Dissertations / Theses on the topic 'Porous foam'
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Osei-Bonsu, Kofi. "Foam-facilitated oil displacement in porous media." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/foamfacilitated-oil-displacement-in-porous-media(f2b2e93b-3a9b-41fa-a841-f81b271e8fad).html.
Full textArmitage, Paul. "Foam flow through porous media : a micromodel study." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46650.
Full textGabbrielli, Ruggero. "Foam geometry and structural design of porous material." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507759.
Full textAlvarez, Martinez José Manuel. "Foam-flow behavior in porous media : effects of flow regime and porous-medium heterogeneity /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full textRodeheaver, Bret Alan. "Open-celled microcellular themoplastic foam." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/18914.
Full textYeates, Christopher. "Multi-Scale Study of Foam Flow Dynamics in Porous Media." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS023/document.
Full textIn this work, we use of a high-complexity micromodel of fixed structure on which we perform a series of experiments with varying injection rates, foam qualities, inlet bubble size distributions and injection methods. We perform individual bubble tracking and associate flow properties with bubble size properties and structural characteristics of the medium. We propose new tools describing the local and global flow in different ways. We establish specific behaviors for different bubble sizes, demonstrating that trapped foams are more likely to have smaller than average bubble sizes, while flowing bubbles also tend to segregate in different flow paths according to bubble size. Larger bubbles tend to flow in high-velocity preferential paths that are generally more aligned with pressure gradient, but smaller bubbles tend to access in supplement transversal paths linking the different preferential paths. Furthermore, for our data we establish the pre-eminence of the trapped foam fraction over bubble density within the microscopic explanation of apparent viscosity, although both contribute to some degree. We structurally characterize consistently trapped zones as areas with either low pore coordination, low entrance throat size, unfavorable throat orientation or a combination thereof. High-flow zones however cannot be characterized in terms of local structural parameters and necessitate integration of complete path information from the entire model. In this regard, in order to capture the high-flow zones, we develop a path-proposing model that makes use of a graph representation of the model, from an initial decomposition into pores and throats, that uses only local throat size and throat orientation relative to pressure gradient to characterize paths
Yeates, Christopher. "Multi-Scale Study of Foam Flow Dynamics in Porous Media." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS023.
Full textIn this work, we use of a high-complexity micromodel of fixed structure on which we perform a series of experiments with varying injection rates, foam qualities, inlet bubble size distributions and injection methods. We perform individual bubble tracking and associate flow properties with bubble size properties and structural characteristics of the medium. We propose new tools describing the local and global flow in different ways. We establish specific behaviors for different bubble sizes, demonstrating that trapped foams are more likely to have smaller than average bubble sizes, while flowing bubbles also tend to segregate in different flow paths according to bubble size. Larger bubbles tend to flow in high-velocity preferential paths that are generally more aligned with pressure gradient, but smaller bubbles tend to access in supplement transversal paths linking the different preferential paths. Furthermore, for our data we establish the pre-eminence of the trapped foam fraction over bubble density within the microscopic explanation of apparent viscosity, although both contribute to some degree. We structurally characterize consistently trapped zones as areas with either low pore coordination, low entrance throat size, unfavorable throat orientation or a combination thereof. High-flow zones however cannot be characterized in terms of local structural parameters and necessitate integration of complete path information from the entire model. In this regard, in order to capture the high-flow zones, we develop a path-proposing model that makes use of a graph representation of the model, from an initial decomposition into pores and throats, that uses only local throat size and throat orientation relative to pressure gradient to characterize paths
Kim, Dae Whan. "Convection and flow boiling in microgaps and porous foam coolers." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/7446.
Full textThesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Mauray, Alexis. "Etude des propriétés de transport de mousse dans des modèles de milieux poreux." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI120/document.
Full textIn enhanced oil recovery (EOR), foams are injected in porous media to improve oil recovery efficiency. The objective is to limit viscous fingering thanks to the high effective viscosity of the foam at low capillary number Ca. Foam is produced by the co-injection of a gas and a solution of surfactants. This thesis focuses on foam formation and transport mechanisms in model porous media using a heterogeneous micromodel made in NOA. Foam formation is studied using two different approaches. The first one consists in studying a co-injection of two fluids thanks to a jet flowing in the center of the system. This experiment shows that the less wetting fluids is dispersed in the other one when the capillary number is higher than 10-5. A second set of experiments is conducted by injected a pre-formed train of big bubbles in model a porous media. The bubbles divide until they reach a diameter of the order of to the pore size, for high enough capillary numbers Ca. Besides, we studied the transport properties of foam in similar model porous media. Direct measurements show that the pressure drop induces by the flow can be at Ca=10-6 as high as 3000 times the pressure corresponding to water injected at the same injection flow rate. This ratio decreases with capillary number. An analysis of the preferential paths by direct observations shows that, for low relative gas flow rate, only a few paths are active. However, an increase of the capillary number or if relative gas flow rate leads to a homogenization of the flow in the medium. Thanks to different simple models of straight or wavy channels, we measure that the pressure drop induced by a single bubble is in good agreement with Bretherton’s law, and scales as Ca2/3. However, in wavy channels the pressure drop due to a single bubble deviates from this prediction and exhibits a plateau at Ca lower than 10-4. In this regime, the motion of the bubble is usually intermittent. Finally, we focus on foam formation and transport properties in presence of oil. Our observations lead to the conclusion that for our setup and surfactant formulations, oil has a negligible influence
Barari, Farzad. "Metal foam regenerators : heat transfer and pressure drop in porous metals." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6366/.
Full textGlass, Joseph. "Modelling and optimisation of metal foam integrated heat exchangers for power electronics cooling." Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALI007.
Full textSeveral decades ago, power electronics (PE) emerged as an important discipline in the world of electrical engineering. Thanks to regular technological advancements, namely the use of "wide band gap" materials for semiconductors, PE devices have become more compact and efficient, but this has unfortunately resulted in a reduced thermal management. Thus, as a collaborated effort between G2Elab, LEGI and SIMAP, this work has studied the use of metal foam as a novel heat exchanger used in a forced-convection cooling system that can be integrated into PE modules for superior cooling. Metal foams are lightweight, have low densities, high specific surface areas, an open-celled structure and good thermal properties. They are typically categorised by their porosity (ε), their pore density (PPI, pores per inch) and by the diameter of the solid fibres (df). The advantages to heat transfer arise from the possibility of an increased specific surface area over other heat exchangers, such as microchannels, and from the tortuous microstructure that generates flow turbulence and improves convective transfers within the coolant. Thermal performances were modelled by developing an analytical model that considered the heat exchangers as a network of resistances in series. This was achieved by simplifying the LTNE equations that govern energy transfer through the solid a fluid phases. The model was initially compared with numerical simulations and experimental results from the scientific literature, where it performed well. As an additional level of validation, an experimental test bench was designed and assembled in-house. Thermal performances was ascertained by using thermocouples to measure the temperature profile of the solid and fluid phases, and hydraulic properties were found by measuring the pressure drop across the heat exchangers. Analytical and experimental results agreed well with each other, deviating on average by less than 10%. The model was then used to optimise the foams physical properties in order to produce a heat exchanger that maximises thermal performances whilst minimising the required hydraulic power. The results show that for a pressure drop of 50kPa, the thermal resistance of a metal foam heat exchanger is 0.127 K/W. Metal foams are thus a viable heat exchanger material and the model proposed in this work can be used as a quick and inexpensive means of performance optimisation
Clark, Laura A. "Investigation and Optimization of a Porous Sintered Ceramic Material in a Grinding Application." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/675.
Full textTorrens, Richard. "Numerical modelling of shock wave propagation through a layer of porous medium." Thesis, Brunel University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342392.
Full textBai, Chengying. "Highly porous geopolymer components." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3427257.
Full textI geopolimeri, polimeri inorganici silicoalluminati tridimensionali semi-cristallini, hanno attirato crescente attenzione da una vasta gamma di interessi scientifici. L'argomento di questo studio riguarda la sintesi, la caratterizzazione e le potenziali applicazioni di geopolimeri porosi (PG) o schiume di geopolimeri (GF, porosità totale> 70% vol), realizzati attraverso diversi percorsi di lavorazione. In primo luogo, i processi sono suddivisi in cinque categorie: (i) schiumatura diretta, (ii) metodo di replica, (iii) modello sacrificale, (iv) stampa 3D e (v) altri. Anche la microstruttura, la porosità e le proprietà dei geopolimeri porosi sono state confrontate e discusse. In secondo luogo, i geopolimeri porosi basati su K sono stati prodotti mediante schiumatura diretta utilizzando perossido di idrogeno come agente chimico di formazione dei pori (PFA) combinato con tre tipi di agente stabilizzante (SA, bianco d'uovo, Tween 80, oli vegetali) e mediante schiumatura diretta più reattivo emulsione che modella. Inoltre, geopolimeri porosi a base di fosfato a cellule aperte sono stati ottenuti con un semplice metodo di schiumatura diretta (usando Triton X-100 come agente fisico di formazione dei pori). Sono state studiate la porosità, la morfologia dei pori, le prestazioni ad alte temperature, l'adsorbimento, le proprietà meccaniche e isolanti delle PG. I PG ad alta resistenza con porosità adattata e struttura macroporosa controllata sono stati fabbricati con diversi processi. I risultati suggeriscono che i geopolimeri porosi promettono candidati altamente porosi a basso costo per potenziali applicazioni come catalizzatori o supporti a membrana (elevata porosità aperta e alta resistenza), adsorbimento (alta efficienza di rimozione e capacità di adsorbimento con elevata porosità aperta) e isolanti (basso materiali di conducibilità termica, elevata porosità e resistenza accettabile).
Kuruneru, Sahan Trushad Wickramasooriya. "Numerical modelling of particle deposition in idealized porous channels." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/90555/1/Sahan_Kuruneru_Thesis.pdf.
Full textKo, Kang-Hoon. "Heat transfer enhancement in a channel with porous baffles." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1519.
Full textLundberg, Eva. "Micro-Structure Modelling of Acoustics of Open Porous Material." Licentiate thesis, KTH, Farkost och flyg, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187322.
Full textThe work has been carried out within the Centre for ECO2 Vehicle Design.
QC 20160523
Echard, Dalton. "Drying Methods for the Fabrication of Polymer Foam Material." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4096.
Full textLind, Eleonora. "Predicting and optimising acoustical and vibrational performance of open porous foams." Licentiate thesis, Stockholm : Department of Aeronautics and Vehicle Engineering, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4820.
Full textLi, Yuan. "Synthesis and mechanical characterization of transversely isotropic nanoporous platinum." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42927.
Full textEsen, Ziya. "Production And Characterization Of Porous Titanium Alloys." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608964/index.pdf.
Full texta long plateau stage
and a densification stage. Whereas, curves of loose powder sintered samples were similar to that of bulk alloy. Shearing failure in foam samples occurred as series of deformation bands formed in the direction normal to the applied load and cell collapsing occured in discrete bands. Average neck size of samples sintered in loose or compacted condition were found to be different even when they had the same porosity, and the strength was observed to change linearly with the square of neck size ratio. The relation between mechanical properties of the foam and its relative density, which is calculated considering the micro porous cell wall, was observed to obey power law. The proportionality constant and the exponent reflect the structure and properties of cell walls and edges and macro pore character.
Geiger, Derek M. "AN EXPERIMENT ON INTEGRATED THERMAL MANAGEMENT USING METALLIC FOAM." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/75.
Full textArjmandi-Tash, Omid. "Interaction of droplets and foams with solid/porous substrates." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24889.
Full textAydogmus, Tarik. "Processing And Characterization Of Porous Titanium Nickel Shape Memory Alloys." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612232/index.pdf.
Full textC resulting from Ni enrichment due to oxidation. By two step sintering processing (holding the sample at 1100 °
C for 30 minutes and subsequently sintering at temperatures higher than the eutectic temperature, 1118 °
C) magnesium may allow sintering probably up to the melting point of TiNi. The processed alloys exhibited interconnected (partially or completely depending on porosity content) open macro-pores spherical in shape and irregular micro-pores in the cell walls resulting from incomplete sintering. It has been found that porosity content of the foams have no influence on the phase transformation temperatures while deformation and oxidation are severely influential. Porous TiNi alloys displayed excellent superelasticity and shape memory behavior. Space holder technique seems to be a promising method for production of porous TiNi alloys. Desired porosity level, pore shape and accordingly mechanical properties were found to be easily adjustable.
Anghelescu, Mihnea S. "Thermal and Mechanical Analysis of Carbon Foam." View abstract, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3353337.
Full textMines, Levi Walden Dyer. "Porous polyurethane foam for use as a particle collection substrate in a Nanoparticle Respiratory Deposition Sampler." Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1701.
Full textMoussa, Nadine. "Multi scale modelling and numerical simulation of metal foam manufacturing process via casting." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC021/document.
Full textThe objective of this work is to elaborate a new manufacturing process of metal foams via casting by modelling the infiltration and solidification of liquid metal inside a porous medium.However, due to the complexity of this problem the study is divided into two steps. First, at local scale one strut of the metal foam is considered as a capillary tube and the infiltration and solidification of liquid metal inside a cylindrical mould is studied. Second, a macroscopic model of diffusive solidification is derived using the volume average method. The local model is coded in an open source CFD tool and three parametric studies were done where the relations between the infiltration length and time as function of the operating parameters are determined. The modelling of the solidification of liquid metal inside a porous medium is simplified by considering that the mould is fully saturated by liquid metal at rest, solidification occurs by pure diffusion. Local thermal equilibrium (LTE) is considered between the solid and liquid phases of the metal while local thermal non equilibrium (LTNE) is retained between the metallic mixture and the mould. The associated closure problems as well as the macroscopic problem were numerically solved
Nakas, Gul Ipek. "The Processing Of Porous Ni-rich Tini Alloys Via Powder Metallurgy And Their Characterization." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615032/index.pdf.
Full textC for 2 h to analyze the microstructure as well as mechanical behavior. SEM, TEM and XRD studies were conducted for the characterization of microstructure and phase analyses in addition to the mechanical characterization performed by monotonic and superelasticity compression tests as well as compressive fatigue tests. It was observed that stress required to trigger martensitic transformation was decreased via increasing porosity. The monotonic compression test results also indicated that altering the porosity content of TiNi foams leads to different monotonic compression behaviors. It was observed that the foams display more bulk deformation like behavior as a composite structure composed of TiNi and macropores when the porosity content was low. As the porosity content has increased, the struts became more effective and deformation proceeds by the collapse of favorable struts. On the other hand, cyclic superelasticity tests results indicated that maximum achieved and recovered strain values at the end of fifth cycle increase while the fraction of strain recovered at the end of fifth cycle decreases with decreasing porosity content. Furthermore, the fatigue lives of the processed foams were observed to vary within a band which has a width decreasing with decreasing &sigma
max / &sigma
y yielding an endurance limit ranging in between 26-89 MPa or 0.5-0.6 &sigma
y. Fractography studies on the failed foams after fatigue testing revealed that the failure occurs by the coalescence of micro-cracks initiated from pore walls leading to macro-cracks aligned at 45o with respect to the loading axis. In addition to the mentioned characterization studies, the effects of sintering temperature and time on TiNi foams with 58 vol% porosity as well as heat treatment on the microstructure and the mechanical behavior of TiNi foams with 49 vol% porosity were analyzed with SEM and compression tests. Aging of TiNi foams with 49 vol% porosity at 450 °
C for 1.5 h has shown that the presence of Ti3Ni4 precipitates improve the superelastic response.
Thomas, Tony. "Fabrication techniques to produce micro and macro porous MAX-phase Ti2AlC ceramic." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669028.
Full textMensire, Rémy. "Hydrodynamics of oil in contact with an aqueous foam : wetting, imbibition dynamics and flow in rough confined media." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1137/document.
Full textThe extraction of raw materials from the soil for energetical (enhanced oil recovery) and environmental purposes (soil remediation) is the subject of intense fundamental and applied research. This field is related to other important topics, such as carbon sequestration and hydraulic fracturing. The goal is to find fewer destructive, as well as energy and material-saving methods. These techniques should also be cost-effective and more efficient. To find a substitution to conventional means, we study an alternative method that puts aqueous foams on the map as the extraction material. Aqueous foams are often used in numerous daily applications, such as cosmetics and detergency, but also in less known fields, such as the decommissioning of nuclear power plants and the oil industry. Thus, surfactants and gas are commonly injected into the soil to improve the recovery processes of oil. We explain two extraction mechanisms that we quantify in terms of efficiency and stability. On one hand, the foam is able to absorb oil, similarly to a solid sponge. On the other hand, when a flow of foam is induced, the foam can entrain oil confined in the roughness of a surface by shearing the oil-water interface. Our work especially lies on a theoretical and experimental analysis, which is multiscale, static and dynamic. We systematically vary the geometrical parameters (oil configuration, bubble size and liquid fraction in the foam) and the physical and chemical parameters (interfacial tensions, interfacial rigidity and viscosity)
Marangoni, Mauro. "Dense and porous glass and glass ceramics from natural and waste raw materials." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424468.
Full textIl principale obiettivo delle attività di ricerca qui presentate riguardano lo sviluppo di nuovi processi e materiali per applicazioni in edilizia adattate alle esigenze dell'Arabia Saudita in base alle informazioni scambiate con i partner di KACST (King Abdulaziz City of Science and Technology). L'attività di ricerca è stata focalizzata sullo sviluppo di una vasta gamma di componenti ceramici mediante sintercristallizzazione di vetri prodotti da rifiuti (ceneri volanti e scorie) con o senza l'aggiunta di fondenti come rottame di vetro o silicati. Le materie prime sono state miscelate in rapporti adeguati alla produzione di composizioni ceramiche adatte all’utilizzo in edilizia; ad esempio piastrelle vetroceramiche, pannelli alleggeriti e aggregati leggeri. Vetroceramiche e ceramiche, dense e porose, sono state realizzate come sostituti alle pietre naturali e ai ceramici tradizionali. Vetroceramici densi presentano proprietà eccezionali (durezza, resistenza meccanica, durabilità), mentre vetroceramiche porose presentano ridotte densità e conducibilità termica. Inoltre sinterizzando fritte vetrose sono stati ottenuti smalti altamente riflettenti con bianchezza corrispondente al marmo di Thassos. Tutti i materiali sviluppati sono basati sull'utilizzo di risorse naturali o materiali di scarto provenienti dall’Arabia Saudita. Inoltre, sono state sviluppate diverse tecniche per la schiumatura diretta di vetroceramiche, portando alla realizzazione di materiali altamente porosi con celle principalmente chiuse. Utilizzando tecniche alternative sono state invece sviluppate vetroceramiche con una prevalenza di celle aperte.
Wöckel, L., A. Seifert, C. Mende, I. Roth-Panke, L. Kroll, and S. Spange. "Resin and carbon foam production by cationic step-growth polymerization of organic carbonates." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-220096.
Full textDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Van, Zyl Willem Heber. "Investigation into the production and application of porous titanium within the biomedical field." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96097.
Full textENGLISH ABSTRACT: In this study, commercially pure titanium foam was produced using space holder powder metallurgy techniques. Titanium foam is attractive as a scaffolding material for bone replacement and implants in the body. The porous morphology of the foam promotes osteogenesis, while the mechanical behaviour of the foam is closer to that of bone, which has an elastic moduli range of 5 - 40 GPa. Titanium foam was manufactured from powder mixtures of commercially pure titanium (CPTi) powder mixed with 41.4 wt% ammonium bicarbonate (ABC) powder and 1.45 wt% polyethyl glycol (PEG) powder. In this study, two CPTi powders with different particle size distributions, < 75 μm (-200 mesh, designated TiAA) and < 200 μm (-100 mesh, designated TiG), were mixed with the space holder ABC powder, that had been sieved into specified particle size ranges. The size ranges of space holder material studied were: 0 - 710, 250 - 425, 425 - 560, and 560 - 710 μm. This allowed foams with different large or macropore distributions to be produced from the different mixtures. The mixtures were uniaxially compacted at 100 MPa into transverse rupture bars. The ABC and PEG was then removed by thermal debinding in air for 5 hours at 100 °C and 1 hour at 330 °C each, consecutively. The debound samples are then sintered under high (10-6 mbar) vacuum on yttria-stabilised zirconia substrates, heating at 5 °C/min to 1200 °C, with a 2 hour hold at temperature. The microstructures of the different foams were evaluated by examining the polished samples using light optical microscopy. Three point bend tests were conducted on the sintered bars in order to determine the flexural strength and flexural modulus of the different foams. The produced foams had a relative density range between 37.5 - 62.5 % and average macro pore size range between 300 - 500 μm. The foams were found to have an elastic modulus similar to that of bone, 2 - 7 GPa. Finally, the mechanical properties of the foams were compared to known open foam mechanical models and other research projects. It was found that: (i) changes in either metal or space holder powder influences the sintering behaviour of metal foams, (ii) sintered titanium foams with similar densities but different macro/micropore size distributions have different mechanical responses to stress and (iii) the Ashby-Gibson model, based on foam density alone, gives a rough estimate of mechanical properties for the titanium foams studied, but does not capture variations due to pore size distribution.
AFRIKAANSE OPSOMMING: In hierdie studie is kommersiële suiwer titaanskuim geproduseer met behulp van ruimtehouer poeier metallurgie tegnieke. Titaanskuim is aantreklik as 'n raamwerkmateriaal vir beenvervanging en -inplantings in die liggaam. Die poreuse morfologie van die skuim bevorder osteogenese, terwyl die meganiese gedrag van die skuim naby aan dié van been is, met ‘n elasticiteitsmodulus tussen 5 - 40 GPa. Titaanskuim is vervaardig van ‘n poeier mengsel van kommersiële suiwer titaan (CPTi) poeier gemeng met 41,4 gew% ammonium bikarbonaat (ABC) poeier en 1.45 gew% poli-etileenglikol (PEG) poeier. In hierdie studie is twee tipes CPTi poeiers met verskillende deeltjiegrootteverspreiding, < 75 μm (-200 stofdigtheid, TiAA genoem) en <200 μm (-100 stofdigtheid, TiG genoem), met die ruimtehouer ABC-poeier, wat in bepaalde deeltjiegroottereekse gesif is, gemeng. Die wisselende groottes van ruimtehouer wat bestudeer is, was: 0 - 710, 250 - 425, 425 - 560, 560 - 710 μm. Dit het die vervaardiging van skuim met verskillende groot of macroporeuse vanaf die verskillende mengsels toegelaat. Die mengsel is teen 100 MPa in een rigting gekompakteer. Die ABC en PEG is dan verwyder word deur termiese ontbinding in lug vir 5 uur by 100 °C en 1 uur by 330 °C elk, onderskeidelik. Die ontbinde monsters is dan onder hoë (10-6 mbar) leemte op yttrium-gestabiliseer zirconia-substraat, met verwarming teen 5 °C/min tot 1200 °C met 'n verdere 2 uur by 1200 °C, gesinterd. Die mikrostrukture van die verskillende skuim is geëvalueer deur gepoleerde monsters met behulp van ‘n ligmikroskopie te ondersoek . Driepunt draaitoetse is op die gesinterd stawe uitgevoer om die buigsterkte en buigmodulus van die verskillende skuime te bepaal. Die vervaardigde skuime se relatiewe digtheid het tussen 37,5 - 62,5 % gewissel en die gemiddelde makroporiegrootte tussen 300 - 500 μm gewissel. Die skuim het 'n elastisiteitsmodulus soortgelyk aan dié van been getoon, 2 – 7 GPa. Ten slotte is die meganiese eienskappe van die skuim met bekende oop skuim meganiese modelle en ander navorsingsprojekte vergelyk. Daar is bevind dat: (i) veranderinge in óf metaal of ruimtehouer poeier beïnvloed die sinteringgedrag van metaalskuime, (ii) gesinterd titaniumskuim met soortgelyke digthede, maar verskillende makro / mikroporeuse verdelings, toon verskillende meganiese reaksies op stres en die Ashby-Gibson model, gebaseer op die skuimdigtheid alleen, (iii) wat 'n rowwe skatting van die meganiese eienskappe vir die bestudeerde titaniumskuime gee, maar nie die variasies ingrootteverspreiding van porieë ondervang nie.
Rožėnas, Paulius. "Putų cementbetonio savybių tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080722_132553-98463.
Full textThe point of this postgraduate studies final work is research the autoclaved porous concrete characteristics, in whose composition is waste of porous concreat. The porous structure is make by foam. This work consists of theoretical and experimental parts. The teoretical part of this work consist of literature analysis, there are given general knowledge about porous concrete, materials, classifications, physical and mechanical characteristics. The autoclaved foam cement concrete was researched like one of the active concrete species. There were analysed foamers, comparables internals of foams. Considerating the waste of porous concreat utilization maiking foam cement concrete. For this purpose were researched various information publikations, compared the cumulated knowledges and experimental results of various authors. In experimental part are described foamers and from their mades foams characteristics. Reserching the waste of porous concreat utilization. Described quantity of foams and concrete wastes influence to density, strength and composition of foam cement concrete.
Haffner, Benjamin. "Stabilité des suspensions fortement aérées." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1095/document.
Full textWe study the drainage of granular suspensions foams. Our control parameters are the gas fraction, the bubble size, the particles size and the interstitial particle fraction. First, we measure the proportion of liquid and particles retained in the foam network as function of the above mentioned parameters. These measurements are performed when the drainage is over, they are essential for the description of drainage velocity. We show that certain combinations of our study parameters lead to the jamming of the three-phase system : gas, liquid, solid. Secondly, we highlight different regimes of drainage velocity, we show that is controlled by two parameters : (i) lambda, the ratio of the particle size and constriction size, (ii) the fraction of particles in the interstitial network : phi. The key to understand these regimes is the trapping of particles in the foam : (i) the jamming, which may occur for surprisingly low fractions due to the geometry of the pore network, (ii) the particles captured by the foam network when they become larger than the constrictions network. Finally, larger particles excluded from the network increase the drainage velocity, as a consequence the minimum for the velocity corresponds to the individual capture. The granular fraction of the suspension in the foam network is the other key parameter. Especially, the drainage can be stopped for sufficiently high fractions for certain values of lambda. This work offers promising outlook for the stability of three-phase materials
Medvescek, James. "Experimental investigation of fully developed flows of a Newtonian fluid in straight rectangular ducts with adjacent open and porous-metal-foam domains." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119474.
Full textAu cours des deux dernières décennies, les mousses métalliques poreuses, MMP, (ayant des valeurs très élevées de superficie d'échange thermique volumétrique, de l'ordre de 10 000 mètres carrés par mètre cube, et valeurs de la porosité de 0,85 à 0,98) sont devenues de plus en plus commun dans plusieurs domaines: le transfert thermique (échangeurs de chaleur ultracompacts, dissipateurs de chaleur, caloducs et des caloducs en boucle), la filtration; la conversion catalytique; et l'acoustique. Les simulations numériques d'écoulements en domaines ouvert / de MMP adjacents se font en résolvant deux équations différentes (moyennées volumétriquement), correspondant aux deux domaines différents. À l'interface de ceux-ci, la pression intrinsèque (moyennée), la vélocité du fluide (moyenné), et la contrainte normale sont supposées être continues, et une discontinuité de la contrainte tangentielle à l'interface, avec deux coefficients réglables, est imposée. La connaissance de ces coefficients réglables, et l'établissement de critères de transition laminaire-turbulent pour ces types d'écoulements nécessitent urgemment des données expérimentales précises. Le travail ci-inclus comprend une étude expérimentale d'écoulements d'air pleinement développés, en canal rectangulaire et uniforme, de rapport largeur/hauteur élevé, et contenant des domaines ouvert / de MMP adjacents. De tels écoulements ressemblent à ceux étudiés dans le problème Beavers-Joseph. Quatre MMP différentes (ayant des pores de tailles nominaux de 20, 40, 60 pores par pouce, une épaisseur nominale de 12,7 mm, et des porosités allant de 0,85 à 0,94) furent examinées. Un dispositif expérimental fut conçu et construit pour permettre des configurations d'hauteurs du domaine ouvert dans la section de mesure de 0 (complètement rempli de MMP), 3,175 mm, 6,35 mm, et 12,7 mm. La largeur nominale et la longueur de la section de mesure furent fixées à 152,4 mm et 457,2 mm, respectivement. La paroi supérieure de la section de mesure possède 64 prises de pression statique et un capteur de contrainte de cisaillement à la paroi. Les débits d'air furent mesurés en utilisant un tube de Venturi (spécialement conçu, construit, et étalonné pour ce travail) et une banque d'éléments laminaires. Les résultats obtenus des expériences menées pour i) des tâches d'analyse comparative; ii) la caractérisation des mousses métalliques (microphotographes; diamètres effectifs des ligaments, des pores et des cellules; porosité); et iii) l'étalonnage du capteur de contrainte de cisaillement sont présentés et interprétés. Les données provenant des expériences mesurant la perméabilité et le coefficient adimensionnel de traînée de forme des MMP furent déterminées selon quatre approches différentes, et comparées. Des ensembles de données expérimentales recueillies en écoulements d'air en domaines ouvert / poreux adjacents (dans les régimes laminaire, de transition, et turbulent) furent présentés et analysés. Ces données, la solution analytique de tels écoulements laminaires, les densités spectrales de puissance des mesures instantanées de la contrainte de cisaillement à la paroi, et les conditions nécessaires correspondantes au régime laminaire furent collectivement utilisées pour obtenir des indicateurs concernant la transition laminaire-turbulent, et pour déduire les deux coefficients dans la condition de discontinuité de la contrainte de cisaillement à l'interface. Les données provenant des mesures dans lesquelles le canal était complètement rempli de MMP furent utilisées pour calculer un coefficient de frottement de Darcy en fonction du nombre de Reynolds (basé sur la vélocité superficielle de l'air et le diamètre effectif des ligaments de la MMP). Les données recueillies dans les expériences en domaines ouverts / poreux adjacents furent utilisées pour obtenir le coefficient de frottement de Darcy (du domaine ouvert) en fonction du nombre de Reynolds correspondant. Ces résultats sont présentés et interprétés.
Delbos, Aline. "Imprégnation forcée de fluides dans des milieux poreux." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00542832.
Full textDel, Campo Estrada Estefania. "Ecoulements de mousse pour la dépollution d'aquifères." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0101/document.
Full textAquifer pollution with hydrocarbons is very persistent and difficult to treat, becoming a major issue for the environment because of the negative effect on human health. In situ foam generation combined with soil washing is an innovative remediation technology that allows a better fluid mobility control in heterogeneous formations. The purpose of this method is to block the flow through the high permeability layers in order to improve the sweep efficiency of low permeability strata.The thesis is divided into two main parts describing an experimental study and a numerical study.A preliminary selection of environmentally-friendly surfactants was carried out on the basis of their foamability. Sucrose laurate (emulsifier from food industry) was selected and compared with a conventional surfactant. 1-D column tests were performed to study the influence of permeability, surfactant type and foam quality on the resistance factor. The results, interpreted using the capillary pressure, show two flow regimes, corresponding to the two foam textures: "weak" and "strong". Experiments on 2-D heterogeneous pilot allowed visualizing the different steps of the remediation process and comparing the sweep efficiency with and without a region blocked by foam.The numerical part includes modeling 1-D column tests using UTCHEM, a sensitivity study of the most important parameters of the model, and a simulation of tracer tests on 2-D pilot using MODFLOW
Mühlbauer, Sebastian J. [Verfasser], Thorsten [Akademischer Betreuer] Pöschel, Thorsten [Gutachter] Pöschel, and Jens [Gutachter] Harting. "Multiscale modeling of heterogeneous catalysis in porous metal foam structures using particle-based simulation methods / Sebastian Josef Mühlbauer ; Gutachter: Thorsten Pöschel, Jens Harting ; Betreuer: Thorsten Pöschel." Erlangen : FAU University Press, 2019. http://nbn-resolving.de/urn:nbn:de:bvb:29-opus4-126488.
Full textMühlbauer, Sebastian Josef [Verfasser], Thorsten [Akademischer Betreuer] Pöschel, Thorsten [Gutachter] Pöschel, and Jens [Gutachter] Harting. "Multiscale modeling of heterogeneous catalysis in porous metal foam structures using particle-based simulation methods / Sebastian Josef Mühlbauer ; Gutachter: Thorsten Pöschel, Jens Harting ; Betreuer: Thorsten Pöschel." Erlangen : FAU University Press, 2019. http://d-nb.info/1203375018/34.
Full textLacoste, Clément. "Mousses rigides de tannins de type procyanidine : formulation et caractérisation." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0259/document.
Full textRigid foams contitute a very important class of materials considering their wide application range and their considerable economic impact. The development of tannin-based foams provided materials made from 90% natural products.In this work, a type of tannins highly reactive, namely « procyanidin », was used. First, tannins composition and reactivity were studied. Then, the foaming process investigation of tannin-based resins leads to a wide pannel of tannin-furanic rigid foams. Their excellent fire resistance, mechanical resistance and high thermal performance make them high quality insulation materials. These foams are also suitable for other applications such acoustic absorption. Thus, new cellular solids from tannin and protein were also developped, offering a new type of materials derived from natural products
Clerget, Mattéo. "Formation et destruction de mousse en écoulement dans un milieu confiné." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS493.
Full textFoam injection into porous media is a highly promising technique for a wide range of applications, including carbon dioxide storage, soil remediation, and enhanced oil recovery. The flow of this foam in a confined environment brings into play different processes of formation or destruction of the bubbles of which it is composed. Understanding the physical mechanisms of these processes is essential to improve this technique, in particular by optimizing the formulation of the liquid phase.Our approach is to decouple these different phenomena, using two-dimensional flow model devices, at the micro- or milli-fluidic scale. Their transparency allows us to visualize the structure of the flowing foam and to relate it to its macroscopic properties. Various surfactants and additives are systematically tested to investigate the ability of our devices to screen them, and the results obtained are systematically compared with those obtained in porous media.Our first experiment, which studies the formation of bubbles during the passage of a gas/liquid co-flow in a microfluidic pore, highlights a formation hysteresis phenomenon explained by a hydrodynamic feedback process initiated by the downstream flow. Using numerical simulations, we also demonstrate the existence of a limit to the quality of foam that can be formed, linked solely to the pore geometry. Different surfactants are investigated, and these results are compared with measurements both in volume and in three-dimensional porous media.Our second experiment studies the influence of an additive on this formation, in particular through the Marangoni effects it generates. A simple theoretical model is developed to account for these effects.Finally, we describe a millifluidic setup for observing and studying foam destruction by bubble coalescence. We show that the results vary drastically depending on the surfactants and additives used
Hourtané, Virginie. "Écoulement de mousse dans des modèles de milieux poreux." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0330/document.
Full textCrude oil is already usually trapped into heterogeneous porous media. In order to increase the recovery efficiency, one of the chemical solutions consists in injecting foams in porous media to expel oil from the rock. Foam is indeed able in some cases to greatly decrease the mobility, leading to a better sweeping of the reservoir. However, the mechanisms controlling the foam mobility are not well known. We propose a microfluidic approach allowing a direct observation of the flow of bubbles in a model of porous media. We observe that the flow is not homogeneous in the porous medium: it is concentrated in some paths. The number of these preferential paths depends of the foam quality and the capillary number. If we simplify the geometry of the porous medium to a loop, we prove that the formation of preferential paths depends of the size of the loop. Indeed we can only immobilize the bubbles if the size of the loop is around the size of the bubbles
Ouali, Chakib. "Caractérisation multi-échelle de l’écoulement de mousses en milieux poreux en contexte EOR." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS001/document.
Full textFoam has long been used as a mobility control agent in Enhanced Oil Recovery (EOR) processes to enhance sweep efficiency and overcome gravity segregation, viscous fingering and gas channeling, which are gas-related problems when the latter is injected alone in the reservoir. However, the systematic use of foam in reservoir engineering requires more in-depth knowledge of its dynamics in porous media. The literature shows two types of experimental approaches based either on petrophysical studies carried out on 3D porous systems and based on pressure measurements, or on microfluidic studies that allow direct visualization of foam flow but are limited to 1D or 2D model systems. The research investigated in this thesis aims to bridge the gap between these two approaches. The proposed strategy is to characterize in situ the foam flow in 3D porous media with techniques providing a wide range of temporal and spatial resolutions. A coreflood setup giving access to classical petro-physical measurements was developed and then coupled to different observation cells designed specifically for each characterization instrument. First, an X-ray CT scanner was used to describe and visualize the foam flow at the core scale. The rheological behavior of foam on this scale was studied as a function of the injection conditions such as gas velocity and foam quality. Secondly, Small Angle Neutron Scattering (SANS) was used to probe the foam structure in situ during the flow, on a wide length scale, up to three orders of magnitude in size. In situ foam texture (size and density of bubbles and lamellae) was measured for different foam qualities and at different propagation distances from the injection point. A comparison to the geometric characteristics of the porous medium was also realized. Thirdly, High Resolution Fast X-ray Micro-tomography on a Synchrotron was used to visualize the foam flow at the pore scale. This allowed to confirm visually some foam characteristics measured with SANS and to investigate on local intermittent gas trapping and mobilization. This study is an important step in the multi-scale characterization of foam flow in 3D porous media and provides some answers to certain generally accepted assumptions
Omirbekov, Sagyn. "Remédiation des sols pollués par injection des mousses tensioactifs : expériences et changement d’échelle." Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE025.
Full textFoam injection in porous media has been investigated for a variety of applications in the oil industry and recently for soil remediation processes to remove contaminants. However, foam injection for soil remediation is still not widespread because of the complex nature of foam and aquifers. In order to investigate application in soil remediation processes, we experimentally studied the behavior of foam on a laboratory scale. The final goal of the research was to study foam flow for diverting the flow of groundwater from contaminated soil areas considering the features of foam flow in highly permeable porous media. Thus, the rheology of pre-generated foam was studied in highly permeable porous media, in capillary tubes, as well as using a rheometer. Moreover, a numerical study was conducted to examine foam flow in a bigger scale based on bulk foam rheology results. As a result, foam flow was showed to feature non-Newtonian behavior. We found that the foam flow behavior in high permeable porous media and in capillary tubes are consistent with the rheology behavior of bulk foam if bubbles are much smaller than the pore size of porous media. Hence, these findings can guide the study of pre-generated foam in very highly permeable porous media
Forey, Natacha. "Mousses renforcées en polymère ou particules : application à la remédiation des sols pollués." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0311.
Full textGiven the possible environmental and health issues occurring when facing a hydrocarbon polluted site, soil remediation is necessary. One of the in-situ technique to remediate a Light Non Aqueous Phase Liquid pollution is the use of foam. Because of its blocking effect, foam is able to create a water blocking barrier, to confine water beneath the floating pollutant. However, the main issue with this technique is the stability of foam facing the oily pollutant. Several options are currently under review to reinforce foam against oil, which includes polymer or particles addition.The present study thus describes the work performed to obtain an oil-resistant foam in porous media, with the use of polymer or solid colloidal particles.In the first part of the study, foamability and stability tests were performed in bulk to select a broad range of products used to formulate such foams. Then, sandpacks experiments were realized in 1D columns in order to optimize the foam injection parameters and finalize the choice of surfactant and additives. Column experiments showed how additives impacted foam strength. Polymer addition led to an increased flow resistance without improving foam strength while particles addition proved to reinforce foam resistance against oil. Those results were then applied to carry out 2D-tank experiments to study foam displacement in a vertical two dimensions’ porous medium. The 2D tank also helped to simulate a foam injection below an oily layer and observe foam behaviour. Finally, the methodology and constrains to take into account to perform a pumping test in a 3D-pilot, were presented in the outlook section
Ouali, Chakib. "Caractérisation multi-échelle de l’écoulement de mousses en milieux poreux en contexte EOR." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS001.
Full textFoam has long been used as a mobility control agent in Enhanced Oil Recovery (EOR) processes to enhance sweep efficiency and overcome gravity segregation, viscous fingering and gas channeling, which are gas-related problems when the latter is injected alone in the reservoir. However, the systematic use of foam in reservoir engineering requires more in-depth knowledge of its dynamics in porous media. The literature shows two types of experimental approaches based either on petrophysical studies carried out on 3D porous systems and based on pressure measurements, or on microfluidic studies that allow direct visualization of foam flow but are limited to 1D or 2D model systems. The research investigated in this thesis aims to bridge the gap between these two approaches. The proposed strategy is to characterize in situ the foam flow in 3D porous media with techniques providing a wide range of temporal and spatial resolutions. A coreflood setup giving access to classical petro-physical measurements was developed and then coupled to different observation cells designed specifically for each characterization instrument. First, an X-ray CT scanner was used to describe and visualize the foam flow at the core scale. The rheological behavior of foam on this scale was studied as a function of the injection conditions such as gas velocity and foam quality. Secondly, Small Angle Neutron Scattering (SANS) was used to probe the foam structure in situ during the flow, on a wide length scale, up to three orders of magnitude in size. In situ foam texture (size and density of bubbles and lamellae) was measured for different foam qualities and at different propagation distances from the injection point. A comparison to the geometric characteristics of the porous medium was also realized. Thirdly, High Resolution Fast X-ray Micro-tomography on a Synchrotron was used to visualize the foam flow at the pore scale. This allowed to confirm visually some foam characteristics measured with SANS and to investigate on local intermittent gas trapping and mobilization. This study is an important step in the multi-scale characterization of foam flow in 3D porous media and provides some answers to certain generally accepted assumptions
Gassara, Omar. "Modélisation des écoulements de mousse dans les milieux poreux en récupération assistée du pétrole." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066588/document.
Full textConventional techniques of oil recovery consist in injecting water and/or gas into the geological formation to force out the oil. These methods may reveal ineffective because of high permeability contrasts, unfavorable mobility ratio between the driving fluid and the oil in place which generally generates viscous fingering, and gravity segregation. In this context, foam has shown a great potential to overcome all these detrimental effects, and thereafter, to improve the volumetric sweep efficiency. Still some key points need to be addressed regarding the predictive calculation of multiphase foam flow in porous media. Methods for modeling foam flow in porous media fall into two categories: population balance (PB) models and (semi)-empirical (SE) models. On the one hand, PB models describe foam lamellas transport in porous media and predict the evolution of foam microstructure as the result of pore-scale mechanisms of lamellas generation and destruction. Within this framework, the modeling of foam effects on gas mobility is directly related to foam texture (lamellas density) along with the effects of other parameters impacting its rheology such as foam quality and velocity, permeability of the porous media, surfactant concentration, etc. On the other hand, SE models are based on the extension of multiphase classical Darcy's model to describe foam flow in porous media, such that the foam texture effects are described indirectly through a multi-parameter interpolation function of parameters measured/observed in laboratory. Such formulation has to be calibrated from foam flow experimental data on a case-by-case basis, which can turn to be a cumbersome task. Furthermore, SE models involve uncertainty because they are not based on mechanistic laws driving lamellas transport in porous media, and their predictive capacity remains low as too few laboratory data are generally available for their calibration. Nonetheless, the reservoir engineer needs a reliable foam model in order to design, assess and optimize foam enhanced oil recovery processes for field application. Accordingly, this thesis aims at providing further insights into the topics related to the parameterization of (semi)-empirical models through better formulated and calibrated laws in order to improve their predictivity. In this work, we have established the physical basis necessary to validate the (semi)-empirical models. Indeed, we developed the equivalence between SE and PB models achieved through relationships between the parameters of these two modeling approaches (industrial and physical). The equivalence has been established and studied using a pre-calibrated PB model of the literature to fit steady-state foam measurements. In addition, this equivalence allowed us to develop a new procedure to calibrate the (semi)-empirical models in a reliable and deterministic way. This procedure was tested and validated using results from IFPEN core-flood experiments by translating them into steady-state texture measurements. Finally, we proposed scaling laws for empirical model parameters with the permeability of the porous media, by analyzing the fitted parameters on cores of different permeabilities. Different interpretations of the scaling laws are herein provided using theoretical models for lamellas stability. Then, their importance has been demonstrated through simulations on a two layer reservoir cross-section. The simulation results indicate that the predictions of foam flow in a heterogeneous reservoir require a good knowledge of the scaling laws of SE model parameters with permeability
Petit, Clémence. "Etude des propriétés mécaniques de matériaux cellulaires par la tomographie aux rayons X et par modélisation par éléments finis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0130/document.
Full textCellular materials are highly porous systems for which two scales are mainly important: the mesostructure and the microstructure. The mesostructure corresponds to the architecture of the materials: distribution of solid phase “walls” and macroporosity and can be characterized by X-ray tomographic low resolution images. The link between the architecture of the materials and the mechanical properties has been frequently studied. The microstructure refers to the characteristics of the solid phase. Its microstructural features (presence of a secondary phase or of defects due to the sintering) can have a strong influence on the macroscopic properties. The aim of this work is to link the morphological and microstructural features of metallic and ceramic based cellular materials and their mechanical properties thanks to X-ray tomography and finite element modelling. A new method combining X-ray tomography at different resolutions, image processing and creation of finite element modelling enabled to take into account some microstuctural features of the cellular samples. Four different cellular materials were studied as model materials: aluminium foam fabricated by a liquid state process, cobalt periodic structures made by additive manufacturing, β-TCP porous samples fabricated by conventional sacrificial template processing route and hydroxyapatite/β-TCP composites made by additive manufacturing (robocasting). The metal based materials were provided by colleagues while the ceramic based porous materials were fabricated in the frame of the current study. For each type (metals or ceramics), a stochastic and a regular structure have been compared. For implementing the multiscale method developed in this work, the samples were firstly scanned in a so called “local” tomography mode, in which the specimen is placed close to the X-ray source. This allowed to reconstruct only the small irradiated part of the sample and to obtain a magnified image of a subregion. These images enable to observe some details which are not visible in lower resolution. Different image processing steps were performed to generate low resolution images including microstructural features imaged at high resolution. This was done by a series of thresholding and scaling of the high resolution images. The result of these processing steps was an image of the initial sample. Then, in situ mechanical tests were performed in the tomograph to follow the deformation of the sample at low resolution. The above mentioned initial images were used to produce finite element meshes. Special Java programs were adapted to create finite element input files from initial images and meshes. The initial images containing information about the solid phase, the images from the mechanical tests and the finite element models were combined to explain the mechanical behaviour of the sample by linking the experimental damage locations in the sample and the simulated stress concentration sites
Simone, Anthony E. (Anthony Eugene) 1970. "Porous metals and metallic foams." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10190.
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