Mechanical Engineering Commons^™

Anisotropic Optical Responses Of Layered Thallium Arsenic Sulfosalt Gillulyite, Ravi P. N. Tripathi, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-element two-dimensional (2D) materials hold great promise in the context of tailoring the physical and chemical properties of the materials via stoichiometric engineering. However, the rational and controllable synthesis of complex 2D materials remains a challenge. Herein, we demonstrate the preparation of large-area thin quaternary 2D material flakes via mechanical exfoliation from a naturally occurring bulk crystal named gillulyite. Furthermore, the anisotropic linear and nonlinear optical properties including anisotropic Raman scattering, linear dichroism, and anisotropic third-harmonic generation (THG) of the exfoliated gillulyite flakes are investigated. The observed highly anisotropic optical properties originate from the reduced in-plane crystal symmetry. Additionally, the …

Polarization-Dependent Optical Responses In Natural 2d Layered Mineral Teallite, Ravi P. N. Tripathi, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-element layered materials enable the use of stoichiometric variation to engineer their optical responses at subwavelength scale. In this regard, naturally occurring van der Waals minerals allow us to harness a wide range of chemical compositions, crystal structures and lattice symmetries for layered materials under atomically thin limit. Recently, one type of naturally occurring sulfide mineral, ternary teallite has attained significant interest in the context of thermoelectric, optoelectronic, and photovoltaic applications, but understanding of light-matter interactions in such ternary teallite crystals is scarcely available. Herein, polarization-dependent linear and nonlinear optical responses in mechanically exfoliated teallite crystals are investigated including anisotropic …

Impact Of Surface And Pore Characteristics On Fatigue Life Of Laser Powder Bed Fusion Ti–6al–4v Alloy Described By Neural Network Models, Seunghyun Moon, Ruimin Ma, Ross Attardo, Charles Tomonto, Mark Nordin, Paul Wheelock, Michael Glavicic, Maxwell Layman, Richard Billo, Tengfei Luo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this study, the effects of surface roughness and pore characteristics on fatigue lives of laser powder bed fusion (LPBF) Ti–6Al–4V parts were investigated. The 197 fatigue bars were printed using the same laser power but with varied scanning speeds. These actions led to variations in the geometries of microscale pores, and such variations were characterized using micro-computed tomography. To generate differences in surface roughness in fatigue bars, half of the samples were grit-blasted and the other half were machined. Fatigue behaviors were analyzed with respect to surface roughness and statistics of the pores. For the grit-blasted samples, the contour …

Anisotropy In Impact Toughness Of Powder Bed Fused Aisi 304l Stainless Steel, Sreekar Karnati, Atoosa Khiabhani, Aaron Flood, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The current effort involved investigation into the anisotropy of AISI 304L fabricated through laser powder bed fusion. Charpy V‐notch specimens made from material fabricated at three different build orientations were tested and analyzed. A statistically significant difference among the toughness values indicates the presence of anisotropy within the additively manufactured material. While the lowest toughness was found in vertically built specimens, the horizontal specimens were found to exhibit the highest toughness. From the fracture surfaces, an atypical mode of failure was observed. Exclusive crack propagation along the interlayer track boundaries was observed. The toughness variation correlated with the ease of …

Second-Order Reliability Methods: A Review And Comparative Study, Zhangli Hu, Rami Mansour, Mårten Olsson, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Second-order reliability methods are commonly used for the computation of reliability, defined as the probability of satisfying an intended function in the presence of uncertainties. These methods can achieve highly accurate reliability predictions owing to a second-order approximation of the limit-state function around the Most Probable Point of failure. Although numerous formulations have been developed, the lack of full-scale comparative studies has led to a dubiety regarding the selection of a suitable method for a specific reliability analysis problem. In this study, the performance of commonly used second-order reliability methods is assessed based on the problem scale, curvatures at the …

Sensing Small Interaction Forces Through Proprioception, Fazlur Rashid, Devin Michael Burns, Yun Seong Song

Psychological Science Faculty Research & Creative Works

Understanding the human motor control strategy during physical interaction tasks is crucial for developing future robots for physical human-robot interaction (pHRI). In physical human-human interaction (pHHI), small interaction forces are known to convey their intent between the partners for effective motor communication. The aim of this work is to investigate what affects the human's sensitivity to the externally applied interaction forces. The hypothesis is that one way the small interaction forces are sensed is through the movement of the arm and the resulting proprioceptive signals. A pHRI setup was used to provide small interaction forces to the hand of seated …

Effect Of The Melt Pool Boundary Network On The Anisotropic Mechanical Properties Of Selective Laser Melted 304l, Myranda Spratt, Joseph William Newkirk, Okanmisope Fashanu, K. Chandrashekhara

Materials Science and Engineering Faculty Research & Creative Works

Anisotropic mechanical properties are a well-known issue in selective laser melted parts. The microstructure produced by selective laser melting (SLM) is directional, including the solidified melt pool structures and grains. This work investigates the melt pool boundary's effects on 304L stainless steel's compressive properties. 304L stainless steel solid cylinders were built using a pulse laser SLM machine in four directions using three hatch angle rotations: 0⁰, 67⁰, and 105⁰ . The twelve samples were compression tested, and the results were analyzed. Numerical models were also created with the different hatch angles and directions. The melt pool boundary network (MPBN) in …

Natural Van Der Waals Heterostructure Cylindrite With Highly Anisotropic Optical Responses, Arindam Dasgupta, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The mechanical exfoliation of naturally occurring layered materials has emerged as an easy and effective method for achieving ultrathin van der Waals (vdW) heterostructures with well-defined lattice orientations of the constituent two-dimensional (2D) material layers. Cylindrite is one such naturally occurring vdW heterostructure, where the superlattice is composed of alternating stacks of SnS2-like and PbS-like layers. Although the constituent 2D lattices are isotropic, inhomogeneous strain occurring from local atomic alignment for forcing the commensuration makes the cylindrite superlattice structurally anisotropic. Here, we demonstrate the highly anisotropic optical responses of cylindrite thin flakes induced by the anisotropic crystal structure, including angle-resolved …

Multimodal Ensemble Deep Learning To Predict Disruptive Behavior Disorders In Children, Sreevalsan S. Menon, K. Krishnamurthy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Oppositional defiant disorder and conduct disorder, collectively referred to as disruptive behavior disorders (DBDs), are prevalent psychiatric disorders in children. Early diagnosis of DBDs is crucial because they can increase the risks of other mental health and substance use disorders without appropriate psychosocial interventions and treatment. However, diagnosing DBDs is challenging as they are often comorbid with other disorders, such as attention-deficit/hyperactivity disorder, anxiety, and depression. In this study, a multimodal ensemble three-dimensional convolutional neural network (3D CNN) deep learning model was used to classify children with DBDs and typically developing children. The study participants included 419 females and 681 …

Human-Human Hand Interactions Aid Balance During Walking By Haptic Communication, Mengnan Wu, Luke Drnach, Sistania M. Bong, Yun Seong Song, Lena H. Ting

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Principles from human-human physical interaction may be necessary to design more intuitive and seamless robotic devices to aid human movement. Previous studies have shown that light touch can aid balance and that haptic communication can improve performance of physical tasks, but the effects of touch between two humans on walking balance has not been previously characterized. This study examines physical interaction between two persons when one person aids another in performing a beam-walking task. 12 pairs of healthy young adults held a force sensor with one hand while one person walked on a narrow balance beam (2 cm wide x …

Experimental Investigation Of Additive Manufacturing Of Continuous Carbon Fiber Composites With Multifunctional Electro-Tensile Properties, Ritesh Ghimire, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Manufacturing processes for monofunctional and multifunctional materials vary depending on the design optimization. Multifunctional continuous carbon fiber composites provide great potential in achieving coupled structural and electrical properties for their applications in aircraft, unmanned aircraft systems, and spacecraft. Proper optimization of tensile and electrical properties offers benefits early in the design and continuous operational safety phases to obtain coupled multifunctional properties. In this paper, fused filament fabrication additive manufacturing (AM) technique was used to fabricate continuous carbon fiber solid laminated composites test coupons. The proposed new method characterizes the electrical conductivity's coupled effects on the tensile properties, including the failure …

Construction Of Spatial Filtering Matrices For Norm-Optimal Ilc In Single Point Incremental Forming, Joseph D. Fischer, Mitchell R. Woodside, Douglas A. Bristow, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Iterative Learning Control (ILC) is a control technique used to improve performance in repetitive processes. ILC has grown in popularity in part due to its ease of implementation and ability to achieve high levels of accuracy even in complex nonlinear systems. However, a fundamental limitation of ILC is that it relies on system repetition, making the impact of non-repetitive disturbances (e.g., noise) on the controller's performance severe. Much work has been done to reject noise in the time domain; however, little has been done to address noise which is spatial in nature. In this work, a method for limiting noise …

Toughening Mechanisms For The Attachment Of Architectured Materials: The Mechanics Of The Tendon Enthesis, Mikhail Golman, Adam C. Abraham, Iden Kurtaliaj, Brittany P. Marshall, Yizhong Jenny Hu, Andrea G. Schwartz, X. Edward Guo, Victor Birman, Philipp J. Thurner, Guy M. Genin, Stavros Thomopoulos

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Architectured materials offer tailored mechanical properties but are limited in engineering applications due to challenges in maintaining toughness across their attachments. The enthesis connects tendon and bone, two vastly different architectured materials, and exhibits toughness across a wide range of loadings. Understanding the mechanisms by which this is achieved could inform the development of engineered attachments. Integrating experiments, simulations, and previously unexplored imaging that enabled simultaneous observation of mineralized and unmineralized tissues, we identified putative mechanisms of enthesis toughening in a mouse model and then manipulated these mechanisms via in vivo control of mineralization and architecture. Imaging uncovered a fibrous …

A Control Oriented Comprehensive Degradation Model For Battery Energy Storage System Life Prediction, Yaqi Zhu, Tazdik Plateau, Brody Riemann, Robert Landers, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In order to ensure that stationary battery energy storage systems (BESSs) provide reliable energy buffering, both for power quality and economic purposes, the degradation must be considered. Cell degradation involves various side reactions and is highly dependent on its operating conditions. To accurately track cell degradation and predict its impact on battery behavior, a comprehensive physics-based degradation model based on an electrolyte phase-enhanced single particle (SP) model is developed. Key degradation physics, namely solid electrolyte interphase (SEI) layer formation and growth, Li plating on the graphite anode, and Mn dissolution on cathode of nickel-cobalt-manganese oxide (NMC622) are considered. The model …

Additive Manufacturing Of Stainless Steel -- Copper Functionally Graded Materials Via Inconel 718 Interlayer, Xinchang Zhang, Lan Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The joining of dissimilar materials is becoming increasingly prevalent to integrate different material properties to enhance design flexibility and overall performance. This study introduced an innovative approach to additively manufacture copper on 316L stainless steel (SS316L) via Inconel 718 interlayers using directed energy deposition (DED). The novel multi-material structure was studied both experimentally and theoretically. The microstructure, tensile properties, microhardness, and thermal performance of the structure were characterized. Residual stress distribution over the structure was revealed by experimental-validated numerical modeling. The result exhibits that defect-free structures with excellent interfacial bonding can be achieved by introducing Inconel 718 interlayers. The bonding …

A Novel Laser-Aided Machining And Polishing Process For Additive Manufacturing Materials With Multiple Endmill Emulating Scan Patterns, Mohammad Masud Parvez, Sahil Patel, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In additive manufacturing (AM), the surface roughness of the deposited parts remains significantly higher than the admissible range for most applications. Additionally, the surface topography of AM parts exhibits waviness profiles between tracks and layers. Therefore, post-processing is indispensable to improve surface quality. Laser-aided machining and polishing can be effective surface improvement processes that can be used due to their availability as the primary energy sources in many metal AM processes. While the initial roughness and waviness of the surface of most AM parts are very high, to achieve dimensional accuracy and minimize roughness, a high input energy density is …

Coupled Flexural‐Electrical Evaluation Of Additively Manufactured Multifunctional Composites At Ambient Temperature, Ritesh Ghimire, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multifunctional composites offer a higher strength to weight ratio, electrical properties, etc., thereby providing possible solutions for replacing the physical electrical wirings in aircraft. The lack of research on the coupled multifunctional characterization of 3D printed composites flexural-electrical properties is the main reason for its unsuitability in aerospace applications. The proposed method evaluates multifunctional flexural‐electrical properties of 3D printed multifunctional carbon fiber composites. Traditional methods for conducting structural and electrical analyses for aircraft certification do not accommodate new technologies that are not yet proven. Such technologies are additive manufacturing (AM) techniques, multifunctional composite structures, and the certification requirements for 3D …

Submicron Metal 3d Printing By Ultrafast Laser Heating And Induced Ligand Transformation Of Nanocrystals, Chinmoy Podder, Xiangtao Gong, Xiaowei Yu, Wan Shou, Heng Pan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Currently, light-based three-dimensional (3D) printing with submicron features is mainly developed based on photosensitive polymers or inorganic-polymer composite materials. To eliminate polymer/organic additives, a strategy for direct 3D assembly and printing of metallic nanocrystals without additives is presented. Ultrafast laser with intensity in the range of 1 x 1010 to 1 x 1012 W/cm2 is used to nonequilibrium heat nanocrystals and induce ligand transformation, which triggers the spontaneous fusion and localized assembly of nanocrystals. The process is due to the operation of hot electrons as confirmed by a strong dependence of the printing rate on laser pulse duration varied in …

Stabilization Of Energy Level Sets Of Underactuated Mechanical Systems Exploiting Impulsive Braking, Nilay Kant, Ranjan Mukherjee, Hassan Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recent investigations of underactuated systems have demonstrated the benefits of control inputs that are impulsive in nature. Here we consider the problem of stabilization of energy level sets of underactuated systems exploiting impulsive braking. We consider systems with one passive degree-of-freedom (DOF) and the energy level set is a manifold where the active coordinates are fixed and the mechanical energy equals some desired value. A control strategy comprised of continuous inputs and intermittent impulsive braking inputs is presented. The generality of the approach is shown through simulation of a three-DOF Tiptoebot; the feasibility of implementation of impulsive control using standard …

Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Coalescence of Two Nanobubbles (NBs) in Water is a Process of Great Importance to Many Industrial Applications. in This Work, We Study the Coalescence of Two Equal-Sized Nitrogen NBs in Water using Molecular Dynamics (MD) Simulations and Continuum-Based Theoretical Analysis. We Vary the NB Diameter from 30 to 50 Nm and Study the Coalescence Characteristics Including the Expansion Speed of the Capillary Bridge between Two Coalescing NBs, the Dynamic Regime of NB Coalescence, the Diameter of Fully Merged NBs, and the Temperature Variation of NBs during the Coalescence Process. for All Cases, We Show the MD Simulation Results Can …

Physical-Based Training Data Collection Approach For Data-Driven Lithium-Ion Battery State-Of-Charge Prediction, Jie Li, Will Ziehm, Jonathan W. Kimball, Robert Landers, Jonghyun Park

Electrical and Computer Engineering Faculty Research & Creative Works

Data-Driven approaches for State of Charge (SOC) prediction have been developed considerably in recent years. However, determining the appropriate training dataset is still a challenge for model development and validation due to the considerably varieties of lithium-ion batteries in terms of material, types of battery cells, and operation conditions. This work focuses on optimization of the training data set by using simple measurable data sets, which is important for the accuracy of predictions, reduction of training time, and application to online estimation. It is found that a randomly generated data set can be effectively used for the training data set, …

Numerical Investigation Of Thermo-Mechanical Field During Selective Laser Melting Process With Experimental Validation, Lan Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this study, thermo-mechanical simulation was conducted to predict thermal and stress behavior in Selective Laser Melting (SLM). Temperature-dependent material properties for processed material 304L stainless steel were incorporated into the model in order to capture the change from powder to fully dense solid stainless steel. Temperature and thermal stress history were tracked under conditions of different parameter sets which were designed to reduce defect formation. The thermal model predicted the temperature history for multi-track scans under different process parameters, such as laser power, effective scanning speed and hatch spacing. Subsequently, the corresponding melt-pool size, solidification rate and temperature gradients …

A Kinematic Error Controller For Real-Time Kinematic Error Correction Of Industrial Robots, Mitchell R. Woodside, Joseph Fischer, Patrick Bazzoli, Douglas A. Bristow, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Industrial robots are being used more and more for manufacturing applications that require accuracy beyond what can be obtained from joint measurement. While offline calibration techniques such as volumetric error compensation can be used to correct robot kinematic error, these methods are unable to compensate for robot deformations caused by changing tool loads during the manufacturing operation. This paper explores the use of a real-time robot kinematic error compensation technique where an external high-precision feedback sensor (in this case a laser tracker) directly measures the robot kinematic error and corrections are implemented during processing. A robot kinematic error model is …

Three-Dimensional Laser-Assisted Printing Of Structures From Nanoparticles, Heng Pan, Chinmoy Podder, Wan Shou, Xiaowei Yu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A method for manufacturing a component comprising bombarding nanoparticles in a dispersion with a laser to transform the ligand and cause the nanoparticles to drop out of the dispersion and deposit onto a substrate; and bombarding additional nanoparticles in the dispersion with the laser to transform the ligand and cause the nanoparticles to drop out of the dispersion and deposit onto the nanoparticles previously deposited out of the dispersion.

Fabricating Tinicu Ternary Shape Memory Alloy By Directed Energy Deposition Via Elemental Metal Powders, Yitao Chen, Xinchang Zhang, Mohammad Masud Parvez, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In this paper, a TiNiCu shape memory alloy single-wall structure was fabricated by the directed energy deposition technique with a mixture of elemental Ti, Ni, and Cu powders following the atomic percentage of Ti50Ni45Cu5 to fully utilize the material flexibility of the additive manufacturing process to develop ternary shape memory alloys. The chemical composition, phase, and material properties at multiple locations along the build direction were studied, using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Vickers hardness test-ing, tensile testing, and differential scanning calorimetry. The location-dependent compositions of martensitic TiNi and austenitic TiNi phases, mechanical properties, and functional properties …

Energy-Based Orbital Stabilization Of Underactuated Systems Using Impulse Controlled Poincaré Maps, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of energy-based orbital stabilization of underactuated mechanical systems with one passive degree-of-freedom is addressed. The orbit is a manifold where the active generalized coordinates are fixed, and the total mechanical energy is equal to some desired value. A hybrid control strategy comprised of continuous and intermittent impulsive inputs is presented. The continuous controller is designed using partial feedback inearization to converge the active generalized coordinates to their desired values. The choice of desired energy characterizes a unique orbit which is stable but not asymptotically stable. To stabilize the desired orbit, a Poincaré section is constructed at a fixed …

The Effect Of Nanostructures In Aluminum Alloys Processed Using Additive Manufacturing On Microstructural Evolution And Mechanical Performance Behavior, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper reviews the status of nanoparticle technology as it relates to the additive manufacturing (AM) of aluminum-based alloys. A broad overview of common AM processes is given. Additive manufacturing is a promising field for the advancement of manufacturing due to its ability to yield near-net-shaped components that require minimal post-processing prior to end-use. AM also allows for the fabrication of prototypes as well as economical small batch production. Aluminum alloys processed via AM would be very beneficial to the manufacturing industry due to their high strength to weight ratio; however, many of the conventional alloy compositions have been shown …

Thermal Modeling Of Li-Ion Batteries Using Sp+3d Model, Derrick Barger

Undergraduate Research Conference at Missouri S&T

An ideal battery model must gather sufficient electrochemical data about the system while remaining being computationally efficient. To prevent failure from thermal runaway, understanding the thermal characteristics of a battery is essential.

To achieve this, we have developed a single particle (SP) model, a simplified but accurate approach to battery modeling, and compared this to a previously designed 3D model. After validating the battery electrochemistry, equations were introduced to calculate the heat generation with a coupled 3D heat transfer component to provide data on the cell temperature. This same model was used to simulate a multi-cell pack.

The results indicate …

Effects Of Acetylene Addition To The Fuel Stream On Soot Formation And Flame Properties In An Axisymmetric Laminar Coflow Ethylene/Air Diffusion Flame, Xinrong Xie, Shu Zheng, Ran Sui, Zixue Luo, Shi Liu, Jean Louis Consalvi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The effects of adding acetylene to the fuel stream on soot formation and flame properties were investigated numerically in a laminar axisymmetric coflow ethylene/air diffusion flame using the open-source flame code Co-Flame in conjunction with an elementary gas-phase chemistry scheme and detailed transport and thermodynamic database. Radiation heat transfer of the radiating gases (H2O, C2H2, CO, and CO2) and soot was calculated using a statistical narrow-band correlated-k-based wide band model coupled with the discrete-ordinates method. The soot formation was described by the consecutive steps of soot nucleation, surface growth of soot particles via polycyclic aromatic hydrocarbons (PAHs)-soot condensation or the …

Oxidation Polymerization Additive Manufacturing, Jonghyun Park, Tazdik Patwary Plateau, Hiep Pham

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Various processes for producing three dimensional electrically conductive polymer structures, such as three dimensional structures of poly(3,4-ethylenedioxythiophene), are described as well as materials produced by these processes.