GTBL042-15 GTBL042-Callister-v3 October 4, 2007 11:49

2nd Revised Pages

Chapter 15 Composites

Bidirectional layers. ± 45 °

fiberglass. Provide torsional

stiffness.

Edge. Hardened

steel. Facilitates

turning by “cutting”

into the snow.

Core. Polyurethane

plastic. Acts as a filler.

Damping layer. Polyurethane.

Improves chatter resistance.

Unidirectional layers. 0° (and

some 90°) fiberglass. Provide

longitudinal stiffness.

Base. Compressed carbon

(carbon particles embedded

in a plastic matrix). Hard

and abrasion resistant. Provides

appropriate surface.

Top. ABS plastic having

a low glass transition temperature.

Used for containment and cosmetic

purposes.

Side. ABS plastic

having a low glass

transition temperature.

Containment and

cosmetic.

Unidirectional layers. 0° (and

some 90°) fiberglass. Provide

longitudinal stiffness.

Core wrap. Bidirectional

layer of fiberglass. Acts

as a torsion box and

bonds outer layers

to core.

Bidirectional layer.

± 45 ° fiberglass.

Provides torsional

stiffness.

Bidirectional layer. ± 45 ° fiberglass.

Provides torsional stiffness.

One relatively complex composite structure is the modernski. In this illustration, a cross section of a high-performance snow

ski, are shown the various components. The function of each component is noted, as well as the material that is used in its

construction. (Courtesy of Evolution Ski Company, Salt Lake City, Utah.)

WHY STUDYComposites?

With a knowledge of the various types of composites,

as well as an understanding of the dependence of their

behaviors on the characteristics, relative amounts,

geometry/distribution, and properties of the constituent

phases, it is possible to design materials with property

combinations that are better than those found in the

metal alloys, ceramics, and polymeric materials. For

example, in Design Example 15.1, we discuss how a

tubular shaft is designed that meets specified stiffness

requirements.

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