scholarly journals Simulation and characterization of circular hexagonal braiding fabricstructure

2020 ◽  
Vol 71 (01) ◽  
pp. 23-27
Author(s):  
LI ZHENGNING ◽  
LYU HAICHEN ◽  
CHEN GE ◽  
KO FRANK
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
State Of The Art ◽  
Fiber Volume ◽  
Fabric Structure ◽  
Stitch Length ◽  
Spatial Coordinates ◽  
Fabric Structures ◽  
Initial Arrangement

Hexagonal braiding technology is a kind of state-of-the-art braiding method, which uses hexagonal horngears to driveyarn carriers and make yarns intertwined into fabrics. In terms of hexagonal braiding principles, the braiding parameterslike initial arrangement of yarn carriers, yarn number and horngears sequence were defined, and then the movementpaths of yarn carriers in hexagonal braiding process and stitch length were obtained, which could be converted intocoordinates on the xoy plane and the coordinates along z-axis. In that case, a group of spatial coordinates were got tocreate the yarn trajectories and fabric structures in Matlab. And then, B-spline curve was utilized to fit the yarntrajectories. Considering the compactness of hexagonal fabric, the coordinates conversion algorithm and conversionmatrix were utilized to optimize the fabric structure, so a more compact fabric structure was established. The braidingangle variation and volume fraction of fabric showed that after coordinates conversion the braiding angles became morestable than original fabric model, and the fiber volume fraction of fabric was improved too. So the fabric structure modelwas available to describe hexagonal fabric structure, which can offer the reference for the further study on properties ofhexagonal braiding technology and application of hexagonal braided fabric

Relation of 2D Permeability and Preform Structure Parameters

2011 ◽  
Vol 306-307 ◽  
pp. 1678-1682
Author(s):  
Jin Hua Jiang ◽  
Nan Liang Chen
Keyword(s):  
Significant Influence ◽  
Linear Density ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Structure Parameters ◽  
Capacitive Sensors ◽  
Two Dimensional ◽  
Flow Front ◽  
Fiber Volume ◽  
Fabric Structure

In this paper the influence of parameters of fabric preforms on permeability is described. The two-dimensional (2D) permeability has been determined continuously in a matched metal tool incorporating capacitive sensors with LabView. Beforehand, the glassfiber plain, twill, satin weave textile has been thoroughly evaluated to determine the permeability behavior of the textile in dependence on the fiber volume fraction. The paper reveals the significant influence of the fabric structure, and yarn linear density on the permeability values K1 and K2, the flow front ellipse shape, and the anisotropy of preforms.

The Characterization of Discontinuous Carbon Fiber Mat Reinforced Epoxy Composite Materials

2015 ◽  
Vol 1110 ◽  
pp. 77-81
Author(s):  
Eun Soo Lee ◽  
Daniel Buecher ◽  
Si Hoon Jang ◽  
Dae Young Lim ◽  
Ki Young Kim
Keyword(s):  
Carbon Fiber ◽  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Void Content ◽  
Reinforced Composites ◽  
Fiber Volume ◽  
Fiber Fabric

The carbon fiber mat preforms are prepared by an air laid method with different fiber lengths of 10mm, 30mm and 50mm to characterize the resultant discontinuous composites. The composites are manufactured by a vacuum assisted resin infusion (VaRI) molding technique with the use of epoxy resins to investigate the effects of carbon fiber length on their physical and mechanical properties. The void content and thickness of the composites decrease with the increase in the fiber length at the same VaRI processing conditions. The tensile, flexural, impact properties of the composites are improved by increasing the fiber length in the textile preforms. By comparing with those of carbon fiber fabric reinforced composites, the discontinuous composites demonstrate the excellent performance in strength and modulus in spite of lower fiber volume fraction.

Characterization of Fiber Volume Fraction Gradients in Composite Laminates

2008 ◽  
Vol 42 (5) ◽  
pp. 447-466 ◽  
Author(s):  
Michael T. Cann ◽  
Daniel O. Adams ◽  
Claudio L. Schneider
Keyword(s):  
Composite Laminates ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Volume

Pressure-controlled compaction characterization of fiber preforms suitable for viscoelastic modeling in the vacuum infusion process

2017 ◽  
Vol 51 (9) ◽  
pp. 1209-1224 ◽  
Author(s):  
Bekir Yenilmez ◽  
Baris Caglar ◽  
E Murat Sozer
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Volume ◽  
Compaction Rate ◽  
Vacuum Infusion ◽  
Viscoelastic Modeling ◽  
A Minor ◽  
Fiber Preforms ◽  
Vacuum Infusion Process

A woven fabric’s compaction in the vacuum infusion process is characterized by applying an initial settling under a minor load, compaction, settling under a major load, decompaction and relaxation. The effects of compaction rate, relaxation pressure, wetting and debulking cycles are all investigated. Although wetting helps by increasing fiber volume fraction insignificantly, its contribution is more significant during debulking cycles by increasing the fiber volume fraction to 57.4% as compared to 55.4% for the debulked dry specimens. Recovery during decompaction is much less than the deformation during compaction, and thinning/thickening of the specimens with time under constant pressure, so called settling/relaxation pressures, indicates that fabric specimens are not elastic materials, but viscoelastic. The experimental data of this study will be valuable to compare different viscoelastic and elastic compaction models in our next study.

Microstructural Characterization of “New” 2.5D Woven Reinforcement Materials

2011 ◽  
Vol 217-218 ◽  
pp. 97-100
Author(s):  
Dian Tang Zhang ◽  
Ying Sun ◽  
Wei Hai ◽  
Li Chen ◽  
Ning Pan
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Fiber Volume ◽  
3D Images ◽  
Geometry Model ◽  
Convex Lens ◽  
Woven Reinforcement ◽  
Prediction Of Mechanical Properties

Based on the photographic observation and analysis of different cross section of the materials, it is found that both the section of normal and warp yarns are rectangular in shape, the sections of weft yarns are the convex lens in shape, the weft and normal yarns are kept straight along their directions, the warp yarns are wavy. 3D images and geometry model of normal yarns reinforced 2.5D woven materials are established. This model can be used to calculate the fiber volume fraction of each yarn system. Compared with the experimental data, the computational results show excellent agreement. The work will lay the foundation for prediction of mechanical properties.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Effect of Fiber Volume Fraction on Behavior of Concrete Beams Made with Recycled Concrete Aggregates

2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda
Keyword(s):  
Fiber Volume Fraction ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Beam Specimen ◽  
Rc Beam ◽  
Fiber Volume ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.

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