The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Impact Testing on Reinforced Laminates
In 1985, we conducted two series of impact tests in our
lab. In the first, we looked at the relative effectiveness
of layers of fiberglass cloth in protecting a wood hull
from rocks and floating debris. <strong>The</strong> results of this testing
are useful for strip composite and stripper construction,
so we have included them in Chapter 23. In the second
set of experiments, we examined the effects of adding
layers of fiberglass and Kevlar cloth to a laminated
wood hull. Here, we were particularly interested in
finding out how the location of the synthetic fibers
in the laminate affected resistance to impact.
Panel 1
Load
“A-A”
7.85 E-Glass Cloth (0/90°)
Kevlar 49-095 Cloth
Kevlar 49-095 Cloth
D = 12"
W = 15 1 ⁄4"
Wt = 50 oz
Wt/Sq Ft = 39.3 oz
Before explaining our second test procedure, we should
point out that some of the combinations of cloth used
in this experiment are quite unusual and very expensive.
We were attempting to determine the best schedule of
Kevlar and fiberglass for a boat which will be sailed in
a single-handed, round-the-world race and must, therefore,
be exceptionally strong and damage tolerant. In
most designs, and for most uses, the additional expense
of this type of reinforcement is unwarranted. Our test
used both woven and knit cloth, but the effects of fiber
alignment and orientation were not apparent.
Panel 2
Panel 3 Panel 4
Load
“A-A”
7.85 E-Glass Cloth (0/90°)
17oz KDB Kevlar Cloth
D = 12"
W = 15 1 ⁄16"
Wt = 46 oz
Wt/Sq Ft = 36.6 oz
7.85 E-Glass Cloth (0/90°)
Kevlar 49-095 Cloth
DB 120 E-Glass Cloth
D = 12"
W = 16 1 ⁄2"
Wt = 56 oz
Wt/Sq Ft = 40.7 oz
D = 12"
W = 15 3 ⁄16"
Wt = 42 oz
Wt/Sq Ft = 33.2 oz
Figure E-1 Test samples constructed of synthetic fibers, cedar, and WEST SYSTEM ® epoxy. Arrow indicates direction of impact load.
Load
“A-A”
Load
“A-A”
7.85 E-Glass Cloth (45/45°)
APPENDIX
E