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Hulme-Smith, ChristopherORCID iD iconorcid.org/0000-0002-6339-4612
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Publications (10 of 51) Show all publications
Hulme-Smith, C., Mellin, P., Marchetti, L., Hari, V., Uhlirsch, M., Strandh, E., . . . Meurling, F. (2023). A practicable and reliable test for metal powder spreadability: development of test and analysis technique. Progress in Additive Manufacturing, 8(3), 505-517
Open this publication in new window or tab >>A practicable and reliable test for metal powder spreadability: development of test and analysis technique
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2023 (English)In: Progress in Additive Manufacturing, ISSN 2363-9512, Vol. 8, no 3, p. 505-517Article in journal (Refereed) Published
Abstract [en]

A crucial step in the powder bed metal additive manufacturing process is the formation of a thin layer of powder on top of the existing material. The propensity of the powder to form thin layers under the conditions used in additive manufacturing is critically important, but no test method has yet been established to measure this characteristic, which is sometimes referred to as spreadability. The current work spreads a single layer of powder using commercial equipment from the paint and food industries and derives the density of a layer of powder, which is of a similar thickness to that in additive manufacturing. Twenty-four powders from eight suppliers have been tested and the density of the layers has been measured as a function of various parameters. Twenty-two of the powders successfully form thin layers, with a density of at least 40% of each powder’s apparent density. Hall flow time did not correlate with the spread layer density, although the two powders that did not spread did not pass through the Hall funnel. The roughness of the plate onto which the powder was spread, the recoater speed, the layer thickness, particle size and aspect ratio all affect the measured layer density. Results of the new test are repeatable and reproducible. These findings can be used to develop a test for spreadability for metal powders that can be used for additive manufacturing, which will help to improve the quality of printed components. 

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Additive manufacturing, Layer density, Powder metallurgy, Spreadability
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-327305 (URN)10.1007/s40964-022-00341-3 (DOI)000855599200001 ()2-s2.0-85138390752 (Scopus ID)
Note

QC 20230524

Available from: 2023-05-24 Created: 2023-05-24 Last updated: 2023-06-08Bibliographically approved
Ibrahim, M., Du, Q., Hovig, E. W., Grasmo, G., Hulme-Smith, C. & Aune, R. E. (2023). Gas-Atomized Nickel Silicide Powders Alloyed with Molybdenum, Cobalt, Titanium, Boron, and Vanadium for Additive Manufacturing. Metals, 13(9), Article ID 1591.
Open this publication in new window or tab >>Gas-Atomized Nickel Silicide Powders Alloyed with Molybdenum, Cobalt, Titanium, Boron, and Vanadium for Additive Manufacturing
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2023 (English)In: Metals, ISSN 2075-4701, Vol. 13, no 9, article id 1591Article in journal (Refereed) Published
Abstract [en]

Nickel silicides (NiSi) are renowned for their ability to withstand high temperatures and resist oxidation and corrosion in challenging environments. As a result, these alloys have garnered interest for potential applications in turbine blades and underwater settings. However, their high brittleness is a constant obstacle that hinders their use in producing larger parts. A literature review has revealed that incorporating trace amounts of transition metals can enhance the ductility of silicides. Consequently, the present study aims to create NiSi-based powders with the addition of titanium (Ti), boron (B), cobalt (Co), molybdenum (Mo), and vanadium (V) for Additive Manufacturing (AM) through the process of gas atomization. The study comprehensively assesses the microstructure, phase composition, thermal properties, and surface morphology of the produced powder particles, specifically NiSi11.9Co3.4, NiSi10.15V4.85, NiSi11.2Mo1.8, and Ni-Si10.78Ti1.84B0.1. Commonly used analytical techniques (SEM, EDS, XRD, DSC, and laser diffraction) are used to identify the alloy configuration that offers optimal characteristics for AM applications. The results show spherical particles within the size range of 20–63 μm, and only isolated satellites were observed to exist in the produced powders, securing their smooth flow during AM processing.

Place, publisher, year, edition, pages
MDPI AG, 2023
Keywords
additive manufacturing (AM), gas atomization, nickel (Ni), nickel silicide (NiSi), silicon (Si)
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-338058 (URN)10.3390/met13091591 (DOI)001077839800001 ()2-s2.0-85172873728 (Scopus ID)
Note

QC 20231013

Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-10-25Bibliographically approved
Lin, Z., Surreddi, K. B., Hulme-Smith, C., Dadbakhsh, S. & Rashid, A. (2023). Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium. Advanced Engineering Materials
Open this publication in new window or tab >>Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium
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2023 (English)In: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648Article in journal, Editorial material (Refereed) Published
Abstract [en]

Electron beam powder bed fusion (PBF-EB) is used to manufacture dense nickel titanium parts using various parameter sets, including the beam current, scan speed and post cooling condition. The density of manufactured NiTi parts are investigated with relation to the linear energy input. The results implies the part density increases with increasing linear energy density to over 98% of the bulk density. With a constant energy input, a combination of low power and low scan speed leads to denser parts. This is attributed to lower electrostatic repulsive forces from lower number density of the impacting electrons. After manufacturing, densest parts with distinct parameter sets are categorized into three groups: i) high power with high scan speed and vacuum slow cooling, ii) low power with low scan speed and vacuum slow cooling and iii) low power with low scan speed and medium cooling rate in helium gas. Among these, a faster cooling rate suppresses phase transformation temperatures, while vacuum cooling combinations do not affect the phase transformation temperatures significantly. All the printed parts in this study exhibit almost 8% pseudoelasticity regardless of the process parameters, while the parts cooled in helium have a higher energy dissipation efficiency ( ), which implies faster damping of oscillations. 

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
PBF-EB, cooling rate, NiTi, AM, process paremeters
National Category
Materials Engineering
Research subject
Industrial Engineering and Management
Identifiers
urn:nbn:se:kth:diva-326103 (URN)10.1002/adem.202201818 (DOI)000975548500001 ()2-s2.0-85154049056 (Scopus ID)
Note

QC 20230426

Available from: 2023-04-24 Created: 2023-04-24 Last updated: 2023-11-30Bibliographically approved
Momeni Dolatabadi, A., Saffari Pour, M., Mousavi Ajarostaghi, S. S., Poncet, S. & Hulme-Smith, C. (2023). Last stage stator blade profile improvement for a steam turbine under a non-equilibrium condensation condition: A CFD and cost-saving approach. Alexandria Engineering Journal, 73, 27-46
Open this publication in new window or tab >>Last stage stator blade profile improvement for a steam turbine under a non-equilibrium condensation condition: A CFD and cost-saving approach
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2023 (English)In: Alexandria Engineering Journal, ISSN 1110-0168, E-ISSN 2090-2670, Vol. 73, p. 27-46Article in journal (Refereed) Published
Abstract [en]

Non-equilibrium phenomena and related damages have always been one of the great concerns among researchers, designers, and industry managers. In power plants, the overhaul of turbines during a pre-planned schedule includes checking, repairing, and replacing damaged parts, which always challenge industry investors with variable costs. In this study, a modified profile for the stationary cascade blades of a 200 MW steam turbine is predicted by help of the Computational Fluid Dynamics (CFD) according to a cost-saving approach for a power plant. Wet steam model is used to investigate the flow behavior between the turbine blades, due to the sonication and non-equilibrium phenomena. The numerical model based on the Eulerian-Eulerian approach accounts the turbulence caused by the presence of droplets, condensation shocks and aerodynamics. At first, such model has been carefully validated against the available experimental data. Then, the entrance edge of the blade is designed considering different shapes and sizes. The flow behavior at the entrance edge region has been fully investigated. Finally, according to the criteria for measuring the non-equilibrium flow phenomena (erosion rate, Mach number, entropy, exergy destruction and transfer of mass and heat between flow phases), a modified model for the steam turbine blade considering the economic aspects has been presented. The modified blade model exhibits 88%, 0.13% and 7% reduction in the erosion rate, entropy generation and exergy destruction, respectively. Furthermore, the application of this modified blade profile save 456$ of the total monthly maintenance costs.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Steam turbine, Modified blade profile, Non-equilibrium condensation, Economical analysis, CFD
National Category
Energy Engineering
Research subject
Energy Technology; Applied and Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-328188 (URN)10.1016/j.aej.2023.04.011 (DOI)000990332300001 ()2-s2.0-85153573888 (Scopus ID)
Note

QC 20230613

Available from: 2023-06-05 Created: 2023-06-05 Last updated: 2023-06-13Bibliographically approved
Kuthe, S., Schlothauer, A., Bodkhe, S., Hulme-Smith, C. & Ermanni, P. (2022). 3D printed mechanically representative aortic model made of gelatin fiber reinforced silicone composite. Materials letters (General ed.), 320, 132396, Article ID 132396.
Open this publication in new window or tab >>3D printed mechanically representative aortic model made of gelatin fiber reinforced silicone composite
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2022 (English)In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 320, p. 132396-, article id 132396Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing (AM) is a useful technology to produce artificial aortic models for the training of transcatheter aortic valve replacement (TAVR) surgery. With AM, the models can be tailored towards the individualized aortic anatomy of patients. Most of these reported models so far are manufactured using single rubber-like materials. However, such materials do not replicate the mechanical properties of natural aortic tissue, especially the stress-strain response in higher strain (>0.1) regions. This could be problematic for surgeons training for surgeries using a model which does not exhibit properties of the real aorta. To overcome this limitation, we developed a 3D-printed, mechanically representative aortic model comprising gelatin fibers and silicone. The model is promising as a realistic analog of aortic sinus for mock TAVR surgery. Computerized tomography data was analyzed beforehand using medical imaging to identify the anatomy of a specific patient's aortic sinus and the surrounding blood vessels. A novel silicone matrix composite reinforced with gelatin fibers designed in this work was tested and compared with the stress-strain response of aortic tissue. Such a model comprising both patient-specific geometries as well as realistic material properties of aortic tissue can be helpful for the development of next-generation medical phantoms.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Additive manufacturing, Aortic model, Direct ink writing, Fiber-reinforced composite, Gelatin fiber, Silicone
National Category
Materials Engineering Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:kth:diva-315561 (URN)10.1016/j.matlet.2022.132396 (DOI)000806403800005 ()2-s2.0-85129495863 (Scopus ID)
Note

QC 20220707

Available from: 2022-07-07 Created: 2022-07-07 Last updated: 2023-06-07Bibliographically approved
Ghalambaz, S. & Hulme-Smith, C. (2022). A Scientometric Analysis of Energy Management in the Past Five Years (2018-2022). Sustainability, 14(18), 11358, Article ID 11358.
Open this publication in new window or tab >>A Scientometric Analysis of Energy Management in the Past Five Years (2018-2022)
2022 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 18, p. 11358-, article id 11358Article in journal (Refereed) Published
Abstract [en]

Energy management is an essential part of the integration of renewable energy in energy systems, electric vehicles, energy-saving strategies, waste-heat recovery, and building energy. Although many publications considered energy management, no study addressed the connection between scientists, organizations, and countries. The present study provides a scientometric analysis that addresses the trend of publications and worldwide dynamic maps of connectivity and scientists, organizations, and countries and their contribution to energy management. The results showed that Javaid Nadeem published the most papers in the field of energy management (90) while Xiao Hu received the most citations (1394). The university with the highest number of publications in energy management is the Islamic Azad University (144 papers), while the Beijing Institute of Technology has received the most citations (2061 citations) and the largest h-index (28). China and the United States are in the first and second rank in terms of total publications, citations, and h-index. Pakistan has the most publications relative to the country's research and development investment level. The maps of co-authorship show islands of isolated groups of authors. This implies that the researchers in energy management are not well-connected. Bibliographic coupling of countries revealed China and USA are influential contributors in the field, and other countries were coupled mostly through these two countries.

Place, publisher, year, edition, pages
MDPI AG, 2022
Keywords
energy management, scientometric analysis, bibliographic coupling, connection network
National Category
Applied Psychology
Identifiers
urn:nbn:se:kth:diva-320300 (URN)10.3390/su141811358 (DOI)000860811300001 ()2-s2.0-85138767915 (Scopus ID)
Note

QC 20221024

Available from: 2022-10-24 Created: 2022-10-24 Last updated: 2023-06-08Bibliographically approved
Hulme-Smith, C. (2022). Flow behavior of magnetic steel powder. Particulate Science and Technology, 40(5), 576-588
Open this publication in new window or tab >>Flow behavior of magnetic steel powder
2022 (English)In: Particulate Science and Technology, ISSN 0272-6351, E-ISSN 1548-0046, Vol. 40, no 5, p. 576-588Article in journal (Refereed) Published
Abstract [en]

Flow occurs in most powder-based processes, opposed by various cohesive forces. Magnetism is often overlooked for metal powders. Here, flowability and magnetization were measured for a dual-phase steel powder in size fractions from (Formula presented.) to > 200 µm. The finest fraction did not flow through a Hall flowmeter, then flow time increased continuously with particle size from 12 ± 1 s for the next fraction ((Formula presented.)) to > 28 ± 0.5 s for > 200 µm. Drying had little effect. Key metrics derived from shear tests gave no overall relationship between flow behavior and particle size. Magnetism was considered the most likely reason for this behavior. Magnetometry showed a remanent magnetization of (Formula presented.) which causes ∼ 5 µN cohesion between 200 µm diameter particles. X-ray diffractometry showed that the powder contained 77 wt%-80 wt% of (magnetic) martensite. Liquid bridging, van der Waals forces and friction (in the Hall flowmeter geometry) contribute 50 µN, 0.08 µN and 4 µN, respectively, to cohesion in 200 µm particles. These results can be used to help explain flow behavior in other magnetic powders and allow optimization of powders and/or powder-based processes. 

Place, publisher, year, edition, pages
Informa UK Limited, 2022
Keywords
flowability, magnetism, Powder metallurgy, spreadability, Compressive strength, Flow measurement, Flowmeters, Magnetization, Powder metals, Shear flow, Van der Waals forces, X ray diffraction analysis, Cohesive force, Dual-phases steels, Flow behaviours, Magnetic steel, Particles sizes, Powder-based, Steel powder, Particle size
National Category
Metallurgy and Metallic Materials Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-311804 (URN)10.1080/02726351.2021.1977442 (DOI)000700782900001 ()2-s2.0-85115734056 (Scopus ID)
Note

QC 20220504

Available from: 2022-05-04 Created: 2022-05-04 Last updated: 2023-06-08Bibliographically approved
Forsberg, K. & Hulme-Smith, C. (2022). Materials - a tangible challenge for the electrification of society. In: Fredrik Brounéus & Christophe Duwig (Ed.), Towards the energy of the future – the invisible revolution behind the electrical socket: . Books on Demand
Open this publication in new window or tab >>Materials - a tangible challenge for the electrification of society
2022 (English)In: Towards the energy of the future – the invisible revolution behind the electrical socket / [ed] Fredrik Brounéus & Christophe Duwig, Books on Demand , 2022Chapter in book (Other (popular science, discussion, etc.))
Place, publisher, year, edition, pages
Books on Demand, 2022
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-324145 (URN)
Note

Part of book: ISBN 978-91-89039-14-8, QC 20230228

Available from: 2023-02-21 Created: 2023-02-21 Last updated: 2023-02-28Bibliographically approved
Marchetti, L., Mellin, P. & Hulme-Smith, C. (2022). Negative impact of humidity on the flowability of steel powders. Particulate Science and Technology, 40(6), 722-736
Open this publication in new window or tab >>Negative impact of humidity on the flowability of steel powders
2022 (English)In: Particulate Science and Technology, ISSN 0272-6351, E-ISSN 1548-0046, Vol. 40, no 6, p. 722-736Article in journal (Refereed) Published
Abstract [en]

Atmospheric humidity is introduced into powders during handling, transportation, and storage. High moisture content can increase cohesive forces between particles and make it difficult to spread a powder into thin layers in powder bed processes or to fill a mold in processes such as press-and-sinter. Furthermore, water can cause porosity and uptake of oxygen in the final component, damaging its mechanical properties. In this study, a Freeman FT4 powder rheometer was placed inside a climate chamber. Both flowability and shear tests were performed on four steel powders under a range of humidity and temperatures. Basic flowability energy and specific energy were both found to increase significantly with humidity (typically increase by 50% for 80% of relative humidity compared to dry conditions) and were insensitive to temperature change (10–30 °C). Conversely, the behavior of the powders under shear was neither sensitive to relative humidity nor temperature. Measurements of moisture content revealed that finer powders contained more moisture than coarser ones, but the moisture content was not correlated with humidity, probably due to shortcomings with the measurement method. This knowledge can be used to optimize powder processing conditions.

Place, publisher, year, edition, pages
Informa UK Limited, 2022
Keywords
Flowability, humidity, moisture, powder rheometer, steel powders
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-313436 (URN)10.1080/02726351.2021.1995091 (DOI)000722552700001 ()2-s2.0-85120689865 (Scopus ID)
Note

QC 20220603

Available from: 2022-06-03 Created: 2022-06-03 Last updated: 2023-06-08Bibliographically approved
Ben Khedher, N., Shahabadi, M., Alghawli, A. S., Hulme-Smith, C. & Mehryan, S. A. (2022). Numerical Study of the Flow and Thermomagnetic Convection Heat Transfer of a Power Law Non-Newtonian Ferrofluid within a Circular Cavity with a Permanent Magnet. Mathematics, 10(15), Article ID 2612.
Open this publication in new window or tab >>Numerical Study of the Flow and Thermomagnetic Convection Heat Transfer of a Power Law Non-Newtonian Ferrofluid within a Circular Cavity with a Permanent Magnet
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2022 (English)In: Mathematics, E-ISSN 2227-7390, Vol. 10, no 15, article id 2612Article in journal (Refereed) Published
Abstract [en]

The aim of this study is to analyze the thermo-magnetic-gravitational convection of a non-Newtonian power law ferrofluid within a circular cavity. The ferrofluid is exposed to the magnetic field of a permanent magnet. The finite element method is employed to solve the non-dimensional controlling equations. A grid sensitivity analysis and the validation of the used method are conducted. The effect of alterable parameters, including the power law index, 0.7 <= n <= 1.3, gravitational Rayleigh number, 10(4) <= Ra-T <= 10(6), magnetic Rayleigh number, 10(5) <= Ra-M <= 10(8), the location of the hot and cold surfaces, 0 <= lambda <= pi/2, and the length of the magnet normalized with respect to the diameter of the cavity, 0.1 <= L <= 0.65, on the flow and heat transfer characteristics are explored. The results show that the heat transfer rate increases at the end of both arcs compared to the central region because of buoyancy effects, and it is greater close to the hot arc. The location of the arcs does not affect the heat transfer rate considerably. An increase in the magnetic Rayleigh number contributes to stronger circulation of the flow inside and higher heat transfer. When the Kelvin force is the only one imposed on the flow, it enhances the heat transfer for magnets of length 0.2 <= L <= 0.3.

Place, publisher, year, edition, pages
MDPI AG, 2022
Keywords
non-Newtonian ferrofluid, permanent magnet, thermomagnetic convection, magnetization
National Category
Other Physics Topics Neurosciences Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:kth:diva-316738 (URN)10.3390/math10152612 (DOI)000839933600001 ()2-s2.0-85136814702 (Scopus ID)
Note

QC 20220830

Available from: 2022-08-30 Created: 2022-08-30 Last updated: 2023-06-07Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-6339-4612

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