Characterization and deformation response of orthotropic fibre networks with auxetic out-of-plane behaviour

Neelakantan, Suresh; Bosbach, Wolfram A.; Woodhouse, J.; Markaki, Athina E.

doi:10.1016/j.actamat.2013.11.020

Cited by 41 publications

(79 citation statements)

References 31 publications

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“…Fiber networks were supplied as flat sheets with thicknesses of 1, 2, and 5 mm. Based on our previous study 15 on solid-state sintered 316L fiber networks, it was found that, for a given fiber volume fraction, the network stiffnesses were comparable, irrespective of the thickness of the sheets, suggesting that there were no significant architectural differences between the different sheet thicknesses. For cell culture, discs of 10 -0.5 mm diameters were cut out from sheets of 1 mm using a punch press.…”

Section: Sintered Fiber Networkmentioning

confidence: 99%

“…15,43 In this study, two 444 samples were electro-discharge machined from the network plates into cubes of 5 mm. Tomography scans, with a 7 mm spatial resolution, were acquired using a General Electric Phoenix X-ray Nanotom system (GE Sensing & Inspection Technologies GmbH) equipped with a submicron focal spot X-ray source.…”

Section: Fiber Network Architecturementioning

confidence: 99%

“…Depending on the fiber volume fraction, the network architecture (isotropic or highly oriented), and the fiber segment aspect ratio, experimentally measured Young's moduli values are no higher than a few GPa. [15][16][17][18][19] The elastic properties of highly porous materials are most commonly measured using conventional mechanical (static) testing with the majority of studies focusing on compressive testing as it is easier to carry out compared with tensile testing or even bending. However, it is well known that in highly porous materials inelastic straining commonly occurs at low applied loads.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Physical and Biological Characterization of Ferromagnetic Fiber Networks: Effect of Fibrin Deposition on Short-Term In Vitro Responses of Human Osteoblasts

Spear

Srigengan

Neelakantan

et al. 2015

Tissue Engineering Part A

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Ferromagnetic fiber networks have the potential to deform in vivo imparting therapeutic levels of strain on ingrowing periprosthetic bone tissue. 444 Ferritic stainless steel provides a suitable material for this application due to its ability to support cultures of human osteoblasts (HObs) without eliciting undue inflammatory responses from monocytes in vitro. In the present article, a 444 fiber network, containing 17 vol% fibers, has been investigated. The network architecture was obtained by applying a skeletonization algorithm to three-dimensional tomographic reconstructions of the fiber networks. Elastic properties were measured using low-frequency vibration testing, providing globally averaged properties as opposed to mechanical methods that yield only local properties. The optimal region for transduction of strain to cells lies between the ferromagnetic fibers. However, cell attachment, at early time points, occurs primarily on fiber surfaces. Deposition of fibrin, a fibrous protein involved in acute inflammatory responses, can facilitate cell attachment within this optimal region at early time points. The current work compared physiological (3 and 5 g$L -1 ) and supraphysiological fibrinogen concentrations (10 g$L -1 ), using static in vitro seeding of HObs, to determine the effect of fibrin deposition on cell responses during the first week of cell culture. Early cell attachment within the interfiber spaces was observed in all fibrin-containing samples, supported by fibrin nanofibers. Fibrin deposition influenced the seeding, metabolic activity, and early stage differentiation of HObs cultured in the fibrin-containing fiber networks in a concentration-dependant manner. While initial cell attachment for networks with fibrin deposited from low physiological concentrations was similar to control samples without fibrin deposition, significantly higher HObs attached onto high physiological and supraphysiological concentrations. Despite higher cell numbers with supraphysiological concentrations, cell metabolic activities were similar for all fibrinogen concentrations. Further, cells cultured on supraphysiological concentrations exhibited lower cell differentiation as measured by alkaline phosphatase activity at early time points. Overall, the current study suggests that physiological fibrinogen concentrations would be more suitable than supraphysiological concentrations for supporting early cell activity in porous implant coatings.

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Section: Sintered Fiber Networkmentioning

confidence: 99%

Section: Fiber Network Architecturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Physical and Biological Characterization of Ferromagnetic Fiber Networks: Effect of Fibrin Deposition on Short-Term In Vitro Responses of Human Osteoblasts

Spear

Srigengan

Neelakantan

et al. 2015

Tissue Engineering Part A

View full text Add to dashboard Cite

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“…X-ray tomography is a powerful tool to measure the fiber orientations in fibrous materials, as demonstrated in several works [11,13,19]. Usually, the fibers are idealized as cylinders and the orientation distribution of the cylinder axes is plotted.…”

Section: Structure Analysismentioning

confidence: 99%

“…As the structural changes influence the aeroacoustic performance, not only the mechanical properties, but also the damage behavior is of major interest. X-ray tomography is a non-destructive tool that enables material characterization and in situ experiments to reveal structural changes and damage during mechanical tests and, therefore, it has been used in several studies [8][9][10][11][12][13]. In this study, the damage behavior is analyzed using a combination of tensile tests and three dimensional computed tomography, which allows determination of the damage location with a high resolution.…”

Section: Introductionmentioning

confidence: 99%

Damage Behavior of Sintered Fiber Felts

Lippitz

Rösler

2015

Metals

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The reduction of aircraft noise is important due to a rising number of flights and the growth of urban centers close to airports. During landing, a significant part of the noise is generated by flow around the airframe. To reduce that noise porous trailing edges are investigated. Ideally, the porous materials should to be structural materials as well. Therefore, the mechanical properties and damage behavior are of major interest. The aim of this study is to show the change of structure and the damage behavior of sintered fiber felts, which are promising materials for porous trailing edges, under tensile loading using a combination of tensile tests and three dimensional computed tomography scans. By stopping the tensile test after a defined stress or strain and scanning the sample, it is possible to correlate structural changes and the development of damage to certain features in the stress-strain curve and follow the damage process with a high spatial resolution. Finally, the correlation between material structure and mechanical behavior is demonstrated.

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In Situ X‐Ray Tomography of Sintered Metal Fiber Felts Exhibiting Auxetic Effect under Tension and Compression

Wang

et al. 2022

Adv Eng Mater

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Sintered metal fiber felts (SMFFs) are kinds of the strongest auxetic materials to date, but there are significant differences in the reported auxeticities, due to the lack of investigation on the fabrication process. This study is performed to analyze the influence of fabrication process and structural features on the auxetic effect exhibited by SMFFs. The sequence of compression and sintering processes determines the volume density of the interfiber‐sintered joints and the resulting Poisson's ratio behavior under tension and compression. The SMFFs with a low volume density exhibit strong auxetic effect under tension and achiev a positive Poisson's ratio under compression because of the weak interfiber layer bonding. In contrast, the felts with a high density of interfiber joints reveal a relatively weak auxetic effect under both tension and compression. Moreover, an increase in the thickness and a decrease in the porosity reduce the auxetic effect. In addition, in situ X‐Ray tomography of the tensile testing is performed to elucidate the mechanism of the auxetic effect. To explain the observed Poisson's ratio behavior under tension and compression, periodical finite‐element modeling with real mesostructures is performed. Herein, a new insight into the relationship between the structure features and the Poisson's ratio behaviors is given.

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Characterization and deformation response of orthotropic fibre networks with auxetic out-of-plane behaviour

Cited by 41 publications

References 31 publications

Physical and Biological Characterization of Ferromagnetic Fiber Networks: Effect of Fibrin Deposition on Short-Term In Vitro Responses of Human Osteoblasts

Physical and Biological Characterization of Ferromagnetic Fiber Networks: Effect of Fibrin Deposition on Short-Term In Vitro Responses of Human Osteoblasts

Damage Behavior of Sintered Fiber Felts

In Situ X‐Ray Tomography of Sintered Metal Fiber Felts Exhibiting Auxetic Effect under Tension and Compression

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