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

2019 ◽  
Vol 3 (1) ◽  
pp. 10 ◽  
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.

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

2020 ◽  
pp. 002199832094964
Author(s):  
Mojde Biarjemandi ◽  
Ehsan Etemadi ◽  
Mojtaba Lezgy-Nazargah
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Volume Fraction ◽  
Hollow Spheres ◽  
Matrix Phase ◽  
Fiber Reinforced Composites ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
The Matrix

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.

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

1999 ◽  
Vol 67 (3) ◽  
pp. 437-443 ◽  
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]

scholarly journals Micromechanical evaluation of failure models for unidirectional fiber-reinforced composites

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.

scholarly journals Natural Composite Reinforced by Lontar (Borassus flabellifer) Fiber: An Experimental Study on Open-Hole Tensile Strength

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Jefri Bale ◽  
Kristomus Boimau ◽  
Marselinus Nenobesi
Keyword(s):  
Tensile Strength ◽  
Unsaturated Polyester ◽  
Specific Area ◽  
Matrix Cracking ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Hole Configuration ◽  
The Matrix

A research has been conducted in the present study to investigate the effect of hole configuration on tensile strength of lontar fiber-reinforced composites. The lontar fiber-reinforced composites used in this study were produced by hand lay-up process. The lontar fiber-reinforced composites consist of short random fiber of 5 cm that contains 32% of nominal fiber volume as the reinforcement and unsaturated polyester as the matrix. The results show that the differences of hole configuration have an effect on tensile strength of lontar fiber-reinforced composites. It is found that the specific area of four-hole specimens experiences smaller strain propagation due to the redistributed stress and no stress passes through the hole. The damage of lontar fiber-reinforced composites with different hole configurations in tension is fairly straight and transverse to the loading axis, where the initial damage occurs in the form of matrix cracking, propagates into interfacial failure in form of delamination, and ultimately failed mainly due to the fiber breakage.

scholarly journals A Stochastic Homogenized Peridynamic Model for Intraply Fracture in Fiber-Reinforced Composites

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Ziguang Chen ◽  
Jiangming Zhao ◽  
Florin Bobaru
Keyword(s):  
Failure Modes ◽  
Volume Fraction ◽  
Crack Opening ◽  
Computational Cost ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Peridynamic Model ◽  
Loading Case

The quasi-static transverse fracture behavior in unidirectional fiber-reinforced composites (FRCs) is investigated using a new intermediately-homogenized peridynamic (IH-PD) model and a fully homogenized peridynamic (FH-PD) model. The novelty in the IH-PD model here is accounting for the topology of the fiber-phase in the transverse sample loading via a calibration to the Halpin-Tsai model. Both models can capture well the measured load-displacement behavior observed experimentally for intraply fracture, without the need for an explicit representation of microstructure geometry of the FRC. The IH-PD model, however, is more accurate and produces crack path tortuosity as well as a non-monotonic load-crack-opening softening curve, similar to what is observed experimentally. These benefits come from the preservation of some micro-scale heterogeneity, stochastically generated in the IH-PD model to match the composite’s fiber volume fraction, while its computational cost is equivalent to that of an FH-PD model. We also present a three-point bending transverse loading case in which the two models lead to dramatically different failure modes: the FH-PD model shows that failure always starts from the off-center pre-notch, while the IH-PD model, when the pre-notch is sufficiently off-center, finds that the composite fails from the center of the sample, not from the pre-notch. Experiments that can confirm these findings are sought.

Tensile Properties of Random Distribution Short SMA Fiber Reinforced Composites

2011 ◽  
Vol 488-489 ◽  
pp. 686-689
Author(s):  
Hong Shuai Lei ◽  
Bo Zhou ◽  
Zhen Qing Wang ◽  
Xiao Qiang Wang
Keyword(s):  
Random Distribution ◽  
Volume Fraction ◽  
Effective Elastic Modulus ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
Three Phase

Shape memory alloy (SMA) reinforced composites have been widely used in aerospace engineering fields. In this paper, four basic assumptions were presented to simply the research model based on the Eshelby’s equivalent inclusion method and Mori-Tanaka scheme. Based on the three-phase equivalent system and two-step equivalent process, the effective elastic modulus and thermal expansion coefficient of unidirectional random distribution short SMA fiber reinforced composites were derived. The tensile mechanical properties of composites with fiber volume fraction (15%), size (L=3, D=1; L=5, D=1), and number (N= 30, 50), were simulated using software ANSYS12.0, and discussed the failure mode of the composites.

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

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.

scholarly journals The Road to Improved Fiber-Reinforced 3D Printing Technology

Technologies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 51
Author(s):  
S M Fijul Kabir ◽  
Kavita Mathur ◽  
Abdel-Fattah M. Seyam
Keyword(s):  
3D Printing ◽  
Structural Integrity ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Fiber Reinforced Composites ◽  
Print Quality ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Polymer Distribution

Three-dimensional printing (3DP) is at the forefront of the disruptive innovations adding a new dimension in the material fabrication process with numerous design flexibilities. Especially, the ability to reinforce the plastic matrix with nanofiber, microfiber, chopped fiber and continuous fiber has put the technology beyond imagination in terms of multidimensional applications. In this technical paper, fiber and polymer filaments used by the commercial 3D printers to develop fiber-reinforced composites are characterized to discover the unknown manufacturing specifications such as fiber–polymer distribution and fiber volume fraction that have direct practical implications in determining and tuning composites’ properties and their applications. Additionally, the capabilities and limitations of 3D printing software to process materials and control print parameters in relation to print quality, structural integrity and properties of printed composites are discussed. The work in this paper aims to present constructive evaluation and criticism of the current technology along with its pros and cons in order to guide prospective users and 3D printing equipment manufacturers on improvements, as well as identify the potential avenues of development of the next generation 3D printed fiber-reinforced composites.

scholarly journals Copper and Nickel Coating of Carbon Fiber for Thermally and Electrically Conductive Fiber Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 823 ◽  
Author(s):  
Simon Bard ◽  
Florian Schönl ◽  
Martin Demleitner ◽  
Volker Altstädt
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Carbon Fibers ◽  
Fiber Reinforced Composites ◽  
Lightning Strike ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Coated Fiber

In this paper, the thermal and electrical conductivity and mechanical properties of fiber reinforced composites produced from nickel- and copper-coated carbon fibers compared to uncoated fibers are presented. The carbon fibers were processed by our prepreg line and cured to laminates. In the fiber direction, the thermal conductivity doubled from ~3 W/mK for the uncoated fiber, to ~6 W/mK for the nickel, and increased six times to ~20 W/mK for the copper-coated fiber for a fiber volume content of ~50 vol %. Transverse to the fiber, the thermal conductivity increased from 0.6 W/mK (uncoated fiber) to 0.9 W/mK (nickel) and 2.9 W/mK (copper) at the same fiber content. In addition, the electrical conductivity could be enhanced to up to ~1500 S/m with the use of the nickel-coated fiber. We showed that the flexural strength and modulus were in the range of the uncoated fibers, which offers the possibility to use them for lightning strike protection, for heatsinks in electronics or other structural heat transfer elements.

The Effect of Interphase Modulus and Thickness on Stress Transfer of Short-Fiber-Reinforced Composites

2011 ◽  
Vol 55-57 ◽  
pp. 303-307 ◽  
Author(s):  
Bin Zhang ◽  
Bo Qin Gu
Keyword(s):  
Stress Distribution ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Stress Transfer ◽  
Short Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
The Matrix

In this paper, the stress distribution of short-fiber-reinforced composites (SFRC) using representative volume element (RVE) approach based on the finite element analysis (FEA) was presented. A three-phase model was built, in which loads were applied to the matrix. The influences of interphase parameters like Young’s modulus and thickness were studied. The FEA confirms that interphase Young’s modulus and thickness control stress distribution in SFRC. The stress concentration at the fiber interface becomes greater with high interphase Young’s modulus and thin interphase thickness. The FEA results were also compared with those obtained by analytic method.

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