Author: Richard Orr MaschmeyerPublisher:
ISBN:
Category : Glass-reinforced plastics
Languages : en
Pages : 550
Book Description
Rheology of Concentrated Suspensions of Fibers
Author: Richard Orr MaschmeyerPublisher:
ISBN:
Category : Glass-reinforced plastics
Languages : en
Pages : 550
Book Description
Rheology of Concentrated Suspensions of Fibers in Tube Flow: III. Suspensions with the Same Fiber Length Distribution
Author: Richard O. MaschmeyerPublisher:
ISBN:
Category :
Languages : en
Pages : 36
Book Description
Capillary viscometer measurements were made on a series of concentrated suspensions with the same fiber length distribution. Shear stress-shear rate data are reported for 0, 15, and 30 vol.% glass fiber suspensions in 100, 600, and 1000 P silicone oil. Yield stresses, wall effects, concentration defects, squeeze-through, and capillary entrance exclusion were not significant in the measurements. With other parameters held constant, the suspension viscosity increased with oil viscosity. The data were fit by a dimensionless plot of the form F(fRe, De) = 0 where f is the friction factor for tube flow and Re and De are the Reynolds and Deborah numbers of the system. The suspension viscosity increased with fiber concentration, but the magnitude of the increase was highly shear rate dependent. The data are compared with literature predictions for the dependence of suspension viscosity on fiber concentration and shear rate.
Rheology of Concentrated Suspensions of Fibers in Tube Flow: II. An Exploratory Study
Author: Richard O. MaschmeyerPublisher:
ISBN:
Category :
Languages : en
Pages : 27
Book Description
The viscosities of concentrated suspensions of glass fibers in high viscosity silicone oil were measured with a capillary viscometer using 1/4 inch and 1/8 inch diameter capillaries. Suspension fiber length distributions and rheological properties were highly dependent on mixing technique. The viscosity of the suspensions was strongly dependent on fiber length distribution--a few percent of relatively long fibers in the distribution doubled or tripled the suspension viscosity. Special attention was paid to wall effects which complicate the interpretation of suspension viscosity data. Yield stresses, squeeze-through, the capillary entrance exclusion were observed; their magnitudes increased with fiber length and depended strongly on fiber length distribution.
The Rheology of Concentrated Suspensions of Fibers and Spheres
Author: R. O. MaschmeyerPublisher:
ISBN:
Category :
Languages : en
Pages : 19
Book Description
A review and summary are presented on the existing scientific and technical literature on the viscosity and elasticity of concentrated fiber suspensions, including reinforced plastics. Also discussed is the experimental capillary rheometry of model suspensions of glass fibers in viscous silicone oils. At high volume fraction fibers such suspensions are pseudoplastic, exhibit a yield stress in shear, have large capillary entrance corrections, but show no die swell. A brief account is given of the influence of fiber breakage on suspension viscosity in capillary flow and on the best choice of technique for mixing such suspensions. (Author modified-PL).
The Rheology of Concentrated Fiber Suspensions
Author: Michael L. BecraftPublisher:
ISBN:
Category : Fibrous composites
Languages : en
Pages : 480
Book Description
Rheology of Non-spherical Particle Suspensions
Author: Francisco ChinestaPublisher: Elsevier
ISBN: 0081008120
Category : Science
Languages : en
Pages : 398
Book Description
This book provides a review of the current understanding of the behavior of non-spherical particle suspensions providing experimental results, rheological models and numerical modeling. In recent years, new models have been developed for suspension rheology and as a result applications for nanocomposites have increased. The authors tackle issues within experimental, model and numerical simulations of the behavior of particle suspensions. Applications of non-spherical particle suspension rheology are widespread and can be found in organic matrix composites, nanocomposites, biocomposites, fiber-filled fresh concrete flow, blood and biologic fluids. - Understand how to model and predict the final microstructure and properties of particle suspensions - Explores nano, micro, meso and macro scales - Rheology, thermomechanical and electromagnetic physics are discussed
On the Rheology of Concentrated Fiber Suspensions
Author: Steven Minh DinhPublisher:
ISBN:
Category : Fibrous composites
Languages : en
Pages : 724
Book Description
Mass Transfer and Rheology of Fiber Suspensions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Rheological and mass transfer properties of non-Brownian fiber suspensions are affected by fiber characteristics, fiber interactions, and processing conditions. In this thesis we develop several simulation methods to study the dynamics of single fibers in simple shear flow, as well as the rheology and mass transfer of fiber suspensions. Isolated, rigid, neutrally-buoyant, non-Brownian, slightly curved, nonchiral fibers in simple shear flow of an incompressible Newtonian fluid at low Reynolds number can drift steadily in the gradient direction without external forces or torques. The average drift velocity and direction depend on the fiber aspect ratio, curvature and initial orientation. The drift results from the coupling of rotational and translational dynamics, and the combined effects of flipping, scooping, and spinning motions of the fiber. Irreversible fiber collisions in the suspensions cause shear-induced diffusion. The shear-induced self-diffusivity of dilute suspensions of fibers increases with increasing concentration and increasing static friction between contacts. The diffusivities in both the gradient and vorticity directions are larger for suspensions of curved fibers than for suspensions of straight fibers. For suspensions of curved fibers, significant enhancements in the diffusivity in the gradient direction are attributed to fiber drift in the gradient direction. The shear-induced self-diffusivity of concentrated suspensions of fibers increases with increasing concentration before fiber networks or flocs are formed, after which the diffusivity decreases with increasing concentration. The diffusivity increases with increasing fiber equilibrium bending angle, effective stiffness, coefficient of static friction, and rate of collisions. The specific viscosity of fiber suspensions increases with increasing fiber curvature, friction coefficient between mechanical contacts, and solids concentration. The specific viscosity increases linearly with concentration in the dilute regime, and increases with the cube of the concentration in the semi-dilute regime. Concentrated fiber suspensions are highly viscous, shear thinning, and exhibit significant yield stresses and normal stress differences. Yield stresses scale with volume concentration and fiber aspect ratio in the same way as that observed in experiments. The first normal stress difference increases linearly with shear rate. The shear-induced diffusivity increases linearly with the derivative of the particle contribution to stress for dilute suspensions with respective to concentration. This correlation between rheology and shear-induced diffusion makes it possible to predict diffusivity from easily measured rheological properties.
The Rheology of Concentrated Fibre Suspensions
Author: Michael Lee BecraftThe Rheology of Concentrated Suspensions
Author: Francis A. Gadala-MariaPublisher:
ISBN:
Category : Rheology
Languages : en
Pages : 314
Book Description