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Articles 211 - 240 of 1144
Full-Text Articles in Mechanical Engineering
Nanobubble Capillary Force Between Parallel Plates, Eric Bird, Zhi Liang
Nanobubble Capillary Force Between Parallel Plates, Eric Bird, Zhi Liang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Aggregation of Fine or Ultrafine Particles in Liquid Due to the Nanobubble (NB) Bridging Capillary Force is a Key Process for Many Industrial Applications. the Magnitude and Direction of the NB Capillary Force (NBCF) Are Directly Affected by the Geometry of the NB Gas Bridge between Two Adjoining Particles. Although the NBCF Can Be Accurately Measured using Experimental Techniques, It is Very Challenging to Monitor the Images of a NB Capillary Bridge in Nanoscale Spatial Resolution in NBCF Measuring Experiments. as a Result, the Capillary Force Model that Predicts the Dependence of the NBCF on the Geometry of the …
Frequency Domain Measurements Of Melt Pool Recoil Force Using Modal Analysis, Tristan Cullom, Cody Lough, Nicholas Altese, Douglas A. Bristow, Robert G. Landers, Ben Brown, For Full List Of Authors, See Publisher's Website.
Frequency Domain Measurements Of Melt Pool Recoil Force Using Modal Analysis, Tristan Cullom, Cody Lough, Nicholas Altese, Douglas A. Bristow, Robert G. Landers, Ben Brown, For Full List Of Authors, See Publisher's Website.
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Recoil pressure is a critical factor affecting the melt pool dynamics during Laser Powder Bed Fusion (LPBF) processes. Recoil pressure depresses the melt pool. When the recoil pressure is low, thermal conduction and capillary forces may be inadequate to provide proper fusion between layers. However, excessive recoil pressure can produce a keyhole inside the melt pool, which is associated with gas porosity. Direct recoil pressure measurements are challenging because it is localized over an area proportionate to the laser spot size producing a force in the mN range. This paper reports a vibration-based approach to quantify the recoil force exerted …
2d Layered Sip As Anisotropic Nonlinear Optical Material, Huseyin Sar, Jie Gao, Xiaodong Yang
2d Layered Sip As Anisotropic Nonlinear Optical Material, Huseyin Sar, Jie Gao, Xiaodong Yang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Two-dimensional (2D) material of silicon phosphide (SiP) has recently been shown as a promising optical material with large band gap, fast photoresponse and strong anisotropy. However, the nonlinear optical properties of 2D SiP have not been investigated yet. Here, the thickness-dependent in-plane anisotropic third-harmonic generation (THG) from the mechanically exfoliated 2D layered SiP flakes is reported. The crystal orientation of the SiP flake is determined by the angle-resolved polarized Raman spectroscopy. The angular dependence of the THG emission with respect to the incident linear polarization is found to be strongly anisotropic with the two-fold polarization dependence pattern. Furthermore, the effect …
Naturally Occurring Layered Mineral Franckeite With Anisotropic Raman Scattering And Third-Harmonic Generation Responses, Ravi P. N. Tripathi, Jie Gao, Xiaodong Yang
Naturally Occurring Layered Mineral Franckeite With Anisotropic Raman Scattering And Third-Harmonic Generation Responses, Ravi P. N. Tripathi, Jie Gao, Xiaodong Yang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Vertically stacked van der Waals (vdW) heterostructures have introduced a unique way to engineer optical and electronic responses in multifunctional photonic and quantum devices. However, the technical challenges associated with the artificially fabricated vertical heterostructures have emerged as a bottleneck to restrict their proficient utilization, which emphasizes the necessity of exploring naturally occurring vdW heterostructures. As one type of naturally occurring vdW heterostructures, franckeite has recently attracted significant interest in optoelectronic applications, but the understanding of light-matter interactions in such layered mineral is still very limited especially in the nonlinear optical regime. Herein, the anisotropic Raman scattering and third-harmonic generation …
Anisotropic Optical Responses Of Layered Thallium Arsenic Sulfosalt Gillulyite, Ravi P. N. Tripathi, Jie Gao, Xiaodong Yang
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
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
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
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
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 …
Natural Van Der Waals Heterostructure Cylindrite With Highly Anisotropic Optical Responses, Arindam Dasgupta, Jie Gao, Xiaodong Yang
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
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
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
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
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
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
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
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
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
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
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
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
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 …
Numerical Investigation Of Thermo-Mechanical Field During Selective Laser Melting Process With Experimental Validation, Lan Li, Frank W. Liou
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
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
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.
Energy-Based Orbital Stabilization Of Underactuated Systems Using Impulse Controlled Poincaré Maps, Nilay Kant, Ranjan Mukherjee
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
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 …
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
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
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.
Experimental And Numerical Investigation In Directed Energy Deposition For Component Repair, Lan Li, Xinchang Zhang, Frank W. Liou
Experimental And Numerical Investigation In Directed Energy Deposition For Component Repair, Lan Li, Xinchang Zhang, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Directed energy deposition (DED) has been widely used for component repair. In the repair process, the surface defects are machined to a groove or slot and then refilled. The sidewall inclination angle of the groove geometry has been recognized to have a considerable impact on the mechanical properties of repaired parts. The objective of this work was to investigate the feasibility of repairing various V-shaped defects with both experiments and modeling. At first, the repair volume was defined by scanning the defective zone. Then, the repair volume was sliced to generate the repair toolpath. After that, the DED process was …