Fibers Index

1. Introduction 2. Theoretical Background 2.1 Natural 2.2 Polymeric Fibers 2.3 2.4 Glass Fibers 2.5 Metallic fibers 2.6 SiC Fibers 2.7 Boron fibers 2.8 Alumina fibers 2.9 Ceramic Whiskers 3. Experimental determination of properties 4. Defects effect 5. Interfacial Shear Stress Fibers

Composite Materials 3 Fibers

Classificação das Fibras baseada no seu comprimento.

Composite Materials 4 Fibers

Nonwoven – não tecidas Felt – Feltro – short fibers continuous Fibers

Composite Materials Chopped 5 Product shape

Woven fabric Roving

Mat Composite Materials Chopped 6 Fibers

Yarn – Fio

Woven -tecido Knitted - tricotado Braided - entrançado

Composite Materials 7 Fibers

Composite Materials 8 Natural Fibers - Animal

Composite Materials 9 Natural Fibers - Animal

Silkworm

Composite Materials 10 Natural Fibers - Animal

Silk

Composite Materials 11 Natural Fibers - Mineral

Asbestos (AMIANTO) is a set of six naturally occurring silicate minerals

Anthophyllite

Composite Materials 12 Natural Fibers - Mineral

Composite Materials 13 Natural Fibers - Mineral

Composite Materials 14 Natural Fibers - Mineral

Asbestos was used for its resistance to fire or heat, the fibers often mixed with cement or woven into fabric or mats.

These desirable properties made asbestos very widely used.

Asbestos applications grew throughout most of the 20th century until public awareness of the health risks caused by asbestos dust led to the ban on asbestos in conventional construction.

Composite Materials 15 Natural Fibers - Mineral

Inhalation of asbestos fibers can cause serious and fatal illnesses including lung cancer.

Is forbidden in Europe.

Composite Materials 16 Natural Fibers - Vegetal

Sisal

17 Composite Materials Natural Fibers - Vegetal

18 Composite Materials Natural Fibers - Vegetal

Hemp –Cânhamo Coconut – Coco – Fibra da família da Juta

19 Composite Materials Polymeric fiber

Composite Materials 20 Polyacrylonitrile (PAN) fiber

Composite Materials 21 Polyacrylonitrile (PAN) fiber

Composite Materials 22 Polymeric fiber

Composite Materials 23 fiber

Composite Materials 24 Polyethylene fiber

Composite Materials 25 Polyethylene fiber

Composite Materials 26 Polyethylene fiber

Composite Materials 27 fiber

Composite Materials 28 Kevlar fiber

Composite Materials 29 Kevlar fiber

Composite Materials 30 Kevlar fiber

Typically the price of the fibres type ranges from 15 to 25 euros per kg.

Composite Materials 31 Carbon fiber

[1,5] Composite Materials 32 Carbon fiber

1. Fabrication

precursor PAN

precursor Pitch

[1,5] Composite Materials 33 Carbon fiber

1. Fabrication Oxidation/stabilization: » Pyrolysis of an organic precursor: » cyclization, dehydrogenation PAN » stable ladder-like structure = limiting process (several hours)

Carbonization » in inert atmosphere at ~1500°C » further cyclization and dehydrogenation » graphite-like structure consisting of hexagons bonded by nitrogen » weight decrease of 50 %

Graphitization » at 1500 to 3000°C in Ar-atmosphere » graphite layers form » Young`s modulus depends on graphitization Temperature and Conversion of carbon fiber from the organic precursor PAN applied tension [1,5] Surface treatment and sizing Composite Materials 34 Carbon fiber

Composite Materials 35 Carbon fiber 1. Fabrication » Pyrolysis of an organic precursor: Pitch

Composite Materials 36 Carbon fiber

2. Classification

Production Types:

HT – High Tensile: σT > 3 GPa LM – Low Modulus E < 100 GPa IM – Intermediate Modulus E < 300 Gpa HM – High Modulus E > 300 GPa UHM – Ultra High Modulus E > 500 Gpa

Ideal graphite E~ 1050 GPa

[4,5,6]

Composite Materials 37 Carbon fiber

3. Basic structure □ carbon fibers are not totally crystalline but are composed of both graphitic and noncrystalline regions: TURBOSTRATIC STRUCTURE □ interlayer distance in turbostratic carbon is always greater than graphite due to the presence of sp3 bonds □ typical PAN-based carbon fibers have a layer distance of about 0.355 nm □ fiber diameters normally range between 4 and 10 µm □ non-twisted continuous carbon filaments form tows of 5-10 mm diameter

a. Crystal structure of graphite crystal. b. Structure of turbostratic [1,4] carbon. Composite Materials 38 3. Basic structure Carbon fiber

[1,4]

Composite Materials 39 Carbon fiber

[1,4]

Composite Materials 40 Carbon fiber

[1,4]

Composite Materials 41 Carbon fiber

Composite Materials 42 Carbon fiber

43 Carbon fiber

Price (Euros/Kg) Ultra High Strength 512,1-560,1 High Modulus 160-192 Low Modulus 96,06-128

44

Glass fiber fabric

Composite Materials 45 Glass fiber

Composite Materials 46 Glass fiber

Coating Composite Materials 47 Glass fiber

Crystalline material

Amorphous material Glass

Composite Materials 48 Glass fiber

Amorphous material Isotropic material Glass

Composite Materials 49 Glass fiber

Composite Materials 50 Glass fiber

Composite Materials 51 Glass fiber

Quadro 1 – Propriedades de alguns tipos de fibra de vidro (E e S)

Propriedades E S Densidade, ρ(g/cm³) 2.54 2.49 Diâmetro (microns) 3-20 3-20 Módulo de Elasticidade, E(GPa) 67-72 85 Tensão de rotura, σ(GPa) 1.7-3.5 2 – 4.5 Coeficiente de expansão térmica (10-6/°C) 5.00 2.90 Custo (€/kg) 1.3 15.6

Composite Materials 52 Glass fiber

E-glass fiber types are the most common and inexpensive of all. The price can typically range from 1 – 2 euros/Kg

R or S-glass fibers can be priced from 13 – 20 euros/Kg

Composite Materials 53 Mineral Fibers

Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials (usually basalt). Mineral wool is a non-metallic, inorganic product manufactured from a carefully controlled mix of raw materials, mainly comprising either stone or slag which are heated to a high temperature until molten. The molten glass is then spun and formed into a fibrous material for further processing into finished products.

Composite Materials 54 Mineral Fibers– Lã de Rocha

Composite Materials 55 https://www.sotecnisol.pt/ Mineral Fibers– Lã de Rocha

https://www.sotecnisol.pt/materiais/produtos/solucoes-de-impermeabilizacao-isolamentos-e- drenagens/isolamentos-termicos/la-de-rocha/

Composite Materials 56 Continuous Basalt Fibers

Continuous is a material made from extremely fine fibers of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. The production process it is similar to the fiberglass.

Composite Materials 57 Basalt Fibers

Composite Materials 58 Basalt Fibers

Table.1. Comparative Characteristics Between Basalt Fiber & Other Fiber

Basalt E-glass S-glass Carbon Capability fiber fiber fiber fiber

Density (g/cmm3) 2.67 2,55 2.49 1.79

Tensile strength, MPa 3000~4840 3100~3800 4020~4650 3500~6000

Elastic modulus, gPa 79.3~93.1 72.5~75.5 83~86 230~600

Elongation at break, % 3.1 4.7 5.3 1.5~2.0

Diameter of filament, mµ 6~21 6~21 6~21 5~15

tex 60~4200 40~4200 40~4200 60~2400

Temperature of -260~+500 -50~+380 -50 +300 -50~+700 application, °С

Price, USD/kg 2,5 1,1 1,5 30

http://basaltfm.com/eng/fiber/info.html

Composite Materials 59 Basalt Fibers

Fatigue behavior for Basalt (Bas), Glass and Carbon fibers

Composite Materials 60 Basalt Fibers

https://www.castrocompositesshop.com/pt/146-basalto

Composite Materials 61 Metallic Fiber

Composite Materials 62 Metallic Fiber

Can we use Continuous casting to obtain long fibers?

Composite Materials 63 Metallic Fiber

Spinning fibers from a melt is perhaps the most common technique used to make fibers from polymeric and silica-based glasses.

Such a technique, however, is not very suitable for metallic fibers because molten metals have very low viscosity, rather like that of water, and rather high surface energy.

These characteristics of metals generally preclude the use of casting or extrusion from a molten state to make metallic fibers.

If one were to try such a technique, what would happen is that as soon as the filamentary jet comes out of the die or spinneret, it breaks up into droplets.

Composite Materials 64 Metallic Fiber

For metallic fibers production the common techniques are: a) Melt extraction process for metals – Used to obtain short fibers b) Drawing process for metals – Used to obtain filaments.

Composite Materials 65 Metallic Fiber Melt extraction process for metals – Used to obtain short fibers

Composite Materials 66 Metallic Fiber

Melt extraction process for metals

Composite Materials 67 Metallic Fiber

Melt extraction process for metals

Material – Stainless steel

Composite Materials 68 Metallic Fiber

Melt extraction process for metals

Length 15mm

Shape Straight

Diameter 0.5mm

Composite Materials 69 Metallic Fiber

Melt Drop Extraction process for metals – titanium fibers

Ti Young Modulus 116 GPa

The strength of Titanium 6AL-4V is about 1GPa

Composite Materials 70 Metallic Fiber

Drawing process for metals – Use to obtain filaments with a diameter lower than 100 mm.

Composite Materials 71 Metallic Fiber : Tungsten a) W powders are sintered into an ingot. The sintering involves passage of an electric current (≈5000 A) through the cold pressed ingot. b) The ingot is rolled and/or swaged, followed by drawing to a diameter less than 100 mm by using a series of dies.

Composite Materials 72 Metallic Fiber : Stainless Steel

Drawing process

1. Diameter : 0.2 mm 2. Tensile Stength：~ 1200MPa

Composite Materials 73 Metallic Fiber

Composite Materials 74 Ceramic Fibers

Composite Materials 75 Ceramic Fiber – Polymeric precursor

Composite Materials 76 SiC Fiber – Nicalon process

Composite Materials 77 SiC Fiber – Nicalon process

The multifilament fiber (10-20 mm diameter) as commercially produced consists of a mixture of b-SiC, free carbon and SiO2).

Composite Materials 78 CVD SiC Fiber

Composite Materials 79 CVD SiC Fiber CVD SiC Fiber CVD SiC Fiber (C) CVD SiC Fiber CVD

Boron Fibers are used in ≈ 90% for B-Epoxy composites CVD Boron Fiber

3BCl + 3 H2 2 B + 6HCl CVD Boron Fiber CVD Boron Fiber (W)

Typically the price of the B(W) fibers type ranges from 400 to 450 euros per kg. CVD Boron Fiber Other CVD Fiber Other CVD Fiber

CVD diamond (W) Fiber Al2O3 Fiber

(PVP) polyvinylpyrrolidone

Composite Materials 91 Al2O3 Fiber

Composite Materials 92 Al2O3 Fiber

Composite Materials 93 Al2O3 Fiber

Composite Materials 94 Al2O3 Fiber

Composite Materials 95 Fibers Properties

Composite Materials 96 Fibers Properties

Fibers E Tensile a Density Melting MPa x 104 strength C-1 x10-6 g/cm3 Point MPa (20-1000 oC) oC

97 Fibers Properties

98 Fibers Properties

99 Fibers Properties

Fatigue behavior

R = σmin /σmax = 0,1

at room temperature

Composite Materials 100 Fibers Properties

Ef ?

bNASA Technical Memorandum 83320 1 psi=0.006894757 MPa Boron-B(W); Hms , AS , T300 – Carbon; KEV – Kevlar; S-G , E-G – Glass 1 ksi =6.894757 MPa101 Fibers Properties

bNASA Technical Memorandum 83320

EL

ET

GL

GT

Boron-B(W); Hms , AS , T300 – Carbon fibers

102 Fibers

Whiskers.

Composite Materials 103 Whiskers

Whiskers are monocrystalline, short fibers with extremely high strength.

Composite Materials 104 Whiskers

Whiskers are monocrystalline, short fibers with extremely high strength.

Being monocrystalline, there are no grain boundaries either. Typically, whiskers have a diameter of a few mm and a length of a few mm.

Strength levels approaching the theoretically expected values have been measured in many whiskers.

This high strength, approaching the theoretical strength, has its origin in the almost absence of crystalline imperfections such as dislocations.

Composite Materials 105 Whiskers

V-Vapor L- Liquid S- Solid

Composite Materials 106 Whiskers

Composite Materials 107 Whiskers

Composite Materials 108 Whiskers

SiC Whiskers

Composite Materials 109 Whiskers

Alumina Whiskers

Composite Materials 110 Whiskers

Composite Materials 111 Whiskers

Os valores de tensão de rotura dos Whiskers são muito altos, próximo dos valores teóricos obtidos quando calculamos a tensão necessária para quebrar a ligação ente os átomos.

Composite Materials 112 Whiskers

The values of rupture stress of Whiskers are very high, close to the theoretical values obtained when we calculate the tension necessary to break the bond between the atoms.

Composite Materials 113 Whiskers

Strengths of various fibers and wires

Composite Materials 114 Fibers

Experimental determination of fiber properties

Composite Materials 115 Fibers Experimental determination of fiber properties

200 mm Norma

Composite Materials Fibers Experimental determination of fiber properties

A small initial twist is given to the fiber and the amplitude of the successive oscillations and the period of oscillations is determined. The shear modulus of a fiber of a circular cross-section is given by:

where I is the moment of inertia of the torsion pendulum, l is the fiber length, R is the fiber radius and T is the period of oscillations.

Composite Materials 117 Fibers

Defects effect

Composite Materials 118 Fibers

Composite Materials 119 Fibers Superficial defect

Composite Materials 120 Fibers Defeito Superficial

Composite Materials 121 Fibers Defects effect

Composite Materials 122 Fibers Internal Defects

Composite Materials 123 Fibers Internal Defects

Composite Materials 124 Fibers - Defects effect

Composite Materials 125 Fibers Defects effect

2 1/2 KIc = [(2Egf)/(1-n )]

1/2 KIc = Y sf a

YMax ≈ 2

1/2 sf ≈ KIc /(2.a )

Composite Materials 126 Fibers - Defects effect

Example: Alumina 1/2 sf ≈ KIc /(2.a ) 1/2 KIc ≈3,8 MPa.m (constante do material)

Bulk Fiber

Defeitos com =7mm dimensões da a ≈ 0,3mm ordem de a ≈ 40mm sf ≈ 3,4GPa sf ≈ 300MPa Composite Materials 127 Fibers -Defects effect

Weibull statistics

The so called Weibull modulus (m) is a measure of scatter and is roughly inversely related to the coefficient of variation, Cv:

where ഥσ is the mean strength and s the standard deviation. Composite Materials 128 Fibers Properties

Length effect – lets use Carbon as example Composite Materials 129 Fibers Properties

EN 1007-5:2001 norm Test Length = 200 mm F σ r = 2,1 GPa m=5

Composite Materials 130 Fibers Properties

EN 1007-5:2001 norm Test Length = 200 mm F σ r (200mm)= 2,1 GPa m=5

Se ensaiarmos fibras de com Lo = 50 mm, que valor de tensão de rotura devo esperar?

F σ r (50mm)= ?

(vamos aplicar a estatística de Weibull) 131 Fibers Properties

EN 1007-5:2001 norm Test Length = 200 mm F σ r (200mm)= 2,1 GPa m=5

If you test carbon fibers in a specimen with Lo = 50 mm, what fibers rupture value should I use?

F σ r (50mm)= ?

(Lets use Weibull statistic) 132 Fibers Properties

EN 1007-5:2001 norm Test Length = 200 mm F σ r (200mm)= 2,1 GPa m=5

Lo = 50 mm

Same Area Ao , different lengths F σ r (Lo = 50mm)= ?

F F 1/5 σ r (50mm)= σ r (200mm). (200/50)

F 0,2 σ r (50mm)= 2,1. (200/50)

F σ r (50mm)= 2,8 GPa

The mean rupture stress increases because the probability of finding a worse defect decreases as the volume decreases. Composite Materials Fibers Properties

Short fibers versus Continuous Fibers

Continuous Fibers Ec = Ef Vf + Em (1-Vf )

Short fibers Empirical approach (h1 )

Ec = h1Ef Vf + Em (1-Vf )

Composite Materials 134 Fibers Properties

Short fibers versus Continuous Fibers

Short fibers Empirical approach (h1 ) Ec = h1Ef Vf + Em (1-Vf )

For l ≥ 10 mm h1 = 0,99 so, we can use

Ec ≈ Ef Vf + Em (1-Vf ) Equation for Long Fibers Composite Materials 135 Fibers Properties

Short fibers versus Continuous Fibers

When there is a distribution of fiber orientation the reinforcing efficiency of the fibers reduced.

New Empirical approach (ho )

Ec =ho h1Ef Vf + Em (1-Vf )

where ho is an orientation efficiency factor.

For unidirectional laminae ho = 1 when tested to the fibers,

ho = 3/8 for in-plane random fiber distributions and

ho = 1/5 for three-dimensional random distributions

Composite Materials 136 Coatings

Composite Materials 137 Coatings

Typical fiber-coating applications:

Temporary protection of fibers before (sizing); (Proteção temporária antes de ser tecido)

Lubricants - Protect filaments from abrading and breaking;

Protectors - Coating on brittle fibers to improve elasticity and breaking strength;

Binders - Pre-coating of fibers for embedding in fiber-reinforced composites, playing with the interface adhesion.

Composite Materials 138 Interfacial Shear Stress

Methods to measure the Interfacial Shear Stress (MPa).

Grip Matrix Fiber

Pull out test

Composite Materials 139 Interfacial Shear Stress

Methods to measure the Interfacial Shear Stress (MPa).

Indentation

Composite Materials 140 Interfacial Shear Stress

Methods to measure the Interfacial Shear Stress (MPa).

Push-out

Composite Materials 141 Interfacial Shear Stress

Composite Materials 142 Coatings Effect

Interfacial Shear Stress (MPa)

Composite Materials 143 Product shape

Fiber - Fiber fabrics

Kevlar - Glass Kevlar - Carbon Glass - Carbon

Composite Materials 144 Product shape

Other Fiber Products

GlassWool – Insulation Filters Refractories Bricks Lã de Vidro

Composite Materials 145 Cross-sectional shape

Composite Materials 146 Fibers

Fiber - Fiber composite ?

Composite Materials 147 Fibers

Geosynthetic

Composite Materials 148 Geosynthetic Types (ASTM D4439):

•Geotextile: “A permeable geosynthetic comprised solely of .”

•Geogrid: “A geosynthetic formed by a regular network of integrally connected elements with apertures greater than ¼ in. to allow interlocking with surrounding soil, rock, earth, and other materials to function primarily as reinforcement.”

•Geonet: “A geosynthetic consisting of integrally connected parallel sets of ribs overlying similar sets at various angles for planar drainage of liquids and gases.”

•Geomembrane: is a very low permeability synthetic membrane liner or barrier used in geotechnics.

•Geocomposite “A product composed of two or more materials, at least one of which is a geosynthetic.” Composite Materials 149 Other Fiber Products

Geotextile Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain.

Typically made from polypropylene or , geotextile fabrics come in three basic forms: woven (resembling mail bag sacking), needle punched (resembling felt), or heat bonded (resembling ironed felt).

Geotextile composites are able to withstand many things, are durable and is able to soften a fall if someone falls down.

Overall, these materials are referred to as geosynthetics and each configuration:

-Geonets, Geosynthetic clay liners, Geogrids, Geotextile filter, and others, can yield benefits in geotechnical and environmental engineering design.

Composite Materials 150 Geotextil

O Geotêxtil é um material textil utilizado em contacto com o solo, aterros, taludes, atuando como elemento com excelentes características mecânicas e hidráulicas. Para aplicação em obras de drenagem, filtração, separação e reforço de solos.

O desempenho dos geotêxteis procura assegurar as seguintes funções:

-protecção e reforço, que consiste na prevenção ou limitação de danos locais de um dado elemento ou material e na melhoria das propriedades mecânicas do solo ou de outros materiais de construção;

-separação, ou seja, a prevenção da mistura de solos com outros materiais;

-filtração, isto é, a retenção do solo ou de outras partículas sujeitas a forças hidrodinâmicas permitindo a passagem de líquidos através do geotêxtil;

-drenagem, a qual envolve a recolha e o transporte das águas pluviais, subterrâneas e/ou outros líquidos.

Composite Materials 151 Other Fiber Products

Geogrid - Geogrelha Geotextile filter - Geotêxtil

Composite Materials 152 Other Fiber Products

Geonet - Georede Geosynthetic clay liners (GCLs) are factory manufactured hydraulic barriers consisting of a layer of bentonite or other very low-permeability material supported by geotextiles.

Composite Materials 153 Geosynthetic

Geomembrane

Composite Materials 154 Other Fiber Products

The basic philosophy behind geocomposite materials is to combine the best features of different materials in such a way that specific applications are addressed in the optimal manner and at minimum cost. In some cases it may be more advantageous to use a nonsynthetic material with a geosynthetic one for optimum performance and/or least cost.

Composite Materials 155 Other Fiber Products

Composite Materials 156 Fibers

Intelligent fabrics

Composite Materials 157 Other Fiber Products

Intelligent Fabric:

Can be defined as a structural which not only can sense but can also react and respond to environmental conditions or stimuli.

These stimuli, as well as response, could be thermal, chemical, mechanical, electric, magnetic or from other source. Composite Materials 158 Other Fiber Products

Intelligent fabrics

Electronics and microsystems can be integrated into even the most delicate fabrics

Composite Materials 159 Other Fiber Products

Intelligent fabrics

Composite Materials 160 Fibers

Thank You!

Obrigado pela Atenção!

Composite Materials 161 Fibers

END

FIM

Composite Materials 162