Stacking Sequence
A composite laminate is defined as the stacking of two or more unidirectional plies with the same or different fiber orientations. The plies (layers) can be made of the same or different materials, with individual thicknesses.
The stacking sequence, shown in Figure 3-1, is defined by the fiber orientation of each ply with respect to the first axis of the laminate coordinate system. The stacking sequence is interpreted from bottom to top, and the orientation angles are in general specified in degrees.
Figure 3-1: Example of a stacking sequence [0/45/90/-45/0] used in a composite laminate.
The stacking sequence is expressed in a concise form that is particularly suitable for laminates with a large number of plies (layers), using the fact that most laminates are either symmetric or contain many plies of the same orientation.
Some examples of stacking sequences are given in the table below:
Table 3-1: Example Stacking Sequences
Stacking sequence
Order of the Plies
Plies
[45/-30/0]
45°, -30°, 0°
3
[45/-30/0]s
45°, -30°, 0°, 0°, -30°, 45°
(s = symmetric)
6
[45/-30/0]3
Three repeated sets of 45°, -30°, 0°
9
[(45)2/-30/(0)3]s
45°, 45°, -30°, 0°, 0°, 0°, 0°, 0°, 0°, -30°, 45°, 45°
12
[45/-30/0]as
45°, -30°, 0, °0°, 30°, -45°
(as = antisymmetric)
6