Topic
Rheometer
About: Rheometer is a research topic. Over the lifetime, 5759 publications have been published within this topic receiving 125849 citations.
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TL;DR: In this article, a kind of shear thickening fluids (STFs) including silicon carbide particles are presented, which is based on nanosize fumed silica suspended in a liquid medium, polyethylene glycol.
Abstract: In this paper, shear thickening fluids (STFs) including silicon carbide particles are presented. We fabricated a kind of STF based on nanosize fumed silica suspended in a liquid medium, polyethylene glycol, at a constant concentration of 20 wt.%. Then, different particle size silicon carbide (SiC) particles were added to the STF with various amounts. Their rheological properties under various temperatures were tested by using a rheometer. The suspension exhibits different systematic variations with respect to the varied parameters.
77 citations
TL;DR: In this article, the viscosity of natural rhyolitic melt from Lipari, the Aeolian Islands and melt-bubble emulsions (30-50 vol% porosity) generated from lipari rhyolite have been measured in a concentric cylinder rheometer at temperatures and shear rates in the range 925-1150°C and 10−3-10−1.2 s−1, respectively.
77 citations
TL;DR: Using dimensional analysis, the hardness and probe displacement in TPA were mathematically transformed into corresponding rheological parameters, namely shearing stress and rate of shear, thereby allowing the application of the power law (eta = kgamma(n)) to textural data.
77 citations
TL;DR: In this article, the authors used the coupling between the instrumental inertia and the material's elasticity to follow the rheological behavior of a solution of iota carrageenan both above and below the yield stress.
Abstract: We describe a new method for characterizing the non-linear behavior of complex fluids at both small and large deformations. For creep measurements, we use the coupling between the instrumental inertia and the material‘s elasticity to follow the rheological behavior of a solution of iota carrageenan both above and below the yield stress. It is shown that this coupling selectively excites one particular frequency of the relaxation spectrum. An analytical calculation is used to quantify the non-linear behavior near the yield stress. The “free“ oscillations observed during the first few seconds allow us to choose the most appropriate mechanical model. Comparison with experiment shows that even above the yield stress, a linear model can still give independently reliable information about the changes in each element of the mechanical model. A comparison of free and forced oscillations in controlled stress rheometry shows both experimentally and theoretically the conditions under which the use of free oscillations is advantageous.
76 citations
TL;DR: In this article, a capillary rheometer has been constructed and mounted on a molding-injection machine, and the shear viscosity of filled polypropylene (PP) composites was determined from the capillary Rheometer, after corrections for entrance effects, was found to be very close to that of unfilled PP.
Abstract: Long glass fiber-filled polypropylene (PP) composites are produced by pultrusion, and the extrudate is cut at different lengths producing composites containing long fibers of controlled length. The rheological properties of such composites in the molten state have been studied using different rheometers. A capillary rheometer has been constructed and mounted on a molding-injection machine. The shear viscosity of filled PP determined from the capillary rheometer, after corrections for entrance effects, was found to be very close to that of unfilled PP. However, large excess pressure losses at the capillary entrance were observed and these data have been used to obtain an apparent elongational viscosity. The apparent elongational viscosity was shown to be considerably larger than the shear viscosity for PP and filled PP, and it increased markedly with fiber length and fiber content. Rotational rheometers with a parallel-plate geometry were used to investigate the viscoelastic properties of these composites and their behavior was found to be non-linear, exhibiting a yield stress. A model is proposed to describe the shear viscosity from a solid-like behavior at low stresses to fluid-like behavior at high shear stresses taking into account fiber content and orientation. A modified model, proposed for elongational flow, describes relatively well the apparent elongational data.
76 citations