A solution for transverse thermal conductivity of composites with quadratic or hexagonal unidirectional fibres

2014 ◽  
Vol 21 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Xueliang Xiao ◽  
Andrew Long
Keyword(s):  
Thermal Conductivity ◽  
Cfd Simulation ◽  
Volume Fraction ◽  
Thermal Contact ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Fluid Interface ◽  
Transverse Thermal Conductivity ◽  
Computational Fluid Dynamics Cfd ◽  
Unidirectional Fibre

AbstractA solution for the transverse thermal conductivity (Ke) of unidirectional fibre arrays, quadratic and hexagonal, is developed analytically. The solution integrates the thermal conductivity of fibre (Kf) and fluid (Km) based on electricity analogy without thermal contact resistance (Rc) at the fibre/fluid interface. The expression Ke is a function of Kf and Km, as well as of the fibre volume fraction (Vf). In this article, Ke values of four composites were predicted and verified by computational fluid dynamics (CFD) simulations. The results showed good agreement when the ratio of Kf/Km is close to 1. An increase in the ratio or Vf gives poorer agreement owing to the local temperature gradient at the fibre/fluid interface. CFD simulation also showed that Ke is decreasing as the Rc value increases.

scholarly journals Thermal conductivity of textile reinforcements for composites

2018 ◽  
Vol 1 ◽  
pp. 251522111775115 ◽  
Author(s):  
Yue El-Hage ◽  
Simon Hind ◽  
François Robitaille
Keyword(s):  
Thermal Conductivity ◽  
Carbon Fibre ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Three Dimensional ◽  
Fibre Volume ◽  
Published Data ◽  
Manufacturing Processes ◽  
Composites Manufacturing ◽  
The Relationship

Thermal conductivity data for dry carbon fibre fabrics are required for modelling heat transfer during composites manufacturing processes; however, very few published data are available. This article reports in-plane and through-thickness thermal conductivities measured as a function of fibre volume fraction ( Vf) for non-crimp and twill carbon reinforcement fabrics, three-dimensional weaves and reinforcement stacks assembled with one-sided carbon stitch. Composites made from these reinforcements and glass fibre fabrics are also measured. Clear trends are observed and the effects of Vf, de-bulking and vacuum are quantified along with orthotropy ratios. Limited differences between the conductivity of dry glass and carbon fibre fabrics in the through-thickness direction are reported. An unexpected trend in the relationship between that quantity and Vf is explained summarily through simple simulations.

scholarly journals Modified rule of Mixtures for prediction of Tensile strength of Unidirectional Fibre Reinforced Composites

1997 ◽  
Vol 6 (5) ◽  
pp. 096369359700600 ◽  
Author(s):  
C. S. Lee ◽  
W. Hwang
Keyword(s):  
Tensile Strength ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Reinforced Composites ◽  
Strength Data ◽  
Rule Of Mixtures ◽  
Unidirectional Fibre ◽  
Fibre Reinforced Composites ◽  
Good Agreement

The rule of mixtures was modified based on the concept of effective fibre volume fraction. The degradation parameter of effective fibre volume fraction was proposed in consideration of the microgeometry of composite components. It was shown that the modified rule has good agreement with the experimental strength data and the degradation parameter of effective fibre volume fraction used in this study can be used on general composites.

Thermal transport properties of carbon-carbon fibre composites III. Mathematical modelling

1990 ◽  
Vol 430 (1878) ◽  
pp. 199-211 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Microstructural Characterization ◽  
Fibre Volume ◽  
Porosity Level ◽  
Using Data ◽  
Carbon Fibre Composites ◽  
Good Agreement

Measured thermal transport data are interpreted using data obtained by careful microstructural characterization concerning the porosity distribution and graphite grain sizes. The separate thermal conductivity components for one-dimensional composites are deduced using a simple series addition to determine ג f1 and ג m1 and using an adaptation of the Bruggeman analysis for calculating ג f┴ and ג m┴ . Parallel to the fibre axis the calculated thermal conductivities are shown to be in good agreement with existing theories of the thermal conductivity of graphite using experimentally determined values of grain size. The derived data are recombined in a simple series model to predict the thermal conductivity of two-dimensional composites containing a different fibre volume fraction and porosity level. Good agreement with measured data is obtained.

scholarly journals Geometrical modelling and thermal analysis of nonwoven fabrics

2017 ◽  
Vol 48 (2) ◽  
pp. 405-431
Author(s):  
Muhammad Owais Raza Siddiqui ◽  
Danmei Sun ◽  
Ian B Butler
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Element ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Finite Element Models ◽  
Insulation Property ◽  
Nonwoven Fabrics

Nonwoven fabric can be produced for thermal insulation. It has low fibre volume fraction. Thermal insulation property of fibrous materials depends on not only the thermal conductivity of fibre but also the entrapped static air. If fibre volume fraction is low in fibrous assembly it means that more air in the volume, therefore, the insulation property of the fabric increases, or vice versa. In this research thermal bonded nonwoven fabrics were used to analyse the heat transfer phenomena and predict the effective thermal conductivity and thermal resistance by using finite element method. Finite element models of nonwoven fabrics were created by two techniques: 3D reconstruction and solid modelling. For validation purpose, the effective thermal conductivity results obtained from an in-house developed instrument were compared with predicted results from the developed finite element models. Furthermore, this research work also contains an investigation of the effect of fibre volume fraction and thermal conductivity of fibre on the overall heat transfer of nonwoven structures.

Synthesis and Analysis of the Thermal Behavior of SiC-Fibre Reinforced Copper Matrix Composites as Heat Sink Material

2008 ◽  
Vol 59 ◽  
pp. 153-157 ◽  
Author(s):  
Verena Paffenholz ◽  
Stefan Lindig ◽  
Annegret Brendel ◽  
Harald Bolt
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Copper Matrix ◽  
Fibre Volume ◽  
Matrix Composites ◽  
Scanning Calorimetry ◽  
Fibre Direction ◽  
Copper Matrix Composites

Copper matrix composites reinforced with silicon carbide fibres (SiCf/Cu) are considered as heat sink materials for the divertor of DEMO as they combine high thermal conductivity and good mechanical strength at high temperature. A new method was developed to synthesise a metal matrix composite (MMC) consisting of about 3-6 unidirectional reinforced layers (UD-layers). The UD-layers were prepared by two subsequent electroplating processes which allow to adjust various fibre volume fractions. These single UD layers were stacked with different relative fibre orientations (0°/0° and 0°/90°) and consolidated by vacuum hot pressing to form the MMC specimen. The thermal conductivity perpendicular to fibre direction was obtained by laser flash apparatus (LFA) measurements. It is about 310 Wm-1K-1 for electroplated copper (Cu) and above 200 Wm-1K-1 for MMC specimens with a fibre volume fraction of 8-13%. Due to the manufacturing process, boundaries within the matrix were found resulting in a reduction of the values. In addition, DSC (differential scanning calorimetry) measurements were performed which gave similar results.

Effect of fibre content on the mechanical properties of hemp fibre woven fabrics/polypropylene composite laminates

2021 ◽  
pp. 096739112110239
Author(s):  
Sheedev Antony ◽  
Abel Cherouat ◽  
Guillaume Montay
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Woven Fabrics ◽  
Fibre Content ◽  
Viscoelastic Behaviour ◽  
Hemp Fibre

Nowadays natural fibre composites have gained great significance as reinforcements in polymer matrix composites. Composite material based on a polymer matrix reinforced with natural fibres is extensively used in industry due to their biodegradability, recyclability, low density and high specific properties. A study has been carried out here to investigate the fibre volume fraction effect of hemp fibre woven fabrics/PolyPropylene (PP) composite laminates on the tensile properties and impact hammer impact test. Initially, composite sheets were fabricated by the thermal-compression process with desired number of fabric layers to obtain composite laminates with different fibre volume fraction. Uniaxial, shear and biaxial tensile tests were performed and mechanical properties were calculated. Impact hammer test was also carried out to estimate the frequency and damping parameters of stratified composite plates. Scanning Electron Microscope (SEM) analysis was performed to observe the matrix and fibre constituent defects. Hemp fabrics/PP composite laminates exhibits viscoelastic behaviour and as the fibre volume fraction increases, the viscoelastic behaviour decreases to elastic behaviour. Due to this, the tensile strength increases as the fibre content increases. On the other hand, the natural frequency increases and damping ratio decrease as the fibre volume fraction increases.

scholarly journals Insulation Characteristics of Sisal Fibre/Epoxy Composites

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
A. Shalwan ◽  
M. Alajmi ◽  
A. Alajmi
Keyword(s):  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Thermal Characteristics ◽  
Fibre Volume ◽  
Point Of View ◽  
Natural Fibres ◽  
Epoxy Composites ◽  
Ongoing Research ◽  
Sisal Fibre ◽  
The Impact

Using natural fibres in civil engineering is the aim of many industrial and academics sectors to overcome the impact of synthetic fibres on environments. One of the potential applications of natural fibres composites is to be implemented in insulation components. Thermal behaviour of polymer composites based on natural fibres is recent ongoing research. In this article, thermal characteristics of sisal fibre reinforced epoxy composites are evaluated for treated and untreated fibres considering different volume fractions of 0–30%. The results revealed that the increase in the fibre volume fraction increased the insulation performance of the composites for both treated and untreated fibres. More than 200% insulation rate was achieved at the volume fraction of 20% of treated sisal fibres. Untreated fibres showed about 400% insulation rate; however, it is not recommended to use untreated fibres from mechanical point of view. The results indicated that there is potential of using the developed composites for insulation purposes.

New Development of Cattail Fibre in Composite Uses

2013 ◽  
Vol 746 ◽  
pp. 385-389
Author(s):  
Li Yan Liu ◽  
Yu Ping Chen ◽  
Jing Zhu
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Environmental Benefits ◽  
Bending Properties ◽  
New Development ◽  
Original Plant ◽  
Reinforcing Material ◽  
Pp Composites

This paper is aiming to develop the cattail fibre as reinforcing material due to its environmental benefits and excellent physical and insulated characteristics. The current work is concerned with the development of the technical fibres from the original plant and research on their reinforcing properties in the innovative composites. Polypropylene (PP) fibre was used as matrix in this research which was fabricated into fibre mats with cattail fibre together with different fibre volume fractions. Cattail fibre reinforced PP laminates were manufactured and compared with jute/PP composites. The tensile and bending properties of laminates were tested. The SEM micrographs of fracture surface of the laminates were analyzed as well. The results reveal that the tensile and bending properties of cattail/PP laminates are closed to those of jute/PP composites. The mechanical properties of cattail/jute/PP laminates with fibre volume fraction of 20/35/45 is betther than those of laminate reinforced with cattail fibers.

scholarly journals The Mechanical Properties of Steel-Polypropylene Fibre Composites Concrete (HyFRCC)

2015 ◽  
Vol 773-774 ◽  
pp. 949-953 ◽  
Author(s):  
Izni Syahrizal Ibrahim ◽  
Wan Amizah Wan Jusoh ◽  
Abdul Rahman Mohd Sam ◽  
Nur Ain Mustapa ◽  
Sk Muiz Sk Abdul Razak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Polypropylene Fibre ◽  
Experimental Results

This paper discusses the experimental results on the mechanical properties of hybrid fibre reinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study. Meanwhile, the concrete strength is maintained for grade C30. The percentage proportion of SF-PPF fibres are varied in the range of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% of which the total fibre volume fraction (Vf) is fixed at 0.5%. The experimental results reveal that the percentage proportion of SF-PPF fibres with 75-25% produced the maximum performance of flexural strength, tensile strength and flexural toughness. Meanwhile, the percentage proportion of SF-PPF fibres with 100-0% contributes to the improvement of the compressive strength compared to that of plain concrete.

scholarly journals Postheated Model of Confined High Strength Fibrous Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Kaleem A. Zaidi ◽  
Umesh K. Sharma ◽  
N. M. Bhandari ◽  
P. Bhargava
Keyword(s):  
High Temperature ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
High Strength ◽  
Fibre Volume ◽  
Experimental Results ◽  
Confined Concrete ◽  
Structural Safety ◽  
Stress Strain ◽  
Fibrous Concrete

HSC normally suffers from low stiffness and poor strain capacity after exposure to high temperature. High strength confined fibrous concrete (HSCFC) is being used in industrial structures and other high rise buildings that may be subjected to high temperature during operation or in case of an accidental fire. The proper understanding of the effect of elevated temperature on the stress-strain relationship of HSCFC is necessary for the assessment of structural safety. Further stress-strain model of HSCFC after exposure to high temperature is scarce in literature. Experimental results are used to generate the complete stress-strain curves of HSCFC after exposure to high temperature in compression. The variation in concrete mixes was achieved by varying the types of fibre, volume fraction of fibres, and temperature of exposure from ambient to 800°C. The degree of confinement was kept constant in all the specimens. A comparative assessment of different models on the high strength confined concrete was also conducted at different temperature for the accuracy of proposed model. The proposed empirical stress-strain equations are suitable for both high strength confined concrete and HSCFC after exposure to high temperature in compression. The predictions were found to be in good agreement and well fit with experimental results.

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