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- Additive manufacturing (2)
- Aluminum alloys (2)
- Homotopy class (2)
- Additive manufacturing (AM) (1)
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- And compressive stress (1)
- Atomization (1)
- CALPHAD (1)
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- ECN; Radiation; EGR; Soot; NOX (1)
- Functionalized carbon nanotubes (1)
- Gravimetric sensor (1)
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- Indoor air quality monitoring (1)
- Integrated diffusion coefficient (1)
- Inverse kinematics (1)
- Kinematics (1)
- Laser powder bed fusion (1)
- Line-by-line (1)
- Low-discrepancy sequence (1)
- Manipulation planning (1)
- Mg alloy (1)
- Microstructure (1)
- Monte Carlo (1)
- Monte Carlo ray tracing (1)
- Non-planar interface (1)
Articles 1 - 11 of 11
Full-Text Articles in Engineering
Globally Optimal Passive Compliance Control For Tasks Having Multiple Homotopy Classes, Jacob J. Rice, Joseph M. Schimmels
Globally Optimal Passive Compliance Control For Tasks Having Multiple Homotopy Classes, Jacob J. Rice, Joseph M. Schimmels
Mechanical Engineering Faculty Research and Publications
Redundant serial manipulators with variable stiffness actuators (VSAs) are capable of passive compliance control, in which the elastic behavior of the end-effector is controlled for robust interaction with a stiff environment. This paper addresses the problem of finding the globally optimal joint manipulation path (sequence of joint positions and compliances) that yields a desired task manipulation path (sequence of end-effector positions and compliances) when there is one degree of redundancy. The space of admissible joint paths can be very complex, with multiple bifurcations resulting in multiple homotopy classes of joint paths. Bifurcations due to singularities in the combined kinematic and …
Modifying The Surface Chemistry And Nanostructure Of Carbon Nanotubes Facilitates The Detection Of Aromatic Hydrocarbon Gases, John N. Hodul, Allison K. Murray, Nikhil F. Carneiro, Joseph R. Meseke, Jacob Morris, Xinping He, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Jeffrey F. Rhoads, Bryan W. Boudouris
Modifying The Surface Chemistry And Nanostructure Of Carbon Nanotubes Facilitates The Detection Of Aromatic Hydrocarbon Gases, John N. Hodul, Allison K. Murray, Nikhil F. Carneiro, Joseph R. Meseke, Jacob Morris, Xinping He, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Jeffrey F. Rhoads, Bryan W. Boudouris
Mechanical Engineering Faculty Research and Publications
The benzene, toluene, and xylene (BTX) compounds currently utilized in many building materials and paints have been linked to deleterious health effects, and thus, monitoring the presence of these compounds is of increasing importance with respect to public health. As such, there is a critical need for next-generation low-cost, selective, and sensitive indoor BTX sensors. Current BTX detection systems require multicomponent, complex devices or require high power input to achieve BTX detection at meaningful concentrations, but this long-standing paradigm can be altered through the introduction of tailored nanomaterials. Specifically, we demonstrate a selective BTX resonant mass sensor platform that leverages …
Anomalous Growth Of Al8Mo3 Phase During Interdiffusion And Reaction Between Al And Mo, Abhishek Mehta, Le Zhou, Dennis D. Keiser Jr., Yongho Sohn
Anomalous Growth Of Al8Mo3 Phase During Interdiffusion And Reaction Between Al And Mo, Abhishek Mehta, Le Zhou, Dennis D. Keiser Jr., Yongho Sohn
Mechanical Engineering Faculty Research and Publications
No abstract provided.
Understanding The Laser Powder Bed Fusion Of Alsi10mg Alloy, Holden Hyer, Le Zhou, Sharon Park, Guilherme Gottsfritz, George Benson, Bjorn Tolentino, Brandon Mcwilliams, Kyu Cho, Yongho Sohn
Understanding The Laser Powder Bed Fusion Of Alsi10mg Alloy, Holden Hyer, Le Zhou, Sharon Park, Guilherme Gottsfritz, George Benson, Bjorn Tolentino, Brandon Mcwilliams, Kyu Cho, Yongho Sohn
Mechanical Engineering Faculty Research and Publications
We examine the microstructural characteristics of LPBF AlSi10Mg produced by using a wide range of LPBF processing parameters with independently varied laser power, hatch spacing, scan speed, slice thickness, and the normalized energy density. The lower energy density produced lack of fusion flaws from residual interparticle spacing, while the higher energy density produced spherical pores from trapped gas. The highest density (> 99%) samples were produced by using an energy density of 32 to 54 J/mm3. Within this energy density range, use of smaller slice thicknesses increased the processing window that would produce dense AlSi10Mg samples. A cellular …
Multi-Homotopy Class Optimal Path Planning For Manipulation With One Degree Of Redundancy, Jacob J. Rice, Joseph M. Schimmels
Multi-Homotopy Class Optimal Path Planning For Manipulation With One Degree Of Redundancy, Jacob J. Rice, Joseph M. Schimmels
Mechanical Engineering Faculty Research and Publications
Redundant manipulators have an infinitely large set of joint paths that yield a desired end-effector path in the task space. A unique joint path can be obtained by minimizing a global cost function. Prior optimal control methods minimize a global cost function to find a local minimum within a homotopy class. Many possible locally optimal joint paths are in different homotopy classes. This paper presents an algorithm that effectively searches the solution space and finds many locally optimal paths in all relevant homotopy classes. The path with the lowest cost is very likely the globally optimal path. The algorithm is …
Mechanical Analysis And Modeling Of Porous Thermal Barrier Coatings, Shiyu Cui, Wenping Liang, Luis Saucedo Mora, Qiang Miao, Joseph P. Domblesky, Hao Lin, Lijia Yu
Mechanical Analysis And Modeling Of Porous Thermal Barrier Coatings, Shiyu Cui, Wenping Liang, Luis Saucedo Mora, Qiang Miao, Joseph P. Domblesky, Hao Lin, Lijia Yu
Mechanical Engineering Faculty Research and Publications
Thermal barrier coatings (TBCs) are applied to the surface of components that are used in gas turbines and aircraft engines in order to increase the heat load. In this study, the cross-sectional microstructures of TBCs were investigated via scanning electron microscopy. After calculating the porosity and the pore size distribution, a two-dimensional finite element model with four different porosities (0, 1, 3, and 5%) were established. A stochastic method was used to generate a randomly distributed porous structure. Based on the results of FE analysis and nanoindentation tests, It was found that, at a high porosity (>3%), radial cracks …
Additive Manufacturing Of Dense We43 Mg Alloy By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, George Benson, Brandon Mcwilliams, Kyu Cho, Yongho Sohn
Additive Manufacturing Of Dense We43 Mg Alloy By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, George Benson, Brandon Mcwilliams, Kyu Cho, Yongho Sohn
Mechanical Engineering Faculty Research and Publications
WE43 is a high-strength, corrosion-resistant Mg-alloy containing rare earths such as Y and Nb, and has potential for many lightweight structural or bioresorbable prosthetic applications. In this study, additive manufacturing of dense WE43 alloy by laser powder bed fusion (LPBF) from gas atomized powders has been accomplished through studies involving single track scan of wrought WE43, parametric variation of LPBF, microstructural analysis and mechanical testing, both in compression and tension. The Archimedes method and image analyses from optical micrographs were employed to document the LPBF of dense (>99 % relative density) WE43 using optimum parameters of 200 W laser …
Detailed Modeling Of A Small-Scale Turbulent Pool Fire, Bifen Wu, Somesh Roy, Xinyu Zhao
Detailed Modeling Of A Small-Scale Turbulent Pool Fire, Bifen Wu, Somesh Roy, Xinyu Zhao
Mechanical Engineering Faculty Research and Publications
Turbulent pool fires have been studied as a canonical configuration in fire science with wide interest. A numerical study of a small-scale turbulent heptane pool fire is conducted in the present study to understand the interactions and coupling among turbulence, chemistry, soot, and radiation in pool fires. A Monte Carlo ray tracing based radiation solver, with line-by-line spectral models for five gaseous species and soot, is coupled with a fireFOAM-based reacting flow solver to describe the dynamics of the target fire. A 33-species skeletal mechanism is employed to describe the finite-rate chemistry. A two-equation soot model with C2H …
An Integrated Computational Materials Engineering-Anchored Closed-Loop Method For Design Of Aluminum Alloys For Additive Manufacturing, Saket Thapliyal, Mageshwari Komarasamy, Shivakant Shukla, Le Zhou, Holden Hyer, Sharon Park, Yongho Sohn, Rajiv S. Mishra
An Integrated Computational Materials Engineering-Anchored Closed-Loop Method For Design Of Aluminum Alloys For Additive Manufacturing, Saket Thapliyal, Mageshwari Komarasamy, Shivakant Shukla, Le Zhou, Holden Hyer, Sharon Park, Yongho Sohn, Rajiv S. Mishra
Mechanical Engineering Faculty Research and Publications
A closed-loop approach based on integrated computational material engineering was used to design, fabricate and characterize an Al–1.5Cu–0.8Sc–0.4Zr (wt%) alloy for laser powder bed fusion additive manufacturing (AM). Finalization of composition and prediction of solidification behavior and mechanical properties were done using calculation of phase diagrams (CALPHAD) and analytical tools. The microstructure of the printed alloy in as-built condition consisted of crack-free regions with fine-equiaxed grains which was consistent with CALPHAD results. Yield strength (YS) of ~349 ± 8 MPa was also in more than 90% agreement with predicted YS. The findings demonstrate an efficient methodology for application-based alloy design …
A Quasi-Monte Carlo Solver For Thermal Radiation In Participating Media, Joseph Farmer, Somesh Roy
A Quasi-Monte Carlo Solver For Thermal Radiation In Participating Media, Joseph Farmer, Somesh Roy
Mechanical Engineering Faculty Research and Publications
The Monte Carlo (MC) method is the most accurate method for resolving radiative heat transfer in participating media. However, it is also computationally prohibitive in large-scale simulations. To alleviate this, this study proposes a quasi-Monte Carlo (QMC) method for thermal radiation in participating media with a focus on combustion-related problems. The QMC method employs low-discrepancy sequences (LDS) in place of the traditional random numbers. Three different low-discrepancy sequences – Sobol, Halton, and Niederreiter – were examined as part of this work. The developed QMC method was first validated against analytical solutions of radiative heat transfer in several one-dimensional configurations. Then …
Effect Of O2 Concentration In Ambient Mixture And Multiphase Radiation On Pollutant Formation In Ecn Spray-A, Khaled Mosharraf Mosharraf Mukut, Somesh Roy
Effect Of O2 Concentration In Ambient Mixture And Multiphase Radiation On Pollutant Formation In Ecn Spray-A, Khaled Mosharraf Mosharraf Mukut, Somesh Roy
Mechanical Engineering Faculty Research and Publications
The present study investigates the formation and evolution of soot and NOX in a high-pressure constant-volume combustion chamber. This work focuses on the effect of multiphase thermal radiation and O2 dilution in ambient/exhaust gases, some- times also referred to as exhaust gas recirculation(EGR), qualitatively and quantitatively. The spray-A case (n-dodecane as fuel) from Engine Combustion Network (ECN) is used as the target condition. Two different soot modeling approaches have been considered: a semi-empirical two-equation model and a detailed method of moments with interpolative closure (MOMIC) model. A multiphase photon Monte Carlo (PMC) solver with line-by-line (LBL) spectral data …