Predictions of the axial tensile property of the unidirectional composite influenced by microfiber breakage defects

2021 ◽  
pp. 004051752110342
Author(s):  
Tao Liu ◽  
Yuan Gao ◽  
Wei Fan ◽  
Xingzhong Gao ◽  
Jianhua Ma
Keyword(s):  
Mathematical Model ◽  
Volume Fraction ◽  
Tensile Modulus ◽  
Simulation Method ◽  
Unidirectional Composite ◽  
Fiber Breakage ◽  
Micro Computed Tomography ◽  
Fiber Volume ◽  
Computed Tomography Images ◽  
Defect Volume

This paper primarily investigated the effect of fiber breakage defects on tensile properties of the unidirectional composite (UD) using the numerical simulation method. Different kinds of fiber breakage defects were firstly proved to exist in the UD according to the sub-micro computed tomography images at the microscale level. A strict random uniform distribution hypothesis was then proposed to introduce fiber breakage defects into the composite. Numerous microstructural models within random fiber breakage defects were created with the Monte Carlo method to analyze the fiber breakage defect effect on the UD. The results show that the tensile modulus of the UD was reduced by 17% when the fiber breakage defect volume fraction was only 1%, which indicates the effect of this kind of defect was very significant. The fiber volume fraction, defect volume fraction and property all have influences on the decrease of the UD caused by the fiber breakage defect. Finally, we derived a mathematical model to calculate the tensile modulus of the UD based on the numerical results. The proposed mathematical model has an application on the prediction of the axial modulus of the UD or the fiber tow containing large numbers of fiber breakage defects in the composites with complicated structure.

ACHIEVING REALISTIC TOW FIBER VOLUME FRACTIONS IN TEXTILE COMPOSITE MODELS BY INDUCING FIBER ENTANGLEMENT

2021 ◽  
Author(s):  
GEORGE BARLOW ◽  
MATHEW SCHEY ◽  
SCOTT STAPLETON
Keyword(s):  
Process Simulation ◽  
Manufacturing Process ◽  
Fiber Bundle ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Simulation Method ◽  
Textile Composite ◽  
Compression Pressure ◽  
Fiber Volume ◽  
Composite Models

Modeling composites can be an effective way to understand how a part will perform without requiring the destruction of costly specimens. By combining artificial fiber entanglement with manufacturing process simulation, a method was developed to create fiber bundle models using entanglement to control the fiber volume fraction. This fiber entanglement generation uses three parameters, probability of swapping (p_(r_S )), swapping radius standard deviation (r_(σ_S )), and the swapping plane spacing (l_S), to control the amount of entanglement within the fiber bundle. A parametric study was conducted and found that the more entanglement within a fiber bundle, the more compression mold pressure required to compact the fiber bundle to the same fiber volume fraction as that required for a less entangled bundle. This artificial fiber entanglement and manufacturing process simulation method for creating fiber bundles shows the potential to be able to create bundles with controlled final volume fraction using a desired mold compression pressure.

Semianalytical compressive strength criteria for unidirectional composites

2017 ◽  
Vol 37 (4) ◽  
pp. 238-246
Author(s):  
Uri Breiman ◽  
Jacob Aboudi ◽  
Rami Haj-Ali
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Volume Fraction ◽  
Unidirectional Composite ◽  
Fiber Volume ◽  
Unidirectional Composites ◽  
Analysis And Design ◽  
Composite Systems ◽  
Wide Range ◽  
Laminated Structures

The compressive strength of unidirectional composites is strongly influenced by the elastic and strength properties of the fiber and matrix phases, as well as by the local geometrical properties, such as fiber volume fraction, misalignment, and waviness. In the present investigation, two microbuckling criteria are proposed and examined against a large volume of measured data of unidirectional composites taken from the literature. The first criterion is based on the compressive strength formulation using the buckling of Timoshenko’s beam. It contains a single parameter that can be determined according to the best fit to experimental data for various types of polymeric matrix composites. The second criterion is based on buckling-wave propagation analogy using the solution of an eigenvalue problem. Both criteria provide closed-form expressions for the compressive strength of unidirectional composites. We propose modifications of the two criteria by a fitting approach, for a wide range of fiber volume fractions, applied to four classes of unidirectional composite systems. Furthermore, a normalized form of the two models is presented after calibration in order to compare their prediction against experimental data for each of the material systems. The new modified criteria are shown to give a good match to a wide range of unidirectional composite systems. They can be employed as practical compression failure criteria in the analysis and design of laminated structures.

Micro-computed tomography analysis of natural fiber and bio-matrix tubular-braided composites

2019 ◽  
Vol 53 (28-30) ◽  
pp. 4003-4013 ◽  
Author(s):  
Brianna M Bruni-Bossio ◽  
Garrett W Melenka ◽  
Cagri Ayranci ◽  
Jason P Carey
Keyword(s):  
Computed Tomography ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Void Content ◽  
Micro Computed Tomography ◽  
Braided Composites ◽  
Fiber Volume ◽  
Increasing Demand ◽  
Materials Used ◽  
Curing Method

There is an increasing demand for the use of “green”-based materials as reinforcement and matrix materials in composites. However, the ability of these natural-based materials to perform as consistently and reliably as conventional materials is still relatively unknown. A key importance in the viability of these materials is the evaluation of the content of voids and imperfections, which may affect the properties of the entire composite. In this study, the microstructure of tubular-braided composites manufactured from cellulose fibers and a partially bio-derived resin was studied with the use of micro-computed tomography. These methods were used to determine the effect of modifying braid angle, resin type, and curing method on fiber volume fraction, void volume, and void distribution. It was determined that the void content increased with the increase in braid angle, and vacuum-bagging reduced the total void content. The sample with the smallest braid angle produced with vacuum-bagged curing contained a void fraction of 1.5%. The results of this study proved that the materials used could be viable for further testing and development and that micro-computed tomography imaging is valuable for identifying how to improve consistency and minimize imperfections to create more accurate and reliable natural fiber-braided composites.

Analysis of Composite Plates Containing Cracks

1992 ◽  
Vol 114 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Y. W. Kwon
Keyword(s):  
Stress Intensity Factor ◽  
Material Properties ◽  
Composite Plate ◽  
Crack Tip ◽  
Composite Plates ◽  
Unidirectional Composite ◽  
Matrix Crack ◽  
Fiber Breakage ◽  
Fiber Volume ◽  
Element Analysis

Effect of microcracks, such as local matrix crack and fiber breakage, on a macroscale crack in a unidirectional composite plate was studied for various fiber volume fractions, as well as different material properties of fiber and matrix materials. A finite element analysis was performed for this study. It showed that microcracks, located near a macroscale crack tip, resulted in a significant increase of stress intensity factor at the crack tip.

Analysis of yarn fiber volume fraction in textile composites using scanning electron microscopy and X-ray micro-computed tomography

2018 ◽  
Vol 38 (5) ◽  
pp. 199-210 ◽  
Author(s):  
Xiu-Wei Yu ◽  
Hao Wang ◽  
Zhong-Wei Wang
Keyword(s):  
Electron Microscopy ◽  
Computed Tomography ◽  
Scanning Electron Microscopy ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Textile Composites ◽  
Micro Computed Tomography ◽  
Fiber Volume ◽  
Cross Sectional ◽  
Scanning Electron

Variation of yarn fiber volume fraction, induced by the compression between adjacent yarns during the manufacturing process of textile composites, is difficult to be determined by using a single imaging method. A method combining scanning electron microscopy and micro-computed tomography is proposed to quantify the variation of yarn fiber volume fraction of textile composites, which is decomposed into systematic trend and stochastic deviation. The method takes the advantages of high resolution of scanning electron microscopy and wide 3D view of micro-computed tomography. Average fiber cross-sectional areas are acquired by analyzing hundreds of fiber cross-sectional areas in scanning electron microscopic images. Yarn cross-sectional area is determined by fitting ellipse to the labeled yarn cross-section in slices of micro-computed tomography images. The results of E-glass/epoxy and carbon/epoxy specimens show that their systematic trends of yarn fiber volume fraction combined with standard deviations of stochastic deviation, relative to the respective global means, fluctuate between [−11.4%, 15.3%] and [−12.9%, 10.7%], respectively. Yarn FVF varies in specimen obviously and needs to be considered in mechanical property prediction.

Microstructural analysis of melt-blown nonwoven fabric by X-ray micro computed tomography

2018 ◽  
Vol 89 (9) ◽  
pp. 1734-1747
Author(s):  
Tatsuya Ishikawa ◽  
Yujiro Ishii ◽  
Yutaka Ohkoshi ◽  
Kyoung Hou Kim
Keyword(s):  
Computed Tomography ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Diameter ◽  
Nonwoven Fabric ◽  
Micro Computed Tomography ◽  
Machine Direction ◽  
Melt Blowing ◽  
Fiber Volume ◽  
X Ray

The structures of melt-blown nonwoven fabric, including the fiber volume fraction and fiber orientation, are decided by the melt-blowing conditions, such as the die-to-collector distance (DCD), air suction and air flow rate. In this study, the effects of these melt-blowing conditions on the structure of melt-blown fabric was investigated by X-ray micro computed tomography with a resolution of 1 µm/voxel and a measurement area of 1 mm2. The structural profile along the thickness direction of the fabric was also analyzed. Obtained averages of fiber diameter and basis weight were almost identical to the results of scanning electron microscopy measurements and tests following the standard of International Organization for Standardization. Samples produced with insufficient air suction showed larger deviation of basis weight on the 1 mm2 scale compared with those produced with sufficient air suction. The fiber volume fraction changed steeply around the fabric surface, which was attributed to surface roughness. Insufficient DCD increased the fiber diameter and surface roughness, and decreased the thickness of the fabric. The fiber volume fraction gradually decreased from the collector side to the die side for fabrics with sufficient DCD. The fibers were oriented along the machine direction rather than the cross-machine direction for all layers and samples, and orientation profiles corresponded to the zero-span tensile strength of corresponding samples.

Manufacture and Characteristics of Fibrous Composite Z-Pins

2010 ◽  
Vol 33 ◽  
pp. 110-113 ◽  
Author(s):  
Xu Xu Wang ◽  
Li Chen
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fibrous Composite ◽  
Tensile Modulus ◽  
Elongation Rate ◽  
Aramid Fiber ◽  
Thickness Direction ◽  
Fiber Volume

Z-pins are thin fibrous composite or metallic rods that could increase the strength of laminated composites in the thickness direction. In this paper, three kinds of composite z-pins were made by improved pultrusion method. The length of pultrusion die is shortened to 30mm with no function of curing. The curing equipment is individual control drying ovens. And then, tensile properties of z-pins were reported as well as the appearance and fiber content. Results show that three kinds of z-pins have good flexural resilience. The fiber volume fraction is around 60%. Carbon fiber z-pin has smoother surface than aramid fiber z-pin. And, The thinner z-pin corresponds to the higher tensile strength and tensile modulus. The elongation rate of aramid fiber z-pin is greater than that of carbon fiber one.

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.

Establishing RVE model composed of dry fibers and matrix for 3D four-directional braided composites

2018 ◽  
Vol 53 (14) ◽  
pp. 1917-1931 ◽  
Author(s):  
Long Zhang ◽  
Dianyin Hu ◽  
Rongqiao Wang ◽  
Yuqi Zeng ◽  
Chongdu Cho
Keyword(s):  
Volume Fraction ◽  
Tensile Modulus ◽  
Good Prediction ◽  
Braided Composites ◽  
Fiber Volume ◽  
Numerical Application ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Good Prediction Accuracy ◽  
Braiding Angle

Traditional representative volume element (RVE) model composed of impregnated yarns and surrounding matrix for the 3D four-directional braided composites, requires periodic mesh in order to impose periodic boundary condition, which is quite challenging and time-consuming due to complex internal mesoscopic architecture. In this regard, this study presents a novel approach to establish a parametric RVE model comprised of dry fibers and matrix through integrating Matlab with Abaqus. The technique is able to produce RVE models of arbitrary braiding angle, fiber volume fraction, etc. by simply changing the input values for the Matlab procedure. Based on this, finite element analysis is performed on the proposed model to predict tensile modulus of the 3D four-directional braided composites and examine the influence of mesoscopic geometry and material parameters. Numerical application demonstrates that this technique has good prediction accuracy for the small braiding angle case while great deviation for the big braiding angle case. In the end, the technique’s advantages and disadvantages over the traditional RVE model, and its potential applications are discussed.

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