Processing technique and geometric model of an imperfect orthogonal 3D braided material

2016 ◽  
Vol 47 (3) ◽  
pp. 297-309 ◽  
Author(s):  
Wensuo Ma ◽  
Zhenyu Ma ◽  
Jianxun Zhu
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Geometric Model ◽  
Processing Technique ◽  
Experimental Results ◽  
Automatic Process ◽  
Fiber Volume ◽  
Representative Volume ◽  
Volume Unit ◽  
3D Orthogonal Woven

A novel 3D braided material was found based on the traditional 3D orthogonal woven process. The mesostructure of novel 3D braided material is similar to the 3D orthogonal woven material, but only coincide in the Z-direction. The processing technique is easy to operate in automatic process. The representative volume unit has been proposed to establish geometric model. The fiber volume fraction of novel 3D braided material is analyzed and its value is higher than the traditional 3D orthogonal woven material ones. The experimental results show that the braided process of the imperfect orthogonal 3D braided material is rational and feasible.

Experimental Research on Stress-Strain Curve of Carbon Fiber Reinforced Concrete

2013 ◽  
Vol 668 ◽  
pp. 640-644 ◽  
Author(s):  
Xiao Chu Wang ◽  
Jun Wei Wang ◽  
Hong Tao Liu
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Fiber Volume ◽  
Stress Strain

In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.

The Tensile Properties of Three Dimensional Air Textured Aramid Reinforced Composites

2003 ◽  
Author(s):  
Thomas Brice Langston ◽  
Yiping Qiu
Keyword(s):  
Tensile Test ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Woven Composites ◽  
Reinforced Composites ◽  
Fiber Volume ◽  
Plane Shear ◽  
3D Orthogonal Woven ◽  
Lower Tensile Strength

Air-textured aramid yarns (ATAY) and regular aramid yarns (RAY) were used in this study to fabricate 3D orthogonal woven composites. The composites were tested in warp, weft, and 45° directions to determine the engineering constants of the composites. The ATAY composite had a much lower fiber volume fraction than the RAY composite due to the bulkiness of the textured yarns. With the same fiber volume fraction, the ATAY composite had a slightly lower tensile strength and modulus, but a 120% higher in-plane shear modulus, than the RAY composite. Unlike the RAY composite that demonstrated a brittle failure, the ATAY composite failed in a ductile manner with multiple diverting cracks propagating during failure. The ATAY composite had a much higher yield point in the 45° direction tensile test and a much higher softening point in the warp direction tensile test than the RAY composite. The loop entanglements of ATAY are responsible for all the improvements observed in this study.

Property Prediction of Composites with Different Fiber Volume Fractions by Representative Volume Element Method

2013 ◽  
Vol 275-277 ◽  
pp. 1605-1609
Author(s):  
Nan Zhang ◽  
Cheng Hong Duan
Keyword(s):  
Elastic Properties ◽  
Representative Volume Element ◽  
Fiber Volume Fraction ◽  
Empirical Equation ◽  
Volume Fraction ◽  
Volume Element ◽  
Fiber Volume ◽  
Finite Element Software ◽  
Representative Volume ◽  
Properties Of Composites

In this paper, a representative volume element (RVE) model of composites with different fiber volume fraction is established by ANSYS finite element software. The stiffness matrix of the RVE model can be calculated by studying its stress field, and then the elastic properties of composites could be obtained. By comparing with the results from NASA empirical equation, the reliability of the method can be proved. This is a new way to predict the elastic properties of composites.

Meso-structure and modeling of a new three-dimensional braided tubular material

2017 ◽  
Vol 37 (5) ◽  
pp. 310-320 ◽  
Author(s):  
Wensuo Ma ◽  
Zhenyu Ma ◽  
Bingjie Ren ◽  
Weifeng Fan
Keyword(s):  
Mathematical Model ◽  
Structural Properties ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Geometrical Parameters ◽  
Fiber Volume ◽  
Space Group ◽  
Volume Unit ◽  
Symmetry Operations

A new three-dimensional braided tubular preform was introduced in this study. The new preform structure can be derived from the representative volume unit which was deduced by the symmetry operations of space group P4. The braiding process of the tubular preform has been discussed. A mathematical model was established to analyze the structural properties of the three-dimensional braided tubular preform. The interrelation of geometrical parameters is analyzed. The fiber volume fraction of the preform was predicted. The new tubular preform was obtained in laboratory to verify the feasibility of the braiding process.

Automatic generation and discretization of fully periodic representative volume elements of plain woven composites

2018 ◽  
Vol 52 (29) ◽  
pp. 4061-4073 ◽  
Author(s):  
Nadine Jendrysik ◽  
Konrad Schneider ◽  
Swantje Bargmann
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Automatic Generation ◽  
Woven Composites ◽  
Reinforced Composites ◽  
Fiber Volume ◽  
Simple Method ◽  
Representative Volume ◽  
Representative Volume Elements ◽  
Practical Feasibility

This paper introduces an efficient and simple method to automatically generate and mesh geometrically parametrized representative volume elements for plain woven fiber-reinforced composites. The presented approach is capable of generating representative volume elements with 10%–55% fiber volume fraction. The practical feasibility of the model is demonstrated on numerical examples for isotropic and anisotropic tow materials which are compared to analytical solutions.

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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