The Strength of Fibres in All-Ceramic Composites

1986 ◽  
Vol 78 ◽  
Author(s):  
Kevin Kendall ◽  
N. Mcn. Alford ◽  
J. D. Birchall
Keyword(s):  
Elastic Modulus ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Ceramic Composites ◽  
Fibre Volume ◽  
Matrix Cracking ◽  
Fibre Strength ◽  
All Ceramic ◽  
The Matrix ◽  
Fibre Matrix

ABSTRACTWhen considering the strength of a fibre reinforced ceramic composite, it is often assumed that the fibres retain their full strength of several GPa after cracking of the weaker matrix. The strength of the composite after matrix cracking is then calculated by the rule of mixtures as the product of fibre volume fraction and fibre strength. This paper demonstrates that such a calculation is not consistent with the principles of fracture mechanics for an isolated fibre embedded in an elastic matrix of the same elastic modulus, because the strength of the fibre is much reduced by the stress concentration arising from the matrix crack. Experimental measurements of the strength of a glass fibre embedded in a brittle matrix support the theory. The case of a fibre in a matrix of different elastic modulus is also considered, together with the proDlem of cracking along the fibre-matrix interface.

scholarly journals Fabrication and Characterization of Unidirectional Silk Fibre Composites

2011 ◽  
Vol 471-472 ◽  
pp. 20-25 ◽  
Author(s):  
Mansur Ahmed ◽  
Md. Saiful Islam ◽  
Qumrul Ahsan ◽  
Md Mainul Islam
Keyword(s):  
Volume Fraction ◽  
Flexural Modulus ◽  
Fibre Volume Fraction ◽  
Initial Study ◽  
Fibre Volume ◽  
Silk Fibre ◽  
Specific Strength ◽  
Pull Out ◽  
The Matrix ◽  
Strength And Stiffness

Natural fibres offer a number of benefits as reinforcement for synthetic polymers since they have high specific strength and stiffness, high impact strength, biodegradability etc. The aim of this study is to fabricate and determine the performance of unidirectional silk fibre reinforced polymer composites. In the present initial study, alkali treated silk fibres were incorporated as reinforcing agent, while a mixture of 20% maleic anhydride grafted polypropylene (MAPP) and commercial grade polypropylene (PP) was used as matrix element. The unidirectional composites were fabricated by using hot compression machine under specific pressure, temperature and varying fibre loading. Tensile, flexural, impact and hardness tests were carried out by varying silk fibre volume fraction. Composites containing 45% fibre volume fraction had higher tensile and flexural strength, Young’s modulus and flexural modulus compared to other fabricated composites including those with untreated silk fibres. SEM micrographs were taken to examine composite fracture surface and interfacial adhesion between silk fibre and the matrix. These micrographs suggested less fibre pull out and better interfacial bonding for 40% fibre reinforced composites.

The effects of interfacial debonding on the elastoplastic response of unidirectional silicon carbide—titanium composites

2010 ◽  
Vol 224 (2) ◽  
pp. 259-269 ◽  
Author(s):  
M J Mahmoodi ◽  
M M Aghdam ◽  
M Shakeri
Keyword(s):  
Volume Fraction ◽  
Yield Criterion ◽  
Fibre Volume Fraction ◽  
Three Dimensional ◽  
Fibre Volume ◽  
Interfacial Debonding ◽  
Successive Approximation Method ◽  
Interface Damage ◽  
The Matrix ◽  
Von Mises

A three-dimensional micromechanics-based analytical model is presented to investigate the effects of initiation and propagation of interface damage on the elastoplastic behaviour of unidirectional SiC—Ti metal matrix composites (MMCs) subjected to off-axis loading. Temperature-dependent properties are considered for the matrix. Manufacturing process thermal residual stress (RS) is also included in the model. The selected representative volume element consists of r× c unit cells in which a quarter of the fibre is surrounded by matrix sub-cells. The constant compliance interface model is used to model interfacial debonding and the successive approximation method together with von Mises yield criterion is used to obtain elastoplastic behaviour. Dominance mode of damage including fibre fracture, interfacial debonding, and matrix yielding and ultimate tensile strength of the SiC—Ti MMC are predicted for various loading directions. The effects of thermal RS and fibre volume fraction on the stress—strain response of the SiC—Ti MMC are studied. Results revealed that for more realistic predictions, both interface damage and thermal RS effects should be considered in the analysis. The contribution of interfacial debonding and thermal RS in the overall behaviour of the material is also investigated. Comparison between results of the presented model shows very good agreement with the finite-element micromechanical analysis and experiment for various off-axis angles.

Effect of Different Vacuum Pressure on the Tensile Properties of Sugar Palm Frond Fibre Reinforced Polyester Composites

2013 ◽  
Vol 701 ◽  
pp. 23-27
Author(s):  
S.A. Syed Azuan ◽  
M.M. Saufi ◽  
M.G. Azniah ◽  
J.M. Juraidi
Keyword(s):  
Tensile Properties ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Tensile Modulus ◽  
Fibre Volume ◽  
Vacuum Pressure ◽  
The Matrix ◽  
Polyester Composites ◽  
The One ◽  
Palm Frond

Sugar palm frond fibre has a potential to be as reinforcement in natural fibres reinforced polyester composites. This paper investigates the tensile properties of sugar palm frond fibre reinforced polyester composites. The sugar palm frond fibres were mixed with polyester composites at the 5 % fibre volume fraction with three different vacuum pressure of 5, 10 and 15 psi. The composites panels were fabricated using a vacuum bagging techniques. The tensile test was carried out in accordance to ASTM D638 respectively. The results showed that the vacuum pressure at 15 psi gave maximum value for tensile strength and tensile modulus. The results indicate that by increasing the vacuum pressure, it created a better bonding between fibre and the matrix. Minitab software was used to perform the one-way ANOVA analysis to measure the significant. From the analysis, there is a significant effect of vacuum pressure on the tensile properties.

Fabrication of SiC Fibre Reinforced MoSi2 Based Composites by Low Pressure Plasm a Spraying

2000 ◽  
Author(s):  
K.H. Baik ◽  
P.S. Grant ◽  
A.R. Bhatti ◽  
R.A. Shatwell
Keyword(s):  
Residual Stresses ◽  
Volume Fraction ◽  
Design Method ◽  
Fibre Volume Fraction ◽  
Deposition Efficiency ◽  
Low Pressure ◽  
Fibre Volume ◽  
Matrix Cracking ◽  
Experimental Design Method ◽  
Cte Mismatch

Abstract SiC fibre reinforced SiAlON-MoSi2 composites have been manufactured by concurrent fibre winding and low pressure plasma spraying (LPPS), producing multi-layer, circumferentially fibre-reinforced composite rings. LPPS parameters for the powder used were optimised by a two-level experimental design method followed by additional tuning, achieving smooth sprayed surfaces with low matrix porosity and good deposition efficiency. The microstructure of the SiAlON-MoSi2 matrix consisted of a lamellar structure and uniformly distributed SiAlON splats throughout the MoSi2 matrix. The spray/wind composites exhibited 2% porosity and well controlled fibre distribution. Matrix cracking occurred after heat treatment at 1500°C and was attributed to the development of large tensile residual stresses during cooling due to CTE mismatch. Increasing the SiAlON to MoSi2 ratio in the composite solved the problem. Simulations based on residual stresses showed that the maximum permissible fibre volume fraction to avoid matrix cracking was 0.06 for SiC/MoSi2 and 0.23 for SiC/SiAlON(40v/o)-MoSi2.

An experimental study on the interdependence of mercerization, moisture absorption and mechanical properties of sustainable Phoenix sp. fibre-reinforced epoxy composites

2018 ◽  
Vol 49 (9) ◽  
pp. 1233-1251 ◽  
Author(s):  
G Rajeshkumar
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Length ◽  
Fibre Volume ◽  
Epoxy Composites ◽  
Compression Moulding ◽  
Fibre Matrix ◽  
Fibre Reinforced Composites

This paper represents the first effort aimed to study the interdependence of mercerization, moisture absorption and mechanical properties of sustainable Phoenix sp. fibre-reinforced epoxy composites fabricated by compression moulding technique. The investigation was carried out by varying the fibre length (10, 20 and 30 mm), fibre volume fraction (10%, 20%, 30%, 40% and 50%), concentration of sodium hydroxide for fibre treatment (5%, 10% and 15%) and immersion temperature (10℃, 30℃ and 60℃). The fibre–matrix interface and failure mechanism was studied by using scanning electron microscopy. The results revealed that the moisture absorption rate increased with the increase in fibre length, fibre volume fraction and immersion temperature result in loss of tensile and flexural properties. The moisture absorbed samples shows 15% and 7% drop in tensile and flexural strength, respectively. However, this loss was less in mercerized fibre-reinforced composites.

scholarly journals Damping Performance of Thermoplastic-Elastomer Interleaved Cfrp - Effect of Viscoelasticity of the Inter-Laminar Films and Stiffness of the Intra-Laminar Region -

2005 ◽  
Vol 14 (3) ◽  
pp. 096369350501400 ◽  
Author(s):  
Hajime Kishi ◽  
Manabu Kuwata ◽  
Satoshi Matsuda ◽  
Toshihiko Asami ◽  
Atsushi Murakami
Keyword(s):  
Elastic Modulus ◽  
Viscoelastic Properties ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Local Strain ◽  
Thermoplastic Elastomer ◽  
Considerable Effect ◽  
Fibre Volume ◽  
Damping Properties ◽  
And Control

The objective of this study is to characterize damping performance of carbon-fibre reinforced interleaved toughened laminates using two types of thermoplastic-elastomer films as the interleaf materials. The damping properties of interleaved laminates depend not only on the viscoelastic properties of the interleaf films but also on the laminate sequence. The stiffness of the intra-laminar region, which can be determined by the fibre volume fraction, the elastic modulus of the fibres and the fibre arrangements, would give considerable effect on the local strain of the interleaf films and control the damping properties of the whole interleaved laminates.

The effect of local bending stiffness on the wrinkling of sandwich panels

2003 ◽  
Vol 217 (2) ◽  
pp. 111-119
Author(s):  
L Fagerberg
Keyword(s):  
Elastic Modulus ◽  
Sandwich Panel ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Bending Stiffness ◽  
Face Sheet ◽  
Stacking Sequence ◽  
The Core ◽  
The Face

The use of the face sheet elastic modulus versus the face sheet local bending stiffness while designing against wrinkling is discussed in this paper. It shows that there are several ways to improve the critical wrinkling load of a sandwich panel without replacing the core. It is often possible to increase the wrinkling load by as much as 25 per cent without virtually any increase in weight or cost of the sandwich. This is achieved by improving the local bending stiffness of the sandwich face sheet by either optimizing the stacking sequence, lowering the fibre volume fraction or adding some extra layers of a cheap fibre material to the sandwich face, creating a minisandwich within the face sheet. Experiments are performed that clearly show the potential for increasing the critical wrinkling load by means of altering the face sheet.

Elastic Interphase with Variable Properties in Fibrous Composites

1992 ◽  
Vol 11 (1) ◽  
pp. 82-97 ◽  
Author(s):  
A. V. Pournaras ◽  
G. C. Papanicolaou
Keyword(s):  
Distribution Function ◽  
Elastic Modulus ◽  
Theoretical Model ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Elastic Fibre ◽  
Variable Properties ◽  
Longitudinal Elastic Modulus ◽  
Dirac Distribution

In the present work a theoretical model for composite materials with a Poisson's ratio v = 0.5 is developed in order to evaluate the mechanical stresses around a single cylindrical elastic fibre inclusion. The model considers a gradual and continuous variation of the longitudinal elastic modulus EL in the area between matrix and fibre, the former being under hydrostatic pressure po · EL is expressed as a Fermi-Dirac distribution function of important parameters such as the rate of variation of EL, the extent of the interphase and the fibre volume fraction. Results indicate a strong effect of the above parameters on the stress state developed around the fibre.

scholarly journals Review on Manufacture of Military Composite Helmet

2021 ◽  
Author(s):  
Yazhen Liang ◽  
Xiaogang Chen ◽  
Constantinos Soutis
Keyword(s):  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Structural Heterogeneity ◽  
Processing Parameters ◽  
Fibre Volume ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Protective Function ◽  
The Matrix ◽  
Manufacturing Technologies

AbstractDespite of the fact that more and more accessory devices are integrated to functionalize a ballistic helmet system, its core ballistic protective function needs to be improved with weight reduction was and still is the main course in engineering design. The two major generic classes of synthetic fibres for ballistic composites are Ultra High Molecular Weight Polyethylene (UHMWPE) fibre (0.97 g/cm3) and aramid fibre (1.44 g/cm3). In the area of military helmets, these fibres are constructed into different topologies, draping/forming into double-curvature geometric shape in multiple plies, serving as reinforcement for composite shell. The preforming ways influence the subsequent impregnation / solidification and curing step in manufacture, in terms of the fibre orientation and fibre volume fraction. The inherent structural heterogeneity thus leads to scatter in permeability and composite thickness, and have further impact in generating process-induced defects. During the processing, the fibre continuity without wrinkles, together with voids-free are determinative factors to a quality final part. The aim of this paper is to review the manufacturing technologies characterised by thermo-mechanical forming and Liquid Composite Moulding (LCM), relating their processing parameters respectively to the properties of reinforcements in one dimension (1D), two dimensions (2D) and three dimensions (3D), along with that of the matrix in dry or wet phase, interdependency of them are sought.

scholarly journals DAYA SERAP AIR DAN KANDUNGAN SERAT (FIBER CONTENT) KOMPOSIT POLIESTER TIDAK JENUH (UNSATURATED POLYESTER) BERPENGISI SERAT TANDAN KOSONG SAWIT DAN SELULOSA

2013 ◽  
Vol 2 (3) ◽  
pp. 17-21 ◽  
Author(s):  
Michael ◽  
Elmer Surya ◽  
Halimatuddahliana
Keyword(s):  
Water Absorption ◽  
Palm Oil ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Cellulose Content ◽  
Content Increase ◽  
Empty Fruit Bunch ◽  
The Matrix

This study was aimed to investigate the effect of empty fruit bunch palm oil and cellulose content as filler in water absorption and fibre volume fraction of the unsaturated polyester composites. The composites were made by hand-lay up method by mixing unsaturated polyester with the composition of each fillers (empty fruit bunch palm oil and cellulose) of 5,10,15,20 wt%. The parameter which was carried on the prepared samples was water absorption for each sample every 24 hours until the composites have constant absorption. It was found that the addition of fillers to the matrix caused the water absorption of composites increased at each of composition of fillers (empty fruit bunch palm oil and cellulose) and the fibre volume fraction increased as the filler content increase.

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