Scattering Characteristics of Fibrous Media Containing Closely Spaced Parallel Fibers

AbstractIn this work, an extension of the strain energy for fibrous metamaterials composed of two families of parallel fibers lying on parallel planes and joined by connective elements is proposed. The suggested extension concerns the possibility that the constituent fibers come into contact and eventually scroll one with respect to the other with consequent dissipation due to friction. The fibers interact with each other in at least three different ways: indirectly, through microstructural connections that could allow a relative sliding between the two families of fibers; directly, as the fibers of a family can touch each other and can scroll introducing dissipation. From a mathematical point of view, these effects are modeled first by introducing two placement fields for the two fiber families and adding a coupling term to the strain energy and secondly by adding two other terms that take into account the interdistance between the parallel fibers and the Rayleigh dissipation potential (to account for friction).

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Bounding transverse permeability of fibrous media: A statistical study from random representative volume elements with consideration of fluid slip

International Journal of Multiphase Flow ◽

10.1016/j.ijmultiphaseflow.2021.103751 ◽

2021 ◽

pp. 103751

Author(s):

Aubin Geoffre ◽

Maydine Ghestin ◽

Nicolas Moulin ◽

Julien Bruchon ◽

Sylvain Drapier

Keyword(s):

Statistical Study ◽

Fibrous Media ◽

Representative Volume ◽

Transverse Permeability ◽

Representative Volume Elements

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Correlations Between Air Drag and Movement of Water Droplets in Fibrous Media

Separation and Purification Technology ◽

10.1016/j.seppur.2021.118602 ◽

2021 ◽

pp. 118602

Author(s):

S. Neda Mehdizadeh ◽

Amir Mehdi Pasdar ◽

George G. Chase

Keyword(s):

Water Droplets ◽

Fibrous Media ◽

Air Drag

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Removal of Emulsified Water from Diesel Fuel Using Polypropylene Fibrous Media Modified by Ionization during Meltblow Process

Separation Science and Technology ◽

10.1080/01496395.2014.974818 ◽

2014 ◽

Vol 50 (10) ◽

pp. 1541-1547 ◽

Cited By ~ 5

Author(s):

Andrzej Krasinski ◽

Patrycja Wierzba

Keyword(s):

Diesel Fuel ◽

Fibrous Media ◽

Emulsified Water

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Development of Permeability Models for Saturated Fluid Flow across Arrays of Fibre Clusters

Advanced Composites Letters ◽

10.1177/096369350201100303 ◽

2002 ◽

Vol 11 (3) ◽

pp. 096369350201100

Author(s):

E.M. Gravel ◽

T.D. Papathanasiou

Keyword(s):

Analytical Models ◽

Dual Porosity ◽

Hydraulic Permeability ◽

Fibrous Media ◽

Fibre Bundles ◽

Hexagonal Packing ◽

Composites Manufacturing ◽

Starting Point ◽

Wide Range ◽

Flow Through

Dual porosity fibrous media are important in a number of applications, ranging from bioreactor design and transport in living systems to composites manufacturing. In the present study we are concerned with the development of predictive models for the hydraulic permeability ( Kp) of various arrays of fibre bundles. For this we carry out extensive computations for viscous flow through arrays of fibre bundles using the Boundary Element Method (BEM) implemented on a multi-processor computer. Up to 350 individual filaments, arranged in square or hexagonal packing within bundles, which are also arranged in square of hexagonal packing, are included in each simulation. These are simple but not trivial models for fibrous preforms used in composites manufacturing – dual porosity systems characterised by different inter- and intra-tow porosities. The way these porosities affect the hydraulic permeability of such media is currently unknown and is elucidated through our simulations. Following numerical solution of the governing equations, ( Kp) is calculated from the computed flowrate through Darcy's law and is expressed as function of the inter- and intra-tow porosities (φ, φt) and of the filament radius ( Rf). Numerical results are also compared to analytical models. The latter form the starting point in the development of a dimensionless correlation for the permeability of such dual porosity media. It is found that the numerically computed permeabilities follow that correlation for a wide range of φ i, φt and Rf.

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Fractographical Analysis and Biomechanical Considerations of a Tooth Restored With Intracanal Fiber Post: Report of the Fracture and Importance of the Fiber Arrangements

Operative Dentistry ◽

10.2341/15-262-s ◽

2016 ◽

Vol 41 (5) ◽

pp. E149-E158 ◽

Cited By ~ 4

Author(s):

VF Wandscher ◽

CD Bergoli ◽

IF Limberger ◽

TP Cenci ◽

P Baldissara ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Glass Fiber ◽

Shear Stresses ◽

Fiber Post ◽

Element Analysis ◽

Parallel Fibers ◽

Tooth Structure ◽

Anterior Teeth ◽

Compressive Stresses

SUMMARY Objective: This article aims to present a fractographic analysis of an anterior tooth restored with a glass fiber post with parallel fiber arrangement, taking into account force vectors, finite element analysis, and scanning electron microscopy (SEM). Methods: A patient presented at the Faculty of Dentistry (Federal University of Santa Maria, Brazil) with an endodontically treated tooth (ETT), a lateral incisor that had a restorable fracture. The treatment was performed, and the fractured piece was analyzed using stereomicroscopy, SEM, and finite element analysis. Results: The absence of remaining coronal tooth structure might have been the main factor for the clinical failure. We observed different stresses actuating in an ETT restored with a fiber post as well as their relationship with the ultimate fracture. Tensile, compression, and shear stresses presented at different levels inside the restored tooth. Tensile and compressive stresses acted together and were at a maximum in the outer portions and a minimum in the inner portions. In contrast, shear stresses acted concomitantly with tensile and compressive stresses. Shear was higher in the inner portions (center of the post), and lower in the outer portions. This was confirmed by finite element analysis. The SEM analysis showed tensile and compression areas in the fiber post (exposed fibers=tensile areas=lingual surface; nonexposed fibers=compression areas=buccal surface) and shear areas inside the post (scallops and hackle lines). Stereomicroscopic analysis showed brown stains in the crown/root interface, indicating the presence of microleakage (tensile area=lingual surface). Conclusion: We concluded that glass fiber posts with parallel fibers (0°), when restoring anterior teeth, present a greater fracture potential by shear stress because parallel fibers are not mechanically resistant to support oblique occlusal loads. Factors such as the presence of remaining coronal tooth structure and occlusal stability assist in the biomechanical equilibrium of stresses that act upon anterior teeth.

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