TM 1-1500-204-23-11
concern when working with carbon iber laminates.
the cure cycle may cause the part to warp and twist
If care is not taken when designing laminates using
harness satins, the thermal stresses generated during
Figure 4-9. Example Satin Weave Showing Alternating Warp and Fill Faces Used for Lamination
b. Unidirectional Materials. Unidirectional materi-
(2) Unidirectional Fabric. A
unidirectional
als fall into one of two categories; unidirectional tapes,
(UD) fabric is one in which the majority of ibers run
and unidirectional fabrics.
in one direction only. Unlike unidirectional tapes, a
small amount of iber or other material may run in
other directions in order to hold the primary ibers in
(1) Unidirectional Tapes. Unidirectional tapes,
position. These cross ibers afford some structural
or uni-tapes, come in a variety of widths to suit the
properties, but their primary contribution is that they
manufacturer s needs. The thickness of a ply of carbon
make it possible to deliver unidirectional fabrics as
unidirectional tape is usually expressed as a function
dry broadgoods. In unidirectional fabric construction;
of its areal weight per square meter. For instance,
there are various methods of maintaining the primary
Grade 145 uni-tape weighs 145 grams per square
ibers in position in a unidirectional including weaving,
meter and its cured thickness is approximately .006".
stitching, and bonding. Some weavers of 0/90-degree
Carbon uni-tape is generally available in Grades 95,
fabrics term a fabric with only 75 percent of its weight
145, 160, 180, and 190. Since there are no cross
in one direction as a unidirectional, while for others
ibers at all in uni-tape it is usually only available in
the unidirectional designation only applies to those
pre-preg form.
fabrics with more than 90 percent of the iber weight
in one direction. True unidirectional fabrics offer the