Large-Amplitude Oscillatory Shear

Giacomin, A. Jeffrey; Dealy, John M.

doi:10.1007/978-94-011-2114-9_4

Cited by 119 publications

(64 citation statements)

References 34 publications

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“…In contrast, LAOS tests are useful for a broad class of complex fluids and soft matter because strain amplitude and frequency can be varied independently allowing a broad spectrum of conditions to be attained [7]. Furthermore, LAOS does not involve any sudden imposed jumps in speed or position, and consequently it is a relatively easy flow to generate and control [8].…”

Section: Dynamic Oscillatory Shear Testmentioning

confidence: 99%

“…During the 1990's, book chapters by Dealy and Wissbrun [4] and Giacomin and Dealy [8] described LAOS test protocols and provided rich sources of information on the LAOS experiments and analysis at the time. Dealy and Giacomin [4,7,8,[22][23][24][25][26][27] investigated the LAOS behavior of various polymer melts with a unique sliding plate rheometer (SPR, see Fig.…”

Section: Historical Survey Of Laosmentioning

confidence: 99%

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A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS)

Hyun

Wilhelm

Klein

et al. 2011

Progress in Polymer Science

1,278

699

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Dynamic oscillatory shear tests are common in rheology and have been used to investigate a wide range of soft matter and complex fluids including polymer melts and solutions, block copolymers, biological macromolecules, polyelectrolytes, surfactants, suspensions, emulsions and beyond. More specifically, Small Amplitude Oscillatory Shear (SAOS) tests have become the canonical method for probing the linear viscoelastic properties of these complex fluids because of the firm theoretical background [1][2][3][4] and the ease of implementing suitable test protocols. However, in most processing operations the deformations can be large and rapid: it is therefore the nonlinear material properties that control the system response. A full sample characterization thus requires well-defined nonlinear test protocols. Consequently there has been a recent renewal of interest in exploiting Large Amplitude Oscillatory Shear (LAOS) tests to investigate and quantify the nonlinear viscoelastic behavior of complex fluids. In terms of the experimental input, both LAOS and SAOS require the user to select appropriate ranges of strain amplitude (γ 0 ) and frequency (ω). However, there is a distinct difference in the analysis of experimental output, i.e. the material response. At sufficiently large strain amplitude, the material response will become nonlinear in LAOS tests and the familiar material functions used to quantify the linear behavior in SAOS tests are no longer sufficient. For example, the definitions of the linear viscoelastic moduli G΄(ω) and G˝(ω) are based inherently on the assumption that the stress response is purely sinusoidal (linear). However, a nonlinear stress response is not a perfect sinusoid and therefore the viscoelastic moduli are not uniquely defined; other methods are needed for quantifying the nonlinear material response under LAOS deformation. In the present review article, we first summarize the typical nonlinear responses observed with complex fluids under LAOS deformations. We then introduce and critically compare several methods that quantify the nonlinear oscillatory stress response. We illustrate the utility and sensitivity of these protocols by investigating the nonlinear response of various complex fluids over a wide range of frequency and amplitude of deformation, and show that LAOS characterization is a rigorous test for rheological models and 3 advanced quality control.

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Section: Dynamic Oscillatory Shear Testmentioning

confidence: 99%

Section: Historical Survey Of Laosmentioning

confidence: 99%

A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS)

Hyun

Wilhelm

Klein

et al. 2011

Progress in Polymer Science

1,278

699

View full text Add to dashboard Cite

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“…There is an ongoing effort to meld two experimental approaches-small amplitude oscillatory shear and steady shear-into one technique, so-called large amplitude oscillatory shear, or LAOS [see, e.g., Dealy and Wissbrun (1990); Giacomin and Dealy (1993); Hyun et al (2002); Ewoldt et al (2008)]. In such an approach, a rheometer imposes a steady oscillatory simple-shear of arbitrary amplitude and frequency, and the time-dependent shear stress is measured.…”

Section: Introductionmentioning

confidence: 99%

Large amplitude oscillatory microrheology

Swan¹,

Zia²,

Brady³

2014

Journal of Rheology

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SynopsisWe study the motion of a colloidal particle as it is driven by an oscillating external force of arbitrary amplitude and frequency through a colloidal dispersion. Large amplitude oscillatory flows (LAOFs) are examined predominantly from a phenomenological perspective in which experimental measurements inform constitutive models. Here, we investigate a LAOF from a microstructural perspective by connecting motion of the probe particle to the material response while making no assumptions a priori about how stress relaxes in the material. The suspension exerts nonconservative, hydrodynamic forces on the probe, while distortions in the particle configuration exert conservative forces: Brownian and interparticle forces, for example. The relative importance of each of these contributions to particle motion evolves with the degree of displacement from equilibrium. When the force on the probe is weak, the linear microviscoelasticity of the suspension is probed [see, e.g., Khair and Brady, J. Rheol. 49, 1449-1481]. When oscillation rate is slow, the steady microrheology is probed [see, e.g., Squires and Brady, Phys. Fluids 17, 073101 (2005); Khair and Brady, J. Fluid Mech. 557, 73-117 (2006)]. This article develops a micromechanical model that recovers these limiting cases and then uses the same model to reveal the microrheology of colloidal dispersions deformed by a probe driven with arbitrary force amplitude and frequency. A chief result of this work is the discovery of a regime in which the resistance to motion of the probe particle is on average weaker than the resistance the probe experiences when deformed by high frequency oscillation. This hypoviscous effect arises when the reciprocating motion of the probe particle opens a a)

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“…The frequency spectra of the strain response are dominated by the fundamental (imposed) frequency and contain odd harmonics, confirming that the measurement is within the nonlinear viscoelastic regime. 21 The magnitude of the even harmonics FIG. 2.…”

Section: Analysis Of Laostress Waveformsmentioning

confidence: 99%

“…11,20 However, it is important to recognise that, under such conditions, the resulting waveform is non-sinusoidal and thus does not pertain to the theory of linear viscoelasticity. 21 Other workers have exploited inertio-elastic oscillations in controlled stress rheometry to provide a measurement of tangent moduli. 22 Several studies have reported the application of a pre-stress followed by the superposition of small amplitude oscillatory shear stress to probe the rheological properties in terms of differential moduli.…”

Section: Introductionmentioning

confidence: 99%

The application of large amplitude oscillatory stress in a study of fully formed fibrin clots

et al. 2017

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The suitability of controlled stress large amplitude oscillatory shear (LAOStress) for the characterisation of the nonlinear viscoelastic properties of fully formed fibrin clots is investigated. Capturing the rich nonlinear viscoelastic behaviour of the fibrin network is important for understanding the structural behaviour of clots formed in blood vessels which are exposed to a wide range of shear stresses. We report, for the first time, that artefacts due to ringing exist in both the sample stress and strain waveforms of a LAOStress measurement which will lead to errors in the calculation of nonlinear viscoelastic properties. The process of smoothing the waveforms eliminates these artefacts whilst retaining essential rheological information. Furthermore, we demonstrate the potential of LAOStress for characterising the nonlinear viscoelastic properties of fibrin clots in response to incremental increases of applied stress up to the point of fracture. Alternating LAOStress and small amplitude oscillatory shear measurements provide detailed information of reversible and irreversible structural changes of the fibrin clot as a consequence of elevated levels of stress. We relate these findings to previous studies involving large scale deformations of fibrin clots. The LAOStress technique may provide useful information to help understand why some blood clots formed in vessels are stable (such as in deep vein thrombosis) and others break off (leading to a life threatening pulmonary embolism).

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Large-Amplitude Oscillatory Shear

Cited by 119 publications

References 34 publications

A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS)

A review of nonlinear oscillatory shear tests: Analysis and application of large amplitude oscillatory shear (LAOS)

Large amplitude oscillatory microrheology

The application of large amplitude oscillatory stress in a study of fully formed fibrin clots

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