Is the von Mises criterion generally applicable to soft solids?

Sica, Luiz Umberto Rodrigues; Mendes, Paulo R. de Souza; Thompson, Roney L.

doi:10.1039/d0sm00762e

Cited by 19 publications

(17 citation statements)

References 19 publications

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“…In addition, our experiments have some conceptual similarities to those recently conducted by Sica et al. (2020) (for dynamically inactive ambient fluids), who analysed the yielding of several materials in elongation and compression loading conditions, while proposing new criteria for yielding. In the former condition, gravity is the main source of the induced stress that eventually overcomes the yield stress.…”

Section: Summary and Concluding Remarkssupporting

confidence: 65%

“…This approach has been previously demonstrated and used by Sica et al. (2020) and Thompson & de Souza Mendes (2020) in conceptually similar contexts. Figure 8( a ) plots the length of the viscoplastic core at the yielding onset from the experiments () for small injection velocities.…”

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 96%

“…(ii) Relevant to (i), a possible source of mismatch may be due to differences between extensional and viscometric yielding (which is the most widely used method to probe viscoplastic fluid rheology). For instance, Sica, de Souza Mendes & Thompson (2020) and Thompson & de Souza Mendes (2020) have considered extensional and compressional states of viscoplastic fluids extruded into air and they have quantified the corresponding yield stresses (namely static and dynamic yield stress values), which can be different from those delivered by steady-state shear rheometry. (iii) Another source of discrepancy between the model and experiments may be related to considering only normal components in the viscoplastic fluid flow and ignoring shear components in our asymptotic scaling analysis.…”

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 99%

“…Following Sica et al. (2020) and Thompson & de Souza Mendes (2020), it is possible to use a linear least-squares fit as a crude way to estimate the yielding length at the limit of the zero-injection velocity, namely where the fitted line crosses the vertical axis, i.e. .…”

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 99%

“…Equation (4.10) can also provide a way to approximate the yield stress, provided that the yielding length is known at the limit of zero-injection rates. This approach has been previously demonstrated and used by Sica et al (2020) and in conceptually similar contexts. Figure 8(a) plots the length of the viscoplastic core at the yielding onset from the experiments ( ˆ experiment y ) for small injection velocities.…”

Section: 2mentioning

confidence: 97%

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From breakup to coiling and buckling regimes in buoyant viscoplastic injections

Akbari

Taghavi

2022

J. Fluid Mech.

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We study the injection flow of a heavy viscoplastic fluid into a light Newtonian fluid, via modelling and experiments. The injection is carried out downward, via an eccentric inner pipe inside a vertical closed-end outer pipe. This configuration results in a core viscoplastic fluid surrounded by an annular Newtonian fluid. The flow is structured and mixing is negligible. As the injection rate increases in a typical experiment, we observe three distinct flow regimes, associated with the core fluid behaviour, namely the breakup, coiling and buckling (bulging) regimes. In the breakup regime, the core fluid is yielded due to the extension caused by buoyancy, while in the buckling regime the yielding occurs due to the compression promoted by the pressure and the interfacial shear stress applied by the upward flow of the annular fluid. For the coiling regime, the core fluid remains largely unyielded until it exhibits a coiling behaviour. We develop a lubrication approximation model, using the Herschel–Bulkley constitutive equation, with dimensionless flow parameters including the Bingham number, the power-law index, the buoyancy number, the viscosity ratio, the diameter ratio, the eccentricity and the aspect ratio. Based on a reasonable prediction to the yielding onset, the model allows us to classify the flow regimes versus an elegant combination of the dimensionless numbers.

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Section: Summary and Concluding Remarkssupporting

confidence: 65%

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 96%

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 99%

Section: Model Results and Comparisons With Experimentsmentioning

confidence: 99%

Section: 2mentioning

confidence: 97%

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From breakup to coiling and buckling regimes in buoyant viscoplastic injections

Akbari

Taghavi

2022

J. Fluid Mech.

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The complex rheological behavior of a simple yield stress fluid

Accetta,

Venerus

2024

Rheol Acta

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Concentrated emulsions and foams and microgels are comprised of deformable particles making these materials display complex rheological behavior that includes a yielding transition from an elastic solid to viscous fluid. Most studies of this class of soft matter involve shear flows and only a few report both shear and normal stresses. Here, we report measurements of the shear stress and two normal stress differences for a Carbobol microgel, which is usually classified as simple yield stress fluid, subjected to constant shear rate flows. Similar to our previous study, the shear stress evolves through the yield point in a manner indicative of simple yield stress fluid behavior while the normal stress differences evolve in a reproducibly chaotic manner. We also find that the evolution of the stresses is dependent on the whether the microgel has been in a state of relaxation or recovery prior to the measurement.

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