Published 1994 .
Written in EnglishRead online
|The Physical Object|
|Number of Pages||159|
Download Statistical geometry of paper modelling fibre orientation and flocculation.
Flocculation is modelled with a completely novel approach in pulp and paper industry, a Fibre Floc Evolution (FFE) model, which is based on a population balance. In the FFE model the fibre suspension has been modelled as turbulent Eulerian two phase flow.
Simulating Effects of Fiber Crimp, Flocculation, Density, and Orientation on Structure Statistics of Stochastic Fiber Networks June SIMULATION: Transactions of The Society for Modeling.
paper and its alignment is an important aspect of paper structure. Statistically, fiber alignment is defined as a fiber orientation distribution as a function of angle θ when the machine direction of a web or sheet is set to θ = 0.
Fiber orientation occurs due to a flow of pulp suspension including the turbulence level and orienting shear, so the. We start with paper structure. Paper is made by dewatering a suspension of fibres starting from very low content of solids. The processes of aggregation, sedimentation and clustering are familiar from statistical mechanics.
Statistical growth models or packing models can simulate paper formation well and teach a lot about its by: of curvature. The model is also intended to give the geometry foundation for a FE-model.
The model uses several linked circle arcs to describe a ﬁbre, which accommodates for modelling varying degrees of out of plane curl and kinks. A program has been developed that, from distributions of the aforementioned key. In this article, mathematical models of fibre orientation in fibrous materials are derived and demonstrated with the help of Statistical geometry of paper modelling fibre orientation and flocculation.
book studies of real fibrous materials. The theoretical results on fibre orientation in plane are found to be in good agreement with the experimental results obtained from real fibrous structures. calculate the fiber orientation of each single fiber and consequently also for the whole probe.
Figure 2 shows the fiber orientation tensor along the flow direction A11 for the sample taken at the center of the sector (A) and stripe (B).
Obviously, the parallel flow of the stripe cavity results in higher A11 values compared to the sector. Simulating the effects of fibre crimp, flocculation, density and orientation on structure statistics of stochastic fibre networks. Simul. Trans.
Soc. Model. Simul. Int. Keywords: Fibre orientation, Composites, Numeric simulation, Finite element analysis, Stereology INTRODUCTION This paper deals with the numerical modelling of the fiber orientation of reinforced thermoplastics. These materials show non-homogeneous orientation of the reinforcement, hence developing a local anisotropic behavior.
This paper considers the distribution of fibres in yarns and discusses the development of a model for the simulation of fibre distributions; the concept of ‘virtual location’ within the cross-section domain, which may contain a fibre, is introduced.
The distribution of fibres in real yarns is compared with computer-generated distributions. Abstract. In this paper, a statistical atlas of DT-MRIs based on a population of nine ex vivo normal canine hearts is compared with a human cardiac DT-MRI and with a synthetic model of the fibre orientation.
The aim of this paper is to perform a statistical inter-species comparison of the cardiac fibre architecture and to assess the quality of a synthetic description of the fibre orientation. Statistical geometry offibrousnetwork 19 intersections in l (or the fraction of sections containing n intersections) is givenby-e-N11L (NIIL)n p(n).
()2c n Here, Nl/Lis themeannumber offibres intersectinglengthl andis indepen-dentofthe direction ofscanning, becauseofthe random fibre orientation.
As a result, continuum models that do not Statistical geometry of paper modelling fibre orientation and flocculation. book for the dispersion are not able to capture accurately the stress–strain response of these layers. The purpose of this paper, therefore, is to develop a structural continuum framework that is able to represent the dispersion of the collagen fibre orientation.
Fibres in a network, for simplicity, can be modelled as solid straight rods characterized by three variables: length, λ, width, ω, and linear density, linear density of a fibre is defined as its mass per unit length, and is given by the product of the density of the solid from which the fibre is formed, and the cross-sectional area of the fibre.
The evolution of paper microstructure parameters, such as porosity and fibre orientation, as a function of papermaking conditions is most often studied at a macroscopic scale. However, modelling the physical and mechanical properties of papers using upscaling approaches requires understanding the deformation micro-mechanisms that are induced by papermaking.
Geometry of design integrates drafting technology based on experience with engineering design education. This workbook has evolved from the course “Computer-Aided Graphics and Design” at the University of Florida, and many pages of this textbook can be used for student assignments.
Concept of Geometry, Materials, Load Conditions and Homogenization. - David Garoz Gómez. Chapter 2 - Micro-scale Representative Volume Element - Generation and Statistical Characterisation - António R. Melro and Riccardo Manno. Chapter 3 - Geometry modelling and elastic property prediction for short fiber composites - Jörg Hohe.
orientation distribution . Variation in fibre orientation in paper sheet contributes to dimensional instabilities, optical differences, porosity and smoothness differences, and diminished mechanical properties in the finished paper sheet . Problems like curl, twist warp, down warp are a direct result of improper fibre orientation .
For fibrous materials such as nonwoven fabrics, paper and paperboards, inter-fiber bonds play a critical role by holding fibers, thus providing internal cohesion. Being a physical phenomenon, inter-fiber bonds occur at every fiber crossing and can be also geometrically detected.
In relation to the idea, a statistical geometrical model was developed to investigate the effects of fiber geometry. These three major orientation components have been included in the orientation considerations: fiber orientation in the flow direction, varying from 0 tofiber orientation transverse to flow, varying from 0 totilt of orientation in the plane, varying from to Optimum strength and stiffness can be achieved in a composite by aligning the fibres parallel to the direction of loading.
However, in this case, the composite can perform very poorly when the load is applied perpendicular to the fibres.A method of producing a more isotropic composite is to randomly orient the fibres within the matrix.
However, this decreases the overall strengthening effect. the, J Donghua 12 Abstract This paper presents a full set of numerical methods for predicting the effective thermal conductivity of natural fibrous materials accurately, which includes a random generation-growth method for generating micro morphology of natural fibrous materials based on existing statistical macroscopic geometrical characteristics and a highly efficient lattice Boltzmann.
understanding of the fiber orientation-based fiber failure mechanisms occurring in the micro-machining of FRP composites by employing two unique modeling techniques.
In this research, both experimental and finite element-based modeling approaches are undertaken. Fibers oriented in 0, 45, 90, and degrees with respect to the direction of tool. An in-plane elasto-plastic material model and a hygroexpansivity-shrinkage model for paper and board are introduced in this paper.
The input parameters for both models are fiber orientation. Modelling of as manufactured geometry for prediction of impact and compression after impact behaviour of variable angle tow laminates.
EPSRC Centre for Doctoral Training in Statistical Applied Mathematics (SAMBa) Materials and Structures Centre (MAST) fibre orientation. KW - thickness variation. KW - fibre angle variation. In this paper, we present the results of an online measurement performed with a prototype instrument in a fibre production facility.
We have modelled the fibre geometry with a finite-element method, and measured the same type of fibre in real-time, while causing various geometrical deviations in layers. THEORY AND MODELLING. In Europe, low back pain (LBP) affects the quality of life of up to 30% of the active population.
Although the origin of LBP is not well identified and is probably not unique, epidemiological studies suggest that the severity of the disease is correlated with mechanical factors. The lumbar spine is a complex structure where bone, cartilage, ligaments, and muscles have specific and functional.
Our simulation results demonstrated that the loss of nucleus swelling caused a slight change in the disc geometry and fiber orientation, but a distinct deterioration in the resistance to intervertebral rotations including sagittal bending, lateral bending, and axial torsion.
Fiber quality requirements can be specified in a number of ways; the most typical is to state a required diameter and give a tolerance band to allow for manufacturing variations. Actual fiber diameter statistics have been shown to be close to Gaussian for a certain range of fiber lengths.
These fiber statistics are discussed showing the bounds of stationarity and their relation to fiber. This paper presents a study on the fiber flocculation dynamics in an accelerating base flow which is directly relevant to papermaking.
Experiments are conducted with % suspension of pine fibers in a plane convergent channel. The suspension is fluidized at the inlet of the channel. As the turbulence decays, the fiber flocs are growing. Methods: A DTI template-based framework was developed to estimate cardiac fiber orientations from 3D ultrasound images using an animal model.
It estimated the cardiac fiber orientations of the target heart by deforming the fiber orientations of the template heart, based on the deformation field of the registration between the ultrasound geometry of the target heart and the MRI geometry of the.
paper. A finite element code, based on an implicit solver, is develop to model samples of woven fabrics as assemblies of beams submitted to large displacements and developing contact-friction interactions between themselves.
Special attention is paid to the detection and modeling of the numerous contacts occurring in this kind of structures. The model generates realistic random fibre architectures containing high filament count bundles (>3k) and high (∼50%) fibre volume fractions.
Fibre bundles are modelled as thin shells using a multidimensional modelling strategy, in which fibre bundles are distributed and compacted to simulate pressure being applied from a matched mould tool. In diffusion-weighted magnetic resonance imaging, the estimation of the orientations of multiple nerve fibers in each voxel (the fiber orientation distribution (FOD)) is a critical issue for exploring the connection of cerebral tissue.
In this paper, we establish a convex semidefinite programming (CSDP) model for the FOD estimation. Fiber orientation distributions (FODs) based on diffusion-sensitized magnetic resonance imaging are usually symmetric, primarily due to the nature of the diffusion.
In contrast, the underlying fiber configurations are not, as bending or fanning configurations are inherently asymmetric. We propose to dismiss the symmetry of the FOD to additionally encode the asymmetry of the underlying fiber.
The overall fibre orientation in a composite can be statistically characterized by a fibre-orientation distribution. Fibre-orientation studies have concentrated on two major areas: those dealing with continuous fibres and those dealing with short fibres.
This paper presents a novel two-section based method for statistical characterization of. Anatoli Juditsky and Arkadi Nemirovski. Octo Convex Optimization, Statistics, Statistical Inference, Textbooks. case. Then fiber orientation is computed and used to model the structural performance of the part under load.
Results are compared to structural performance modeled without taking in consideration fiber orientation. The pa-per shows up to % difference on the final stress when fiber orientation is taken into account. These results. The models used in fiber orientation prediction have three major groupings: micro-mechanics models, thermal expansion coefficient models, and fiber closure approximation models.
Additional general research is also considered. 1 FIBER ORIENTATION MEASUREMENTS IN COMPOSITE MATERIALS R. BLANC 1, Ch. GERMAIN 1, J.P. DA COSTA, P. BAYLOU, M. CATALDI2 1Equipe Signal et Image, LAPS - UMR CNRS – ENSEIRB, ENITAB, Université Bordeaux1 cours de la Libération - TALENCE cedex - FRANCE 2Snecma Propulsion Solide, Snecma Group, Les Cinq Chemins Le Haillan - France.
Purchase Composite Reinforcements for Optimum Performance - 1st Edition. Print Book & E-Book. ISBNThe relevance of this correlation to pore geometry is the final part we analyze simulated areal density maps and show that their variance relative to that of a random fibre network of the same constituent fibres, as quantified by the formation number, depends at small scales on the flocculation intensity only and depends at large.Vulcanized natural rubber (unfilled and filled with 20 phr carbon black) is strained.
We suppress the macroscopic formation of fiber symmetry by choosing strip-shaped samples ("pure-shear geometry") and investigate the orientation of the resulting crystallites by two-dimensional wide-angle X-ray diffraction (WAXD), additionally rotating the sample tape about the straining direction.