Improving Hygrothermal Performance in Epoxy-Biofibre Composites

Confocal microscopy and water diffusivity measurements were used to characterise the development of defects in biofibre-reinforced composite materials. Biofibres swelled more than the matrix when the specimen was immersed in water, but the associated distortion of the matrix rarely caused defects. The biofibres shrank faster than the matrix when the specimen was dried in air, causing debonding at the fibre-matrix interfaces and microcracks within the fibres. We started with coarse technical fibres from the leaves of harakeke (Phormium tenax), treated a portion with 1% NaOH, and pulped a portion at 170 °C. Water diffusivities for the corresponding composites increased over the first 3 wet-dry cycles, particularly for the composite made with untreated fibre, but were too small to be of concern for the composite made from pulped fibre.

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A Study of the Fiber-Matrix Interface in Composite Materials

Journal of Applied Mechanics ◽

10.1115/1.2899482 ◽

1992 ◽

Vol 59 (2S) ◽

pp. S163-S165 ◽

Cited By ~ 1

Author(s):

Jin O. Kim ◽

Haim H. Bau

Keyword(s):

Composite Materials ◽

Experimental Technique ◽

Stress Waves ◽

Matrix Interface ◽

Fiber Reinforced ◽

Fiber Reinforced Composite ◽

Reinforced Composite ◽

The Matrix ◽

Fiber Matrix Interface ◽

Dispersion And Attenuation

A novel experimental technique for studying the characteristics of the interface between the fibers and the matrix in both undamaged and damaged fiber-reinforced composite materials is described. The experimental technique involves the transmission of stress waves in one or more fibers of the composite. The characteristics of the stress waves, such as speed, dispersion, and attenuation, are measured. These measured variables can be correlated with the characteristics of the bonding between the fiber and the matrix.

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An analysis of piezoelectric composite materials containing ellipsoidal inhomogeneities

Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences ◽

10.1098/rspa.1993.0145 ◽

1993 ◽

Vol 443 (1918) ◽

pp. 265-287 ◽

Cited By ~ 185

Keyword(s):

Composite Materials ◽

Effective Properties ◽

Mean Field ◽

Piezoelectric Medium ◽

Piezoelectric Composite ◽

High Concentration ◽

Reinforced Composite ◽

The Matrix ◽

Eshelby’S Tensor ◽

Piezoelectric Solids

A set of four tensors corresponding to Eshelby’s tensor in elasticity are obtained for an ellipsoidal inclusion embedded in an infinite piezoelectric medium. These tensors, which describe the elastic, piezoelectric, and dielectric constraint of the matrix, are obtained from W. F. Deeg’s solution to inclusion and inhomogeneity problems in piezoelectric solids. These tensors are then used as the backbone in the development of a micromechanics theory to predict the effective elastic, dielectric, and piezoelectric moduli of particle and fibre reinforced composite materials. The effects of interaction among inhomogeneities at finite concentrations are approximated through the Mori-Tanaka mean field approach. This approach, although widely utilized in the study of uncoupled elastic and dielectric behaviour, has not before been applied to the study of coupled behaviour. To help ensure confidence in the theory, the analytical predictions are proven to be self-consistent, diagonally symmetric, and to exhibit the correct behaviour in the low and high concentration limits. Finally, numerical results are presented to illustrate the effects of the concentration, shape, and material properties of the reinforcement on the effective properties of piezoelectric composites and analytical predictions are shown to result in good agreement with existing experimental data.

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Carbon Fiber Polymer Composites

Quality Production Improvement - QPI ◽

10.2478/cqpi-2019-0037 ◽

2019 ◽

Vol 1 (1) ◽

pp. 276-280

Author(s):

Lenka Markovičová ◽

Viera Zatkalíková ◽

Patrícia Hanusová

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

Carbon Fiber ◽

Polymer Composite ◽

Fiber Orientation ◽

Environmental Damage ◽

Fiber Reinforced ◽

Fiber Reinforced Composite ◽

Reinforced Composite ◽

The Matrix

Abstract Carbon fiber reinforced composite materials offer greater rigidity and strength than any other composites, but are much more expensive than e.g. glass fiber reinforced composite materials. Continuous fibers in polyester give the best properties. The fibers carry mechanical loads, the matrix transfers the loads to the fibers, is ductile and tough, protect the fibers from handling and environmental damage. The working temperature and the processing conditions of the composite depend on the matrix material. Polyesters are the most commonly used matrices because they offer good properties at relatively low cost. The strength of the composite increases along with the fiber-matrix ratio and the fiber orientation parallel to the load direction. The longer the fibers, the more effective the load transfer is. Increasing the thickness of the laminate leads to a reduction in the strength of the composite and the modulus of strength, since the likelihood of the presence of defects increases. The aim of this research is to analyze the change in the mechanical properties of the polymer composite. The polymer composite consists of carbon fibers and epoxy resin. The change in compressive strength in the longitudinal and transverse directions of the fiber orientation was evaluated. At the same time, the influence of the wet environment on the change of mechanical properties of the composite was evaluated.

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The Effects of Ultrasonic Treatment on Fiber-Reinforced Composite Materials

ASME 2009 International Manufacturing Science and Engineering Conference, Volume 1 ◽

10.1115/msec2009-84149 ◽

2009 ◽

Author(s):

Chad Braver ◽

Matthew Tumey ◽

Adam Harlow ◽

Qingyou Han

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

Ultrasonic Treatment ◽

Void Content ◽

Fiber Reinforced ◽

Fiber Reinforced Composite ◽

Three Point Bending ◽

Reinforced Composite ◽

The Matrix ◽

Reinforcement Fiber

The mechanical properties of fiber-reinforced composite materials are highly dependent on proper saturation of the resin within the reinforcement fibers. The research evaluates the effect of ultrasonic treatment during composite curing, in an effort to increase interlaminar bonding strength, lower void content, and improve the matrices ability to transfer stresses to the reinforcement fiber. The testing methods that were performed evaluated the effects or the ultrasonic treatment on the specimen in three point bending, and shear between layers of the matrix. The mechanical properties and the microstructure of the test specimen are discussed.

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Computer Simulation Model for Multi-Size Spherical Particles Reinforced Composite Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.508.361 ◽

2012 ◽

Vol 508 ◽

pp. 361-364 ◽

Cited By ~ 1

Author(s):

Zhuo Chen ◽

Zhi Xiong Huang ◽

Rong Yang Dou ◽

Jing Dai ◽

Min Xian Shi ◽

...

Keyword(s):

Computer Simulation ◽

Composite Materials ◽

Simulation Model ◽

Volume Fraction ◽

Particle Volume Fraction ◽

Spherical Particles ◽

Computer Simulation Model ◽

Particle Volume ◽

Reinforced Composite ◽

The Matrix

In this Research a Method for Computer Simulation Model of Composite Materials, which Are Reinforced by Multi-Size Particles, Is Introduced. All Particles Are Embedded in the Matrix Randomly. Composite of Different Particle Volume Fraction Were Simulated and Visualized. Statistic Results Shows that the Particles Disperse Distribution Are Uniform which Could Be Used in the Further Study of Composite.

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Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

Archives of Foundry Engineering ◽

10.2478/afe-2013-0037 ◽

2013 ◽

Vol 13 (2) ◽

pp. 59-63 ◽

Cited By ~ 4

Author(s):

J.W. Kaczmar ◽

K. Granat ◽

K. Naplocha ◽

A. Kurzawa ◽

E. Grodzka ◽

...

Keyword(s):

Composite Materials ◽

Elevated Temperatures ◽

Bending Strength ◽

Copper Matrix ◽

Casting Method ◽

Bending Tests ◽

Three Point Bending ◽

Infiltration Pressure ◽

The Matrix ◽

Fibre Matrix

Abstract Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu - 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300oC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

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In-Situ Observations of Microscale Ductility in a Quasi-Brittle Bulk Scale Epoxy

Polymers ◽

10.3390/polym12112581 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2581 ◽

Cited By ~ 1

Author(s):

Olivier Verschatse ◽

Lode Daelemans ◽

Wim Van Paepegem ◽

Karen De Clerck

Keyword(s):

Plastic Deformation ◽

Composite Materials ◽

Epoxy Resin ◽

Deformation Behavior ◽

Fiber Reinforced Composite ◽

Reinforced Composite ◽

Reinforcing Fibers ◽

The Matrix ◽

Bulk Scale

Fiber reinforced composite materials are typically comprised of two phases, i.e., the reinforcing fibers and a surrounding matrix. At a high volume fraction of reinforcing fibers, the matrix is confined to a microscale region in between the fibers (1–200 µm). Although these regions are interconnected, their behavior is likely dominated by their micro-scale. Nevertheless, the characterization of the matrix material (without reinforcing fibers) is usually performed on macroscopic bulk specimens and little is known about the micro-mechanical behavior of polymer matrix materials. Here, we show that the microscale behavior of an epoxy resin typically used in composite production is clearly different from its macroscale behavior. Microscale polymer specimens were produced by drawing microfibers from vitrifying epoxy resin. After curing, tensile tests were performed on a large set of pure epoxy microfiber specimens with diameters ranging from 30 to 400 µm. An extreme ductility was observed for microscale epoxy specimens, while bulk scale epoxy specimens showed brittle behavior. The microsized epoxy specimens had a plastic deformation behavior resulting in a substantially higher ultimate tensile strength (up to 380 MPa) and strain at break (up to 130 %) compared to their bulk counterpart (68 MPa and 8%). Polarized light microscopy confirmed a rearrangement of the internal epoxy network structure during loading, resulting in the plastic deformation of the microscale epoxy. This was further accompanied by in-situ electron microscopy to further determine the deformation behavior of the micro-specimens during tensile loading and make accurate strain measurements using video-extensometry. This work thus provides novel insights on the epoxy material behavior at the confined microscale as present in fiber reinforced composite materials.

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