Mechanical Engineering Commons^™

Effects Of Identical Parts On A Common Build Plate On The Modal Analysis Of Slm Created Metal, Tristan Cullom, Troy Hartwig, Ben Brown, Kevin Johnson, Jason Blough, Andrew Barnard, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The frequency response of parts created with Additive Manufacturing (AM) is a function of not only process parameters, powder quality, but also the geometry of the part. Modal analysis has the potential to evaluate parts by measuring the frequency response which are a function of the material response as well as the geometry. A Frequency Response Function (FRF) serves as a fingerprint of the part which can be validated against the FRF of a destructively tested part. A practical scenario encountered in Selective Laser Melting (SLM) involves multiple parts on a common build plate. Coupling between parts influences the FRF …

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, 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 …

Incorporation Of Automated Ball Indentation Methodology For Studying Powder Bed Fabricated 304l Stainless Steel, Sreekar Karnati, Jack L. Hoerchler, Aaron Flood, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Automated Ball Indentation (ABI) is a viable method for estimating the ductility, yield stress, and ultimate stress, among other metrics, in different metallic materials. Currently, ABI data analysis utilizes Holloman’s Power Law to model the plastic region of the true stress-true strain curve. While this formulation is accurate for some materials, its relevance for additively manufactured austenitic stainless steels, such as 304L, needed investigation. The deviation of the material’s plastic behavior from the Power Law was investigated. In order to better model this behavior, both the Voce and Ludwigson formulation were investigated. These formulations were tested for both wrought and …

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, …

Effects Of Thermal Camera Resolution On Feature Extraction In Selective Laser Melting, Xin Wang, Cody S. Lough, Douglas A. Bristow, Edward C. Kinzel, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective Laser Melting (SLM) is a common additive manufacturing process which uses a laser energy source to fuse metal powder layer by layer. Engineering properties and microstructure are related to the part’s thermal history. It is important to measure the thermal history in-situ to qualify parts and provide the sensing which is necessary for process control. A common measurement tool for this purpose is a thermal camera that records the thermal emission of the part’s surface.

This study investigates the effects of spatial sampling resolution of thermal cameras when monitoring the temperature in SLM processes. High-fidelity simulation of an SLM …

Development Of Pre-Repair Machining Strategies For Laser-Aided Metallic Component Remanufacturing, Xinchang Zhang, Wenyuan Cui, Leon Hill, Wei Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Remanufacturing worn metallic components can prolong the service life of parts that need frequent replacement but are extremely costly to manufacture, such as aircraft titanium components, casting dies. Additive manufacturing (AM) technology enables the repair of such valuable components by depositing filler materials at the worn area layer by layer to regenerate the missing geometry. In general, damaged parts would be inspected and pre-machined prior to material deposition to remove oil, residue, oxidized layers or defects located in inaccessible regions. Therefore, the motivation of this paper is to introduce pre-repair machining strategies for removing contaminated materials from damaged components and …

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 …

Chemo-Thermo Cure Of Viscoelastic Materials For Semiconductor Packaging Applications, Anjali Pradeep Kumar

Dissertations and Theses

Viscoelastic polymer materials are being actively considered as a novel material for semiconductor packaging applications as a result of their ability to develop strong adhesive bonds at lower temperatures. Viscoelastic thermoset materials are impacted by the stresses generated during the curing process, which is also accompanied by a dissipation of thermal energy. There is a need to develop a generic modeling formulation that is applicable to any material of interest in order to enable the study of different bonding materials and develop optimized curing cycles. This study reports a numerical formulation to evaluate the stress generated and energy dissipated during …

Micro Combustion Of Primary Reference Fuels In Narrow Heated Channels, Veerendra Naralasetti

LSU Master's Theses

Conventional fuel testing machines like CFR engines require large quantities of fuel. The current study seeks to overcome this limitation by introducing an alternative method using a microscale combustion reactor which consumes relatively small amounts of fuel (100-250 ml). For this reason, Primary Reference Fuels (PRF’s: volumetric mixtures of n-heptane and iso-octane) which are simple surrogates of gasoline are selected to test using micro reactor. The primary goal is to determine the effectiveness of using the micro reactor setup to differentiate fuels of different octane number. Experiments with stoichiometric PRF/air mixtures are performed inside a cylindrical quartz tube of 1mm …

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 …

Development And Application Of Rotation And Curvature Correction To Wray-Agarwal Turbulence Model, Xiao Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Computational Fluid Dynamics (CFD) is increasingly playing a significant role in the analysis and design of aircrafts, turbomachines, automobiles, and in many other industrial applications. In majority of the applications, the fluid flow is generally turbulent. The accurate prediction of turbulent flows to date remains a challenging problem in CFD. In almost all industrial applications, Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a turbulence model are employed for simulation and prediction of turbulent flows. Currently the one-equation (namely the Spalart-Allmaras (SA) and Wray-Agarwal (WA) and two-equation (namely the k-ε and Shear Stress Transport k-ω) turbulence models remain the most widely …

Experimental And Modeling Study Of Compressive Creep In 3d-Woven Ni-Based Superalloys, Hoon-Hwe Cho, Dinc Erdeniz, Keith W. Sharp, David C. Dunand

Mechanical Engineering Faculty Research and Publications

Micro-architectured Ni-based superalloy structures, with Ni-20Cr-3Ti-2Al (wt.%) composition and γ/γ′-microstructure, are created by a multi-step process: (i) non-crimp orthogonal 3D-weaving of ductile, 202 μm diameter Ni-20%Cr wires, (ii) gas-phase alloying with Al and Ti, (iii) simultaneous transient-liquid phase (TLP) bonding between wires and homogenization within wires via interdiffusion, (iv) solutionizing to create a single-phase solid solution, and (v) aging to precipitate the γ′ phase. The creep behavior of these 3D-woven γ/γ′ nickel-based superalloys is studied under uniaxial compression via experiments at 825 °C and via finite element (FE) analysis, using a 3D model of the woven structures obtained …

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 …

Schlieren Visualization Of Shaping Air During Operation Of An Electrostatic Rotary Bell Sprayer: Impact Of Shaping Air On Droplet Atomization And Transport, Adnan Darwish Ahmad, Ahmad M. Abubaker, Ahmad A. Salaimeh, Nelson K. Akafuah

Institute of Research for Technology Development Faculty Publications

Electrostatic rotary bell sprayers (ERBSs) are widely used in the automotive industry. In ERBS, atomization is facilitated using centrifugal forces which disintegrate the paint film inside the cup into droplets at the cup edge. The droplets are then transported by the flow of a shaping air (SA) and electrostatic forces to a target surface; the characteristics of these droplets dramatically influence the quality of a painted surface and the painting transfer efficiency. In the current paper, a novel Schlieren-based visualization of the shaping air in the absence of paint droplets was performed during a qualitative investigation to delineate shaping air …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• Mechanical Faculty Among Focus on Excellence Award Recipients

Hydrodynamics Of An Anguilliform Swimming Motion Using Morison’S Equation, Naga Sasi Devarakonda

LSU New Orleans Theses and Dissertations

In this study, the hydrodynamic performance of anguilliform swimming motion is computed using Morison’s equation. This method was shown to predict the servo motor torques well. The anguilliform swimming motion is sinusoidal with increasing amplitude from head to tail. A “wakeless” swimming motion proposed by Vorus and Taravella (2011) with zero net circulation is considered.

This method is compared to the existing slender body theory and is validated with reference to the experimental results of NEELBOT-1.1 (Potts, 2015). The results for the study indicates that self-propulsion speed of the motion is independent of the oscillating tail amplitude at a constant …

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, 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 …

Multi-Pred: A Software Module For Predictive Modeling Of Coupled Multi-Physics Systems, Dan Gabriel Cacuci, Ruixian Fang, Madalina C. Badea

Faculty Publications

The software module MULTI-PRED implements the methodology for predictive modeling of coupled multi-physics systems (PM-CMPS) formulated by Cacuci [Ann. Nucl. Energy, Vol. 70, p, 266 (2014)]. This methodology fully takes into account the coupling terms between the systems but requires only the computational resources that would be needed to perform predictive modeling on each system separately. The PM-CMPS methodology uses the maximum entropy principle to construct an optimal approximation of the unknown a priori distribution based on a priori known mean values and uncertainties characterizing the experimental and computational parameters and results of interest responses called for the multi-physics models …

Efficacy Of Eluted Antibiotics In 3d Printed Orthopaedic Implants, Mohammed Mehdi Benmassaoud

Theses and Dissertations

Costs associated with musculoskeletal diseases in the United States account for 5.7 % of the Gross Domestic Product (GDP) [1]. As such, there is a need to pursue new ideas in orthopaedic implants that can decrease cost and improve patient care. In the recent years, 3D printing using Fused Deposition Modeling (FDM) or Stereolithography (SLA) has opened several exciting possibilities to create orthopaedic implants. Such implants can be engineered to release antibiotics in a controlled manner either by infusing the drug into the material during manufacturing or by using built-in design features such as micro-channels and reservoirs [2]. The use …

Internet Traffic Forecasting Model Using Self Organizing Map And Support Vector Regression Method, Enrico Laoh, Fakhrul Agustriwan, Chyntia Megawati, Isti Surjandari

Makara Journal of Technology

Internet traffic forecasting is one of important aspect in order to fulfill the customer demand. So, the service quality of internet service provider (ISP) can be maintained at the good level. In this study self-organizing map (SOM) and support vector regression (SVR) algorithm are used as forecasting method. SOM is first used to decompose the whole historical data of traffic internet into clusters, while SVR is used to build a forecasting model in each cluster. This method is used to forecast ISPs traffic internet in Jakarta and surrounding areas. The result of this study shows that SOM-SVR method gives more …

Effects Of The Preheating Temperature On The Crystal Structure And Texture Of Martensitic Stainless Steel, Tri Hardi Priyanto, Rifai Muslih, Herry Mugirahardjo, Bharoto Bharoto, Andon Insani, Muzzakiy Muzzakiy

Makara Journal of Technology

Theoretically, the preheating temperature refers to the start martensite temperature (Ms), and the martensite transformation can be considered as the conservation of the invariant habit-plane in the lattice structure. The habit-plane is the interface plane between austenite and martensite as measured on a macroscopic scale. From the calculation, Ms = 252 °C. The martensite formation can be affected by temperature or stress treatment. In this experiment, temperature treatment was conducted. The sample was treated at 250 °C ± 10 °C. Before and after the pre-heat treatment, the sample was characterized using the neutron diffraction method. BATAN’s Texture Diffractometer (DN2) with …

Investigation Of Ship Hull Girder Strength With Grounding Damage, Muhammad Zubair Muis Alie, Ristiyanto Adiputra

Makara Journal of Technology

The objective of the present study is to investigate ship hull girder strength as a result of grounding damage upon longitudinal bending. A bulk carrier and tanker are analyzed and Smith’s Method is adopted and implemented in the analysis program. An efficient solution procedure is performed by assuming the cross-section remains plane and the vertical bending moment is applied to the cross section. As a fundamental case, the damage is simply created by removing the elements from the cross section. Welding residual stress, initial imperfections, and crack extensions are not considered. The grounding damage is made by two conditions, namely …

Development Of Closures For Collisions Between Realistic Particles, Cary Faulkner, Aaron Morris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Systems consisting of solid particles can exhibit fluid-like motion and are common in industrial applications such as pharmaceutical or food processing. Such granular flows are often studied using simulation methods. One common simulation method is the discrete element method (DEM), which solves for the motion of individual particles based on Newton’s laws. However, large-scale particulate systems are difficult to study using DEM due to excessively long simulation times. The goal of this study is to reduce the computational load of these large-scale simulations. Instead of resolving particle trajectories throughout each collision, a scattering function is developed that directly relates the …

Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding the behaviors of bacteria near surfaces is crucial in many biological and ecological applications. This knowledge can be used to hinder undesired biofilm formation on medical instruments and wounds. On top of that, it could also provide further insights in biodegradation of dispersed oil. In this work, the behavior of Escherichia Coli near a surface was experimentally studied. We utilized an inverted microscope in the phase filed illumination mode and processed acquired images to track the motions of bacteria near surfaces with high accuracy and repeatability. Distribution of the cells when they reached a steady state shows that the …

Validation Of Lateral Gap Leakage Objective Function For Use In Multi-Objective Optimization Of Gerotor Pumps, Kevin Cohen, Andrew Robison, Andrea Vacca

The Summer Undergraduate Research Fellowship (SURF) Symposium

Gerotor pumps are a common pump choice used in the automotive, agricultural, and construction fields for their low cost and durability. Recently, demanding applications have called for significant design improvements in gear geometry. To address these design challenges, multi-objective optimization has been applied to gear geometry. The goal of this work is to introduce minimizing of lateral-gap leakage to the multi-objective optimization. An objective function for evaluating lateral-gap leakage based on 1D, pressure driven flow is proposed. This simplified approach is compared to CFD simulation solving of Reynolds equation with two pressure boundaries. Comparison of the simplified relation and the …

Micro-Manipulation Using Learned Model, Matthew A. Lyng, Benjamin V. Johnson, David J. Cappelleri

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microscale devices can be found in applications ranging from sensors to structural components. The dominance of surface forces at the microscale hinders the assembly processes through nonlinear interactions that are difficult to model for automation, limiting designs of microsystems to primarily monolithic structures. Methods for modeling surface forces must be presented for viable manufacturing of devices consisting of multiple microparts. This paper proposes the implementation of supervised machine learning models to aid in automated micromanipulation tasks for advanced manufacturing applications. The developed models use sets of training data to implicitly model surface interactions and predict end-effector placement and paths that …

Experimental Validation Of A Numerical Phase Change Model For Microchannel Slug Flow Boiling, Christian J. Retter, Todd A. Kingston, Justin A. Weibel, Suresh V. Garimella

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermal management of high-power electronic devices continues to be a critical challenge. Flow boiling in microchannel heat sinks has been demonstrated to be an effective method for removing high heat fluxes from these devices owing to utilization of the latent heat of the fluid and the large surface area enhancement for heat exchange. However, microchannel flow boiling technologies have yet to be broadly implemented due to a lack of experimentally validated prediction and design tools. The goal of this study is to use high-fidelity experimental data to validate a previously developed numerical phase change model, to help enable physics-based prediction …

Purdue Air Sense: A Methodology For Improving The Accuracy Of Ambient Aerosol Mass Concentration And Size Distribution Measurement With Low-Cost Optical Sensing Techniques, Rishabh Ramsisaria, Satya Sundar Patra, Brandon Emil Boor

The Summer Undergraduate Research Fellowship (SURF) Symposium

There is a global lack of a means for monitoring air pollutant levels at a local level due to expensive and bulky instrument requirements. It is important to monitor toxic gas levels, as well as particulate matter levels, in the atmosphere to study their effects on human health and to further develop city- and community-level air pollution solutions. In this study, with the means of a Raspberry Pi, low-cost Alphasense Optical Particle Counter and gas sensors, and methodical calibration techniques, we built a portable 3-D printed module powered by clean electricity generated by an on-board Voltaic solar cell that measures …