Evaluation of mechanical properties of fiber reinforced composites filled with hollow spheres: A micromechanics approach

Recent researches show that the embedment of hollow spheres in the matrix phase of composite materials improves the strength of these structures against crack propagations. Rare studies are reported for calculating equivalent elastic constants of fiber reinforced composites containing hollow spheres. In this paper, the effects of hollow spheres on mechanical characteristics of fiber reinforced composite are studied for the first time. To achieve this aim, a micromechanics based finite element method is employed. Representative volume elements (RVEs) including hollow spheres with different radius, thickness and volume fraction of hollow spheres, are modeled by using 3D finite elements. The equivalent elastic constants are calculated through homogenization technique. The results are compared with available experimental works. Good agreements find between two sets of results. Also, the volume fraction, number and thickness of hollow spheres as effective parameters on mechanical properties of composite were investigated. The results show the equivalent elastic properties increase with increasing the volume fraction and number of hollow spheres and decrease with increasing the number of hollow spheres. Furthermore, the equivalent Young’s modulus in transverse directions to the fiber direction and shear modulus of the composite increase with increasing the thickness of hollow spheres. As a final result, the presence of hollow spheres in the matrix phase generally increases the equivalent elastic constants without significant changes in the weight of structures.

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Prediction of Orthotropic Hygroscopic Swelling of Fiber-Reinforced Composites from Isotropic Swelling of Matrix Polymer

Journal of Composites Science ◽

10.3390/jcs3010010 ◽

2019 ◽

Vol 3 (1) ◽

pp. 10 ◽

Cited By ~ 2

Author(s):

Andrey Krauklis ◽

Abedin Gagani ◽

Andreas Echtermeyer

Keyword(s):

Volume Fraction ◽

Fiber Reinforced Composites ◽

Fiber Direction ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Fiber Volume ◽

Element Analysis ◽

Matrix Polymer ◽

Hygroscopic Swelling ◽

The Matrix

Swelling in fiber-reinforced composites is anisotropic. In this work, dealing with glass fiber epoxy composite immersed in distilled water, swelling coefficients are obtained in each direction experimentally. Swelling behaviour in the fiber direction was constrained by the non-swelling fibers and was close to null, while swelling in the transverse directions was found to occur freely—similar to the unconstrained polymer. An analytical method for predicting anisotropic swelling in composites from the swelling of the matrix polymer is reported in this work. The method has an advantage that it is simple to use in practice and requires only a swelling coefficient of the matrix polymer, elastic constants of the matrix and fibers, and a known fiber volume fraction of the composite. The method was validated using finite element analysis. Good agreement was obtained and is reported between experimental hygroscopic swelling data, analytical and numerical results for composite laminates, indicating the validity of this predictive approach.

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Efficient Hydrophobic Modification of Old Newspaper and Its Application in Paper Fiber Reinforced Composites

Polymers ◽

10.3390/polym11050842 ◽

2019 ◽

Vol 11 (5) ◽

pp. 842 ◽

Cited By ~ 4

Author(s):

Weiwei Zhang ◽

Jin Gu ◽

Dengyun Tu ◽

Litao Guan ◽

Chuanshuang Hu

Keyword(s):

Mechanical Properties ◽

Aspect Ratio ◽

Natural Fiber ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Oh Groups ◽

Uniform Dispersion ◽

The Matrix ◽

Paper Fibers

Paper fibers have gained broad attention in natural fiber reinforced composites in recent years. The specific problem in preparing paper fiber reinforced composites is that paper fibers easily become flocculent after pulverization, which increases difficulties during melt-compounding with polymer matrix and results in non-uniform dispersion of paper fibers in the matrix. In this study, old newspaper (ONP) was treated with a low dosage of gaseous methyltrichlorosilane (MTCS) to solve the flocculation. The modified ONP fibers were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TG). Then the modified ONP fibers and high-density polyethylene (HDPE) were extruded and pelletized to prepare ONP/HDPE composites via injection molding. Maleic anhydride-grafted polyethylene (MAPE) was added to enhance the interfacial bonding performance with the ultimate purpose of improving the mechanical strength of the composites. The mechanical properties such as tensile, flexural, and impact strength and the water absorption properties of the composite were tested. The results showed that the formation of hydrogen bonding between ONP fibers was effectively prevented after MTCS treatment due to the reduction of exposed –OH groups at the fiber surface. Excessive dosage of MTCS led to severe fiber degradation and dramatically reduced the aspect ratio of ONP fibers. Composites prepared with ONP fibers modified with 4% (v/w) MTCS showed the best mechanical properties due to reduced polarity between the fibers and the matrix, and the relatively long aspect ratio of treated ONP fibers. The composite with or without MAPE showed satisfactory water resistance properties. MTCS was proven to be a cheap and efficient way to pretreat old newspaper for preparing paper fiber reinforced composites.

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Micromechanical evaluation of failure models for unidirectional fiber-reinforced composites

Journal of Composite Materials ◽

10.1177/0021998319867470 ◽

2019 ◽

Vol 54 (6) ◽

pp. 791-800

Author(s):

Azam Arefi ◽

Frans P van der Meer ◽

Mohammad Reza Forouzan ◽

Mohammad Silani ◽

Mahmoud Salimi

Keyword(s):

Matrix Material ◽

Element Model ◽

Failure Criteria ◽

Fiber Reinforced Composites ◽

Fiber Direction ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Wide Range ◽

The Matrix ◽

Stress States

In this paper, micromechanical simulations are employed to evaluate the performance of the Tsai–Wu and Hashin failure criteria for fiber-reinforced composites, especially in stress states whose experimental reproduction is complicated. Micromechanical responses are generated using a finite element model of a representative volume element, in which only the matrix material experiences damage and the fibers are assumed to be elastic. Micromechanical simulations of basic load cases are used to calibrate macrolevel criteria. Finally, the response of the micromodel and macromodels is compared for various load combinations. Despite a good agreement between Tsai–Wu criterion predictions and micromodel results in a wide range of stress states, some stress combinations are highlighted for which the strength is not predicted accurately. Additionally, accuracy of the Hashin criterion suffers from ignoring the influence of stress in fiber direction on matrix failure.

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Large scale fabrication of dumbbell-shaped biomimetic SiC/SiO2 fibers

CrystEngComm ◽

10.1039/c5ce01892g ◽

2015 ◽

Vol 17 (48) ◽

pp. 9318-9322 ◽

Cited By ~ 6

Author(s):

Wenna Liu ◽

Junhong Chen ◽

Kuo-Chih Chou ◽

Xinmei Hou

Keyword(s):

Mechanical Properties ◽

Large Scale ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Interface Adhesion ◽

The Matrix

The mechanical properties of dumbbell-shaped fiber-reinforced composites are expected to be improved via enhancing the interface adhesion between the matrix and the fibers from the viewpoint of biomimetics.

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An Energy-Based Model of Longitudinal Splitting in Unidirectional Fiber-Reinforced Composites

Journal of Applied Mechanics ◽

10.1115/1.1311276 ◽

1999 ◽

Vol 67 (3) ◽

pp. 437-443 ◽

Cited By ~ 9

Author(s):

K. Oguni ◽

G. Ravichandran

Keyword(s):

Volume Fraction ◽

Effective Properties ◽

Confining Pressure ◽

Fiber Reinforced Composites ◽

Fiber Direction ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Fiber Volume ◽

Unidirectional Fiber ◽

Longitudinal Splitting

Unidirectional fiber-reinforced composites are often observed to fail in a longitudinal splitting mode in the fiber direction under far-field compressive loading with weak lateral confinement. An energy-based model is developed based on the principle of minimum potential energy and the evaluation of effective properties to obtain an analytical approximation to the critical stress for longitudinal splitting. The analytic estimate for the compressive strength is used to illustrate its dependence on material properties, surface energy, fiber volume fraction, fiber diameter, and lateral confining pressure. The predictions of the model show good agreement with available experimental data. [S0021-8936(00)02003-1]

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Mechanical Properties of Sisal Fibre Reinforced Polymer Matrix Composite

Mechanics and Mechanical Engineering ◽

10.2478/mme-2018-0025 ◽

2020 ◽

Vol 22 (1) ◽

pp. 295-300 ◽

Cited By ~ 1

Author(s):

A. Francis ◽

S. Rajaram ◽

A. Mohanakrishnan ◽

B. Ashok

Keyword(s):

Mechanical Properties ◽

Natural Fibers ◽

Vital Role ◽

Fiber Reinforced Composites ◽

Sisal Fiber ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Sisal Fibre ◽

The Matrix ◽

Fibre Reinforced Polymer

AbstractThe composite materials plays a vital role in increase the strength and weight reduction purpose. The natural fibers increase the additional strength to the composites. This paper is related to the mechanical properties of the sisal fiber reinforced composites and it is compared with the another preparation of sisal fiber reinforced composite. The graphs shows the comparison about the mechanical properties on the fiber reinforced composites. The strength can be improved by using some melted polypropylene to increase the bonding between the matrix and the fiber. The sample material is immersed in water for twenty four hours and at the same time the properties also measured by using various testing methods. The final comparison indicates the better process for the preparation of the composite.

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Design, Fabrication and Analysis of Advanced Polymer Based Kevlar-49 Composite Material

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.592-594.122 ◽

2014 ◽

Vol 592-594 ◽

pp. 122-127

Author(s):

M. Kaliraj ◽

P. Narayanasamy ◽

M. Rajkumar ◽

M. Mohammed Mohaideen ◽

I. Neethi Manickam

Keyword(s):

Composite Material ◽

Volume Fraction ◽

Fatigue Behavior ◽

Fiber Reinforced Composites ◽

Matrix Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Wide Range ◽

The Matrix ◽

Set Up

The fatigue behavior of reinforced composites is complex and the present knowledge of fatigue study still needs extensive investigation of the micromechanical composite behavior. In fiber reinforced composites mechanical properties are highly dependent on their compositions, the matrix type as well as the volume fraction of the reinforcement and their arrangements such as random orientation and distribution, which increase the complexity in the study of fatigue damage behavior. There exist several classes of models to predict the fatigue life or the fatigue degradation of fiber reinforced composites but there exists so far no fatigue model that can be applied to a wide range of fiber reinforced composites. Thus, modifications of fatigue models are always needed in accordance with the micromechanical behavior of different fiber/matrix composites. In this paper the fatigue failure is rectified by using polymer based Kevlar composite material. The design and fabrication involves the design of polymer matrix like as fiber and resin, hardener etc. Kevlar-49 is chosen for as fabricating material to carry out this work. The fabrication set up is made by Vacuum Bag and it is demonstrated satisfactorily.

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Influences of graphene oxide addition on mechanical properties of aramid fiber reinforced composites

Materials Express ◽

10.1166/mex.2019.1544 ◽

2019 ◽

Vol 9 (6) ◽

pp. 578-586 ◽

Cited By ~ 2

Author(s):

Xiaoma Ding ◽

Ziling Zhang ◽

Haijuan Kong ◽

Mengmeng Qiao ◽

Zhifeng Hu ◽

...

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Tensile Modulus ◽

Aramid Fiber ◽

Matrix Phase ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Stress Concentrations ◽

Test Standards

In this paper, the graphene oxide (GO) was prepared by the modified Hummers' method in advance, and the obtained GO was used as a kind of filler added into the epoxy resin (EP) system (including the EP and corresponding curing agent) with different contents (relative to the total weight of the GO-EP system hybrid) ranging from 0.1 to 0.4 wt% to improve the mechanical properties of the aramid fiber reinforced composites (AFRC) through the autoclave forming technology. Then, a series of mechanical properties of the AFRC were measured according to the relevant test standards. Results showed that partial mechanical properties of the AFRC, especially the interlayer property, changed with the different contents of GO. Nevertheless, the tensile strength and tensile modulus of the AFRC presented no obvious changes for different contents of GO. Overall, the matrix phase EP system modified by the GO played an important role in the interlayer toughness of AFRC without reducing its tensile property. This was because the addition of the small amount of GO could prevent the generation of stress concentrations caused by the gaps between the reinforcing phase aramid fibers (AFs) and matrix phase EP system owing to their poor bondings.

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