Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

GTBL042-15 GTBL042-Callister-v2 August 29, 2007 8:52

650 • Chapter 15 / Composites

Helical winding

Circumferential winding

Polar winding

Figure 15.15 Schematic representations of

helical, circumferential, and polar filament

winding techniques. [From N. L. Hancox

(Editor),Fibre Composite Hybrid Materials,

The Macmillan Company, New York, 1981.]

which virtually eliminates the need for hand labor. These automated methods are

essential for many applications of composite materials to be cost effective.

Filament Winding

Filament windingis a process by which continuous reinforcing fibers are accurately

positioned in a predetermined pattern to form a hollow (usually cylindrical) shape.

The fibers, either as individual strands or as tows, are first fed through a resin bath

and then are continuously wound onto a mandrel, usually using automated winding

equipment (Figure 15.15). After the appropriate number of layers have been applied,

curing is carried out either in an oven or at room temperature, after which the mandrel

is removed. As an alternative, narrow and thin prepregs (i.e., tow pregs) 10 mm or

less in width may be filament wound.

Various winding patterns are possible (i.e., circumferential, helical, and polar)

to give the desired mechanical characteristics. Filament-wound parts have very high

strength-to-weight ratios. Also, a high degree of control over winding uniformity

and orientation is afforded with this technique. Furthermore, when automated, the

process is most economically attractive. Common filament-wound structures include

rocket motor casings, storage tanks and pipes, and pressure vessels.

Manufacturing techniques are now being used to produce a wide variety of

structural shapes that are not necessarily limited to surfaces of revolution (e.g.,

I-beams). This technology is advancing very rapidly because it is very cost effec-

tive.

Structural Composites

structural composite Astructural compositeis normally composed of both homogeneous and compos-

ite materials, the properties of which depend not only on the properties of the

constituent materials but also on the geometrical design of the various structural