Glass fibers are made by letting molten glass drop
through minute orifices and then atten-uating(lengthening)
them by air jet. The standard glass fiber used in
glass-reinforced com-posite materials is E-glass,
a borosilicate type of glass. The glass fibers
produced,with di-ameters from 5 to 25 µm, are formed into
strands having a tensile strength of 5 GPa.
Chopped glass used as a filler material in polymeric resins for
molding consists of glass fibers chopped into very short lengths.
E-glass is the first glass developed for use as
continuous fibers. It is composed of 55% silica, 20% calcium
oxide, 15% aluminum oxide, and 10% boron oxide.
It is the stan-dard grade of glass used in fiber glass and has
a tensile strength of about 3.45 GPa and high resistivity.
S-glass was developed for high-tensile-strength applications
in the aerospace indus-try. It is about one-third
stronger than E-glass and is composed of 65% silicon dioxide,
25% aluminum oxide, and 10% magnesium oxide.
GRPs represent the earliest and the most widely used (over three-
fourths of total fiber-reinforced composite production) fiber-resin
composites. With glass fibers in various forms coupled with either
a thermosetting or thermoplastic resin, these composites can be produced
without the need for high curing temperatures or pressures.
The product contains a very good balance of properties, has high corrosion
resistance, and is low in cots for a multitude of uses as structural,
industrial, and consumer-related prod-ucts, ranging in size from minute
circuit boards to boat hulls. Using 20% to 40% fiber load-ings, the
composites will, in general, double the strength and stiffness of the
plastic resin used alone. Continuous fibers will increase these properties
fourfold, with accompanying desirable decreases in thermal expansion
and creep rate and with increases in impact strength, heat-deflection
temperatures, and dimensional stability. These fibers may take the from
of continuous filaments (monofilaments) or yarn.
The disadvantages accompanying these composites arise, in the main,
from the fact that they are especially two-phase structures. This
leads to a degree of environmental degradation greater than that
experienced by either component material alone. Residual stresses
and electrochemical effects result from the marriage of two dissimilar
materials. Furthermore, the diffusion of fiber materials into the
matrix materials, and vice versa, may take place at several stages.
Variation in the thermal expansion of these two materials leads.......作者: sin7198129 時間: 2010-12-8 00:15
有中文版嗎作者: ddLimin 時間: 2010-12-8 00:17
加油!!!我明天要考流體力學今天也要通宵念書了= =