《复合材料 Composites》课程教学资源（学习资料）第一章 复合材料基础_纤维增强复合材料 Fibre Reinforced Composite（FRC）Structures with Potential Applications：Literature Review

International Journal of Applied Engineering Research issN 0973-4562 Volume 4 Number 10(2009)pp 1939-1954 C Research India Publications http://www.ripublication.com/ijaer.htm Fibre reinforced Composite(frc) structures with Potential Applications: Literature Review Hakim S Sultan Aljibori Mechanical Engineering Department, Faculty of Engineering University Malaya, 50603 Kuala lumpur, Malaysia Abstract Modern technology requires new materials of special properties. One of the reasons for interest in materials of unusual mechanical properties comes from the fact that they can be used as matrices to form composites with other materials of other required properties. After many years of applications, it is interesting to review the present state of a new knowledge and technology of fibre reinforcement composite(FRC) structures. The aim of the paper is to describe the present state of knowledge and technology of FRC and to discuss main directions of their applications. In general, composite and particularly composite with dispersed fibre reinforcement is becoming a high-tech material that provides excellent performance but requires competent design and execution Keywords: Composite Structures, Materials, Fibre and matrix Introduction It is reasonable to begin an introduction to composite materials by defining what these materials are. The term "Composite"refers to an assembly of different materials which when used together; a composite material is defined as a material containing at least two distinct phases on microscopic scale. These are the fibres reinforcing material and the matrix supporting the material [1]. The term"advanced composites refers to the group of materials usually used in the automotive and aerospace industr Composites to be materials in which a homogeneous matrix component is reinforced by a stronger and stiffer constituent that is usually fibrous but may have a particulate or other shape, the term FRC(Fiber Reinforced Composite)usually indicates a thermosetting polyester matrix containing fibers, and this particular composite has the lions share of today's commercial market [2]. The technological advances in various ectors have created demand for newer materials, where they are required to perforn

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 4 Number 10 (2009) pp. 1939–1954 © Research India Publications http://www.ripublication.com/ijaer.htm Fibre Reinforced Composite (FRC) Structures with Potential Applications: Literature Review Hakim S. Sultan Aljibori Mechanical Engineering Department, Faculty of Engineering, University Malaya, 50603 Kuala Lumpur, Malaysia Abstract Modern technology requires new materials of special properties. One of the reasons for interest in materials of unusual mechanical properties comes from the fact that they can be used as matrices to form composites with other materials of other required properties. After many years of applications, it is interesting to review the present state of a new knowledge and technology of fibre reinforcement composite (FRC) structures. The aim of the paper is to describe the present state of knowledge and technology of FRC and to discuss main directions of their applications. In general, composite and particularly composite with dispersed fibre reinforcement is becoming a high-tech material that provides excellent performance but requires competent design and execution. Keywords: Composite Structures, Materials, Fibre and Matrix. Introduction It is reasonable to begin an introduction to composite materials by defining what these materials are. The term "Composite" refers to an assembly of different materials which when used together; a composite material is defined as a material containing at least two distinct phases on microscopic scale. These are the fibres reinforcing material and the matrix supporting the material [1]. The term "advanced composites' refers to the group of materials usually used in the automotive and aerospace industry. Composites to be materials in which a homogeneous matrix component is reinforced by a stronger and stiffer constituent that is usually fibrous but may have a particulate or other shape, the term FRC (Fiber Reinforced Composite) usually indicates a thermosetting polyester matrix containing fibers, and this particular composite has the lion's share of today's commercial market [2]. The technological advances in various sectors have created demand for newer materials, where they are required to perform

1940 Hakim S. Sultan Alibori in stringent conditions, high pressure temperature, highly corrosive environments, which the conventional materials failed to service. This has triggered the development needs for engineered materials to cater to customized needs. Industry has recognized the ability of composite materials to produce high-quality, durable, cost-effective products. In recent years there is an increasing demand in the use of composite materials for the automotive, aerospace and rail industry. The automotive and aerospace applications over the past quarter-century have been primarily in special areas such as energy absorber devices. When using composite in the body structure of a vehicle, considerable weight reductions can be achieved compared to conventional isotropic structures, which leads to reduced fuel consumption and consequently lower carbon dioxide emissions Material Constituents The major constituents in a fiber-reinforced composite material are the reinforcing fibers and the matrix. FRC can be classified into broad categories according to the matrix used: polymer, Metal, ceramic, and carbon Polymer matrix composite include thermoset or thermoplastic resins reinforced with glass fiber, carbon(graphite) aramid(Kevlar), or boron fibers. They are used primarily in relatively low temperature application. Metal matrix composite consists of metal or alloys reinforced with boron, carbon(graphite), or ceramic fibers Composite materials were developed because no single, homogeneous structural material could be found that had all of the desired attributes for a given application in the aerospace industry [3] Ibre One of the most commonly used fibers among the new composite materials is the carbon fiber. Among the advantages of carbon fibers is their exceptionally high tensile strength to weight ratio as well as tensile modulus to weight ratios, high fatigue strength and very low coefficient of linear thermal expansion. Where they can maintain their strength up to 2000oC, thus providing the dimensional stability required in space applications. Due to the high cost of these fibers: they are mostly used in the aerospace industry, where weight saving is more critical than cost. Glass fibers commonly used are the E-glass and S-lass. In addition to these glass types there are others that are not usually included in advanced composites because they are used in different fields. For example, the C-glass: is used for chemical resistance in the manufacture of tanks, ducts, blower hoods, fan housings, and other structures. where resistance to corrosion is required Another new fiber gaining wide acceptance is Kevlar. It also has a unique property to a degree which neither Carbon nor glass fibers have that is adequate fracture toughness. There are two types of Kevlar: Kevlar 29 and Kevlar 49. The Kevlar that usually finds its way into structures is Kevlar 49. It is of equal strength but has a higher modulus than Kevlar 29. Unlike Carbon fibers, Kevlar does not conduct electricity. It also has a low compressive strength and modulus compared to the high tensile properties. Kevlar acts more like a glass fiber to transmit electric radiation such as antenna windows

1940 Hakim S. Sultan Aljibori in stringent conditions, high pressure & temperature, highly corrosive environments, which the conventional materials failed to service. This has triggered the development needs for engineered materials to cater to customized needs. Industry has recognized the ability of composite materials to produce high-quality, durable, cost-effective products. In recent years there is an increasing demand in the use of composite materials for the automotive, aerospace and rail industry. The automotive and aerospace applications over the past quarter-century have been primarily in special areas such as energy absorber devices. When using composite in the body structure of a vehicle, considerable weight reductions can be achieved compared to conventional isotropic structures, which leads to reduced fuel consumption and consequently lower carbon dioxide emissions. Material Constituents The major constituents in a fiber-reinforced composite material are the reinforcing fibers and the matrix. FRC can be classified into broad categories according to the matrix used: polymer, Metal, ceramic, and carbon. Polymer matrix composite include thermoset or thermoplastic resins reinforced with glass fiber, carbon (graphite). aramid (Kevlar), or boron fibers. They are used primarily in relatively low temperature application. Metal matrix composite consists of metal or alloys reinforced with boron, carbon (graphite), or ceramic fibers. Composite materials were developed because no single, homogeneous structural material could be found that had all of the desired attributes for a given application in the aerospace industry [3]. Fibre One of the most commonly used fibers among the new composite materials is the carbon fiber. Among the advantages of carbon fibers is their exceptionally high tensile strength to weight ratio as well as tensile modulus to weight ratios, high fatigue strength and very low coefficient of linear thermal expansion. Where they can maintain their strength up to 2000°C, thus providing the dimensional stability required in space applications. Due to the high cost of these fibers: they are mostly used in the aerospace industry, where weight saving is more critical than cost. Glass fibers commonly used are the E-glass and S-lass. In addition to these glass types: there are others that are not usually included in advanced composites because they are used in different fields. For example, the C-glass: is used for chemical resistance in the manufacture of tanks, ducts, blower hoods, fan housings, and other structures, where resistance to corrosion is required. Another new fiber gaining wide acceptance is Kevlar. It also has a unique property to a degree which neither Carbon nor glass fibers have that is adequate fracture toughness. There are two types of Kevlar: Kevlar 29 and Kevlar 49. The Kevlar that usually finds its way into structures is Kevlar 49. It is of equa1 strength but has a higher modulus than Kevlar 29. Unlike Carbon fibers, Kevlar does not conduct electricity. It also has a low compressive strength and modulus compared to the high tensile properties. Kevlar acts more like a glass fiber to transmit electric radiation such as antenna windows

Fibre reinforced Composite(FRC) Structures 1941 The fiber provides virtually all of the load carrying characteristics of the composite. The desirable characteristic of most reinforcing fibers are high strength, high stiffness and relatively low density. Each type has its own advantages and disadvantages [4]. Unidirectional lamina and typical stacking sequence of composite laminates show in Figures 1 and 2 L Unidirectional continues fiber 圉圉十 Unidirectional Discontinues fiber 屡凌 L Random discontinues fiber Figure 1: Unidirectional Lamina of Composite material Figure 2: Typical Laminates of Composite material Matrix The matrix is essenti binder material of the composite. Basically, the key to composite ures is the resin matrix. The purpose of the composite matrix is to hold the together in the structure unit by virtue of its cohesive and adhesive characteristics, to transfer and distribute the applied load to and between

Fibre Reinforced Composite (FRC) Structures 1941 The fiber provides virtually all of the load carrying characteristics of the composite. The desirable characteristic of most reinforcing fibers are high strength, high stiffness and relatively low density. Each type has its own advantages and disadvantages [4]. Unidirectional lamina and typical stacking sequence of composite laminates show in Figures 1 and 2. Figure 1: Unidirectional Lamina of Composite material. Figure 2: Typical Laminates of Composite material. Matrix The matrix is essentially the binder material of the composite. Basically, the key to producing composite structures is the resin matrix. The purpose of the composite matrix is to hold the fibers together in the structure unit by virtue of its cohesive and adhesive characteristics, to transfer and distribute the applied load to and between Unidirectional continues fiber Bidirectional continues fiber Unidirectional Discontinues fiber Random discontinues fiber

1942 Hakim S. Sultan Alibori fibers, to protect them from environments and external damage, and in many cases contributes some needed property such as ductility, toughness, or electrical insulation. Experimental studies on polymers reveal that matrix behavior is dependent on time of rate and frequency of the load application and the ambient temperature [5-6]. High stiffness and strength usually require a high proportion of fibers in the composite This can be achieved by aligning a large number of fibers into a thin sheet(alumina or ply). The thickness of the lamina is usually in the range of 0. 1 to 1.0 mm. there are many Classification based on Matrices Manufacturing of Composites Various processes have been developed for manufacturing composite materials and composite structures. Composite materials are fabricated using wet lay up, filament winding. Compression molding, injection molding. Pultrusion, Prepreg, resin transfer molding, sheet molding compounds and auto clave molding. The early manufacturing opposites used a hand lay-up technique(Fig 3) Although hand lay-up is a reliable process, it is by nature very slow and labor intensive. In recent years, particularly due to the interest generated in all types of industry, there is more emphasis on the development of manufacturing methods that can support high production rates. This section describes the different processes used to fabricate composites Mold Gel Coat Resin Release Film Reinforcements Figure 3: Hand Lay up Process of Composite Structure Hand lay-up The hand lay-up is the oldest fabrication process for the advanced materials. ( Fig. 3) However, the hand lay-up is the simplest and most widely used fabrication process Essentially, it involves manual placement of dry fibre in the mould or mandrel and succeeding application of resin matrix. Then the wet composite is rolled using the hand rollers to facilitate uniform resin distribution to ensure better interaction between the reinforcement and the matrix and to achieve the required thickness the

1942 Hakim S. Sultan Aljibori fibers, to protect them from environments and external damage, and in many cases contributes some needed property such as ductility, toughness, or electrical insulation. Experimental studies on polymers reveal that matrix behavior is dependent on time of rate and frequency of the load application and the ambient temperature [5-6]. High stiffness and strength usually require a high proportion of fibers in the composite. This can be achieved by aligning a large number of fibers into a thin sheet (alumina or ply). The thickness of the lamina is usually in the range of 0.1 to 1.0 mm. there are many Classification based on Matrices. Manufacturing of Composites Various processes have been developed for manufacturing composite materials and composite structures. Composite materials are fabricated using wet lay up, filament winding. Compression molding, injection molding. Pultrusion, Prepreg, resin transfer molding, sheet molding compounds and auto clave molding. The early manufacturing method for fiber-reinforced composites used a hand lay-up technique (Fig 3). Although hand lay-up is a reliable process, it is by nature very slow and labor intensive. In recent years, particularly due to the interest generated in al1 types of industry, there is more emphasis on the development of manufacturing methods that can support high production rates. This section describes the different processes used to fabricate composites. Figure 3: Hand Lay up Process of Composite Structure. Hand Lay-up The hand lay-up is the oldest fabrication process for the advanced materials. (Fig. 3) However, the hand lay-up is the simplest and most widely used fabrication process. Essentially, it involves manual placement of dry fibre in the mould or mandrel and succeeding application of resin matrix. Then the wet composite is rolled using the hand rollers to facilitate uniform resin distribution, to ensure better interaction between the reinforcement and the matrix and to achieve the required thickness. The

Fibre Reinforced Composite(FRC) Structures 1943 layered structure is then cured In general the hand lay-up fabrication process is divided into four essential steps: mould preparation, gel coating, lay-up and curing Recently, partial automation of the hand lay-up is achieved by spray-up process. In which the application method of the resin matrix is slightly different from hand lay up. The hand lay-up fabrication process is mainly used in the application of marine and aerospace structures [7] A few examples of this processes uses are: boats, portable toilets, picnic tables, car bodies. diesel truck cabs hard shell truck bed covers and air craft skins and interiors. The hand lay-up process is labour intensive plus the plastic resins produce toxic fumes requiring well ventilated facilities and protective equipment for workers Filament windir In a filament winding process, a band of continuous resin impregnated roving or monofilaments is wrapped around a rotating mandrel and then cured either at room temperature or in an oven to produce the final product as shown in Fig 4. The mandrel the applications of filament winding are cylindrical and spherical pressure vessel can be cylindrical, round or any shape that does not have re-entrant curvature. Amor pipe lines, oxygen other gas cylinders, rocket motor casings, helicopter blades large underground storage tanks(for gasoline, oil, salts, acids, water etc. ) The process is not limited to axiS-symmetric structures: prismatic shapes and more complex parts such as tee-joints, elbows may be wound on machines equipped with the appropriate number of degrees of freedom. Modern winding machines are numerically controlled with higher degrees of freedom for laying exact number of layers of reinforcement Mechanical strength of the filament wound parts not only depends on composition of component material but also on process parameters like winding angle, fibre tension, esin chemistry and curing cycle. Typical Properties of Filament Wound Pipes(Glass Fibre reinforced) are listed in Table 2 TRAVERSE CARRIAGE PAY OUT EYE FIBRE SPOOLS Figure 4: Schematic Representation of the Wet Filament Winding Process

Fibre Reinforced Composite (FRC) Structures 1943 layered structure is then cured. In general the hand lay-up fabrication process is divided into four essential steps: mould preparation, gel coating, lay-up and curing. Recently, partial automation of the hand lay-up is achieved by spray-up process. In which the application method of the resin matrix is slightly different from hand lay￾up. The hand lay-up fabrication process is mainly used in the application of marine and aerospace structures [7]. A few examples of this processes uses are: boats, portable toilets, picnic tables, car bodies, diesel truck cabs, hard shell truck bed covers and air craft skins and interiors. The hand lay-up process is labour intensive plus the plastic resins produce toxic fumes requiring well ventilated facilities and protective equipment for workers. Filament Winding In a filament winding process, a band of continuous resin impregnated roving or monofilaments is wrapped around a rotating mandrel and then cured either at room temperature or in an oven to produce the final product as shown in Fig 4. The mandrel can be cylindrical, round or any shape that does not have re-entrant curvature. Among the applications of filament winding are cylindrical and spherical pressure vessels, pipe lines, oxygen & other gas cylinders, rocket motor casings, helicopter blades, large underground storage tanks (for gasoline, oil, salts, acids, water etc.). The process is not limited to axis-symmetric structures: prismatic shapes and more complex parts such as tee-joints, elbows may be wound on machines equipped with the appropriate number of degrees of freedom. Modern winding machines are numerically controlled with higher degrees of freedom for laying exact number of layers of reinforcement. Mechanical strength of the filament wound parts not only depends on composition of component material but also on process parameters like winding angle, fibre tension, resin chemistry and curing cycle. Typical Properties of Filament Wound Pipes (Glass Fibre Reinforced) are listed in Table 2. Figure 4: Schematic Representation of the Wet Filament Winding Process

1944 Hakim S Sultan Alibori Advantage of Filament (1) Accurate, repeatable fibre placement from layer to layer and from part to part (2) Capability to use continuous fibres over the length of a component area (3) Glass Fibre can reduce weight by 25-35% and Carbon Fibre reduce weight by 40-60% if replaced with the steel as shown in Table 1 (5) Low tooling costs and Large structures can be produce ons (4)Weight Reduction= Fuel Economy Emission Reductio (6) High fibre volume content (7) Low material costs (8)Complex shape st be wound as a pre-form and then moulded to near net shape (9) High energy absorption (10) Strength& stiffness: high value, directional property (11) Surface properties: corrosion resistant, weather, resistant, tailored surface (12)Low thermal conductivity, low coefficient of thermal expansion. Torsion stiffness axial stiffness tensile strength. hardness abrasion and wear resistance 8 Table 1: Lightweight Material and material replaced with the mass Reduction Material Mass Reduction Relative Cost ightweight material Replaced (per part) High Strength Steel Mild Steel Aluminum(al) teel, Cast Iron 40-60 Magnesium Steel or Cast Iron/60-75 5-2.5 Magnesium Aluminum -1.5 Glass FRP Composites teel 5-35 -1.5 raphite FRP Composites Steel coCo 0-60 b-10+ Al matrix Composites Steel or Cast Iron 50-65 1.5-3+ Itanium Alloy steel 0-55 5-10+ Stainless Steel Carbon steel .2-1.7 ncludes both materials and manufacturing

1944 Hakim S. Sultan Aljibori Advantage of Filament (1) Accurate, repeatable fibre placement from layer to layer and from part to part. (2) Capability to use continuous fibres over the length of a component area (3) Glass Fibre can reduce weight by 25 -35% and Carbon Fibre reduce weight by 40-60% if replaced with the steel as shown in Table 1. (4) Weight Reduction = Fuel Economy & Emission Reductions (5) Low tooling costs and Large structures can be produced (6) High fibre volume content (7) Low material costs (8) Complex shapes can first be wound as a pre-form and then moulded to near net shape (9) High energy absorption (10) Strength & stiffness: high value, directional property (11) Surface properties: corrosion resistant, weather, resistant, tailored surface finish. (12) Low thermal conductivity, low coefficient of thermal expansion.Torsion stiffness, axial stiffness, tensile strength, hardness, abrasion and wear resistance [8]. Table 1: Lightweight Material and material replaced with the mass Reduction. Lightweight Material Material Replaced Mass Reduction (%) Relative Cost (per part)* High Strength Steel Mild Steel 10 1 Aluminum (AI) Steel, Cast Iron 40 - 60 1.3 - 2 Magnesium Steel or Cast Iron 60 - 75 1.5 - 2.5 Magnesium Aluminum 25 - 35 1 - 1.5 Glass FRP Composites Steel 25 - 35 1 - 1.5 Graphite FRP Composites Steel 50 - 60 2 - 10+ Al matrix Composites Steel or Cast Iron 50 - 65 1.5 - 3+ Titanium Alloy Steel 40 - 55 1.5 - 10+ Stainless Steel Carbon Steel 20 - 45 1.2 - 1.7 * Includes both materials and manufacturing

Fibre Reinforced Composite(FRC) Structures 1945 Table 2: Typical Properties of Filament Wound Pipes( Glass Fiber Reinforced) Property Typical Predominant Process Variables Values Density 188-2.26 Glass/Resin ratio Tensile Strength. MPa 344-1034Glass Type, Glass/Resin Ratio Compressive Strength MPa 276-551 Glass/Resin Ratio, Resin Type Shear Strength, MPa, Interlaminar21-137 Resin Type, Glass/Resin Ratio, Resin t Modulus of Elasticity(Tension),21-41 Glass type, Wind Pattern GPa Modulus of Rigidity, (Torsion), 11-14 Wind Pattern Flexural strengt 344-517 Wind Pattern Glass/ Resin Ratio *The Predominant Process Variables are those, which have the greatest influence upon the range in the particular values reported Disadvantage of filament Some limitations of filament winding, these limitations are discussed below: a) Shape of component must be such that the mandrel can be removed Therefore, segmented mandrels or a mandrel made from sacrificial material such as plaster, may be used for parts with complex geometry. The mandrel is disassembled or dissolved after the part is cured and also difficulty in winding reverse curvatures(concave) b)relatively rough exterior surface (c) Expensive raw materials and higher fabrication cost and susceptibility to moisture It should be pointed out that structural materials are generally far more efficient in an extensional rather than in a flexural mode, making the arch and shell preferable over the beam and plate [8]. In general the layers are wound on a rotating mandrel,as presented in Figures 5 and 6

Fibre Reinforced Composite (FRC) Structures 1945 Table 2: Typical Properties of Filament Wound Pipes (Glass Fiber Reinforced). Disadvantage of Filament Some limitations of filament winding, these limitations are discussed below: (a) Shape of component must be such that the mandrel can be removed. Therefore, segmented mandrels or a mandrel made from sacrificial material, such as plaster, may be used for parts with complex geometry. The mandrel is disassembled or dissolved after the part is cured and also difficulty in winding reverse curvatures (concave). (b) Relatively rough exterior surface. (c) Expensive raw materials and higher fabrication cost and susceptibility to moisture. It should be pointed out that structural materials are generally far more efficient in an extensional rather than in a flexural mode, making the arch and shell preferable over the beam and plate [8]. In general the layers are wound on a rotating mandrel, as presented in Figures 5 and 6. Property Typical Values Predominant Process Variables* Density 1.88-2.26 Glass/Resin Ratio Tensile Strength, MPa 344-1034 Glass Type, Glass/Resin Ratio Compressive Strength, MPa 276-551 Glass/Resin Ratio, Resin Type, Shear Strength, MPa, Interlaminar 21-137 Resin Type, Glass/Resin Ratio, Resin Type Modulus of Elasticity (Tension), GPa 21-41 Glass type, Wind Pattern Modulus of Rigidity,(Torsion), GPa 11-14 Wind Pattern Flexural Strength 344-517 Wind Pattern, Glass/Resin Ratio *The Predominant Process Variables are those, which have the greatest influence upon the range in the particular values reported

1946 Hakim S Sultan Alibori (a) Filament Winding Composite (b) Filament Winding Composite Tubes Specimens for Internal pressure Test for Crushing test (c) Glass fiber/epoxy composite (d) Carbon fiber/epoxy composite Figure 5: Filament Winding glass and carbon fibre Composite of Internal Pressure Filament Wound Pressure Vessel Storage Tank

1946 Hakim S. Sultan Aljibori (a) Filament Winding Composite Specimens for Internal pressure Test (b) Filament Winding Composite Tubes for Crushing Test (c) Glass fiber/epoxy composite (d) Carbon fiber/epoxy composite Figure 5: Filament Winding glass and carbon fibre Composite of Internal Pressure and Crushing Tests. Filament Wound Pressure Vessel Storage Tanks

Fibre reinforced Composite(FRC) Structures 1947 Filament Wound Carbon/Epoxy Filament Wound, Pipe Fittings P (Tee elbow) Figure 6: Filament Wound Composite Material and Structures General Applications Composite materials are particularly attractive aviation and aerospace applications because of their exceptional strength and stiffness- to density ratios and superior physical properties. Success of aviation depends on new materials, engines, and manufacturing technologies. Commercial and industrial applications of fibre reinforced composites are so varied that it is almost impossible to list them all.A potential for weight saving with composites exists in many engineering fields and putting them to actual use would require careful design practices and appropriate process developments based on the understanding of their unique mechanical and physical characteristics Aerospace Applications Composites have become the basic material for major aerospace vehicles (see Fig 7) Weight is the primary reason for using fibre reinforced composites in many space reduction vehicles due to the expensive rates imposed on launch. By using carbon fibre reinforced composite, it has been found that there is a weight savings of about 40 percent over all titanium space fames. The other major factor in the selection of composite materials for many space applications is their stability over a wide temperature range. In general, there are many space components which have been fabricated using composites such as the support structures, truss structures, plate forms, pressure vessels, tanks and shells. However, composites have become an essential material for fabricating two major antenna components for commercial advance tele- communications operating in space. Another notable composite application on space shuttles is the pay-load bay doors, which the largest composite structure is ever built. Commercial production aircrafts such as the Boeing and airbus re using reinforced composites in different components such as forward wings, main landing gear doors, ailerons, flaps, rudders, elevators and many other components. In addition, composites are also widely used in the interiors parts such as overhead gage compartments. Ceiling floors are made in general of fiber reinforced epoxy in honeycomb sandwich constructions. The resin system is used because of its

Fibre Reinforced Composite (FRC) Structures 1947 Filament Wound Carbon/Epoxy Pipe Filament Wound, Pipe Fittings (Tee & elbow) Figure 6: Filament Wound Composite Material and Structures. General Applications Composite materials are particularly attractive aviation and aerospace applications because of their exceptional strength and stiffness- to density ratios and superior physical properties. Success of aviation depends on new materials, engines, and manufacturing technologies. Commercial and industrial applications of fibre reinforced composites are so varied that it is almost impossible to list them all. A potential for weight saving with composites exists in many engineering fields and putting them to actual use would require careful design practices and appropriate process developments based on the understanding of their unique mechanical and physical characteristics. Aerospace Applications Composites have become the basic material for major aerospace vehicles (see Fig 7). Weight is the primary reason for using fibre reinforced composites in many space reduction vehicles due to the expensive rates imposed on launch. By using carbon fibre reinforced composite, it has been found that there is a weight savings of about 40 percent over all titanium space fames. The other major factor in the selection of composite materials for many space applications is their stability over a wide temperature range. In general, there are many space components which have been fabricated using composites such as the support structures, truss structures, plate forms, pressure vessels, tanks and shells. However, composites have become an essential material for fabricating two major antenna components for commercial advance tele- communications operating in space. Another notable composite application on space shuttles is the pay-load bay doors, which the largest composite structure is ever built. Commercial production aircrafts such as the Boeing and airbus are using reinforced composites in different components such as forward wings, main landing gear doors, ailerons, flaps, rudders, elevators and many other components. In addition, composites are also widely used in the interiors parts such as overhead luggage compartments. Ceiling floors are made in general of fiber reinforced epoxy resin honeycomb sandwich constructions. The resin system is used because of its

1948 Hakim S Sultan Alibori excellent fire resistant properties [2]. The major structural application for fibre- reinforced composites are in the field of military for which weight reduction is critical for higher speeds and increased payloads. Because composites are strong, durable and damage tolerant, they have become an increasingly attractive alternative to metal for many aircraft components. The aircraft industry has found that proper use of these fibres reinforced composite offers the potential for reducing the weight as much as 50 percent. The shaping(forming) of composite material product is a difficult task to make and therefore is expensive. Raytheon Starship 2000(Fig 8)has all composite rames. Major joints are still metal Figure 7: Advanced Lightweight Figure 8: Using Composite Material in Composite Structures( Carriage and Aerospace Application Launch of rockets Marine applications In recent years, glass fibre-reinforced polyester laminates and Kevlar 49 have found use in marine applications. Among the application areas are boat hulls, decks bulkheads, frames and some other parts. The principal advantage here is also weight reduction, which translates into higher cruising speed acceleration and fuel efficiency Other advantages are increased stiffness, increased damage resistance, durability and ease of handling. Other applications of Kevlar 49 are manufacturing of the hulls of both large and small racing sailboats where the light weight increases speed, provides optimum weight distribution and facilitates portability. It is also used in the manufacturing of hulls and decks of small fishing boats. One of the most common types of layered composite failure is de-lamination and de-bonding of one layer from another(see Fig 9 Design and construct of Sun-boat composite structures were created and tested on computer. The 11.3m(37) 5.5m(18)tri-hulled boat is powered by the energy generated from 1728 solar cells. Construction of the boat involved sophisticated construction methods and has resulted in a boat of great strength, light weight and

1948 Hakim S. Sultan Aljibori excellent fire resistant properties [2]. The major structural application for fibre￾reinforced composites are in the field of military for which weight reduction is critical for higher speeds and increased payloads. Because composites are strong, durable and damage tolerant, they have become an increasingly attractive alternative to metal for many aircraft components. The aircraft industry has found that proper use of these fibres reinforced composite offers the potential for reducing the weight as much as 50 percent. The shaping (forming) of composite material product is a difficult task to make and therefore is expensive. Raytheon Starship 2000 (Fig.8) has all composite frames. Major joints are still metal. Figure 7: Advanced Lightweight Composite Structures (Carriage and Launch of rockets. Figure 8: Using Composite Material in Aerospace Application. Marine Applications In recent years, glass fibre-reinforced polyester laminates and Kevlar 49 have found use in marine applications. Among the application areas are boat hulls, decks, bulkheads, frames and some other parts. The principal advantage here is also weight reduction, which translates into higher cruising speed acceleration and fuel efficiency. Other advantages are increased stiffness, increased damage resistance, durability and ease of handling. Other applications of Kevlar 49 are manufacturing of the hulls of both large and small racing sailboats where the light weight increases speed, provides optimum weight distribution and facilitates portability. It is also used in the manufacturing of hulls and decks of small fishing boats. One of the most common types of layered composite failure is de-lamination and de-bonding of one layer from another (see Fig 9) Design and construct of Sun-boat composite structures were created and tested on computer. The 11.3m (37') x 5.5m (18') tri-hulled boat is powered by the energy generated from 1728 solar cells. Construction of the boat involved sophisticated construction methods and has resulted in a boat of great strength, light weight and