A fiber network model to understand the effects of fiber length and height on the deformation of fibrous materials

2016 ◽  
Author(s):  
Alp Karakoç ◽  
Keyword(s):  
Network Model ◽  
Fiber Length ◽  
Fibrous Materials ◽  
Fiber Network

A Model of Stress and Strain in the Interosseous Ligament of the Forearm Based on Fiber Network Theory

2006 ◽  
Vol 128 (5) ◽  
pp. 725-732 ◽  
Author(s):  
H. James Pfaeffle ◽  
Kenneth J. Fischer ◽  
Arun Srinivasa ◽  
Theodore Manson ◽  
Savio L-Y. Woo ◽  
...  
Keyword(s):  
Network Model ◽  
Network Theory ◽  
Three Dimensional ◽  
Experimental Result ◽  
Stress And Strain ◽  
Forearm Rotation ◽  
Fiber Network ◽  
Interosseous Ligament

Fiber network theory was developed to describe cloth, a thin material with strength in the fiber directions. The interosseous ligament (IOL) of the forearm is a broad, thin ligament with highly aligned fibers. The objectives of this study were to develop a model of the stress and strain distributions in the IOL, based on fiber network theory, to compare the strains from the model with the experimentally measured strains, and to evaluate the force distribution across the ligament fibers from the model. The geometries of the radius, ulna, and IOL were reconstructed from CT scans. Position and orientation of IOL insertion sites and force in the IOL were measured during a forearm compression experiment in pronation, neutral rotation, and supination. An optical image-based technique was used to directly measure strain in two regions of the IOL in neutral rotation. For the network model, the IOL was represented as a parametric ruled three-dimensional surface, with rulings along local fiber directions. Fiber strains were calculated from the deformation field, and fiber stresses were calculated from the strains using average IOL tensile properties from a previous study. The in situ strain in the IOL was assumed uniform and was calculated so that the net force predicted by the network model in neutral rotation matched the experimental result. The net force in the IOL was comparable to experimental results in supination and pronation. The model predicted higher stress and strain in fibers near the elbow in neutral rotation, and higher stresses in fibers near the wrist in supination. Strains in neutral forearm rotation followed the same trends as those measured experimentally. In this study, a model of stress and strain in the IOL utilizing fiber network theory was successfully implemented. The model illustrates variations in the stress and strain distribution in the IOL. This model can be used to show surgeons how different fibers are taut in different forearm rotation positions—this information is important for understanding the biomechanical role of the IOL and for planning an IOL reconstruction.

Fiber Network Model for Reduced Order Composite Microstructural Models

2022 ◽  
Author(s):  
Scott E. Stapleton ◽  
Sagar Shah ◽  
Micheal Donovan
Keyword(s):  
Network Model ◽  
Fiber Network ◽  
Reduced Order

scholarly journals Percolation of collagen stress in a random network model of the alveolar wall

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dylan T. Casey ◽  
Samer Bou Jawde ◽  
Jacob Herrmann ◽  
Vitor Mori ◽  
J. Matthew Mahoney ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Network Model ◽  
Random Network ◽  
Collagen Fibers ◽  
Tissue Mechanics ◽  
Alveolar Wall ◽  
Stress Strain ◽  
Fiber Network ◽  
Strain Behavior ◽  
Nonlinear Stress

AbstractFibrotic diseases are characterized by progressive and often irreversible scarring of connective tissue in various organs, leading to substantial changes in tissue mechanics largely as a result of alterations in collagen structure. This is particularly important in the lung because its bulk modulus is so critical to the volume changes that take place during breathing. Nevertheless, it remains unclear how fibrotic abnormalities in the mechanical properties of pulmonary connective tissue can be linked to the stiffening of its individual collagen fibers. To address this question, we developed a network model of randomly oriented collagen and elastin fibers to represent pulmonary alveolar wall tissue. We show that the stress–strain behavior of this model arises via the interactions of collagen and elastin fiber networks and is critically dependent on the relative fiber stiffnesses of the individual collagen and elastin fibers themselves. We also show that the progression from linear to nonlinear stress–strain behavior of the model is associated with the percolation of stress across the collagen fiber network, but that the location of the percolation threshold is influenced by the waviness of collagen fibers.

The effect of fiber dimensions on fiber network activation and tensile strength

Holzforschung ◽  
2012 ◽  
Vol 66 (1) ◽  
Author(s):  
Iiro Pulkkinen ◽  
Ville Alopaeus
Keyword(s):  
Tensile Strength ◽  
Wall Thickness ◽  
Fiber Length ◽  
Fiber Quality ◽  
Pulp Fibers ◽  
Fiber Network ◽  
Network Activation ◽  
Fiber Wall ◽  
Technical Properties ◽  
Comparison Of The Results

Abstract The objective of this work was to check the fiber network activation parameter developed earlier by the authors for eucalypt pulp fibers to predict technical properties of paper. The fiber size analyses were performed with an optical fiber analyzer that applies 2D image analysis techniques on single fibers. The effects of fiber length, fiber width, fiber wall thickness, and fiber curl distributions on the quality potential of eucalypt fibers were evaluated. Fiber curl and fiber wall thickness based parameters were found to have a high potential for evaluation of eucalypt fiber quality. The variations in technical properties of paper were explained with differences in fiber wall thickness and fiber curl distributions. When the model was tested against industrial long fiber pulps, a further modification for fiber length was needed. The Page tensile strength model and the shear-lag theory were applied for comparison of the results obtained by the network activation model. With the approach presented in this article, the strength characteristics of hardwood and softwood pulps can be easily evaluated based on fiber geometry and water retention value.

Local Response of Actin Networks is Controlled by Tensile Strains in the Stress-Fibers: Insights From a Discrete Network Model

2019 ◽  
Vol 11 (08) ◽  
pp. 1950072
Author(s):  
Naeem Zolfaghari ◽  
Mahdi Moghimi Zand ◽  
Roozbeh Dargazany
Keyword(s):  
Network Model ◽  
Random Network ◽  
Initial Response ◽  
Shear Loading ◽  
Elastic Response ◽  
Fibrous Materials ◽  
Actin Networks ◽  
Fibrous Network ◽  
Cross Links ◽  
Tensile Strains

Using a discrete random network model of the actin cytoskeleton, we studied the effect of stretching of a stiff-fiber on the elastic response of a fibrous network. In real networks, this component can either be a stress-fiber, bundle of fibers within the network, or a microtubule. We analyze the response of this network due to shear loads while the stiff component is under or free of tensile strains. It is observed that the initial response of this network under shear loading is highly dependent on the amount of tensile strain in the stiff-fiber. In addition, the response depends on the amount and the direction of the shear loading, which is either a softening or a stiffening response depending on the loading direction. As a result, the apparent shear modulus of the network containing a preloaded stiff-fiber may become larger or smaller compared to a network with a relaxed stiff-fiber. This effect intensifies for higher levels of tensile strains in the stiff-fiber and for stiffer cross-links, and lessens for higher network densities. The results of the current research are useful in deciphering the response of soft fibrous materials such as the cell cytoskeleton or other networks comprising a random fibrous network containing a stiffer component than the main fibers of the network.

Deeper insight into the morphological features of sunflower stalk as Biorefining criteria for sustainable production

2019 ◽  
Vol 34 (3) ◽  
pp. 250-263
Author(s):  
Hassan Mehdikhani ◽  
Hossein Jalali Torshizi ◽  
Mohammad Dahmardeh Ghalehno
Keyword(s):  
Wall Thickness ◽  
Fiber Length ◽  
Agricultural Waste ◽  
Lumen Diameter ◽  
Eucalyptus Species ◽  
Fibrous Materials ◽  
Shape Factors ◽  
Chemical Treatments ◽  
Flexibility Coefficient ◽  
Rigidity Coefficient

Abstract Effective utilization of fibrous materials plays a major role in techno-economic viability of the resources. Sunflower stalk (SS) as one of highest bio-fibrous waste was assessed respect to fiber features in biorefinery approach. The lumen diameter, wall thickness and fiber length were measured as (∼12 µm), (5.25 µm) and (1.58 mm), respectively. The wider lumen diameter makes its suitable for chemical treatments and purification. The applied Pulping conditions decreased the fiber length and wall thickness, with the least reduction by soda-anthraquinone. Derived indices involved rigidity and flexibility coefficients, aspect and Runkel ratios, solid and Luce’s shape factors were also calculated based on the measured values. The aspect ratio (77.5) put SS fibers as very good resources for lignocellulosic products and composites. The flexibility coefficient (57) belongs to the elastic category and was not altered by pulping. The Runkel ratio was lesser than 1 (>0.9) but decreased by the pulping, to some extent. The Luceʼs shape factor was nearly calculated 0.5, near to the bagasse and eucalyptus species. Solid factor (0.17) and rigidity coefficient (0.51) were considered to be good fiber resource. Totally due to the SS fiber characteristics, the agricultural waste suitability for value adding bio-based production could be reported.

scholarly journals Compression Strength Mechanisms of Low-Density Fibrous Materials

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 384 ◽  
Author(s):  
Jukka Ketoja ◽  
Sara Paunonen ◽  
Petri Jetsu ◽  
Elina Pääkkönen
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Regenerated Cellulose ◽  
Low Density ◽  
Fibrous Materials ◽  
High Speed Imaging ◽  
Fiber Network ◽  
Fiber Networks ◽  
Fiber Materials ◽  
Heterogeneous Deformation

In this work we challenge some earlier theoretical ideas on the strength of lightweight fiber materials by analyzing an extensive set of foam-formed fiber networks. The experimental samples included various different material densities and different types of natural and regenerated cellulose fibers. Characterization of the samples was performed by macroscopic mechanical testing, supported by simultaneous high-speed imaging of local deformations inside a fiber network. The imaging showed extremely heterogeneous deformation behavior inside a sample, with both rapidly proceeding deformation fronts and comparatively still regions. Moreover, image correlation analysis revealed frequent local fiber dislocations throughout the compression cycle, not only for low or moderate compressive strains. A new buckling theory including a statistical distribution of free-span lengths is proposed and tested against the experimental data. The theory predicts universal ratios between stresses at different compression levels for low-density random fiber networks. The mean ratio of stresses at 50% and 10% compression levels measured over 57 different trial points, 5.42 ± 0.43, agrees very well with the theoretical value of 5.374. Moreover, the model predicts well the effect of material density, and can be used in developing the properties of lightweight materials in novel applications.

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