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bre with a core of rigid polyurethane foam, the component parts of the coach bodies were constructed. To allow the inclusion of GRP reinforcing webs which ties the two outer skins together, the foam was interrupted at regular intervals. This minimizes the risk of buckling failure. In the case of tank wagons, light weight and corrosion resistance is needed. Various types of tank wagon or tank containers have been experimented by the European railways. GRP containers have been used for the transport of milk, Hydrochloric acid and other chemicals [7]. In 1990 composite railway auto carrier was designed and built by Alcoa/Goldsworthy Engineering for the Union Pacific Railroad [8].

2.4.3 Automotive

The reasons for choosing composites in automotive applications include lower weight, greater durability, corrosion resistance, fatigue life, wear and impact resistance. The main applications of composites in automotive includes drive shaft, fan blades and shrouds, springs, bumpers, interior panels, tires, brake shoes, clutch plates, gaskets, hoses, belts, and engine parts. Hybrid composite drive shaft is used for trucks. It is manufactured by pultrusion. For the manufacturing of drive shaft for trucks by pultrusion, Morrison Moulded fiberglass is used. It is manufactured by the pultrusion of carbon and glass fibre composites over an aluminium cylinder. It is significantly lighter and less expensive. One reason the composite shaft is less expensive is that it is fabricated as a single component [8].

GRP is used in automobile because of its advantage over standard materials like light weight, lack of corrosion, high strength to weight ratio and good surface finish. In addition to this the complex contours and shapes can be obtained without the need for expensive tools. The variation of the shape can be made at any time with minimum cost. GRP is easy to repair and results in much lower stress due to thermal expansion than with steel and other materials due to a lower modulus. The tensile strength can be high depending on the type of reinforcement and its method of application. Two of the disadvantages of GRP with regard to vehicle manufacture are that the labour content is high and the speed of production is slow compares with the most conventional methods involving metal [7].

2.4.4 Medical

Composite materials have a diversity of applications in medical field. They are used to decrease weight and prolong durability [8]. The main advantages of composites like high specific properties, high fatigue resistance and flexibility of manufacture are all helpful in the medical field. Recent progress includes a wider use of carbon fibre to include load-carrying links in the joint mechanisms, foot keels with sprung energy return. Shock loads are dampened using hybrid design incorporating elastomers [9]. The chemical inertness of carbon fibre has led to a number of surgical applications. Carbon composites are being implanted into cartilage to promote biological resurfacing of damaged areas [9]. Lightweight wheel chairs and crutches offer an obvious advantage to the user. Composites are used as a replacement for hip joint [8].

Other applications of composites include electronic, military, industrial, and marine. In addition to these applications, composites are used in consumer products like skis, golf clubs, and tennis rackets [21].