SAMPE Journal - March/April 2017 - 10

Feature Article
[90]-axis. It is also indicated that the
continuous axial layers from root to
tip is 67%. This is important to know
strength and reliability along the
beam axis. In many bricky or patchy
design of beams based on black
aluminum it is not so certain what
is the axial layer percentage from
root-to-tip is. The other two cases in
Figure 5 have 50% axial layup from
root to tip.
In Figure 6 are two examples of
multiple zones with the laminate
thickness plotted against the length
of beam for 3 layup ratios of 6:0, 4:2
and 3:3. The lowest thickness is taken

as the final tapering of the beam. On
the left, there are 2 zones; on the
right, 3 zones, with their layup ratios
for each zone indicated. A balance
between laminate thickness and the
number of zones must be made.
For each additional zone, the layup
time will increase and a transition
zone must be added. Thus, it may
be justified to use the single zone for
the case on the left in Figure 6. The
case of 4:2 is preferred over that of
3:3 for a faster layup because the [0]axis layer is repeated once (there are
2 layers along the [0]-axis).

Figure 4. Three layup ratios for homogenized beams of 1:0, 2:1 and 1:1. Single ply
drops along the horizontal tool side are shown.

Figure 5. Three cases of beams with two layup zones and transition zone with percentage of uninterrupted axial layers from root to tip.
10

Weight Savings and Relative Layup
Speed
In Figure 7, the optimized weight
of the skin of a beam subjected to
combined in-plane loading8 is listed
relative to aluminum in the upper
part; and its layup time relative
to [π/4] in the lower part. On the
abscissa, 3 laminates based on
black aluminum (soft: [0/±454/90],
[π/4] and hard: [05/±45/90]), and 12
laminates from uni and crossed triaxial from C-Ply are listed. Each of
C-Ply laminates is labeled below
the abscissa axis that starts with
the off-axis angle of 60°, 45° or 30°,
thick-thin combination of bi-angle
C-Ply, (layup ratios on 3 cases), and
the number of layup zones in 1, 2 or
3. The weight savings in each case
is calculated based on the sizing
method in Reference8, while the
speed of layup relative to 4-axis for
[π/4] is extrapolated from the result
in Figure 3: for one zone 1:0 layup
the factor is 5 (2 cases), and 2:1 is 3
(3rd from the right), and 1:1 is 2 (4th
from the right); 3 zones is 3.1; 2 zones
is 2.7 (a total of 6 cases in the middle).
For the 3 black aluminum laminates
their relative weight is again
calculated from the sizing method
in Reference8. Their relative speed
of layup is estimated with [π/4] as
unity; hard having 4 additional [0] is
faster; while soft having 80% [±45] is
the slowest.
In Figure 8, 3 merits of weight
savings and speed of layup are listed
in the table on the right, and a semilog plot on the right. The first merit
in the first column in the table as
well as the plot on the right is shown
in blue. It is a linear ratio between
weight over speed (wt/speed).
The numerical results using the
data in Figure 7 is listed in the table
and in the plot as well. This linear
ratio merit is ranked with increasing
value in the table. The lower the merit
the lighter or faster layup speed (lost
manufacturing cost).
In the second column, weight
savings is squared; i.e., (wt)2/speed.
This merit factor give more value/
importance to weight than speed.
SAMPE Journal, Volume 53, No. 2, March/April 2017

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