Finite element modeling of the uniaxial compression behavior of carbon microballoons

Carlisle, K.; Lewis, Matthew W.; Chawla, K. K.; Koopman, M.; Gladysz, Gary M.

doi:10.1016/j.actamat.2006.11.026

Cited by 44 publications

(17 citation statements)

References 9 publications

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“…Chung et al [33] reported hollow brittle spheres to fail due to tensile stresses on the inside of the shell in the region close to contact zone between platen and sample when compressed between two parallel platens. This behaviour was observed experimentally and predicted by computer modelling and later confirmed in another computer simulation by Carlisle et al [46,47].…”

Section: Strength Calculation Of Brittle Spheres Under Uniaxial Comprsupporting

confidence: 60%

Mechanical properties of lightweight aggregates

Bernhardt

Tellesbø²,

Justnes

et al. 2013

Journal of the European Ceramic Society

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Lightweight aggregates (LWA) were successfully produced both in a pilot-scale rotary kiln and in a laboratory chamber furnace. The mechanical properties of LWA were investigated in detail applying the European standard crushing resistance test (CR-test) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 stresses in the centre of the pellet and the strength was observed to increase exponentially with decreasing sample size. The relationship between the CR-and spc-test has been established facilitating "translation" of strength data between the two different test methods.

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Section: Strength Calculation Of Brittle Spheres Under Uniaxial Comprsupporting

confidence: 60%

Mechanical properties of lightweight aggregates

Bernhardt

Tellesbø²,

Justnes

et al. 2013

Journal of the European Ceramic Society

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“…The mesh chosen was validated using a much denser mesh, with 20 element layers to model the shell thickness, and a total of 7,200 elements (Figure S1b). Further evidence of the mesh adequacy for a similar problem can be found in Carlisle et al20 Different shell thickness h to initial radius r ratios were simulated, between 0.6–9.1%. The liquid core of the microcapsules was designed using FAX2 elements (2‐node linear axisymmetric hydrostatic fluid) with a density of 1000 kg m −3 .…”

Section: Methodsmentioning

confidence: 71%

Failure of elastic‐plastic core–shell microcapsules under compression

et al. 2011

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Characterization of the failure behavior of microcapsules is extremely important to control the release of their core actives by mechanical forces. The strain and stress of elastic-plastic uninflated core-shell microcapsules at failure (rupture or bursting) has been determined using finite element modeling (FEM) and micromanipulation compression experiments. The ductile failure of polymeric microcapsules at high deformations is considered to occur when the maximum strain in the shell exceeds a critical strain, resulting in their rupture. FEM has been used to determine the maximum strains present in the capsule wall at different deformations for three types of shell material: elastic, elastic-perfectly plastic and elasticperfectly plastic with strain hardening at large strains. The results obtained were used to determine the failure strain and stress of melamine-formaldehyde microcapsules, with average population values of $0.48 and $350 MPa, respectively. Thus, the elastic-plastic stress-strain relationship has been determined for the core-shell microcapsules tested. Figure 3. Log-linear plot of maximum von Mises stress (closed symbols) and strain H max (open symbols) in a fully elastic microcapsule (h/r 5 0.62%) vs. fractional deformation.Results from Smith et al. 17 are for inflated core-shell spheres with different initial stretch ratios (SR), shown for comparison.Continuous lines represent H max , the largest of the three plane strains at each fractional deformation. H max for the fully elastic scenario is shown for comparison. Inset shows the position of the most strained nodes as described in Figure 4b.Points are the results for the conditions of Figure 11, with the following best-fitted equation: F/r Y rh ¼ 1.945 þ 1.12 Â 10 À15 exp(48.5) þ 0.0143exp(10.29) for 0.3 \ \ 0.75.

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“…When thick shell spheres start rupturing under compression at very small ε LE , the largest stressed area occurs in the shell area under the compressing planes, as discussed by Carlisle et al 86 for carbon microballoons. Figure 16 shows the 3D FEM distribution of the principal stress σ p normalized with E at a fractional deformation ε of 0.06, around ε LE of the PMMA microcapsules.…”

Section: ■ Appendix Finite Element Modeling (Fem) Of the Compression mentioning

confidence: 92%

Structure and Mechanical Properties of Consumer-Friendly PMMA Microcapsules

Pan

Mercadé‐Prieto

York

et al. 2013

Ind. Eng. Chem. Res.

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Environmentally and consumer-friendly poly(methyl methacrylate) (PMMA) microcapsules were prepared on the basis of an in situ polymerization reaction to encapsulate perfume oil, which aims to be delivered to fabric surfaces via liquid detergents. Microcapsules with a narrow size distribution were produced using a membrane emulsification system; results were compared with a standard homogenization procedure. The shell thickness of microcapsules was found to increase with the polymerization reaction time, which was measured using a lipophilic fluorescent dye dissolved in the perfume oil and confocal laser scanning microscopy. Microcapsules with a wide range of shell thicknesses could be produced by modifying the reaction time. The force versus displacement profiles obtained from compression of single such microcapsules between two parallel surfaces based on micromanipulation were very different: thin-shell microcapsules burst under compression, whereas thick-shell microcapsules did not. However, the intrinsic mechanical properties of the PMMA shells, determined with finite element modeling (FEM) and the experimental data, such as the elastic modulus and the rupture stress, were found independent of the reaction time. The microcapsules with a wide range of shell thicknesses may be used to encapsulate different oil-based active ingredients for potential industrial applications.

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Finite element modeling of the uniaxial compression behavior of carbon microballoons

Cited by 44 publications

References 9 publications

Mechanical properties of lightweight aggregates

Mechanical properties of lightweight aggregates

Failure of elastic‐plastic core–shell microcapsules under compression

Structure and Mechanical Properties of Consumer-Friendly PMMA Microcapsules

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