Relevant bibliographies by topics / Melt Pools

Academic literature on the topic 'Melt Pools'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Melt Pools"

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Schmid, Simon, Johannes Krabusch, Thomas Schromm, Shi Jieqing, Stefan Ziegelmeier, Christian Ulrich Grosse, and Johannes Henrich Schleifenbaum. "A new approach for automated measuring of the melt pool geometry in laser-powder bed fusion." Progress in Additive Manufacturing 6, no. 2 (March 12, 2021): 269–79. http://dx.doi.org/10.1007/s40964-021-00173-7.

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AbstractAdditive manufacturing (AM) offers unique possibilities in comparison to conventional manufacturing processes. For example, complex parts can be manufactured without tools. For metals, the most commonly used AM process is laser-powder bed fusion (L-PBF). The L-PBF process is prone to process disturbances, hence maintaining a consistent part quality remains an important subject within current research. An established indicator for quantifying process changes is the dimension of melt pools, which depends on the energy input and the cooling conditions. The melt pool geometry is normally measured manually in cross sections of solidified welding seams. This paper introduces a new approach for the automated visual measuring of melt pools in cross-sections of parts manufactured by L-PBF. The melt pools are first segmented in the images and are then measured. Since the melt pools have a heterogeneous appearance, segmentation with common digital image processing is difficult, deep learning was applied in this project. With the presented approach, the melt pools can be measured over the whole cross section of the specimen. Furthermore, remelted melt pools, which are only partly visible, are evaluated. With this automated approach, a high number of melt pools in each cross-section can be measured, which allows the examination of trends over the build direction in a specimen and results in better statistics. Furthermore, deviations in the energy input can be estimated via the measured melt pool dimensions.
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Kube, Christopher M. "Acoustics for in-process melt pool monitoring during metal additive manufacturing." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A188. http://dx.doi.org/10.1121/10.0015980.

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Intrinsic to most metal additive manufacturing (AM) processes are melt pools generated from directed energy sources like lasers. Melt pools are critical as they function to join powder layers to previous layers during the process. Their criticality extends deeper as most porosity in AM parts stems from melt pool behavior while melt pool solidification dictates the parts’ microstructure. Significant breakthroughs in metal AM are severely hindered by the lack of access to experimental tools to study melt pools and modeling that do not fully capture the complex physics. Thus, melt pool related defects are often difficult to predict in occurrence and location while determining optimal process parameters to eliminate defects is extremely challenging and costly. Furthermore, the many exciting opportunities such as realizing new AM alloys, developing gradient materials/structure, and tailoring microstructure to intended applications are possible only with further understanding of melt pool behavior. With these clear needs, in-process acoustics have been proposed as plausible experimental tools for studying melt pool behavior. This presentation will provide an overview of the current activity in this area in addition to the specific needs the acoustics community can potentially address.
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Schwerz, Claudia, and Lars Nyborg. "Linking In Situ Melt Pool Monitoring to Melt Pool Size Distributions and Internal Flaws in Laser Powder Bed Fusion." Metals 11, no. 11 (November 18, 2021): 1856. http://dx.doi.org/10.3390/met11111856.

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In situ monitoring of the melt pools in laser powder bed fusion (LPBF) has enabled the elucidation of process phenomena. There has been an increasing interest in also using melt pool monitoring to identify process anomalies and control the quality of the manufactured parts. However, a better understanding of the variability of melt pools and the relation to the incidence of internal flaws are necessary to achieve this goal. This study aims to link distributions of melt pool dimensions to internal flaws and signal characteristics obtained from melt pool monitoring. A process mapping approach is employed in the manufacturing of Hastelloy X, comprising a vast portion of the process space. Ex situ measurements of melt pool dimensions and analysis of internal flaws are correlated to the signal obtained through in situ melt pool monitoring in the visible and near-infrared spectra. It is found that the variability in melt pool dimensions is related to the presence of internal flaws, but scatter in melt pool dimensions is not detectable by the monitoring system employed in this study. The signal intensities are proportional to melt pool dimensions, and the signal is increasingly dynamic following process conditions that increase the generation of spatter.
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Guo, Kai, Yunping Ji, Yiming Li, Xueliang Kang, Huiyi Bai, and Huiping Ren. "Numerical Simulation of Temperature Field and Melt Pool Characteristics of CP-Ti Manufactured by Laser Powder Bed Fusion." Metals 13, no. 1 (December 20, 2022): 11. http://dx.doi.org/10.3390/met13010011.

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A coupled heat source model that combined a Gauss surface heat source with a Gauss cylindrical volumetric heat source was introduced to simulate temperature field distribution and melt pool characteristics using a finite element simulation (FEM) method for the deep and narrow melt pools formed in laser powder bed fusion (L-PBF) aiming at commercial pure titanium (CP-Ti). For comparison, the same simulations using the Gauss surface heat source model and the double ellipsoid heat source model were also performed. The simulated melt pool geometries using the coupled heat source model match well with the measurements, with an average error of 1% for the melt pool depth and 7% for the width. Based on the single-track experimental results, it was found by comparing the simulated results from the three heat source models that the coupled heat source model had better accuracy than the other two. Then, the temperature field and the melt pool geometries of CP-Ti fabricated at different laser power levels from 300 W to 500 W and scanning speeds from 600 mm/s to 4000 mm/s were simulated. According to the simulated maximum temperature and geometries of the melt pool, a suitable process parameters map for CP-Ti was obtained. The reported experimental results agree well with the simulated map. The coupled heat source model is more accurate and applicable for the deep and narrow melt pools formed during L-PBF.
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Tranter, Martyn, Andrew G. Fountain, W. Berry Lyons, Thomas H. Nylen, and Kathy A. Welch. "The chemical composition of runoff from Canada Glacier, Antarctica: implications for glacier hydrology duringa cool summer." Annals of Glaciology 40 (2005): 15–19. http://dx.doi.org/10.3189/172756405781813753.

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AbstractVariations in the chemical composition of subsurface runoff within Canada Glacier, Antarctica, are used to identify the main source waters, which are vertical surfaces, and melt from solar-heated debris within channels, cryoconite holes and pools. The main flow paths are subsurface connections between cryoconite holes, pools and riffles. The latter may become partially disconnected during hard freeze. The chemical composition of runoff at the outlet of Canada Glacier during January 2000 was dominated by Ca2+, HCO3– and sea salt (Na+ and Cl–), and became depleted in sea-salt and non-sea-salt (*) SO42– as the subsurface drainage system in a frozen pool-and-riffle system was flushed and the melting ice surface became depleted of overwinter dry deposited salts. Only during 2 days of hard freeze did sea salt and *SO42– increase in concentration together. Otherwise, sea salt and *SO42– declined while *Ca2+ and HCO3– increased. The latter ions are derived from the chemical weathering of sediment in frozen-topped pools, channels and cryoconite holes. It is inferred that the hydrochemical processes which occur in the vestigial, subsurface drainage system are the elution of ions from ice melt, dilution of these ions downstream by ice melt from vertical surfaces and the dissolution of dust, in subsurface pools, channels and/or cryoconite holes.
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Fotovvati, Behzad, Steven F. Wayne, Gladius Lewis, and Ebrahim Asadi. "A Review on Melt-Pool Characteristics in Laser Welding of Metals." Advances in Materials Science and Engineering 2018 (2018): 1–18. http://dx.doi.org/10.1155/2018/4920718.

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Laser welding of metals involves with formation of a melt-pool and subsequent rapid solidification, resulting in alteration of properties and the microstructure of the welded metal. Understanding and predicting relationships between laser welding process parameters, such as laser speed and welding power, and melt-pool characteristics have been the subjects of many studies in literature because this knowledge is critical to controlling and improving laser welding. Recent advances in metal additive manufacturing processes have renewed interest in the melt-pool studies because in many of these processes, part fabrication involves small moving melt-pools. The present work is a critical review of the literature on experimental and modeling studies on laser welding, with the focus being on the influence of process parameters on geometry, thermodynamics, fluid dynamics, microstructure, and porosity characteristics of the melt-pool. These data may inform future experimental laser welding studies and may be used for verification and validation of results obtained in future melt-pool modeling studies.
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Wang, Xiang, Jinwu Kang, Tianjiao Wang, Pengyue Wu, Tao Feng, and Lele Zheng. "Effect of Layer-Wise Varying Parameters on the Microstructure and Soundness of Selective Laser Melted INCONEL 718 Alloy." Materials 12, no. 13 (July 5, 2019): 2165. http://dx.doi.org/10.3390/ma12132165.

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Selective laser melting (SLM) is a promising powder bed fusion additive manufacturing technique for metal part fabrication. In this paper, varying scanning speed in the range of 500 mm/s to 1900 mm/s, and laser power in the range of 100 W to 200 W, were realized from layer to layer in a cycle of 56 layers in a single cuboid Inconel 718 alloy specimen through SLM. Layer-wise variation of microstructure and porosity were acquired, showing the layer-wise controlling capability of microstructural soundness. The melt pool size and soundness are closely linked with the energy input. High energy density led to sound regions with larger, orderly stacked melt pools and columnar grains, while low energy density resulted in porous regions with smaller, mismatched melt pools, un-melted powder, and equiaxed grains with finer dendrites. With the increase of laser energy density, the specimen shifts from porous region to sound region within several layers.
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Tan, M. J., D. H. Cho, and F. B. Cheung. "Thermal Analysis of Heat-Generating Pools Bounded From Below by Curved Surfaces." Journal of Heat Transfer 116, no. 1 (February 1, 1994): 127–35. http://dx.doi.org/10.1115/1.2910846.

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A computer code that features the use of a directional effective thermal conductivity in modeling natural convection in heat-generating pools has been developed to analyze heat transfer in such pools, which are bounded from below by curved surfaces. Illustrative calculations pertaining to two published experimental studies on convective heat transfer in water pools with uniformly distributed volumetric energy sources are carried out using the code. The water pools used in the two studies under consideration were cooled either from the top or from the bottom, but not from both. The utility as well as the limitations of the effective thermal conductivity approach in the context of addressing the issue of melt-pool coolability is demonstrated by comparisons of calculated results with the experimental data.
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Shi, Wanyuan, and Nobuyuki Imaishi. "Hydrothermal waves in rotating annular pools of silicon melt." Microgravity Science and Technology 19, no. 3-4 (October 2007): 159–60. http://dx.doi.org/10.1007/bf02915785.

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Tam, A. S., and D. E. Hardt. "Weld Pool Impedance for Pool Geometry Measurement: Stationary and Nonstationary Pools." Journal of Dynamic Systems, Measurement, and Control 111, no. 4 (December 1, 1989): 545–53. http://dx.doi.org/10.1115/1.3153090.

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The most elusive quantity in describing weld pool geometry is the depth, since it cannot be directly observed; yet it is the most important quantity to be regulated during welding. This paper addresses the problem of depth feedback measurement for full penetration welds, where the objective is to completely melt the cross section. It has been demonstrated that the existence and size of a full penetration weld can be detected by measuring the mechanical impedance of the resulting weld pool. Previous work in modeling this phenomenon has been limited to stationary welds, and experiments have either used impractical measurement methods or have not provided conclusive results. In this paper, a model of pool motion is developed that applies to both the stationary and moving weld case, and the pool motion is detected directly from changes in the arc voltage. A description of pool motion is derived from an elliptical membrane model, and the total system transfer function, including arc and pool dynamics is derived. A series of experiments demonstrates that the pool motion can indeed be detected for the moving pool case. However, the exact determination of pool oscillation frequencies requires knowledge of the pool perimeter geometry, since the elliptical system has many closely spaced eigenvalues arising from both symmetric and antisymmetric mode shapes.
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Dissertations / Theses on the topic "Melt Pools"

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Prasad, Himani Siva. "Phenomena in material addition to laser generated melt pools." Licentiate thesis, Luleå tekniska universitet, Produkt- och produktionsutveckling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-73754.

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Lee, Joon Yul. "Transient thermal convection in laser melt stationary weld pool /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu14876852049678.

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Fox, Jason Cho. "Transient Melt Pool Response in Additive Manufacturing of Ti-6Al-4V." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/746.

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Additive manufacturing (AM) processes are candidates for manufacturing and repair in the aerospace industry. For process stability, control of melt pool dimensions is imperative. This can be achieved via feedback and/or feedforward control approaches; however, the time needed for a change in process variables (beam power and travel velocity) to translate into changes in melt pool dimensions is a critical concern. Prior works have determined the relationship between process variables and melt pool geometry, which can be monitored in situ for feedback control. In the current work, Ti-6Al-4V is studied as it is commonly used in aerospace applications due to its desirable properties. Melt pool depth response is determined in terms of response distance rather than response time in order to develop a relationship that is not dependent on the position or path taken in the Power-Velocity (P-V) Process Map, but instead on the initial and final melt pool geometry. Research is performed through finite element simulations run in the ABAQUS™ software package and validated by experiments performed at the NASA Langley Research Center on their Electron Beam Free Form Fabrication system and at Carnegie Mellon University on their Arcam system. The work presented investigates the transient melt pool response due to changes in process variables in steady state build geometries, as well as extending relationships to transient build geometries and other AM systems yielding a comprehensive understanding of melt pool response across all direct metal AM processes. These relationships will allow for the development of effective feedback and feedforward control systems.
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Svenungsson, Josefine. "Conduction laser welding : modelling of melt pool with free surface deformation." Licentiate thesis, Högskolan Väst, Avdelningen för svetsteknologi (SV), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-13943.

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Laser welding is commonly used in the automotive-, steel- and aerospace industry. It is a highly non-linear and coupled process where the weld geometry is strongly affected by the flow pattern in the melt pool. Experimental observations are challenging since the melt pool and melt flow below the surface are not yet accessible during welding. Improved process control would allow maintaining, or improving, product quality with less material and contribute further to sustainability by reducing production errors. Numerical modelling with Computational Fluid Dynamics, CFD, provides complementary understanding with access to process properties that are not yet reachable with experimental observation. However, the existing numerical models lack predictability when considering the weld shape. The work presented here is the development of a model for conduction laser welding. The solver upon which the model is based is first described in detail. Then different validation cases are applied in order to test specific parts of the physics implemented. Two cases focus on thermocapillary convection in two-phase and three-phase flows with surface deformation. Finally, a third case considers the melt pool flow during conduction mode welding.It is concluded that the convection of fusion enthalpy, which was neglected in former studies, should be included in the model. The implementation of the thermo capillary force is recommended to be consistent with the other surface forces to avoid unphysical solution. Free surface oscillations, known from experimental observations, are also computed numerically. However, further investigation is needed to check that these oscillations are not disturbed b ynumerical oscillations.
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Simon, Daniel H. 1973. "Mathematical modeling of the melt pool during a physical vapor deposition process." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/39625.

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Böttger, Roman. "Self-organized nanostructures by heavy ion irradiation: defect kinetics and melt pool dynamics." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-132624.

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Self-organization is a hot topic as it has the potential to create surface patterns on the nanoscale avoiding cost-intensive top-down approaches. Although chemists have promising results in this area, ion irradiation can create self-organized surface patterns in a more controlled manner. Different regimes of pattern formation under ion irradiation were described so far by 2D models. Here, two new regimes have been studied experimentally, which require modeling in 3D: subsurface point defect kinetics as well as ion impact-induced melt pool formation. This thesis deals with self-organized pattern formation on Ge and Si surfaces under normal incidence irradiation with heavy monatomic and polyatomic ions of energies up to several tens of keV. Irradiation has been performed using liquid metal ion sources in a focused ion beam facility with mass-separation as well as by conventional broad beam ion implantation. Irradiated samples have been analyzed mainly by scanning electron microscopy. Related to the specific irradiation conditions, investigation and discussion of pattern formation has been divided into two parts: (i) formation of Ge morphologies due to point defect kinetics and (ii) formation of Ge and Si morphologies due to melt pool dynamics. Point defect kinetics dominates pattern formation on Ge under irradiation with monatomic ions at room temperature. Irradiation of Ge with Bi and Ge ions at fluences up to 10^17 cm^(-2) has been performed. Comprehensive studies show for the first time that morphologies change from flat surfaces over hole to nanoporous, sponge-like patterns with increasing ion energy. This study is consistent with former irradiations of Ge with a few ion energies. Based on my studies, a consistent, qualitative 3D model of morphology evolution has been developed, which attributes the ion energy dependency of the surface morphology to the depth dependency of point defect creation and relaxation. This model has been proven by atomistic computer experiments, which reproduce the patterns found in real irradiation experiments. At extremely high energy densities deposited by very heavy ions another mechanism dominates pattern formation. The formation of Ge and Si dot patterns by very heavy, monatomic and polyatomic Bi ion irradiation has been studied in detail for the first time. So far, this formation of pronounced dot pattern cannot be explained by any model. Comprehensive, experimental studies have shown that pattern formation on Ge is related to extremely high energy densities deposited by each polyatomic ion locally. The simultaneous impact of several atoms leads to local energy densities sufficient to cause local melting. Heating of Ge substrates under ion irradiation increases the achievable energy density in the collision cascade substantially. This prediction has been confirmed experimentally: it has been found that the threshold for nanomelting can be lowered by substrate heating, which allows pattern formation also under heavy, monatomic ion irradiation. Extensive studies of monatomic Bi irradiation of heated Ge have shown that morphologies change from sponge-like over highly regular dot patterns to smooth surfaces with increasing substrate temperature. The change from sponge-like to dot pattern is correlated to the melting of the ion collision cascade volume, with energy densities sufficient for melt pool formation at the surface. The model of pattern formation on Ge due to extremely high deposited energy densities is not specific to a single element. Therefore, Si has been studied too. Dot patterns have been found for polyatomic Bi ion irradiation of hot Si, which creates sufficiently high energy densities to allow ion impact-induced melt pool formation. This proves that pattern formation by melt pool formation is a novel, general pattern formation mechanism. Using molecular dynamics simulations of project partners, the correlation between dot patterning and ion impact-induced melt pool formation has been proven. The driving force for dot pattern formation due to high deposited energy densities has been identified and approximated in a first continuum description.
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Zhao, Yuer. "A Numerical Study of Melt Pool Heat Transfer in the IVR of a PWR." Thesis, KTH, Fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297867.

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This thesis aims to provide the thermal condition of melt pool convection by CFD simulation, which is important to the assessment of the invessel melt retention (IVR) strategy widely adopted in Generation III pressurized water reactors (PWRs). As a severe accident mitigation measure, the IVR strategy is realized through external cooling of the lower head of a reactor pressure vessel (RPV). To achieve the coolability and retention of the corium pool in the RPV lower head, the heat flux at the outer surface of the vessel should be less than the critical heat flux (CHF) of boiling around the lower head. Under such condition, the integrity of the RPV is guaranteed by the adequate thickness of the unmelted vessel wall. The thesis work starts from the selection and validation of a turbulence model in the CFD computational tool chosen (Fluent). Afterwards a numerical model is set up for estimation of melt pool heat transfer of a reference PWR with the power capacity of 1000 MWe, including a mesh sensitivity study. Based on the numerical model of a twolayer melt pool, four tasks are carried out to investigate the effects of Zr oxidation ratio, Fe content, and radiation emissivity on heat flux profiles, as well as the focus effect under extreme conditions. Selection and validation of the turbulence model are conducted by comparing the simulation results of different turbulence models with the DNS data on the convection of volumetrically heated fluid layer bounded by rigid isothermal horizontal walls at equal temperature. The internal Rayleigh numbers of the flow reach up to 10e6. The comparison shows a good agreement of the SST k-ω turbulence model results with the DNS data. The simulations with the Zr oxidation ratio of 0, 0.2 and 0.5, correspondingly, the oxide layer of 1.389m, 1.467m and 1.580m, and the metal layer of 0.705m, 0.646m and 0.561m in height, show that, the temperature of the oxide layer will increase with Zr oxidation ratio, while the temperature of the metal layer will decrease resulting in more heat transfer through the oxide layer sidewall and less top radiation. Nevertheless, the effect of the Zr oxidation ratio is not pronounced in the range of 00.5. The simulations with the Fe mass of 22t, 33t and 45t, and respective height of the metal layer of 0.462m, 0.568m and 0.646m, show that, the inner metal layer will significantly increase the temperatures of both the metal layer and the oxide layer. The percentage of heat transfer at the oxide layer sidewall will increase to supplement the reduction of that at the metal layer. The simulations with the radiation emissivity of 0.2, 0.35, 0.45 and 0.7 show that, the emissivity below 0.45 has an impact on heat transfer, and the temperatures and sidewall heat flux of both the oxide layer and the metal layer will increase with decreasing emissivity. The impact is negligible when the emissivity is above 0.45. The simulations under the hypothetically extreme conditions with either an adiabatic top boundary or a very thin metal layer show the focusing effect may occur, i.e., the heat flux through the metal sidewall is larger than that in the oxide layer. But the local high heat flux is flattened by the vessel wall with good heat conductivity. In summary, the simulations demonstrate that, except for the cases under extreme conditions, the heat fluxes of the melt pools in all other cases are significantly lower than the CHF of external cooling of the lower head. Therefore, the safety margin of the IVR strategy of the PWR chosen is seems sufficient. However, due to some limitations (e.g., simplification and assumptions) in the simulation cases and coupling of different influential factors, as indicated by the present study, the precise predictions of heat flux under all scenarios are still difficult. Therefore, the conclusions could not be generalized to the other conditions or other configurations of the molten pools. By discussing the model and simplifications/assumptions adopted in this work, the improvement directions of the numerical model and other perspectives are proposed at the end of the thesis.
Denna avhandling syftar till att tillhandahålla det termiska tillståndet för smältbassängskonvektion genom CFD-simulering, vilket är viktigt för bedömningen av IVR-strategin som allmänt antagits i tryckvattenreaktorer (PWR) i Generation III. Som en åtgärd för att mildra allvarliga olyckor realiseras IVR-strategin genom extern kylning av det nedre huvudet av ett reaktortryckkärl (RPV). För att uppnå kylbarhet och kvarhållning av koriumbassängen i det nedre RPV-huvudet bör värmeflöde vid den yttre ytan av kärlet vara mindre än det kritiska värmeflödet (CHF) som kokar runt det nedre huvudet. Under sådant tillstånd garanteras RPV: s integritet av den osmälta kärlväggens tillräckliga tjocklek. Examensarbetet startar från valet och valideringen av en turbulensmodell i det valda CFD-beräkningsverktyget (Fluent). Därefter sätts en numerisk modell upp för uppskattning av smältbassängens värmeöverföring av en referens PWR med en effektkapacitet på 1000 MWe, inklusive en nätkänslighetsstudie. Baserat på den numeriska modellen för en tvålagers smältbassäng utförs fyra uppgifter för att undersöka effekterna av Zr-oxidationsförhållande, Fe-innehåll och strålningsemissivitet på värmeflödesprofiler, liksom fokuseffekten under extrema förhållanden. Val och validering av turbulensmodellen utförs genom att jämföra simuleringsresultaten för olika turbulensmodeller med DNS-data för konvektionen av volymetriskt uppvärmt fluidskikt avgränsat av styva isoterma horisontella väggar vid lika temperatur. De interna Rayleigh-siffrorna i flödet når upp till 10e6. Jämförelsen visar att SST k-ω turbulensmodellresultaten överensstämmer med DNS-data. Simuleringarna med Zr-oxidationsförhållandet 0, 0,2 och 0,5, motsvarande oxidskiktet på 1,389 m, 1,467 m och 1,580 m, och metallskiktet på 0,705 m, 0,664 m och 0,561 m i höjd, visar att temperaturen av oxidskiktet kommer att öka med Zr-oxidationsförhållandet, medan metallskiktets temperatur kommer att minska vilket resulterar i mer värmeöverföring genom oxidskiktets sidovägg och mindre toppstrålning. Ändå är effekten av Zr-oxidationsförhållandet inte uttalad i intervallet 00,5. Simuleringarna med Fe-massan på 22t, 33t och 45t och respektive höjd av metallskiktet på 0,462m, 0,568m och 0,664m visar att det inre metallskiktet avsevärt kommer att öka temperaturerna för både metallskiktet och oxiden lager. Andelen värmeöverföring vid oxidskiktets sidovägg ökar för att komplettera minskningen av den vid metallskiktet. Simuleringarna med strålningsemissiviteten 0,2, 0,35, 0,45 och 0,7 visar att emissiviteten under 0,45 påverkar värmeöverföringen, och temperaturerna och sidoväggens värmeflöde för både oxidskiktet och metallskiktet kommer att öka med minskande emissivitet. Effekten är försumbar när strålningen är över 0,45. Simuleringarna under de hypotetiskt extrema förhållandena med antingen en adiabatisk övre gräns eller ett mycket tunt metallskikt visar att fokuseringseffekten kan uppstå, dvs. värmeflödet genom metallsidan är större än det i oxidskiktet. Men det lokala höga värmeflödet plattas ut av kärlväggen med god värmeledningsförmåga. Sammanfattningsvis visar simuleringarna att, förutom fall under extrema förhållanden, är värmeflödet från smältpoolerna i alla andra fall betydligt lägre än CHF för extern kylning av nedre huvudet. Därför verkar säkerhetsmarginalen för IVR-strategin för den valda PWR tillräcklig. På grund av vissa begränsningar (t.ex. förenkling och antaganden) i simuleringsfall och koppling av olika inflytelserika faktorer, vilket indikeras av den aktuella studien, är de exakta förutsägelserna av värmeflöde under alla scenarier fortfarande svåra. Därför kunde slutsatserna inte generaliseras till de andra förhållandena eller andra konfigurationer av de smälta poolerna. Genom att diskutera modellen och förenklingar / antaganden som antagits i detta arbete föreslås förbättringsriktningarna för den numeriska modellen och andra perspektiv i slutet av avhandlingen.
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Narra, Sneha Prabha. "Melt Pool Geometry and Microstructure Control Across Alloys in Metal Based Additive Manufacturing Processes." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/914.

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There is growing interest in using additive manufacturing for various alloy systems and industrial applications. However, existing process development and part qualification techniques, both involve extensive experimentation-based procedures which are expensive and time-consuming. Recent developments in understanding the process control show promise toward the efforts to address these challenges. The current research uses the process mapping approach to achieve control of melt pool geometry and microstructure in different alloy systems, in addition to location specific control of microstructure in an additively manufactured part. Specifically, results demonstrate three levels of microstructure control, starting with the prior beta grain size control in Ti-6Al-4V, followed by cell (solidification structure) spacing control in AlSi10Mg, and ending with texture control in Inconel 718. Additionally, a prediction framework has been presented, that can be used to enable a preliminary understanding of melt pool geometry for different materials and process conditions with minimal experimentation. Overall, the work presented in this thesis has the potential to reduce the process development and part qualification time, enabling the wider adoption and use of additive manufacturing in industry.
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Kell, James. "Melt pool and microstructure manipulation using diffractive holographic elements in high power conduction laser welding." Thesis, Loughborough University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479315.

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Gockel, Joy E. "Integrated Control of Solidification Microstructure and Melt Pool Dimensions In Additive Manufacturing Of Ti - 6Al - 4V." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/374.

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Additive manufacturing (AM) offers reduced material waste and energy usage, as well as an increase in precision. Direct metal AM is used not only for prototyping, but to produce final production parts in the aerospace, medical, automotive and other industries. Process mapping is an approach that represents process outcomes in terms of process input variables. Solidification microstructure process maps are developed for single bead and thin wall deposits of Ti-6Al-4V via an electron beam wire feed and electron beam powder bed AM process. Process variable combinations yielding constant beta grain size and morphology are identified. Comparison with the process maps for melt pool geometry shows that by maintaining a constant melt pool cross sectional area, a constant grain size will also be achieved. Additionally, the grain morphology boundaries are similar to curves of constant melt pool aspect ratio. Experimental results are presented to support the numerical predictions and identify a proportional size scaling between beta grain widths and melt pool widths. Results demonstrate that in situ, indirect control of solidification microstructure is possible through direct melt pool dimension control. The ability to control solidification microstructure can greatly accelerate AM process qualification potentially allow for tailored microstructure to the desired application.
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Books on the topic "Melt Pools"

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New Jersey. Legislature. General Assembly. Independent Authorities Committee. Public hearing before Assembly Independent Authorities Committee: Current and future manpower needs of the casino industry, the availability of qualified casino employees to meet those needs, and the impact on the casino employee labor pool of the planned opening of a new casino : March 20, 1990, Open Public Meeting Room, Casino Control Commission, Arcade Building, Atlantic City, New Jersey. Trenton, N.J: The Committee, 1990.

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Inc, Game Counselor. Game Counselor's Answer Book for Nintendo Players. Redmond, USA: Microsoft Pr, 1991.

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W, Tarbell W., U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Systems Research., and Sandia National Laboratories, eds. Pressurized melt ejection into water pools. Washington, DC: Division of Systems Research, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1991.

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Renee, Rob. Meet the Poo's. Lulu Press, Inc., 2013.

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Hobson, Melody. Meet the Poos from Pooville. AuthorHouse, 2016.

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Hobson, Melody. Meet the Poos from Pooville. Horizons Literary Management LLC, 2021.

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Yang, Kun. Observed Regional Climate Change in Tibet over the Last Decades. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.587.

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The Tibetan Plateau (TP) is subjected to strong interactions among the atmosphere, hydrosphere, cryosphere, and biosphere. The Plateau exerts huge thermal forcing on the mid-troposphere over the mid-latitude of the Northern Hemisphere during spring and summer. This region also contains the headwaters of major rivers in Asia and provides a large portion of the water resources used for economic activities in adjacent regions. Since the beginning of the 1980s, the TP has undergone evident climate changes, with overall surface air warming and moistening, solar dimming, and decrease in wind speed. Surface warming, which depends on elevation and its horizontal pattern (warming in most of the TP but cooling in the westernmost TP), was consistent with glacial changes. Accompanying the warming was air moistening, with a sudden increase in precipitable water in 1998. Both triggered more deep clouds, which resulted in solar dimming. Surface wind speed declined from the 1970s and started to recover in 2002, as a result of atmospheric circulation adjustment caused by the differential surface warming between Asian high latitudes and low latitudes.The climate changes over the TP have changed energy and water cycles and has thus reshaped the local environment. Thermal forcing over the TP has weakened. The warming and decrease in wind speed lowered the Bowen ratio and has led to less surface sensible heating. Atmospheric radiative cooling has been enhanced, mainly through outgoing longwave emission from the warming planetary system and slightly enhanced solar radiation reflection. The trend in both energy terms has contributed to the weakening of thermal forcing over the Plateau. The water cycle has been significantly altered by the climate changes. The monsoon-impacted region (i.e., the southern and eastern regions of the TP) has received less precipitation, more evaporation, less soil moisture and less runoff, which has resulted in the general shrinkage of lakes and pools in this region, although glacier melt has increased. The region dominated by westerlies (i.e., central, northern and western regions of the TP) received more precipitation, more evaporation, more soil moisture and more runoff, which together with more glacier melt resulted in the general expansion of lakes in this region. The overall wetting in the TP is due to both the warmer and moister conditions at the surface, which increased convective available potential energy and may eventually depend on decadal variability of atmospheric circulations such as Atlantic Multi-decadal Oscillation and an intensified Siberian High. The drying process in the southern region is perhaps related to the expansion of Hadley circulation. All these processes have not been well understood.
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Books, Rhyme Time. Meet the Poops!: A Fun Novelty Rhyming Book for 2-5 Year Olds. Independently Published, 2019.

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Books, Rhyme Time. Meet the Poos!: A Fun Novelty Rhyming Book for 2-5 Year Olds. Independently Published, 2019.

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Finder, Gabriel N., Natalia Aleksiun, and Antony Polonsky, eds. Polin: Studies in Polish Jewry Volume 20. Liverpool University Press, 2007. http://dx.doi.org/10.3828/liverpool/9781904113058.001.0001.

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Although the reconciliation of Jewish and Polish memories of the Holocaust is the central issue in contemporary Polish–Jewish relations, this is the first attempt to examine these divisive memories in a comprehensive way. Until 1989, Polish consciousness of the Second World War subsumed the destruction of Polish Jewry within a communist narrative of Polish martyrdom and heroism. Post-war Jewish memory, by contrast, has been concerned mostly with Jewish martyrdom and heroism. Since the 1980s, however, a significant number of Jews and Poles have sought to identify a common ground and have met with partial but increasing success, notwithstanding the new debates that have emerged in recent years concerning Polish behaviour during the Nazi genocide of the Jews that Poles had ignored for half a century. This volume considers these contentious issues from different angles. Among the topics covered are Jewish memorial projects, both in Poland and beyond its borders, the Polish approach to Holocaust memory under communist rule, and post-communist efforts both to retrieve the Jewish dimension to Polish wartime memory and to reckon with the dark side of the Polish national past. An interview with Henryk Grynberg touches on many of these issues, as do the three poems by Grynberg reproduced here. The 'New Views' section features innovative research in other areas of Polish–Jewish studies. A special section is devoted to research concerning the New Synagogue in Poznan, built in 1907, which is still standing only because the Nazis turned it into a swimming pool.
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Book chapters on the topic "Melt Pools"

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Hayes, Cedric, Caleb Schelle, Greg Taylor, Bridget Martinez, Garrett Kenyon, Thomas Lienert, Yongchao Yang, and David Mascareñas. "Imager-Based Techniques for Analyzing Metallic Melt Pools for Additive Manufacturing." In Special Topics in Structural Dynamics & Experimental Techniques, Volume 5, 63–69. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-12243-0_10.

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Nourgaliev, R. R., T. N. Dinh, and B. R. Sehgal. "Natural Convection in Volumetrically Heated and Side-Wall Heated Melt Pools: Three Dimensional Effects." In Notes on Numerical Fluid Mechanics (NNFM), 202–9. Wiesbaden: Vieweg+Teubner Verlag, 1996. http://dx.doi.org/10.1007/978-3-322-89838-8_27.

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Suurmond, Jeanine, Conny Seeleman, Karien Stronks, and Marie-Louise Essink-Bot. "Een Poolse man met brandwonden." In Een arts van de wereld, 207–14. Houten: Bohn Stafleu van Loghum, 2012. http://dx.doi.org/10.1007/978-90-313-9147-9_23.

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Ehrhard, P., and CH Hölle. "Buoyancy-Driven Melt Pool Convection during Laser Surface Treatment." In Interactive Dynamics of Convection and Solidification, 217–20. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2809-4_34.

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Ding, Xiao, Ymchiro Koizumi, and Akihiko Chiba. "Parameter Optimization for Electron Beam Melting of IN718 Based on Melt Pool Characterization." In Superalloys 2016, 367–73. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119075646.ch40.

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Evgenii, Borisov, Starikov Kirill, Popovich Anatoly, and Popovich Vera. "Melt Pool Evolution in High-Power Selective Laser Melting of Nickel-Based Alloy." In TMS 2021 150th Annual Meeting & Exhibition Supplemental Proceedings, 142–48. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65261-6_13.

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Dellarre, Anthony, Maxime Limousin, and Nicolas Beraud. "Melt Pool Acquisition Using Near-Infrared Camera in Aluminum Wire Arc Additive Manufacturing." In Advances on Mechanics, Design Engineering and Manufacturing IV, 803–14. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-15928-2_70.

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Zielinski, Jonas, Henrik Kruse, Marie-Noemi Bold, Guillaume Boussinot, Markus Apel, and Johannes Henrich Schleifenbaum. "Melt Pool Formation and Out-of-Equilibrium Solidification During the Laser Metal Deposition Process." In Lecture Notes in Mechanical Engineering, 113–22. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70332-5_11.

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Wyffels, Pat, and Anke Smets. "Een 18-jarige patiënte met lichte koorts, uitslag en een pijnlijke pols, met dramatische afloop." In Orthopedische casuïstiek, 619–20. Houten: Bohn Stafleu van Loghum, 2010. http://dx.doi.org/10.1007/978-90-313-8803-5_179.

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Wyffels, Pat, and Anke Smets. "7 Een 18-jarige patiënte met lichte koorts, uitslag en een pijnlijke pols, met dramatische afloop." In Onderzoek en behandeling van artrose en artritis, 63–65. Houten: Bohn Stafleu van Loghum, 2009. http://dx.doi.org/10.1007/978-90-313-8000-8_10.

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Conference papers on the topic "Melt Pools"

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Chakraborty, Nilanjan, and Suman Chakraborty. "Modelling of Turbulent Transport in Laser Melt Pools." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45774.

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In this paper, we present a modified k-ε model capable of addressing turbulent molten metal-pool convection in the presence of a continuously evolving phase-change interface during a laser melting process. The phase change aspects of the present problem are addressed using a modified enthalpy-porosity technique. The k-ε model is suitably modified to account for the morphology of the solid-liquid interface. A three-dimensional mathematical model is subsequently utilised to simulate a typical laser melting process with high power, where effects of turbulent transport can actually be realised. In order to investigate these effects on laser molten pool convection, simulations with laminar transport and turbulent transport are carried out for same problem parameters. Finally, results of the simulation using the present turbulence model are compared with the results of laminar simulation with same problem parameters. Significant effects of turbulent transport on penetration and the geometrical features of the molten pool are observed which is an outcome of the thermal history of the pool. The thermal history in turn determines the microstructure of the work piece, which finally governs the mechanical properties of the work piece.
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Luo, Simin, Xin'an Wang, Yapei Zhang, Dalin Zhang, Suizheng Qiu, and Guanghui Su. "Numerical Research on Melt Pool Flow Characteristics Under Rolling Condition." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81994.

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In-vessel-retention (IVR) has become an important subject of severe accident mitigation strategy. Up to now, many experimental and numerical investigations have been performed on the natural convection characteristics in melt pools with volumetric heating. But these studies are limited to the melt pools under static condition. As floating nuclear reactors become increasingly popular among both commercial and military ships, for successful application of IVR in this occasion, research should be done on the heat transfer characteristics of melt pool under moving conditions. Currently, the specially-designed facility is under construction in Xi'an China for the relevant experiment and numerical studies are performed beforehand. In this paper, a hemisphere with an inner radius of 0.5m, similar to LIVE experimental facility, is chosen to simulate the melt pool. Its flow behaviors under periodic rolling condition are simulated by means of CFD calculation. This work may cast a light on the melt pool characteristics under moving conditions and could be further evaluated by future experimental data.
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Martukanitz, R. P., K. D. Parks, S. S. Babu, and S. A. David. "Analysis of hard particle retention in laser melt pools." In ICALEO® 2000: Proceedings of the Laser Materials Processing Conference. Laser Institute of America, 2000. http://dx.doi.org/10.2351/1.5059479.

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Safdar, Shakeel, Andrew J. Pinkerton, Richard Moat, Lin Li, Mohammed A. Sheikh, Michael Preuss, and Philip J. Withers. "An anisotropic enhanced thermal conductivity approach for modelling laser melt pools." In ICALEO® 2007: 26th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing. Laser Institute of America, 2007. http://dx.doi.org/10.2351/1.5061002.

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Sato, Matthew M., Vivian Wen Hui Wong, Kincho H. Law, Ho Yeung, Zhuo Yang, Brandon Lane, and Paul Witherell. "Anomaly Detection of Laser Powder Bed Fusion Melt Pool Images Using Combined Unsupervised and Supervised Learning Methods." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-88313.

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Abstract Laser Powder Bed Fusion (LPBF) is one of the most promising forms of Additive Manufacturing (AM), allowing easily customized metal manufactured parts. Industry use is currently limited due to the often unknown and unreliable part quality, which is largely caused by the complex relationships between process parameters that include laser power, laser speed, scan strategy, and other machine settings. Melt pools can be monitored with a camera aligned co-axially with the laser to monitor part quality. However, the number of images acquired can be large, exceeding hundreds of thousands for a single part. This paper investigates how the K-Means algorithm, an unsupervised machine learning method, can be used to cluster images of melt pools based on their shape, including undesirable anomalous melt pools. Another unsupervised learning method in this paper is the U-Net autoencoder, which identifies anomalous melt pools by identifying images with a large reconstruction loss. The K-Means clustering or autoencoder provides labels that can be used for training a convolutional neural network image classifier. The image classifier can then be used to identify anomalous melt pools during the LPBF process. This paper provides a first step for real-time process control of the LPBF process by demonstrating how anomalous melt pools can be automatically identified in real-time.
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Mistry, Utsavkumar, and Madhu Vadali. "Influence of Surface Geometry on Melt Pool Flows and Shape in Pulsed Laser Surface Melting." In ASME 2021 16th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/msec2021-60460.

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Abstract Pulsed Laser Surface Melting (pLSM) is a technique that offers an efficient way to modify the geometry surfaces without any addition or removal of material. In pLSM, an incident laser beam melts a small region on the surface and induces surface tension and viscosity-driven flows that modify the surface geometry. Initial surface geometry plays an important role in deciding the melt pool flows and shape as it governs the initial surface tension acting on the melt pool. In this paper, we present a systematic numerical study that captures the effects of initial geometries using a two-dimensional axisymmetric model. The results show that geometries with higher curvatures result in deeper melt pools and higher surface displacement because higher fluid velocities aid the convection heat transfer. Additionally, we define a modified capillary number (CaM) which elegantly captures these effects.
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Khanzadeh, Mojtaba, Sudipta Chowdhury, Linkan Bian, and Mark A. Tschopp. "A Methodology for Predicting Porosity From Thermal Imaging of Melt Pools in Additive Manufacturing Thin Wall Sections." In ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-2909.

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The microstructure and mechanical properties of Laser Based Additive Manufacturing (LBAM) are often inconsistent and unreliable for many industrial applications. One of the key technical challenges is the lack of understanding of the underlying process-structure-property relationship. The objective of the present research is to use the melt pool thermal profile to predict porosity within the LBAM process. Herein, we propose a novel porosity prediction method based on morphological features and the temperature distribution of the top surface of the melt pool as the LBAM part is being built. Self-organizing maps (SOM) are then used to further analyze the 2D melt pool dataset to identify similar and dissimilar melt pools. The performance of the proposed method of porosity prediction uses X-Ray tomography characterization, which identified porosity within the Ti-6Al-4V thin wall specimen. The experimentally identified porosity locations were compared to the porosity locations predicted based on the melt pool analysis. Results show that the proposed method is able to predict the location of porosity almost 85% of the time when the appropriate SOM model is selected. The significance of such a methodology is that this may lead the way towards in situ monitoring and on-the-fly modification of melt pool thermal profile to minimize or eliminate pores within LBAM parts.
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Milaat, Fahad Ali, Zhuo Yang, Hyunwoong Ko, and Albert T. Jones. "Prediction of Melt Pool Geometry Using Deep Neural Networks." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-69259.

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Abstract Selective laser melting (SLM) is modernizing the production of highly complex metal parts across the manufacturing industry. However, achieving material homogeneity and controlling thermal deformation remain major challenges for metal-based, additive manufacturing. Therefore, adequate control systems are needed to monitor build processes, and ensure part quality throughout production. Traditionally, control designs relied on physics-based knowledge in analyzing, characterizing, and modeling complex, nonstationary patterns. Recent advancements in machine learning techniques harness the abundance of data to discover effective control designs. In this paper, we investigate the efficacy of a data-driven approach towards in-situ modeling of melt-pool geometry. Specifically, we propose a new methodology that uses a deep neural network architecture to predict melt pool geometries with linear regression models, which manifest during in-situ processes. Experimental results show that our deep neural network model with multiple input features produced 84% goodness of fit score, outperforming the model with a single feature that scored 37% for the given dataset, and the monitored regression models. These outcomes promote further investigation into new and efficient ways for acquiring real-time data from in-situ processes. Our contribution complements the way we understand properties of in-situ data, and predict patterns of melt pools, based on artificial cognition.
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Ahmadi, Arman, Narges Shayesteh Moghaddam, Mohammad Elahinia, Haluk E. Karaca, and Reza Mirzaeifar. "Finite Element Modeling of Selective Laser Melting 316L Stainless Steel Parts for Evaluating the Mechanical Properties." In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8594.

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Selective laser melting (SLM) is an additive manufacturing technique in which complex parts can be fabricated directly by melting layers of powder from a CAD model. SLM has a wide range of application in biomedicine and other engineering areas and it has a series of advantages over traditional processing techniques. A large number of variables including laser power, scanning speed, scanning line spacing, layer thickness, material based input parameters, etc. have a considerable effect on SLM process materials. The interaction between these parameters is not completely studied. Limited studies on balling effect in SLM, densifications under different processing conditions, and laser re-melting, have been conducted that involved microstructural investigation. Grain boundaries are amongst the most important microstructural properties in polycrystalline materials with a significant effect on the fracture and plastic deformation. In SLM samples, in addition to the grain boundaries, the microstructure has another set of connecting surfaces between the melt pools. In this study, a computational framework is developed to model the mechanical response of SLM processed materials by considering both the grain boundaries and melt pool boundaries in the material. To this end, a 3D finite element model is developed to investigate the effect of various microstructural properties including the grains size, melt pools size, and pool connectivity on the macroscopic mechanical response of the SLM manufactured materials. A conventional microstructural model for studying polycrystalline materials is modified to incorporate the effect of connecting melt pools beside the grain boundaries. In this model, individual melt pools are approximated as overlapped cylinders each containing several grains and grain boundaries, which are modeled to be attached together by the cohesive zone method. This method has been used in modeling adhesives, bonded interfaces, gaskets, and rock fracture. A traction-separation description of the interface is used as the constitutive response of this model. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the material inside the grains. For the experimental verification, stainless steel 316L flat dog bone samples are fabricated by SLM and tested in tension. During fabrication, the power of laser is constant, and the scan speed is changed to study the effect of fabrication parameters on the mechanical properties of the parts and to compare the result with the finite element model.
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Villanueva, Walter, Chi-Thanh Tran, and Pavel Kudinov. "Effect of CRGT Cooling on Modes of Global Vessel Failure of a BWR Lower Head." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54955.

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An in-vessel stage of a severe core melt accident in a Nordic type Boiling Water Reactor (BWR) is considered wherein a decay-heated pool of corium melt inflicts thermal and mechanical loads on the lower-head vessel wall. This process induces creep leading to a mechanical failure of the reactor vessel wall. The focus of this study is to investigate the effect of Control Rod Guide Tube (CRGT) and top cooling on the modes of global vessel failure of the lower head. A coupled thermo-mechanical creep analysis of the lower head is performed and cases with and without CRGT and top cooling are compared. The debris bed heat-up, re-melting, melt pool formation, and heat transfer are calculated using the Phase-change Effective Convectivity Model and transient heat transfer characteristics are provided for thermo-mechanical strength calculations. The creep analysis is performed with the modified time hardening creep model and both thermal and integral mechanical loads on the reactor vessel wall are taken into account. Known material properties of the reactor vessel as a function of temperature, including the creep curves, are used as an input data for the creep analysis. It is found that a global vessel failure is imminent regardless of activation of CRGT and top cooling. However, if CRGT and top cooling is activated, the mode and timing of failure is different compared to the case with no CRGT and top cooling. More specifically, with CRGT and top cooling, there are two modes of global vessel failure depending on the size of the melt pool: (a) ‘ballooning’ of the vessel bottom for smaller pools, and (b) ‘localized creep’ concentrated within the vicinity of the top surface of the melt pool for larger pools. Without CRGT and top cooling, only a ballooning mode of global vessel failure is observed. Furthermore, a considerable delay (about 1.4 h) on the global vessel failure is observed for the roughly 30-ton debris case if CRGT and top cooling is implemented. For a much larger pool (roughly 200-ton debris), no significant delay on the global vessel failure is observed when CRGT and top cooling is implemented, however, the liquid melt fraction and melt superheat are considerably higher in non-cooling case.
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Reports on the topic "Melt Pools"

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Sipf, J. B., L. A. Boatner, and S. A. David. Solidification microstructures in single-crystal stainless steel melt pools. Office of Scientific and Technical Information (OSTI), March 1994. http://dx.doi.org/10.2172/10141631.

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McHugh, P. R., and J. D. Ramshaw. A computational model for viscous fluid flow, heat transfer, and melting in in situ vitrification melt pools. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/10140275.

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McHugh, P. R., and J. D. Ramshaw. A computational model for viscous fluid flow, heat transfer, and melting in in situ vitrification melt pools. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/5504904.

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List, III, Frederick Alyious, Ralph Barton Dinwiddie, Keith Carver, and Joy E. Gockel. Melt-Pool Temperature and Size Measurement During Direct Laser Sintering. Office of Scientific and Technical Information (OSTI), August 2017. http://dx.doi.org/10.2172/1399977.

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Cheung, F. B., B. C. Yang, D. H. Cho, and M. J. Tan. Transient dissolution of a steel structure in an aluminum melt pool. Office of Scientific and Technical Information (OSTI), December 1992. http://dx.doi.org/10.2172/10167175.

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Wyrwas, Richard B. Single-Pass Melt Pool Retention Based on the Ratio of Cesium to Technetium. Office of Scientific and Technical Information (OSTI), May 2019. http://dx.doi.org/10.2172/1513690.

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Barney, R. Investigation of Marangoni convection with high-fidelity simulations for metal melt pool dynamics. Office of Scientific and Technical Information (OSTI), October 2019. http://dx.doi.org/10.2172/1573160.

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Dykhne, A. Theoretical description of laser melt pool dynamics, Task order number B239634, Quarter 3 report. Office of Scientific and Technical Information (OSTI), May 1995. http://dx.doi.org/10.2172/105048.

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Trageser, Jeremy, and John Mitchell. A Bezier Curve Informed Melt Pool Geometry to Model Additive Manufacturing Microstructures Using SPPARKS. Office of Scientific and Technical Information (OSTI), September 2020. http://dx.doi.org/10.2172/1664647.

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Han, Dae-Hyun, Eric Brian Flynn, Charles Reed Farrar, and Lae-Hong Kang. A Study on Melt Pool Depth Monitoring of Direct Energy Additive Manufacturing Using Laser-Ultrasound. Office of Scientific and Technical Information (OSTI), March 2016. http://dx.doi.org/10.2172/1241636.

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