Three dimensional simulation of air permeability of single layer woven structures

2011 ◽  
Vol 1 (4) ◽  
Author(s):  
Radostina Angelova ◽  
Peter Stankov ◽  
Iskra Simova ◽  
Idoya Aragon
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Single Layer ◽  
Woven Fabrics ◽  
Transverse Permeability ◽  
Woven Structures ◽  
Dimensional Simulation ◽  
Jet Cross Sections ◽  
Woven Structure

AbstractThe paper deals with a CFD based study of the transverse permeability of a textile woven structure. The reported numerical investigation is preconditioned by both previous experimental and CFD study on jet systems. It is also based on detailed experimental investigation of the porous structure of single layer woven fabrics, made of staple fiber yarns. The flow in through-thickness direction of the woven structures is presented as jet systems, issuing from set of orifices. Two different types of jet system (3×3 jets and 5×5 jets) with two types of jet cross sections (square and circular), corresponding to two different woven structures, are simulated. An analysis is made in terms of the structure of the woven fabrics (area and shape of the interstices between the threads), the parameters of the flow passing through the textile (velocity profiles and velocity fields through isosurfaces), the role of the type of the jet systems, representing the flow and the influence of the shape of the interstices between the threads on the flow pattern. It was found that the applied approach could be effectively used for studying of the transverse permeability of the woven fabrics.

Determination of the pore size of woven structures through image analysis

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
R. Angelova
Keyword(s):  
Pore Size ◽  
Single Layer ◽  
Woven Fabric ◽  
Virtual Model ◽  
Experimental Procedure ◽  
Porosity And Permeability ◽  
Woven Structures ◽  
Woven Structure ◽  
Non Destructive

AbstractThe paper presents an experimental procedure developed for determination of the pore size, shape and distribution in a single layer woven fabric, for the construction of a virtual model to be incorporated in a future CFD software package. The procedure is based on non-destructive observation and analysis of woven samples. 14 different samples of gray fabrics of 100 % cotton in plain and twill weaves are investigated. The results obtained allow the creation of reality more realistic virtual model of the woven structure, and theoretical investigation of its porosity and permeability through computer simulation.

scholarly journals 3D Hydrodynamic Focusing in Microscale Optofluidic Channels Formed with a Single Sacrificial Layer

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 349 ◽  
Author(s):  
Erik S. Hamilton ◽  
Vahid Ganjalizadeh ◽  
Joel G. Wright ◽  
Holger Schmidt ◽  
Aaron R. Hawkins
Keyword(s):  
Cross Sections ◽  
Optical Waveguides ◽  
Sacrificial Layer ◽  
Three Dimensional ◽  
Single Layer ◽  
Detection Sensitivity ◽  
Low Flow ◽  
Hydrodynamic Focusing ◽  
Induced Focusing ◽  
Pressure Driven Flow

Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity.

Three-Dimensional Simulation of In Vitro Angiogenesis: Effects of Extracellular Matrix Structure and Density

2010 ◽  
Author(s):  
Lowell Taylor Edgar ◽  
James E. Guilkey ◽  
Clayton J. Underwood ◽  
Brenda Baggett ◽  
Urs Utzinger ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Three Dimensional ◽  
Vascular Endothelial ◽  
Chemical Factors ◽  
Dimensional Simulation ◽  
Endothelial Growth Factor ◽  
In Vitro Angiogenesis

The process of angiogenesis is regulated by both chemical and mechanical signaling. While the role of chemical factors such as vascular endothelial growth factor (VEGF) during angiogenesis has been extensively studied, the influence of the mechanostructural environment on new vessel generation has received significantly less attention. During angiogenesis, endothelial cells in the existing vasculature detach and migrate out into the surrounding extracellular matrix (ECM), forming tubular structures that eventually mature into new blood vessels. This process is modulated by the structure and composition of the ECM [1]. The ECM is then remodeled by endothelial cells in the elongating neovessel tip, resulting in matrix condensation and changes in fiber orientation [2]. The mechanism as to how angiogenic vasculature and the ECM influence each other is poorly understood.

Interference in a three-dimensional array of jets

2015 ◽  
Vol 26 (5) ◽  
pp. 795-819
Author(s):  
P. E. WESTWOOD ◽  
F. T. SMITH
Keyword(s):  
Cross Sections ◽  
Flow Direction ◽  
Three Dimensional ◽  
Cross Flow ◽  
Longitudinal Vortex ◽  
Cross Sectional ◽  
Dimensional Array ◽  
Unsteady Jets ◽  
The Cross ◽  
Jet Cross Sections

The theoretical investigation here of a three-dimensional array of jets of fluid (air guns) and their interference is motivated by applications to the food sorting industry especially. Three-dimensional motion without symmetry is addressed for arbitrary jet cross-sections and incident velocity profiles. Asymptotic analysis based on the comparatively long axial length scale of the configuration leads to a reduced longitudinal vortex system providing a slender flow model for the complete array response. Analytical and numerical studies, along with comparisons and asymptotic limits or checks, are presented for various cross-sectional shapes of nozzle and velocity inputs. The influences of swirl and of unsteady jets are examined. Substantial cross-flows are found to occur due to the interference. The flow solution is non-periodic in the cross-plane even if the nozzle array itself is periodic. The analysis shows that in general the bulk of the three-dimensional motion can be described simply in a cross-plane problem but the induced flow in the cross-plane is sensitively controlled by edge effects and incident conditions, a feature which applies to any of the array configurations examined. Interference readily alters the cross-flow direction and misdirects the jets. Design considerations centre on target positioning and jet swirling.

Analysis of beams with piezo-patches by node-dependent kinematic finite element method models

2017 ◽  
Vol 29 (7) ◽  
pp. 1379-1393 ◽  
Author(s):  
Erasmo Carrera ◽  
Enrico Zappino ◽  
Guohong Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Sections ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Single Layer ◽  
Present Contribution ◽  
Stiffness Matrices ◽  
Carrera Unified Formulation ◽  
Element Method

This article presents a family of one-dimensional finite element method models with node-dependent kinematics for the analysis of beam structures with piezo-patches. The models proposed are built by applying Carrera unified formulation. Carrera unified formulation permits to obtain finite element method stiffness matrices through so-called fundamental nuclei whose form is independent of the assumptions made for the displacement/electrical field over the cross section of a beam. In the previous works, uniform kinematic assumptions have been applied to all the nodes within the same element. The present contribution proposes to use different kinematics on different nodes, leading to node-dependent kinematic finite element method formulations. In such an approach, non-uniform cross sections introduced by piezo-patches can be considered. With the help of layer-wise models, piezoelectric and mechanical domains each can possess individual constitutive relations. Meanwhile, node-dependent kinematics can integrate equivalent single layer models and layer-wise models to reach an optimal balance between accuracy and use of computational resources. Static governing equations for beam elements with node-dependent kinematics accounting for electromechanical effects are derived from the principle of virtual displacements. The competence of the proposed approach is validated by comparing the obtained results with solutions taken from the literature and ABAQUS three-dimensional modelling. Both extension and shear actuation mechanisms are considered.

scholarly journals Accuracy of 2D modeling approach for performance simulation of noncircular single- and dual-layer monolithic catalysts

2021 ◽  
Author(s):  
Behnam Mozaffari
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Single Layer ◽  
Flow Region ◽  
3D Models ◽  
Catalytic Performance ◽  
Cross Sectional ◽  
2D Modeling ◽  
Modeling Approach ◽  
Monolithic Catalysts

This study aims to evaluate the accuracy of widely applied approach of modeling noncircular channels and washcoats of monolithic catalysts with equivalent circular geometrical shapes. For this purpose, catalytic performance of equivalent circular and square channel cross-sectional shapes with single-layer Pt/Al2O3 and dual-layer Fe-ZSM-5+Pt/Al2O3 washcoats are investigated. For the noncircular cross-sections, three-dimensional computational fluid dynamics models that consider species gases convection inside the channel bulk flow region, and reaction and diffusion of species inside the washcoat layer(s) are utilized to simulate the performance of one channel of the monolithic catalytic converters. In addition, in order to investigate the amount of inaccuracy of 2D modeling approach for noncircular channels, 2D models are applied to simulate the equivalent monolithic catalysts with circular cross-sections, and the results of the 2D and 3D models are compared together, and also, with the experimental and 1D+1D modeling technique results available in the literature.

scholarly journals Investigating the Performance of Sewn Seams from Woven Fabrics

2021 ◽  
Author(s):  
Md. Shamsuzzaman
Keyword(s):  
Breaking Strength ◽  
Research Work ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Sewing Thread ◽  
Fabric Strength ◽  
Woven Structures ◽  
Thread Strength ◽  
Woven Structure ◽  
Thread Count

Abstract Seam performance ensures the durability, attractiveness, strength etc. of the sewn garments. Fabric types, fabric densities, fabric strength, seam types, sewing thread count, thread strength, stitch densities and stitch types influence the performance of a sewn seam. This paper investigates the performance of sewn seam of various structure of woven fabric. The variables of this research are stitch densities (SPI), sewing thread count, seam types and woven structures. We conduct our research over plain, twill 2/1, twill 2/2, oxford and poplin woven structure. Firstly, we apply lockstitch (301) to produce superimposed, lapped and bound seam on the woven sample by using thread count 27 Tex, 30 Tex, 20/2 Tex, 40 Tex, 40/2 Tex, 40/3 Tex having stitch densities (SPI) 8, 10 and 12. Then according to ASTM D1683 standard, we measured the tensile strength test and recorded the seam breaking strength (N). We apply error bars over each diagram to investigate the standard deviation. Finally, we discuss four hypothesis to conclude our research work. We found higher seam breaking strength with the increase of thread count and SPI. The bound seam samples has shown superior seam breaking strength than superimposed and lapped seam; poplin structure surpassed to others. The seam efficiency of the samples varies from 60–90% and do not exceeds 100%. Finally, we found some significant alternatives hypothesis of the population since F values exceeded F critical values for the sewn seam.

Implications of pericline geometries on 3D fold shape analysis, stress distribution and fracture analysis

2021 ◽  
Author(s):  
Andreas Eckert ◽  
Xiaolong Liu ◽  
Avery Welker ◽  
Peter Connolly ◽  
John Hogan ◽  
...  
Keyword(s):  
Shape Analysis ◽  
Cross Sections ◽  
Three Dimensional ◽  
Single Layer ◽  
Fracture Analysis ◽  
Cross Sectional ◽  
3D Geometry ◽  
Deformation Event ◽  
Dip Isogons ◽  
Distribution Of Stress

<p>The characterization of folds is often limited to two-dimensional cross-sectional views where folds are approximated as cylindrical. This enables simplification of fold shape analysis (using principles such as dip isogons, stereographs, tangent diagrams, and Bezier curve analysis), allows for a simplified analysis of the distribution of stress and strain, and enables and the analysis and visualization of folding associated fractures. However, in a heterogenous medium folds have to terminate somewhere, resulting in more complex three-dimensional geometries. In this study, a 3D finite element modeling approach using a Maxwell visco-elastic rheology is utilized to simulate 3D periclinal folds resulting from single layer buckle folding. With respect to fold shape analysis, we use the forward modeled pericline geometries to demonstrate that geometrical attitude data collected for various cross sections and plotted using traditional 2D methods such as stereographs and tangent diagrams may lead to the misinterpretation of the fold shape as conical. In contrast 3D geometric data such as Gaussian curvature can describe and quantify the 3D fold geometry in its entirety. With respect to folding associated fracture analysis, the 3D modeling results show that shear fractures of various orientations in the fold limb, which cannot be intuitively explained by the strain/stress regimes during 2D buckling and require unrealistic boundary conditions, are feasible to occur during a single deformation event during the development of a pericline. In summary, accounting for the true 3D geometry of buckle fold structures will lead to a better classification of folds, a better understanding of the processes and parameters affecting their development, and enable post-folding failure analysis.</p>

Structural Optimization of Woven Fabric with Curved Surface

2012 ◽  
Vol 443-444 ◽  
pp. 408-411
Author(s):  
Yan Fang Wang ◽  
Xing Feng Guo
Keyword(s):  
Structural Optimization ◽  
Shear Deformation ◽  
Three Dimensional ◽  
Single Layer ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Curved Surface ◽  
Theoretical Formula ◽  
Curved Surfaces

The woven fabric with curved surfaces is a kind of single layer woven fabrics, which was produced to smoothly fit three-dimensional solids. The warp or weft of the winding fabric bend were normally made with different lengths, which may result in shear deformation in many cases and accordingly twisting the structure of the fabric after fitted onto the solid. In order to solve the problem mentioned above, a theoretical formula was used to calculate the optimal intervals of the pick-spacing and an improved structure thus was developed in this study.

Cylindrical Orthotropic Thermal Conductivity of Spiral Woven Composites Part I: Modelling of a Spiral Woven Structure

2003 ◽  
Vol 11 (6) ◽  
pp. 505-511 ◽  
Author(s):  
Chao-Chuan Cheng ◽  
Chang-Hsuan Chiu
Keyword(s):  
Thermal Conductivity ◽  
Cross Sections ◽  
Single Layer ◽  
Geometric Parameters ◽  
Woven Fabric ◽  
Woven Composites ◽  
Shape Functions ◽  
Fundamental Structure ◽  
Geometric Characteristics ◽  
Woven Structure

This is the first a series of papers on the cylindrical orthotropic thermal conductivity of spiral woven composites. The geometric characteristics of spiral woven composites are modelled in the present study. A single layer of spiral woven fabric is considered as a fundamental structure and used to develop representative models, including round disc and polygon ones. In these representative models, crimps, cross-sections, and radial and circumferential arrangements of yarns are illustrated by cosine and arc yarn shape functions. A trapezoidal unit cell extracted from a polygon model will provide the next project in the series, with basic geometric parameters to develop thermal models for determining the thermal conductivities of spiral woven composites.

Sign in / Sign up

Export Citation Format

Share Document