JEC COMPOSITES MAGAZINE - Issue #88 - April 2014 - Special JEC Americas Spring Edition - 53

Fig. 2: Material properties in GenLam C

Then, up to six angles can be entered in the
LamRank tab. These are the angles that will
be considered for building sublaminates.
The number of plies in a sublaminate is
then entered in addition to a safety factor.
The failure criteria available are quadratic or
maximum strain [1]. Once one of the failure
criteria is selected, the laminates will be
ranked according to the strength ratio either
R-Limit or R-Limit* using the following
definitions [1]:

are considered to cover some of the anchor
points of failure envelopes. For this example,
the material selected was T300/5208 and
no safety factor was included (SF=1).
The input information for a 4-ply case is
presented in Figures 3 and 4.
The LamRank outputs are shown in Figures
5 and 6, for the 4-ply laminate and 6-ply
laminate, respectively.
According to the outputs generated in

Fig. 3: Example of input information in LamRank for
a 4-ply laminate

Fig. 5: Example of output information in LamRank
for a 4-ply laminate (T300/5208)

Case study comparing the use
of 6 versus 4 ply angles in a sublaminate

Fig. 4: Example of input information in LamRank for
a 6-ply laminate

Fig. 6: Example of output information in LamRank
for a 6-ply laminate (T300/5208)

No88 April 2014 /

Special JEC Americas 2014

where R-FPF and R-LPF are the strength
ratios for first ply and last ply failure, respectively.

In this example, LamRank is used to
compare two different designs: the first one
considers up to four different ply angles
in a sublaminate while the second uses up
to six ply angles. The angles considered
are 0°, 90°, 45° and -45° for the 4-ply-angle
laminate, and 0°, 90°, 30°, -30°, 60° and -60°
for the 6-ply-angle laminate. Five load cases

Case study comparing the
material dependence on ranking
In this case study, different materials are
considered for the same set of loads given
in the previous case study. The idea is to
investigate how the ranking of the laminates
will change for different materials.

R-Ultimate = Maximum (R-FPF, R- LPF)
R-Limit* = R-Ultimate/Safety Factor
R-Limit = Minimum (R-FPF, R-Limit*)

The laminates will be ranked for the multiple
loading conditions. Up to five loads are
possible. In the next sections, two case studies are presented highlighting evaluations
conducted using LamRank.

LamRank, 35 ply combinations are ranked
for laminates with up to 4 ply angles. For the
loads considered, the [0/90/±45] or [π/4]
quasi-isotropic laminate ranks as number 2.
The "relat." column in the results indicates
the relative strength of each laminate as
compared to a [0/90/±45]ns quasi-isotropic laminate of the same material. Thus, for
the applied loads considered, a 48% improvement in strength is obtained if a cross-ply
[0/90]ns laminate is selected (Figure 5).
Another important feature of LamRank is
the information about the critical load that
controls the design (Figures 5 and 6).
For laminates with up to 6 ply angles, 462
combinations are ranked. The top ranked
laminate is again the [0/90]ns cross-ply with
48% improvement in strength when compared to the [0/90/±45]ns quasi-isotropic
laminate of the same material. Because of
the greater number of combinations possible
in this case, the [0/90/±30/±60] or [π/6]
quasi-isotropic laminate ranks as number 38
for the loads considered.

jec composites magazine 53
JEC COMPOSITES MAGAZINE - Issue #88 - April 2014 - Special JEC Americas Spring Edition

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