia- Castro, Vu Thanh Tra, Chih-Yeh Huang, Wilfredo Ibarra-Hernandez, James Fitch, Sobhit Singh, Jingling Zhou, Guerau Cabrera, Ying-Hao Chu, James M. Lebeau, Aldo H. Romero, Mikel B. Holcomb

Faculty & Staff Scholarship

The Mn valence in thin film La0.7Sr0.3MnO3 was studied as a function of film thickness in the range of 1–16 unit cells with a combination of non-destructive bulk and surface sensitive X-ray absorption spectroscopy techniques. Using a layer-by-layer valence model, it was found that while the bulk averaged valence hovers around its expected value of 3.3, a significant deviation occurs within several unit cells of the surface and interface. These results were supported by first principles calculations. The surface valence increases to up to Mn3.7+, whereas the interface valence reduces down to Mn2.5+. The change in valence from the expected …

Iact Undergraduate Certificate In Applied Creativity (Year 1 - 2018), Brian Laduca

IACT Certificate Program

At the Institute of Applied Creativity for Transformation (IACT) at ArtStreet, we seek to empower a creatively confident 21st-century student with the ability to discover, invent and innovate ambiguous ideas through a disruptive design process that will impact today’s ever-changing global world regardless of degree focus.

IACT is home to the nation’s first undergraduate certificate in Applied Creativity for Transformation. Open to undergraduate students of any major, the certificate is a first step in achieving the University of Dayton’s vision of innovation, applied creativity, entrepreneurship and community engagement for the common good.

Strong Stability Of A Class Of Difference Equations Of Continuous Time And Structured Singular Value Problem, Qian Ma, Keqin Gu, Narges Choubedar

SIUE Faculty Research, Scholarship, and Creative Activity

This article studies the strong stability of scalar difference equations of continuous time in which the delays are sums of a number of independent parameters tau_i, i = 1, 2, . . . ,K. The characteristic quasipolynomial of such an equation is a multilinear function of exp(-tau_i s). It is known that the characteristic quasipolynomial of any difference equation set in the form of one-delayper- scalar-channel (ODPSC) model is also in such a multilinear form. However, it is shown in this article that some multilinear forms of quasipolynomials are not characteristic quasipolynomials of any ODPSC difference equation set. The equivalence …

Analytical Cpg Model Driven By Limb Velocity Input Generates Accurate Temporal Locomotor Dynamics, Sergiy Yakovenko, Anton Sobinov, Valeriya Gritsenko

Faculty & Staff Scholarship

The ability of vertebrates to generate rhythm within their spinal neural networks is essential for walking, running, and other rhythmic behaviors. The central pattern generator (CPG) network responsible for these behaviors is well-characterized with experimental and theoretical studies, and it can be formulated as a nonlinear dynam- ical system. The underlying mechanism responsible for locomotor behavior can be expressed as the process of leaky integration with resetting states generating appropriate phases for changing body velocity. The low-dimensional input to the CPG model generates the bilateral pattern of swing and stance modulation for each limb and is consistent with the desired …

Fabrication And Thermoelectric Characterization Of Transition Metal Silicide-Based Composite Thermocouples, Gunes A. Yakaboylu, Rajalekshmi C. Pillai, Katarzyna Sabolsky, Edward M. Sabolsky

Faculty & Staff Scholarship

Metal silicide-based thermocouples were fabricated by screen printing thick films of the powder compositions onto alumina tapes followed by lamination and sintering processes. The legs of the embedded thermocouples were composed of composite compositions consisting of MoSi2, WSi2, ZrSi2, or TaSi2 with an additional 10 vol % Al2O3 to form a silicide–oxide composite. The structural and high-temperature thermoelectric properties of the composite thermocouples were examined using X-ray diffraction, scanning electron microscopy and a typical hot–cold junction measurement technique. MoSi2-Al2O3 and WSi2-Al2O3 composites exhibited higher intrinsic Seebeck coefficients (22.2–30.0 μV/K) at high-temperature gradients, which were calculated from the thermoelectric data of …

Interval Fuzzy Model For Robust Aircraft Imu Sensors Fault Detection, Michele Crispoltoni, Mario Luca Fravolini, Fabio Balzano, Stephane D'Urso, Marcello Rosario Napolitano

Faculty & Staff Scholarship

This paper proposes a data-based approach for a robust fault detection (FD) of the inertial measurement unit (IMU) sensors of an aircraft. Fuzzy interval models (FIMs) have been introduced for coping with the significant modeling uncertainties caused by poorly modeled aerodynamics. The proposed FIMs are used to compute robust prediction intervals for the measurements provided by the IMU sensors. Specifically, a nonlinear neural network (NN) model is used as central prediction of the sensor response while the uncertainty around the central estimation is captured by the FIM model. The uncertainty has been also modelled using a conventional linear Interval Model …

Learning Local, Quenched Disorder In Plasticity And Other Crackling Noise Phenomena, Stefanos Papanikolaou

Faculty & Staff Scholarship

When far from equilibrium, many-body systems display behavior that strongly depends on the initial conditions. A characteristic such example is the phenomenon of plasticity of crystalline and amorphous materials that strongly depends on the material history. In plasticity modeling, the history is captured by a quenched, local and disordered flow stress distribution. While it is this disorder that causes avalanches that are commonly observed during nanoscale plastic deformation, the functional form and scaling properties have remained elusive. In this paper, a generic formalism is developed for deriving local disorder distributions from field- response (e.g., stress/strain) timeseries in models of crackling …