Effect Of Environmental Variables On Ti-64 Am Simulation Results,
2018
Missouri University of Science and Technology
Effect Of Environmental Variables On Ti-64 Am Simulation Results, Aaron Flood, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In metal AM the environment is critical and therefore care should be taken to ensure that the simulation matches reality. This paper will investigate the effect that various environmental factors have on the results of the simulation. This will help to determine their importance in the simulation setup. The material properties which relate to this are the convective coefficient and the emissivity. These material properties will be investigated to determine their effect on the outcome of the simulation. In addition to these properties, the size of the substrate will be investigated to determine if any results are altered. Lastly, the …
Characterization Of Impact Toughness Of 304l Stainless Steel Fabricated Through Laser Powder Bed Fusion Process,
2018
Missouri University of Science and Technology
Characterization Of Impact Toughness Of 304l Stainless Steel Fabricated Through Laser Powder Bed Fusion Process, Sreekar Karnati, Atoosa Khiabhani, Aaron Flood, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this research, the impact toughness of powder bed based additively manufactured 304L stainless steel was investigated. Charpy specimens were built in vertical, horizontal and inclined (45⁰) orientations to investigate the variation in toughness with build direction. These specimens were tested in as-built and machined conditions. A significant difference in toughness was observed with varying build directions. The lowest toughness values were recorded when the notch was oriented in line with the interlayer boundary. The highest toughness was recorded when the notch was perpendicular to the interlayer boundary. A significant scatter in toughness values was also observed. The variation and …
Additive Manufacturing Of Liners For Shaped Charges,
2018
Missouri University of Science and Technology
Additive Manufacturing Of Liners For Shaped Charges, Jason Ho, Cody Lough, Phillip R. Mulligan, Edward C. Kinzel, Catherine E. Johnson
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
A Shaped Charge (SC) is an explosive device used to focus a detonation in a desired direction, and has applications in oil extraction, weaponry and demolition. The focusing relies on a void in the explosive mass, shaped by a metal liner that becomes a super-heated projectile during detonation. Additive Manufacturing (AM) allows greater design freedom and geometric complexity for the liner portion of the SC. Specifically, hierarchical structuring and functional grading can potentially provide greater velocity, directionality, and efficiency. In this work, Selective Laser Melting (SLM) is used to explore different geometries for an SC liner made out of SS …
Fabricating Functionally Graded Materials By Ceramic On-Demand Extrusion With Dynamic Mixing,
2018
Missouri University of Science and Technology
Fabricating Functionally Graded Materials By Ceramic On-Demand Extrusion With Dynamic Mixing, Wenbin Li, Austin J. Martin, Benjamin Kroehler, Alexander M. Henderson, Tieshu Huang, Jeremy Lee Watts, Greg Hilmas, Ming-Chuan Leu
Materials Science and Engineering Faculty Research & Creative Works
Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. Presented in this paper is a further development of this process focusing on fabrication of functionally graded materials (FGM). A dynamic mixing mechanism was developed for mixing constituent ceramic pastes, and an extrusion control scheme was developed for fabricating specimens with desired material compositions graded in real time. FGM specimens with compositions graded between Al2O3 and ZrO2 were fabricated and ultimately densified by sintering to validate the effectiveness of the CODE process for FGM fabrication. Energy dispersive spectroscopy …
Effect Of Wall Thickness And Build Quality On The Compressive Properties Of 304l Thin-Walled Structures Fabricated By Slm,
2018
Missouri University of Science and Technology
Effect Of Wall Thickness And Build Quality On The Compressive Properties Of 304l Thin-Walled Structures Fabricated By Slm, Myranda Spratt, Sudharshan Anandan, Rafid M. Hussein, Joseph William Newkirk, K. Chandrashekhara, Heath Misak, Michael Walker
Materials Science and Engineering Faculty Research & Creative Works
The specific strength of lightweight lattice structures built with SLM is of interest to the aerospace industry. Honeycombs were manufactured with increasing wall thicknesses (which increases density) and tested under compression. The optimal strength to density ratio was determined from the resulting data. The build quality was also evaluated to determine how/if the results were influenced by the specimen quality. Differences between the nominal and as-built geometry were identified, but considered to be minimal. Microstructural evaluation of the specimens revealed a possible dependence on the ‘border scan’ properties, as the thickness of the specimens was such that the board scan …
Fiber-Fed Printing Of Free-Form Free-Standing Glass Structures,
2018
Missouri University of Science and Technology
Fiber-Fed Printing Of Free-Form Free-Standing Glass Structures, John M. Hostetler, Jason E. Johnson, Jonathan T. Goldstein, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel
Materials Science and Engineering Faculty Research & Creative Works
Additive Manufacturing (AM) of low-profile 2.5D glass structures has been demonstrated using a fiber-fed laser-heated process. In this process, glass fibers with diameters 90-125 μm are supported as they are fed into the intersection of the workpiece and a CO2 laser beam. The workpiece is positioned by a four-axis CNC stage with coordinated rotational/transitional kinematics. The laser energy at λ = 10.6 μm is coupled to phonon modes in the glass, locally heating it above its working point. The rapid heating and cooling process allows for the deposition of various glasses into free-standing three-dimensional structures such as trusses and …
Fast Prediction Of Thermal History In Large-Scale Parts Fabricated Via A Laser Metal Deposition Process,
2018
Missouri University of Science and Technology
Fast Prediction Of Thermal History In Large-Scale Parts Fabricated Via A Laser Metal Deposition Process, Lei Yan, Tan Pan, Joseph William Newkirk, Frank W. Liou, Eric E. Thomas, Andrew H. Baker, James B. Castle
Materials Science and Engineering Faculty Research & Creative Works
Laser metal deposition (LMD) has become a popular choice for the fabrication of near-net shape complex parts. Plastic deformation and residual stresses are common phenomena that are generated from the intrinsic large thermal gradients and high cooling rates in the process. Finite element analysis (FEA) is often used to predict the transient thermal cycle and optimize processing parameters; however, the process of predicting the thermal history in the LMD process with the FEA method is usually time-consuming, especially for large-scale parts. Herein, multiple 3D FEA models with simple assumptions on the heat source and its loading methods are compared and …
Mechanical Properties Evaluation Of Ti-6al-4v Thin-Wall Structure Produced By A Hybrid Manufacturing Process,
2018
Missouri University of Science and Technology
Mechanical Properties Evaluation Of Ti-6al-4v Thin-Wall Structure Produced By A Hybrid Manufacturing Process, Lei Yan, Wenyuan Cui, Joseph William Newkirk, Frank W. Liou, Eric E. Thomas, Andrew H. Baker, James B. Castle
Materials Science and Engineering Faculty Research & Creative Works
The hybrid manufacturing (HM) process combines the precision of computer numerical control (CNC) and the freeform capability of additive manufacturing to expand the versatility of advanced manufacturing. The intent of this paper is to explore the relationship between HM processing parameters and mechanical properties of the final parts manufactured by one type of HM process that combines laser metal deposition (LMD) and CNC milling. The design of experiment (DOE) is implemented to explore the Ti-6Al-4V thin-wall structure fabrication process with different HM build strategies. Vickers hardness, tensile test, and microstructure analyses are conducted to evaluate the mechanical property variance within …
Development Of An Engineering Diagram For Additively Manufactured Austenitic Stainless Steel Alloys,
2018
Missouri University of Science and Technology
Development Of An Engineering Diagram For Additively Manufactured Austenitic Stainless Steel Alloys, Zachary T. Hilton, Joseph William Newkirk, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Austenitic stainless steels are the most widely applied types of stainless steels, due to their good weldability and high corrosion resistance. A number of engineering diagrams exist for the purpose of providing insight into the behavior of these steels. Examples of these diagrams are constitution diagrams (aka Schaeffler Diagrams) which are used to approximate the solidification path of the alloy and the amount of retained ferrite in the solidified matrix. Other diagrams are the Suutala diagram, which approximates cracking susceptibility, and microstructural maps, which predict the solidification path by varying a processing parameter, such as cooling rate. By combining these …
Frequency Response Inspection Of Additively Manufactured Parts For Defect Identification,
2018
Missouri University of Science and Technology
Frequency Response Inspection Of Additively Manufactured Parts For Defect Identification, Kevin Johnson, Jason Blough, Andrew Barnard, Troy Hartwig, Ben Brown, David Soine, Tristan Collum, Edward C. Kinzel, Douglas A. Bristow, Robert G. Landers
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The goal of this paper is to evaluate internal defects in AM parts using dynamic measurements. The natural frequencies of AM parts can be identified by measuring the response of the part(s) to a dynamic input. Different excitation methods such as a modal impact hammer or shakers can be used to excite the parts. Various methods exist to measure the parts' responses and find the natural frequencies. This paper will investigate the use of Doppler lasers, accelerometers and Digital Image Correlation (DIC). The parts evaluated in this work include sets of parts that are still attached to the AM build …
Use Of Swir Imaging To Monitor Layer-To-Layer Part Quality During Slm Of 304l Stainless Steel,
2018
Missouri University of Science and Technology
Use Of Swir Imaging To Monitor Layer-To-Layer Part Quality During Slm Of 304l Stainless Steel, Cody S. Lough, Xin Wang, Christopher C. Smith, Olaseni Adeniji, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper evaluates using in-situ SWIR imaging to monitor part quality and identify potential defect locations introduced during Selective Laser Melting (SLM) of 304L stainless steel. The microstructure (porosity, grain size, and phase field) and engineering properties (density, modulus, and yield strength) depend on the thermal history during SLM manufacturing. Tensile test specimens have been built with a Renishaw AM250 using varied processing conditions to generate different thermal histories. SWIR imaging data is processed layer-to-layer to extract features in the thermal history for each process condition. The features in the thermal history are correlated with resulting part engineering properties, microstructure, …
In-Situ Optical Emission Spectroscopy During Slm Of 304l Stainless Steel,
2018
Missouri University of Science and Technology
In-Situ Optical Emission Spectroscopy During Slm Of 304l Stainless Steel, Cody S. Lough, Luis I. Escano, Minglei Qu, Christopher C. Smith, Robert G. Landers, Douglas A. Bristow, Lianyi Chen, Edward C. Kinzel
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper demonstrates the potential of in-situ Optical Emission Spectroscopy (OES) to monitor the Selective Laser Melting (SLM) process. A spectrometer is split into the beam path of a home-built SLM system to collect visible light emitted from the melt pool and plume. The inline configuration allows signal collection regardless of the laser scan location. The spectral data can be used to calculate the temperature of the vapor plume and correlated with the melt-pool size. The effects of varying the atmosphere and pressure on the OES signal are also explored. These results demonstrate that OES can provide useful feedback to …
An Efficient Constructive Heuristic To Balance Trade-Offs Between Makespan And Flowtime In Permutation Flow Shop Scheduling,
2018
University of Kentucky
An Efficient Constructive Heuristic To Balance Trade-Offs Between Makespan And Flowtime In Permutation Flow Shop Scheduling, Feidi Dang, Wei Li, Honghan Ye
Mechanical Engineering Faculty Publications
Balancing trade-offs between production cost and holding cost is critical for production and operations management. Utilization of a production line affects production cost, which relates to makespan, and work-in-process (WIP) inventories in a production line affect holding cost, which relate to flowtime. There are trade-offs between two objectives, to minimize makespan and to minimize flowtime. Without addressing trade-off balancing issues in flow shop scheduling, WIP inventories are still high in manufacturing, generating unnecessary holding cost. However, utilization is coupled with WIP inventories. Low WIP inventory levels might lower utilization and generate high production cost. Most existing constructive heuristics focus only …
Assessing Production Line Risk Using Bayesian Belief Networks And System Dynamics,
2018
University of Kentucky
Assessing Production Line Risk Using Bayesian Belief Networks And System Dynamics, Sudhir Punyamurthula, Fazleena Badurdeen
Mechanical Engineering Faculty Publications
Increased complexity in product design, strict regulations and a changing market make risk assessment critical for successful operations. Failure in responding quickly to raw material shortages, downtimes, deteriorating equipment conditions or other operational issues can prove to be an expensive affair. A company-wide risk assessment includes both external and internal operations. However, external/supplier risk assessment has been of major interest. Even though the scope of risk assessment at the production line level is not as broad as it is at the supply chain level, assessing risk would help recognize vulnerable areas of the production line, which would in turn help …
Design Survey Of Laminated Composite I-Beam,
2018
Utah State University
Design Survey Of Laminated Composite I-Beam, Mrinmoy Saha
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
Composite I-beams are popular for high-strength low-weight applications. Learning the macro-mechanics and designing the composite I-beam properly are necessary. In this report, a design overview of the composite I-beam is discussed which is based on classical lamination theory where it includes the homogenization approach, the plane stress assumption and the Kirchhoff hypothesis. Using these assumptions, a method was developed to come up with the effective material properties of a beam. Formulas to calculate maximum deflection and maximum bending stress and shear stress and the stress concentration at the connection of web-flange are discussed which describe ways for designing and manufacturing …
Microstructure And Mechanical Properties Of Selective Laser Melted Superalloy Inconel 625.,
2018
University of Louisville
Microstructure And Mechanical Properties Of Selective Laser Melted Superalloy Inconel 625., Md Ashabul Anam
Electronic Theses and Dissertations
Selective Laser Melting (SLM), a powder based Additive Manufacturing (AM) process, has gained considerable attention in the aerospace, biomedical and automotive industries due to its many potential benefits, such as, capability of fabricating complex three-dimensional components, shortened design to product time, reduction in process steps, component mass reduction and material flexibility. This process uses metallic powder and is capable of fabricating complex structures with excellent microstructure which make SLM not only an improvement over other manufacturing processes but also innovative material processing technology. Inconel 625, a nickel-based super alloy is widely popular in aerospace, chemical and nuclear industries. This alloy …
Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys.,
2018
University of Louisville
Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold
Electronic Theses and Dissertations
Additive Manufacturing (AM) with metals has been accomplished mainly through powder bed fusion processes. Initial experiments and simulations using Material Extrusion Additive Manufacturing (MEAM) have been performed by various researchers especially using low melting alloys. Recently Stratasys Inc. submitted a patent application for the use of their Material Extrusion technology also called Fused Deposition Modeling (FDM) where they describe the process using thixotropic semi-solid alloys. Currently this process using semi-solid, engineering type alloys such as A356 or THIXALLOY 540 aluminum have not been researched to evaluate the control parameters. This research combines the in-depth knowledge of applying thixotropic semi-solid aluminum …
Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes,
2018
University of South Florida
Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes, Garrett Craft, Justin Nussbaum, Nathan B. Crane, J. P. Harmon
Faculty Publications
Additive Manufacturing provides many advantages in reduced lead times and increased geometric freedom compared to traditional manufacturing methods, but material properties are often reduced. This paper considers powder bed fusion of polyamide 12 (PA12, Nylon 12) produced by three different processes: laser sintering (LS), multijet fusion (MJF)/high speed sintering (HSS), and large area projection sintering (LAPS). While all utilize similar PA12 materials, they are found to differ significantly in mechanical properties especially in elongation to break. The slower heating methods (MJF/HSS and LAPS) produce large elongation at break with the LAPS process showing 10x elongation and MJF/HSS exhibiting 2.5x the …
Experimental And Theoretical Investigation Of Mechanical Response Of Laser-Sintered Diamond Lattice Structures,
2018
University of South Florida
Experimental And Theoretical Investigation Of Mechanical Response Of Laser-Sintered Diamond Lattice Structures, Clayton Neff, Neil Hopkinson, Nathan B. Crane
Faculty Publications
Typically additive manufacturing (AM) processes are limited to a single material per part while many products benefit from the integration of multiple materials with varied properties. To achieve the benefits of multiple materials, the geometric freedom of AM could be used to build internal structures that emulate a range of different material properties such as stiffness, Poisson’s ratio, and elastic limit using only one build material. This paper examines the range of properties that can be simulated using diamond lattice structures manufactured from Nylon 12 with a commercial laser sintering process. Diamond lattices were fabricated with a unit cell length …
Design Of Lattice Structures With Graded Density Fabricated By Additive Manufacturing,
2018
Missouri University of Science and Technology
Design Of Lattice Structures With Graded Density Fabricated By Additive Manufacturing, Wenjin Tao, Yong Liu, Austin T. Sutton, Krishna C. R. Kolan, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Lattice structures fabricated by Additive Manufacturing (AM) processes are promising for many applications, such as lightweight structures and energy absorbers. However, predicting and controlling of their mechanical behaviors is challenging due to the complexity of modeling and the uncertainties exist in the manufacturing process. In this paper, we explore the possibilities enabled by controlling the local densities. A set of lattice structures with different density gradients are designed using an implicit isosurface equation, and they are manufactured by Selective Laser Melting (SLM) process with 304L stainless steel. Finite element analysis and compression test are used to evaluate their mechanical properties. …
