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Showing 1 to 19 of 19 for “"Large amplitude oscillatory shear"”.
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Thixotropic-viscoelastic rheological fingerprints in large amplitude oscillatory shear
In this work we demonstrate the use of large-amplitude oscillatory shear (LAOS) as a tool to characterize the behavior of constitutive models that exhibit both thixotropic and viscoelastic phenomena. We demonstrate this use of LAOS by first examining the strain controlled LAOS (LAOStrain) response …
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Rheological characterization and modeling of Laponite gels with application to snug-like locomotion
… testing methods: stress sweep, creep tests, and large amplitude oscillatory shear tests, defined as LAOS. Concentrations of 1%, 2%, 2.5%, 3%, and 4% wt. of Laponite and distilled water solutions were tested. Laponite gels over 1% wt. concentrations were characterized as yield stress materials, as …
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Development, characterization and applications of magnetorheological fluid based "smart" materials on the macro-to-micro scale
… class of field-responsive fluids that undergo large, reversible and fast changes in their rheological properties when acted upon by an external magnetic field. 'Smart' or controllable composite materials have been obtained by doping polymers, foams, fabrics etc. with these field-responsive …
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Nonlinear viscoelastic materials : bioinspired applications and new characterization measures
… characterizing nonlinear viscoelasticity using large amplitude oscillatory shear (LAOS) deformation. The LAOS protocol spans the 2D parameter space of deformation amplitude and frequency, known as a Pipkin space. Physically meaningful material measures are proposed, corresponding to clearly …
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Rheology of complex fluid films for biological and mechanical adhesive locomotion
… mucus, and their acrobatic ability is due in large part to the theological properties of this slime. The primary application of the present research is to enable a mechanical crawler to climb walls and walk across ceilings using adhesive locomotion. A properly selected slime simulant will …
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Energy absorption of reticulated foams filled with shear-thickening silica suspensions
… energy absorbing fluid-composite that utilized a shear thickening fluid is developed. Shear-thickening fluids are a class of field responsive fluids that have the ability to transition from low viscosity to high viscosity under an imposed deformation field. Two different types of silica particles …
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High-rate deformation behavior and applications of fluid filled reticulated foams
… energy absorbing fluid-composite that utilized a shear thickening fluid is developed. Shear-thickening fluids are a class of field responsive fluids that have the ability to transition from a low viscosity state to a high viscosity state under an imposed deformation field. A shear thickening fluid …
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Linear to nonlinear rheology of bread dough and its constituents
… of machines that are able to handle and process large volumes of dough. An understanding of the deformational properties can aid in designing machines of this kind. Less obviously, the texture of the bread we eat is governed by the mechanical properties of the dough from which it is proofed and …
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Rheometry and direct flow observations of a model wax-oil system
… using temperature sweeps and stress sweeps. Large amplitude oscillatory shear (LAOS) is also used to gain additional insight into the rheology of the model system. The results from the LAOS measurements show that the wax-oil system exhibits a strain stiffening and shear thinning response …
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Development of Sustainable Thermoplastic Elastomers
… side-chain of the polyacrylates, in the limit of large alkyl side-chains (i.e., more than 10 carbon atoms), in stark contrast to theoretical predictions using group contribution methods and solubility parameter theory. The morphology of SAS was probed by transmission electron microscopy, showing …
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Designing devices using electro-active yield stress fluids
… rheological measurements from wall-driven shear flows e.g. torsional rheometers and in pressure-driven channel flows, that are more applicable to valve applications. Next, we extend this work by introducing the holding pressure drop and power efficiency as key performance metrics for …
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The rheological complexity of waxy crude oils : yielding, thixotropy and shear heterogeneities
… The three phenomena studied are, first: shear heterogeneities, i.e. the manifestation of wall slip, shear banding or other shear-localization events under imposed deformations that are assumed to be homogenous. For these purposes, flow visualization techniques capable of "Rheo-PIV" …
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Asymptotically nonliner oscillatory shear: theory, modeling, measurements and applications of nonlinear elasticity to stimuli-responsive composites
… rheological response to mechanical deformation. Oscillatory shear is a popular deformation protocol for viscoelastic characterization, both linear and nonlinear, the latter referred to as large amplitude oscillatory shear (LAOS). However, the accompanying nonlinear material response in LAOS is …
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The yielding transition in soft materials
… metallization pastes and polymer microgels under large amplitude oscillatory shear (LAOS) by means of the sequence of physical processes (SPP) framework. The SPP approach allows insights to be gained regarding these processes on time scales significantly faster than the period of oscillation, with …
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Low dimensional intrinsic material functions uniquely identify rheological constitutive models and infer material microstructure
Made available in DSpace on 2013-02-03T19:18:23Z (GMT). No. of bitstreams: 2 Narayanan Ashwin Kumar_Bharadwaj.pdf: 5317555 bytes, checksum: 8997d27d51481208eef06a2a2f9726e6 (MD5) license.txt: 4082 bytes, checksum: 4d805d5496639ba3959b750fb2fc8438 (MD5)
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When sticky fluids do and do not stick: yield-stress fluid drop impacts
… deposit itself on the surface, or experience a large splash event. When incoming drop energy (set by drop size and speed) is small compared to arresting forces (set by the material yield stress and surface geometry) all motion is quickly halted, and the drop becomes a lump on the surface. When …
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Structure-property relationships in polymeric materials via advanced rheological and neutron scattering techniques
… when reacting to dynamic flows such as large-amplitude oscillatory shear (LAOS) flows, tend to generate complex material responses. Several analysis approaches have been suggested to interpret the underlying material physics. Despite recent progress in understanding the macroscopic …
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Time-resolved linear and non-linear rheology of thixotropic and aging complex fluids: Application to particulate and biopolymeric physical gels
… of microstructure is commonly both time– and shear-rate (or shear-stress)–dependent resulting in a range of complex phenomena collected under the term thixotropy. It is becoming increasingly im- portant to develop time-resolved rheometric techniques to quantify the behavior of mutating …
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Gel Development Using Cellulose Nanocrystals
… (TEM). The CNC-based gel behavior under large amplitude strains is also characterized by non-linear rheology. The gel collapse behavior and the self-healing dynamics of CNC-based gels are also quantified using fluorescence recovery after photobleaching (FRAP) analysis. It is shown that …