NONDESTRUCTIVE EVALUATION OF
FIBERGLASS USING CHOLESTERIC LIQUID
CRYSTALS:
REVIEW OF TECHNIQUES AND
INDUSTRIAL APPLICATIONS
by
TOMAS A. GONZALEZ
SUBMITTED IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING
at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
(May 1980)
Signature of Author.....v. ........................
.
...
.
........
Department of Mechanic4>ingine ring, 5-9-80
Certified by.
Accepted
by.
.
-
.
......................
Thesis Supervisor
-
q e....
.
Cl airman, Mecha
0*
0000.........................................
,.-nginering Department Committee
vpmlc
TECHNOLOYCRNES
ARCHIVES
JUN 241980
LIBRAp!ES
NONDESTRUCTIVE EVALUATION OF
FIBERGLASS USING CHOLESTERIC LIQUID
REVIEW OF TECHNIQUES AND
CRYSTALS:
INDUSTRIAL APPLICATIONS
by
TOMAS AGUSTIN GONZALEZ
SUBMITTED TO THE DEPARMENT OF MECHANICAL ENGINEERING
ON MAY 9, 1980, IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING
Abstract
Based
fiberglass with
test
for
the
evaluation
mography
and
designed
and
fiberglass
lighting conditions.
determination
minute
flaws
of
the
The
equipment
optimal
in
liquid crystal
ther-
Equipment
heat
built will
flux
for
A special
was
under different
specimens
in fiberglass specimens using
cholesteric liquid crystals.
paper
construction.
fiberglass
built to test
This
hulls.
boat
involved
specimen
of
crystals can provide a simple
fiberglass
of
various techniques
the
reviews
colesteric liquid
evaluation
nondestructive
investigation,
this
on
also aid
the
thermal
in
detection
the
of
testing with
fiberglass panel with 108
flaws of known size and location was built to help establish the
lower limit of resolution of different crystal blends and thermal
test procedures.
This research was exploratory and
initiatory.
The equipment
and specimens built for this research should help in the refineIt is hoped that the
ment of this thermal testing technique.
project
will
be
continued
until
a suitable
field
test
nondestructive evaluation of fiberglass is developed.
Thesis supervisor:
James H. Williams, Jr.
Associate Professor of Mechanical Engineering
for
the
- 3 FOREWORD
Composites
enable
the
design
of
unique
materials
which
combine high strength and high stiffness to an extent unattainable
through conventional
posites
have
a
high
metallurgical
strength/weight
practices.
ratio
which
Fiber
com-
makes
them
attractive materials where increased performance can be achieved
through weight reduction, such as in boat building.
composites
used
in
boat
construction
are
Most fiber
fiberglass
layups.
However, high performance sailboats and powerboats are currently
being built with kevlar, dynel, graphite and other sophisticated
and expensive
fiber materials.
performance applications and
The
capital
investment
Their use
is restricted to high
is done by very few manufacturers.
necessary to
manufacture
boats with
fiberglass is lower than that previously needed to build a boat
out of wood or aluminum.
impact
on
the boating
allows
it
to be
tions.
As a consequence,
industry.
molded
it has had a great
The versatility of
to many shapes
and
material
fiberglass
specifica-
This, combined with the relative ease of manufacture, has
attracted many builders to the boat industry.
Today some 2500 -
3000 builders build pleasure crafts which range in size from 9 100
feet
inboards,
and
are
classified
outboards,
into
various
inboard-outboards,
categories,
ATV's,
such
airboats,
as
sail-
boats, houseboats, custom boats, and canoes and kayaks. 1
There
are
no
enforceable
federal
regulations
regarding
construction of the fiberglass lay-up for pleasure boats.
the
Guide-
- 4 lines are set by the American Bureau of Shipping2 and the American Boat and Yacht Council 3,
but both of these are quite general
and only specify that the builder submit
for
review,
a fabrica-
tion process description before the lay-up is commenced.
the lack of regulations large variations
Due to
in
the qulity of design
and construction of pleasure crafts exists.
Deviation in proper-
ties
for
greater
composite
than
materials
that
on
considered
multiple
acceptable
tests
for
is
somewhat
established metal
technology.
Under the Federal Boat Safety Act of 1971, the Coast Guard is
given
the
power
to
require
the
contains a safety defect to
necessary
repairs
at
the
manufacturer
notify all
of
a boat
which
purchasers and make the
manufacturer's
expense.
The
obstacle to effective enforcement regarding structural
major
integrity
is the lack of quantitative inexpensive NDE techniques which can
be broadly required by the Coast Guard.
Pleasure
boat manufacturers
and
the boating
simple cost-effective method for assessing the
grity
of
fiberglass pleasure
craft may be
unable
to
niques
which
composite
sold
or
establish
are
transferred
quantitative
employed
structures
craft.
are
by
as
public
structural
expensive,
inte-
governmental
aircraft
agencies
Most NDE
industry
complicated
and
are
tech-
to
test
equipment-
intensive.
What this research project aims to establish is:
1)
no
Consequently, substandard
regulations.
the
have
A cost-effective NDE technique for boat manufacturers
prior to craft delivery;
2)
A
procedure
to
assist
governmental
agencies
in
establishing quantitative structural criteria for
pleasure craft;
3)
A technique
to
aid
marine
surveyors
in
conducting
"Condition Surveys" which form an important basis for
craft insurability;
4)
A
simple
test
for
boat
owners
for
assessing
the
structural integrity of their boats;
5)
Laboratory apparatus and techniques which will
meet the aims listed above.
help
- 6 INTRODUCTION
The purpose
easily
of this
utilized
research was to develop an
nondestructive
evaluation
(NDE)
inexpensive
test
for
the
evaluation of fiberglass structures.
Most
defects
common
to
composite
layups
such
as
voids,
delaminations, uncured matrix, improper interface bonds, improper
resin-matrix
ratio and even the
are internal
in nature and are usually undistinguishable from an
neglect of
Nondestructive
undamaged composite.
reinforcing
evaluation
(NDE)
layers,
techniques
must be used to detect the presence of potentially hazardous defects.
Methods for establishing the quality of the manufactured
composite by NDE must be developed to a high level of assurance
for
all
types
of
fiber-matric
composite
layups.
Although
the
science of NDE is very broad, certain categories, each containing
a number
of
NDE
techniques,
offer
characteristic
capabilities
which are likely to be of essential value in revealing the types
of flaws which are most prevalent
method
selection
is
in
generally based
composite materials.
on part
NDE
geometry and com-
position, defect size, location, orientation and availability of
test
equipment.
Very
often
more than one NDE method
because different conditions and defects are revealed.
methods
which
are
likely to prove
most valuable
is used
Some NDE
in evaluating
fiber composites are summarized in Table 1.
The first step in the nondestructive evaluation is the visual
- 7 inspection of the fiber composite layup.
The method for identi-
fication and classification of visual defects in glass reinforced
allowable defects and their
laminates is covered in ASTM D2563;
to
have
be
All composite parts
included in table 2.
acceptance levels are
with
conformance
for
inspected
and
dimensions
Critical areas are defined
tolerances specified of the drawings.
by ASTM as those areas in which the presence of imperfections is
considered to be most detrimental, these areas shall be free of
all defects listed in Table 2.
which
content,
nature,
by
The defects in noncritical
or
not
do
frequency
areas
affect
serviceability of the part are designated as allowable defects.
2.
in Table
described
comply
must
defects
Allowable
The
the
with
presence
acceptance
these
of
defects
levels
must
be
The type of test I am aiming
indicated in the product drawings.
for is one that can be used at any remote location, such as a dry
a boat
dock or
trailer
users
boat
and
as
a variety of
This would result in a test which can
environmental conditions.
aid
and under
1.),
(see fig.
to
a supplement
visual
inspection
for
analyzing the structural integrity of fiberglass boats.
Nondestructive evaluation of fiber composites with cholesteric liquid
process
for
crystals
the
is a cheap,
evaluation
of
accurate
fiberglass
easily
utilized
structures.
Previous
and
research using cholesteric liquid crystals have found them to be
successful
tools
in
the
analysis
of
bonds,
leak
detection,
penetrant detection, thermal definition of cracks and the analysis
of
honeycomb
composites.
The
chemical
properties
of
the
- 8 liquid crystals are discussed in Appendix B.
The first step of
the research was to develop techniques and equipment for a field
test that can be used for the thermographic evaluation of
commercial
formed
and
the
I have per-
The experiments
fiberglass structures.
equipmment I built
for
this
project
should
be
extremely useful for the quantitative analysis of the variety of
defects and material
properties
that can
be obtained from such
techniques.
My
broken
research
down
equipment,
crystal
those
into
in
three
specimen
system.
doing
thermography.
liquid
components,
design
I hope
further
crystal
this
research
and
thermography
(LCT)
the
and
test
jig
construction
thesis can serve
in
the
area
of
and
as
can
recording
the
liquid
a guide
liquid
be
for
crystal
9 -
-
EXPERIMENTAL PROCEDURE
when
LCT,
detection
for
allows
rapidly changing departures
at
the
simultaneous
a large
number
of
The area which can be tested effectively depends on the
points.
area
of
executed,
properly
over
which
monitored.
constant
The test
illustrated
in
intensity
heat
can
stand which I built
figure
2.
This
jig
be
applied
for this
is
and
research is
designed
for
the
irradiation of large surface ares with a uniform intensity light.
The angle and intensity of the lights and the size of the uniform
test area can be controlled by moving the lamps relative to the
area to be tested.
The lights used on this jig are Smith Victor
Model 750/1000 watt quartz-iodine studio lamps and are mounted on
a set of rails that allows them to be placed anywhere within the
shaded area in figure 2.
The flexibility provided by this light
jig can aid, in later research projects, to find the optimal heat
flux
pattern
for
the
detection
of
minute
flaws
in
fiberglass
specimens.
Another
objective
of
this
experimental
set-up
was
to
accommodate specimens of many sizes.
Liquid crystal thermography
(LCT)
can
evaluation
whose
thermal
of
be
material
a useful
tool
for
the
of
any material
response is significantly altered by the presence
discontinuities,
to
the
point
where
it
becomes
present at the surface as a variation in the thermal map.
of
the
specimens
tested
were
others consisted of flat panels
1"
(7"
x
12"
x 7").
strips
of
Some
fiberglass,
The specimen holder
-
10
-
consists of a highly articulated adjustable microscope
(fig.
3)
mount
built by American Optical
Instrument Company.
Specimens
are held on a plane which can be placed and secured
in a large
to be unmounted or
of positions without having
number
touched.
This is extremely convenient for LCT since you avoid disturbing
the liquid crystal
The mounting plate is 4" x 19" and can also be used
or adjusted.
to
layer whenever the specimen needs to be moved
thermometer
stopwatches,
hold
identification
and
probes
labels.
The open design of the test stand permits observation of the
from
LCT
many
Permanent
angles.
thermograms can be made on color
records
of
liquid
considerations
Several
film.
crystal
must be made in color film selection as they have different film
Higher film speeds
resolution and color response.
speed,
(ASA)
allow the use of higher F-stops that provide a greater depth of
High ASA films should be used if the application involves
field.
curved surfaces that are difficult to focus entirely or where the
light
sources
are
located
film
speeds
lose
Higher
more
3'
than
though
resolution
enough to affect thermogram interpreation.
heat up Kodachrome ASA 100 is adequate.
project
is a Nikon FM with
a 135 mm
from
the
not
thermogram.
significantly
For monitoring during
The camera used for this
f/2.8 Autopromaster
lens.
There are a couple of drawbacks to this photographic set-up:
1)
The
promaster
lens does
light meter so that
not
automatically
not
couple
with
the
Nikon
f-stop changes on the lens are
sensed
by
the
light
meter,
thus
-
-
11
correct exposure has to be set manually.
The 135 mm lens is too long, so it does not allow for
2)
specimen.
close-up photos of the
sug-
A couple of
gestions on the recording equipment are to get a 50
mm NIKON MACRO Lens and a motor drive for the camera.
In addition to the photographic recording equipment we used a
digital
portable
thermometer
(Precision Digital
521)
Model
to
monitor the temperature of the specimen surface during the test.
The probe used was
Thermistor
Probe).
cup, epoxy backed.
surface
an attachable
It
consists
Series
(YSI
probe
700
stainless steel
of a 3/8" dia.
The time constant of the probe is 1.1
sec-
onds.
The time constant is a standard measure of probe response
time;
it is the time required for a probe to read 63% of a newly
impressed temperature.
The next step in temperature monitoring
will be to connect the thermometer to an X-Y plotter so that we
get
vs.
time
advise using
temperature
every
of
graphs
I would also
test.
accurate measure-
an air temperature probe to get
ments of the effects of ambient temperature on LCT.
Specimen Design
The
fiberglass
specimens
used
in
this
research
were
dupli-
cates of the lay-up used in the construction of single skin hulls
4
for high performance yachts . The main objective of the specimen
was
to
introduce
location,
current
to
LCT
a number
determine
test.
The
the
of
flaws
lower
of
limit
specimen was
known
of
type,
size
and
of
our
resolution
built of
seven
layers of
-
12
-
glass in a mold shaped as a scale model of popular deep-vee hull
6
This shape was useful in analyzing the
designs (fig. 4)6.
usefulness
of
for
LCT
testing
of
surfaces
and
sizes
different
The construction of fiberglass panels is described
orientations.
(fig. 5) panel contains 108 flaws made
The main
in Appendix A.
to represent small air voids or cracks in the interior of a boat
The flaws come in six sizes (.20 -
hull.
of
flaws
internal
previous
that
interface
the
between
the
glass
layers
flaws are made from micropipettes are more
These
fiberglass
of
than
the
air
(fig.
crystals
can be
used
voids
directly without
applied
6).
representative
The panel was built with a black gel
tests.
liquid
groups of
The location of the flaws varies also; they are
on the panel.
at
in
.80 -
3/4" - 1/2" depending on their location
six with lengths of 1" -
located
.63 -
.56 -
and are built into the specimen
mm diameter)
1.05
.28 -
in
coat so
a backup
Molded fiber glass, whether in a boat, car body, furni-
paint.
ture or other items, is easily repaired with polyester resin and
fiber
glass
mat
and/or
cloth.
Sometimes
the
secondary
bond
between the patch and the hull is not perfect and may fail while
in operation.
LCT can be useful for the detection of air gaps in
the secondary bond as well as internal cracks which may have gone
undetected.
significantly
thermal
The presence of voids
weaken the
in adhesive bonds which may
structure will
diffusivity of the bond line.
coated with
also decrease
the local
As the surface, which is
the liquid crystals, is heated, the face sheet (over
areas with poorer heat transfer) will heat more rapidly than the
-
13
-
adjacent well-bonded areas.
Since
thermal
of
temperature
surface
the
undergoing
a material
is only a few degrees above room temperature a
testing
direct photographic method cannot be used to detect the temperature differences because no photographic material exists which is
the long wavelength
sensitive to
stroms)
region
(8000 Angstroms -
Thermal
in question.
10,000 Ang-
gradients can be detected
and evaluated by various methods most common of which are the use
of
thermal
focused
sensitive
coatings
attention
on the
our
use
of
We
inspection.
infra-red
and
temperature-sensitive
cho-
lesteric liquid crystals for the evaluation of thermal gradients
associated with material discontinuities.
Liquid Crystals
Liquid crystals are described in Appendix B.
with
the
cholerteric
evaluation
liquid crystals can be
odd-shaped
of
surfaces,
particularly useful
and
irregular
which cannot
be assessed by other NDE methods.
thermography
can be useful
any
material
as
long
as
painted with black paint.
for monitoring
the
surface
Thermal testing
is
in
contours
Liquid crystal
thermal
smooth
gradients
and
has
in
been
With liquid crystals it is possible to
make direct observations in high ambient light of small thermal
gradients near room temperature.
Their simplicity, high sensi-
tivity and speed of response make them readily adaptable to the
varied
requirements
vestigations.
of
laboratory
and
process
development
in-
-
14
-
Liquid crystals should be sprayed uniformly over the surface
of the specimen.
Potting depths slow response time and wash out
resolution considerably, and therefore, one must avoid touching
the
surface
affect
of
a coated specimen
response
the
of
the
since streaks and marks also
crystals.
Liquid
crystals
can
be
washed off with acetone, Ajax or any similar detergent; make sure
all the old crystals are washed off before applying a new coat.
Specimens
should be dry and
free
of dust particles before they
are coated with crystals, as these will also adversely affect the
response of the blends.
can be used
left
on
the
Once a specimen is coated the same blend
repeatedly approximately 25 times.
specimen
for
several
damaged by dust or wind exposure.
days
as
long
The coat can be
as
it
is
not
-
15
-
CONCLUSIONS AND RECOMMENDATIONS
nondestructive
specimens
method for the
thermography can be a useful
Liquid crystal
evaluation
prepared
in
of
this
equipment
and
designed to conduct
re-
The
fiberglass.
thesis are
search to develop a field test for the evaluation of boat hulls.
A variable heat
areas has
been
source that
built
(and is
can apply uniform heat over large
now
in
3-365).
This
test
stand
should be used to find the optimal heat flux for the detection of
very small
flaws
in fiberglass.
The jig has
been designed so
A fiberglass panel with
that it is easily adjusted and serviced.
108 flaws of known size and location was also built and
The
present
flaws,
those
system was
only
capable
of the outermost layers.
of
detecting
8 of
testd.
these
The light jig and fiber-
glass panel can be used quantitaviely to rate the effectiveness
of different
crystal blends under different
test conditions.
I
hope this research is continued and that this thesis can serve as
a good starting point
and guide for future research projects in
Liquid Crystal Thermography.
-
Building a fiberglass specimen.
APPENDIX A.
The
construction
-
16
that
factors
the
affect
or
lay-up,
is
an
attention to a large number
elaborate process requiring careful
of
panel,
a fiberglass
of
of
quality
the
Fiberglass
panel.
specimens can be built of any size, shape and strength with good
as
consistency
long
as
the
is
up
lay
carefully
planned
and
There are two basic types of fiberglass panels: single
executed.
Construction of sandwich panels
skin and sandwich construction.
is more difficult than single skin because of the steps necessary
to ensure a good bond between the skins and core. There are three
(1) Those incorporat-
basic core materials in general use today:
ing light weight cores of foam or balsa, in which the bending is
almost
resisted
core.
modulus of the
effective
by
entirely
in bending,
(2)
the
such as plywood, which has
incorporating
the
very
low
a modulus of
For this type the design of
the panel must be based on the lower
Those
to
Those incorporating cores which are
elasticity similar to that of FRP.
(3)
due
skins,
strength
thin FRP webs
of
the
plywood.
to separate the
faces.
This type of construction permits the use of thinner panels since
the shear strength of the webs is far higher than that of foam or
balsa.
The
voids
between
the shear webs
are
generally filled
with low density foam (2 pounds per square foot) both to provide
a mold
buckling
surface
for
laying
of
the
webs
and
to
prevent
their
6
These are
illustrated in figure 7.
For a material of equal
-
-
17
stiffness, a sandwich panel will be both lighter and require less
Sandwich construction is
depth than a single skin with frames.
generally limited to large flat surfaces such as decks, bulkheads
The stiffness of sandwich panels is particularly
and cabin tops.
flexi-
surfaces where the
constructing walking
in
advantageous
bility of thin single skin FRP panels would be unacceptable.
Single
skin panels
are made
successive
of
layers
of
glass
Common layups consist of
reinforcement soaked in a resin matrix.
alternate layers of mat and woven roving repeated 3 or 4 times.
Mat or
chopped mat, consists of randomly oriented chopped glass
fibers
bonded
sheets
into
with
mat
Chopped
adhesive.
a light
comes in various weights (1/2, 3/4, 1, 1 1/2, 2 oz./sq. ft.) and
fiber
lengths
1,
(3/4,
1 3/4,
2 in.),
usually comes
it
and is commonly bought by the square yard.
handling
careful
to
embedded in the skin.
prevent
the
rolls
Chopped mat requires
fibers
glass
in
from
becoming
The women roving (rov) or fiberglass cloth
It
consists of long bundles of glass fibers woven into a cloth.
comes
in
several
commonly used
weights
in hull
(10-40
construction
repairs a lighter cloth --
oz./sq.
being
12-16 oz. --
yard),
the
the 24 oz.
one
most
size;
for
is preferable.
Mold Preparation
The first step in the construction of a fiberglass panel
the design and construction of a mold.
two ways:
is
A panel may be built in
into a female mold or onto a male mold.
In both cases
the construction is basically the same, the only difference being
-
18
-
Molds can be made
in whether you begin or end with the gel coat.
out
wood,
of
to work
only
requirement
I preferred
with.
proper application of a gel coat.
applied
should
surface
is the
polished smooth
be
coat;
since
polished it should be waxed several times
and then
sprayed with a mold
for the
With a female mold, the first
application
before
any scratches
the
or pits
Once a mold
surface of the panel.
appear on the outer
will
gel
outer
female
to work with aluminum
molds be cause we did not have the necessary equipment
layer
is
(so that they don't deform during lay-up) and
that they be stiff
easy
the
or fiberglass;
aluminum,
is
(using ceara mold wax)
sure
release, making
to keep
the
mold clean and free from dust until you are ready to apply to gel
coat.
Preparation of the surface
is all-important.
If
it is
done right, you will never have to do it again...so take you time
and work carefully.
The panel
is built from the outside in.
(4 mats,
ply construction
boat builders for
made
flat;
craft
3 rov)
I selected a seven-
similar to that used by most
from 20-60 ft.
The
first
panels were
more recent panels were scale models of single skin
power boat hulls.
I strongly recommend
that one practice with
small flat panels before attempting to build a complex specimen.
Flaw Design
The key to a successful specimen construction is organization
and
practice.
First,
the
materials
for the
selected and arranged in their proper sequence.
panel
The
have
to be
reinforcing
19
-
-
the correct
At this point one should also design and
flaws that will be
introduced in the specimens.
record should be kept of the flaw types,
included
be
will
analyzing
flaws
in
accurate
the
thermographs.
consistent
and
There
specimen
fiberglass
a
this
specimen;
the
in
in
to prevent
(with paper between the layers
sequence
separation of fibers).
prepare the
stacked
scissors and
can be cut to size using long
material
few
to
Initial
flaws
voids made by cutting out a section or several
when
introduce
can
them
of
later
help
are many ways
but
results.
locations that
sizes,
will
A
produce
consisted
of
sections out of
the layers and creating an air void in the lay-up.
This approach
has several drawbacks:
1)
resin
flows
in the vacant area
filling
up the void
unless one pre-cures the boundaries of the flaw;
2)
easily detectable with
although this type of flaw is
liquid crystals it is unlikely that it ever occurs in
real situations.
Using this technique I placed voids of only one ply thickness
(approximately 1/20") and was able to detect them successfully at
depths of up to 3/16".
Another
technique
for
introducing
flaws
of
known
location is to use small glass tubes, micropipettes.
size
and
The tubes
are first measured to determine the internal diameter, then they
are cut to specific lengths and sealed with wax.
I noticed that
the tubes tend to fill with resin by capillary action rendering
them useless
as
flaws;
this is why
I seal
the
ends with wax.
-
There are several
-
20
such
tubes as flaws,
advantages to using glass
as:
1)
ease of construction,
2)
variety and consistency of size (0.2-1 mm.),
3)
cut to any size and placed at any interface,
4)
their precise
size and
location can be
recorded as
they are placed in the lay up.
The drawbacks are:
1)
they tend to fill up with resin,
2)
they break easily when handlng and during lay-up.
Glass tubes can be used to model small air bubbles and hair line
tubes was that
glass
than
One of
inside a composite.
cracks
the
of
any
they were
flaws
which
the
reasons
available
smaller
sizes much
in
previously
were
I chose to use
detected
using
resolution for our
colicry hence we could set a lower limit of
test as well as a goal for further research in the area.
one
can
either
choose
polyester
or
epoxy
Polyester resin will do a fine job under most conditions
resins.
and
matrix,
the
For
is
most
resin
Epoxy
economical.
costs
more,
but
offers
greater adhesion and superior strength where needed for special
conditions.
adding
to
In addition, there are coloring agents available for
the
resin
polyester
or
tinting
Special
pigment
pigments
should
are
be
used
used
with
difference is the setting times.
for
epoxy
premixed
colors
A maximum of 1 oz. of
normally added to the finish coat only.
coloring
the
one
(1) quart
systems.
of
Another
resin.
major
Polyester resins can harden in
-
be
and
minutes
five
21
fully cured
(which are usually used
-
within
an
hour;
resins
epoxy
in large boat construction) require at
least 4 hours to set and up to 24 hours to be fully cured.
Where to Work
Work should be done under cover,
out-of-doors.
degrees
ferred.
If
Fahrenheit,
working
when
the
if possible, or
shaded
if
is
below
60
shop
is
temperature
a well-ventilated
and
heated
pre-
DO NOT WORK IN DIRECT SUNLIGHT, as this accelerates the
curing of the resin and can cause a distortion of the finish. A
temperature of 70 to 80 degrees Fahrenheit is ideal.
The mold or
other surfaces you are working on should also be at this temperature.
Getting Ready
Make sure the mold has been waxed
the lay-up.
any resin.
and sprayed before doing
Prepare all your tools and materials before mixing
This should include:
3 pairs of plastic gloves (at least)
3 beakers 500 or 1000 ml; have one for mixing resin,
one
with acetone and 1 spare.
2 brushes, 1 1/2" wide with brush hair cut to 3/4" length
1 flat roller
1 grooved roller
1 mold (waxed and sprayed)
5 mats (cut to size)
(one extra)
-
3 rovings
-
22
(cut to size)
epoxy resin -hardener --
DER 331 or similar
VERSAMID 140 or similar
pigments and mixing rod
paper towels
wax paper
flaws and notepads
If you are working with
apply the "gel coat" first
epoxy
resin, as
and let it
I did,
dry overnight.
you should
A gel coat
usually consists of tougher epoxy resin and is the outer layer of
a boat, a pigmented epoxy resin was used for our specimens since
gel coats are expensive and very difficult to work with.
On
cold days,
use more
hardener
to
insure curing;
on warm
days, cut down on the hardener to keep the resin from curing too
soon.
When applying the gel coat use equal amounts of resin and
hardener.
along
This accelerates
the cure
inclined mold surfaces.
and lessens
The "gel
flow of
coat" should be brushed
on the mold with long even strokes making sure all
removed.
resin
bubbles are
Allow the epoxy to settle for a few minutes then remove
any additional bubbles.
It usually takes several coats of resin
to cover the mold properly.
specimen remove excess
resin
If you are making a curved or angled
from corners or grooves;
in
addi-
tion, watch out for thinning out in inclined areas.
If you are working with a polyester resin you will have to be
more
careful
since
bubbles
may
never
get
a chance
to
escape
during the curing process and tend to get trapped at the surface.
-
Do not mix
the hardener with
time
Begin
will
the
resin until you are
be
with small
changed when
batches
until
using
resin
in
larger
approximately 100 ml for the gel coat -For the actual lay-up use about 400 ml.
You will need
1 1/2 sq. foot panel.
(for a seven-ply 1 square
Do not attempt to re-brush an area, particularly
after the resin has begun to harden.
of
amounts.
you have gotten experience with
the lay-up process and the application of resin.
foot specimen).
ready to
Never mix more than one quart at a time since
apply the resin.
gel
-
23
thickening,
discard
If the resin
it
and mix
in your can
another
batch.
shows
signs
After
the
Resin
is hard when your fingernail will not make an indentation
complete
layup
is finished,
allow
resin
harden.
to
in the surface.
Once the "gel coat" has dried you should clean
it
thoroughly
with soap and water to remove any oil or dust that may damage the
bond with the rest of the specimen.
Begin the lay-up by mixing a
batch of resin (2 Resin:1 Hardener), making sure it is well mixed
and that no bubbles are in the mixture.
Apply a coat of resin to
The mat
the mold and then place a layer of chopped mat on it.
should
first
be
rolled,
using
wax
paper
to
prevent
sticking
fibers onto the roller, and then coated with more resin.
Avoid
clumping, air gaps, resin pools for these will affect the quality
of your specimen.
To apply resin start from center and work out
with short rapid brush strokes.
The wet finish coat on top of
the first layer of mat acts as "bedding" coat for the first layer
of cloth.
The cloth
is applied while
the resin
is wet.
Each
-
24
-
layer is saturated from the bottom in this way, and from the top
with additional coats of resin.
Starting at one end of the mold,
the cloth
smoothly working out wrinkles as you go; now wet out
Use squeegee to smooth cloth if you prefer, but do
with resin.
wash hands frequently in bucket of
to use hands;
afraid
not be
unroll the cloth, applying
detergent and water or acetone (or simply put on new gloves).
cloth
the
Roll
out
evenly to
remove
air bubbles, note
all
that the cloth is much easier to roll than the mat since it will
not
have
clump
been
trapped
mat
in the
or
any air that may
below.
layers
Repeat
this
Trim and sand off all whiskers, lumps and extra
The smoother each layer is,
cloth.
remove
Finish up with one or two layers
procedure for all the layers.
of chopped mat.
to
pressure
apply extra
up,
the smoother the entire job
will be.
Let the fiberglass job stand for at least three days; "blushing" or
loosening of coating may develop if
the water
placed in
too soon.
Should air bubbles develop, sand through bubbles after resin
has
hardened,
then
fill
area
with
finish
coat.
Should
air
bubbles or pockets develop due to the cloth pulling away from the
gull
(surface not clean),
you can cut out the entire
area and
patch with cloth and resin.
Resin, chopped mat, roving, pigments, etc.,
from
Allied
Resin
Weymouth, Mass.
Corporation,
02189; Tel:
Weymouth
can be purchased
Industrial
(617) 337-6070.
Park,
East
-
-
25
Liquid Crystals
APPENDIX B.
Cholesteric Liquid Crystals
Liquid crystals are substances which over a clearly defined
temperature range appear to possess the flow characteristics of a
liquid while retaining much of the molecular order of a crystalline
liquid
to
according
lesteric
their
cho-
Cholesteric
long
whose
molecules
or
smectic
structures.
molecular
have parallel
crystals
nematic,
can be
crystals
Liquid
solid.
axis
lies
along very thin planes.
The molecular layers in a cholesteric substance are very thin
(approximately 3 Angstroms) with the long axes of the molecules
parallel to the plane of the
are essentially
flat,
with a
individual molecules
The
layers.
side chain of methyl
groups
(CH3)
projecting upward from the plane of each molecule. This unusual
configuration
of
direction
the
causes
the
long
axes
of
the
molecules in each layer to be displaced slightly
from the cor-
layers.
This
displacement,
which averages about 15 minutes or arc per
layer,
is cumulative
overall
displacement
responding
successive
through
traces
out
in
direction
adjacent
layers,
a helical
path.
so
that
the
pitch
The
of
the
helical
path
is
usually temperature-dependent, and the temperature dependence may
be postive or negative.
structure
can
be
in the cholesteric molecular
The twist
observed
in
the
optical
characteristics
of
homogeneously ordered layers.
The
molecular
architecture
of
cholesteric
liquid
crtystals
-
gives
-
26
rise to anumber of peculiar optical properties. As polar-
ized light transmitted perpendicularly to the molecular layer the
the electric vector
direction of
of
the
light will
be
rotated
progressively to the left along a helical path, thus the plane of
direction
through
poropagation
of
an angle
that
transmitting material.
rotate light
the electric vector and the
is determine by
polarization which
is
also
will
be
to
proportional
to
rotated
the
the
thickness
left,
of
the
Optically active materials, those which
in this fashion, such as
certain types of quartz,
rotate the plane of polarization about 20 degrees per millimeter
An optically active cholesteric
and are considered very active.
substance, on the other hand,
rotates the plane of polarization
through an angle of as much as 198,000 degrees, or 50 rotations
Liquid crystals of this kind are by far the most
per millimeter.
optically active substances known.
Another
strictly crystalline
optical
property
cholesteric liquids is circular dichroism.
light
is directed
separated
into
at
two
a
cholesteric
components,
one
by
When ordinary white
material,
with
exhibited
the
the
light
electric
is
vector
rotating clockwise and the other with the electric vector rotating counter-clockwise.
Depending on the material, one of these
is transmitted and the other
that
gives
color
when
combination
the
is reflected.
cholesteric phase
it
is
illuminated
of
colors depends on
its characteristic
by white
and the angle of the incident beam.
It is this property
light.
the material,
The
the
iridescent
particular
temperature
-
cholesteric
Each
carbon
of
number
over
range
perature
only
exhibit
in
ester
cholesteric
The
acid
the
group,
a fraction
of
the
the
the
tem-
determine
and
colors
they may go
Liquid
spectrum according to their structure.
through the full
the
crystals may
spectrum or
color
to
structure,
Liquid
transition.
this
responses
unique
has
which the crystals exhibit
during
exhibited
colors
atoms
-
crystal
liquid
variations.
temperature
27
crystals can be blended to scatter light over a temperature range
-20
from
degrees
to
250
Centigrade.
degrees
The
color-play
range (temperatures over which colors are given) can vary from 50
to 1 degree Centigrade, the response time is of the order of 0.1
a
with
sec.
resolution
0.1
liquid crystals
literature on
ture7.
of
degree
Centigrade.
The
in the patent
is covered
best
litera-
The important parameters that control a liquid crystal's
usefulness in non-destructive testing are:
1)
availability and cost,
2)
ease of application,
3)
resistance to wind and UV exposure,
4)
dust resistance,
5)
long shelf life,
6)
reliable color play range, at relevant temperatures.
Prepared
Liquid
liquid
Crystal
crystal
Biosystems,
can be
blends
Inc.,
26101
purchased
Miles
Road,
from LCB,
Cleveland,
Ohio 44128.
These are available in spray cans and come in four color play
ranges:
30-33
degrees
Centigrade,
31-34
degrees
Centigrade,
-
33-36
Centigrade,
degrees
32-35
28
-
degrees
blends
The
Centigrade.
are satisfactory for LCT but are not effective for testing thick
panels or performing tests where the relevant thermal differences
occur above 36 degrees Centigrade.
with
made
several
organic
Liquid crystal blends can be
available
chemicals
from
Kodak
and
I experimented with a system of cholesteryl oleyl
other sources.
carbonate and cholesteryl nonanoate and was able to duplicate the
response the blends produced by LCB.
color
I also be prepared
blends to operate at the 50 and 60 degrees Centigrade range.
temperature
room
range of canned blends
temperature and hence
The
just a few degrees above
is
is quite vulnerable
to air
currents
and other forms of convective cooling that affect the accuracy of
a test.
Blends should be applied evenly over the entire area
tested,
the
thickness
of
the
layer
should
be
about
to be
1 mil,
a
thinner layer should be used at first, then if the color response
was not adequate more crystals should be sprayed on.
open
area
newspapers.
for
spraying
When
and
place
the
specimen
flat
Select an
on
some
spraying avoid covering an area too thickly,
use fast strokes from 12-18 inches depending on the spay pattern.
When using your own blends be extremely careful with the atomized
solvent
(hexane,
petroleum ether);
they are
extremely
volatile
and should not be used indoors, unless there is good ventilation.
Blends for field testing will
wind and intense light.
amount
have to be able
to withstand
Using thin crystal films will reduce the
of distortion when exposed to wind.
The
use
of
ultra-
-
violet
stabilizers
such
as
29
PABA
-
(P-amino
benzoic
acid)
can
protect the blends from destruction by UV and can increase their
shelf life substantially 7
The cost of liquid crystal blends varies but
tively cheap compared to other NDE tests.
is still rela-
Cholesteryl nonanoate
is available from Eastman Kodak for 19.05 for 25 g, cholesteryl
oleyl
carbonate
25 g $49.50.
The crystal
blends are
the most
important part of the test and further research should definitely
be
conducted
fiberglass.
to
develop
suitable
blends
for
field
testing of
-
-
30
REFERENCES
1.
Communications
with
Boating
Safety
Devision,
USCG,
First
Coast Guard District, Boston, Mass. Spring, 1977 - Fall, 1977.
2.
Rules
for
Building
and
Classing
Reinforced
Plastic
Vessels
1978, American Bureau of Shipping, N.Y., N.Y.
3.
American
Ave.,
4.
Boat and Yacht
P.O.
Box 806,
190
Ketcham
Amityville, N.Y. (Standards and Recommended Practices).
Photography
Prosystem Inc.,
5.
Council,
of
Liquid
Crystal
Thermograms,
Liquid
Crystal
Cleveland, Ohio.
Survey of Boat Manufacturers, on Materials and Building Stan-
dards,
Prof.
J.
H.
Williams,
Fall,
1977
(for fiberglass
layup
procedure and quality control)
6.
Fiberglass
Boat
Design
&
Construction,
Robert
J.
Scott,
Tuckahoe, N.Y., J de Graff, 1973.
7.
Williams, Edward L.
"Liquid Crystals and Electronic Applica-
tions, Chemical Technology Review, No.
46.
Liquid Crystals and Their applications --
Patent Literature on
a very useful text.
-
31
-
Liquid Crystals
REFERENCES, APPENDIX B.
"Cholesteric Liquid Crystals for Nondestructive
Brown, Shelba P.,
Testing."
Materials Evaluation, Aug.,
Frederick
Davis,
"Liquid
1968,
Crystals:
A
search/Development, June, 1967, p. 24 -
G.
D.
"Cholesteric
Dixon,
p. 163 - 166.
New
in
Testing" Materials Evaluation, June, 1977, p. 51 -
J.
L.
"Liquid Crystal"
Fergason,
No.
2, Aug.,
J.
L.
pp. 77 -
1964,
"Liquid
Fergason,
Applied Optics, Vol.
D.
R.
Green,
Ceramics."
D.
J.
for
and
Re-
Nondestructive
55.
Scientific American, Vol.
211,
85.
in
Crystals
Nondestructive
7, No. 9, Sept., 1968, pp. 1729 -
"Thermal
NDT"
27.
Crystals
Liquid
Tool
Infrared
Testing
of
Testing"
1737.
Composites
and
Materials Evaluation, Nov., 1971.
Hagemaier,
H.
J. McFaul
and J.
T.
Parks,,
"Nondestructive
Testing Techniques for Fiberglass, Graphite Fiber and Boron Fiber
Composite
Aircraft
Structures."
Materials
Evaluation,
Sept.,
1970.
D.
J.
Hagemaier,
H.
J.
McFaul
and
D.
Moon,
"Nondestructive
-
32
-
Materials Evaluation,
Testing of Graphite Composite Structures."
June, 1971.
G.
Edmund
Wunchwind.
Journal
Kenneth
II,
Henneke
Thermography --
Wayne
and
Reifsnider
W.
An NDI Method for Damage Detection,
September
Metals,
of
L.
1979,
p.
11
-
15
(video-
thermography) .
E. W. Kitzscher,
K. H. Zimmerman and J.
L.
Bothin,
"Thermal
and
Infrared Methods for Nondestructive Evaluation of Adhesive-Bonded
Structures."
Materials Evaluation, July, 1968.
Eugene Sprow,
"Liquid-Crystals,
Design, Feb.
1969.
W. E.
Aug.,
W.
E.
with
1968, p. 149 -
Woodmansee,
Liquid Crystals.
1721 -
and
Woodmansee
Discontinuities
1727.
pp. 34 -
H.
L.
Liquid
a film in Your Future."
Machine
41.
Southworth,
Crystals."
"Detection
Materials
of
Material
Evaluation,
154.
"Aerospace
Thermal
Mapping
Applications
of
Applied Optics, Vol. 7, No. 9, Sept, 1968, pp.
-
Figure 1.
drawing
33
-
Field testing with cholesteric liquid crystals.
illustrates
testing.
a possible
A--Regulated
B--Camera.
tective tent.
frequency
C--Technician.
F--Boat.
equipment
and
set-up
amplitude
D--Portable
for
light
generator.
This
on-site
source.
E--Pro-
G--Instrument box with light controls.
w
w
?AN
7:
L-/A
4.
H~~~
Figure 2.
filament.
Light
jig
(top
view)
this
section.
M FAT
AA$
Taken
at mid-
Shows the rails built for this research which permit
quick adjustments on the location of the studio lamps.
areas show possible locations for light filaments.
------- -
Shaded
-
35
-
TABLE 1
APPROPRIATE NONDESTRUCTIVE EVALUATION METHODS
FOR COMPOSITE MATERIALS
DEFECT
FIBERGLASS
BORON FIBER
GRAPHITE FIBER
Disbonds
Sonic
Ultrasonic
Thermal (thin
sections only)
Sonic
Ultrasonic
Thermal (thin
sections only)
Eddy-Sonic
Sonic
Ultrasonic
Delaminations
Eddy-Sonic
Sonic
Ultrasonic
Sonic
Ultrasonic
Thermal (thin
sections only)
Eddy-Sonic
Thermoluminescent Thermoluminescent
Coatings
Coatings
Sonic
Ultrasonic
Thermal (thin
sections only)
Eddy-Sonic
Thermoluminescent
Coatings
Fiber-Orientation Back-lighting
(magnified)
(Tape)
-X-ray (low kv)
Back-lighting
(magnified)
X-ray (low kv)
X-ray (low kv)
FIber-Orientation X-ray
Microscope
(Laminate)
(edge)
X-ray
Microscope
(edge)
Microscope
(edge)
Inclusions
X-ray
Ultrasonic
X-ray
Ultrasonic
X-ray
Ultrasonic
Crushed
X-ray
Ultrasonic
(through
transmission)
X-ray
Ultrasonic
(through
transmission)
Eddy-Sonic
X-ray
Ultrasonic
(through
transmission)
Eddy-Sonic
Resin-rich and
resin-starved
areas
X-ray
Ultrasonic
X-ray
Ultrasonic
X-ray
Ultrasonic
Hicromechanic
studies
Acoustic
emission
Acoustic
emission
Thickness
gaging
Micrometer
Ultrasonic
Micrometer
Ultrasonic
Porosity and
cracks
(internal)
Ultrasonic
X-ray (thin
sections only)
Ultrasonic
X-ray (thin
sections only)
Ultrasonic
X-ray (thin
sections only)
Porosity and
cracks
(external)
Penetrant
Penetrant
Penetrant
Honeycomb
Core
Adhesive
disbonds
joint
*
Acoustic
emission
.Hicrometer
Ultrasonic
Pulse Echo
Pulse Echo
Pulse Echo
(Also, see disbords and dela-minations above.)
-
36
Visual Acceptance Levels
Name
Definition
Level I
+
a small piece broken off an edge or surface
none
Crack
an actual separation of the laminate, visible
on opposite surfaces, and extending
through the thickness
crack existing only on the surface of the laminate
fine cracks at or under the surface of a laminate
Delamination, edge separation of the layers of material at the edge
of a laminate
Delamination, inter- separation of the layers of material in a laminal
nate
Dry-spot
area of incomplete surface film where the reinforcement has not been wetted with resin
metallic particles included in a laminate
Foreign inclusion
which are foreign to its composition
(metallic)
Crazing
Foreign inclusion
(nonmetallic)
Fracture
Air bubble (void)
Blister
Burned
Fish-eye
Lack of fillout
Level II
Level
+----------4
Chip
Crack, surface
-
nonmetallic particles of substance included
in a laminate which seem foreign to its
composition
rupture of laminate surface without complete
penetration
air entrapment within and between the plies
of reinforcement, usually spherical in shape
rounded elevation of the surface of a laminate, with boundaries that may be more or
less sharply defined, somewhat resembling
in shape a blister on the human skin
showing evidence of thermal decomposition
through some discoloration, distortion, or
destruction of the surface of the laminate
small globular mass which has not blended
completely into the surrounding material
and is particularly evident in a transparent
or translucent material
an area, occurring usually at the edge of a
laminated plastic, where the reinforcement
has not been wetted with resin
Table 2.
Ill
_____________________________________
none
maximum dimension of break, 3.0 mm
(/ in.)
none
maximum dimension of break, 6.5 mm
(!4 in.)
none
none
maximum length, 3.0 mm ('6.in.)
maximum lngth 6.5 mm (,
none
none
maximum dimension of crazing, 13 maximum dimension of crazing, 25 mm
mm () in.)
(I in.)
frequency and location to be determined by customer
maximum dimension, 3.0 mm (N in.)
maximum dimension, 6.5 mm (%gin.)
none
none
none
maximum diameter, 9.5 mm (% in.)
none
none, if for electrical use; maximpm none, if for electrical use; maximum
dimension, 0.8 mm 042 in.), 1/0.09
dimension,
1.5 mm (Y4, in.), 1/0.09
m' ( ft'), if for mechanical use
n 2 (I W), if for mechanical use
maximum dimension, 0.8 mm ("Ma in.), maximum dimension, 1.5 mm (%a in.);
1/0.09 m2 (I ft')
1/0.09 M2 (I ft)
none
in.)
none
maximum diameter, 14 mm (9/e in.)
none
maximum dimension, 21-mmn (Ij6 in.) maximum immension, mm
29
none
none
maximum diameter, 1.5 mm (Ye in.); maximum diameter, 3.0 mm (% in.);
2/in.'
4/in.'
maximum diameter, 3.0 mm (%.Jin.); maximum diameter, 6.5 mm (4 in.);
height from surface not to be outside
height from surface not to be outside
drawing tolerance
drawing tolerance
none
none
none
none
maximum diameter, 9.5 mm (% in.)
maximum diameter, 13 mm (.1- in.)
none
maximum diameter, 6.5 mm (i4 in.)
maximum diameter, 9.5 mm (h in.)
Allowable defects.
ASTM 2563.
(lh in.)
1
CD
-
37
-
Visual Acceptance Levels
Name
Definition
Orange-peel
Pimple
Pit (pinhole)
Porosity (pinhole)
uneven surface somewhat resembling an
orange peel
small, sharp, or conical elevation on the surface of a laminate
small crater in the surface of a laminate, with
its width approximately of the same order
of magnitude as its depth
none
maximum diameter, 14 mm (?J6 in.)
none
none
none
presence of numerous visible pits (pinholes)
none
maximum diameter, 0.4 mm (4 in.); maximum diameter, 0.8 mm (2 in.);
depth less than 20 percent of wall
depth less than I percent of wall
thickness
thickness
frequency and location to be determined by customer
maximum of 25 pits (pinholes) in po- maximum of 50 pits (pinholes) in porous area of size listed in Level Ill
rous area of size listed in Level II
maximum dimension, 13 mm (I in.);
maximum dimension, 6.5 mm (% in.)
height above surface not to be outside
height above surface not to be out
drawing tolerance
side drawing tolerance
an unintentional extra layer of cured resin on
part of the surface of the laminate
(This condition does not include gel
coats.)
an apparent accumulat,itin of excess resin in a
Resin-pocket
small localized area within the laminate
insufficient reinforcing material at the edge of
Resin-rich edge
molded laminate
Shrink-mark (sink) depression in the surface of a molded laminate where it has retracted from the mold
Pre-gel
Wash
Wormhole
Wrinkles
Scratch
Short
Level III
Level II
[Level I
area where the reinforcement of molded plastic has moved inadvertently during closure of
the mold resulting in resin-rich areas
elongated air entrapment which is either in or
near the surface of a laminate and may be
covered by a thin film of cured resin
in a laminate, an imperfection that has the
appearance of a wave molded into one or
more plies of fabric or other reinforcement
material
shallow mark, groove, furrow, or channel
caused by improper handling or storage
in a laminate, an incompletely filled out condition
NOTE-this may be evident either through
an absence of surface film in some areas, or
as lighter unfused particles of material
showing through a covering surface film,
possibly accompanied by thin-skinned blisters
Table 2 (cont.).
none
|
maximum diameter, 29 mm (11- in.)
maximum diameter, 3.0 mm (Li in.)
none
maximum diameter, 3.0 mm (!' in.)
maximum diameter, 6.5 mm (Ij in.)
none
none
maximum, 0.4 mm (4 in.) from thi
edge
maximum diameter, 9.5 mm (% in.)
depth not greater than 25 percent o
wall thickness
maximum dimension 21 mm (1%6 in.)
maximum, 0.8 mm (362 in.) from the
edge
maximum diameter, 14 mm (ia in.);
depth not greater than 25 percent of
wall thickness
maximum dimension 29 mm (4 in.)
none
maximum diameter, 3.0 mm (I in.)
maximum diameter, 6.5 mm (!/ in.)
none
none
none
none
maximum length surface side, 13 mn
(1i in.); maximum length opposit
side, 13 mm (M in.); depth less tha
10 percent of wall thickness
maximum length, 25 mm (1.0 in.); maxi
mum depth, 0.125 (0.005 in.)
none
Allowable defects.
maximum length surface side, 25 mm (I
in.); maximum length opposite side,
25 mm (I in.); depth less than 15 percent of wall thickness
maximum length, 25 mm (1.0 in.); maximum depth, 0.255 (0.010 in.)
none
ASTM 2563.
-
38
-
U eZx4" L&H ~ FeAM=
Figure 3.
Specimen
holder.
This
settings for the specimen holder.
drawing
shows
the
!5(PPCW T
range
of
-
39
-
Aiuminum/
Storage Pock
FRP Bonding A
Portable Plywood
Panel
Foam
Reinforcement
-Plywood Stringer
Covered with FRP
-Plywood Girder Covered with FrP
led-in Spray Strip
Reinforcement
Inboard/Outboard Power Cruiser
Figure 4.
Deep vee hull section.'
(6
I I III
I I II
II I I
II
II I Ii j*4t3
Ii I
f
42
~,
Sb~
1.1
100
188
~-
to
0
-.
to
-
1*
-w
I
I0 I
Io
00
I',
1.
-1
2.
I0
~-1
*2.0
r
2.0
I
-2.
ia3
____
S0
k~?l
1
~~0
2.0
-1oo
10
100
-roe vimA4
noe
-I---
4OZ
Figure 5.
&
zo
as
1bIcA1-5- r.Ao2
ZO.m
Z=.2'9rmm
hA.)
:(ITr
1.5
6
mm
I
..b3mm
0 z.20 o m
/ 00
/. .05mm
Fiberglass panel showing approximate flaw locations.
I
-
41
-
'I'
===I
_
MAT #3
~
I1-~
MAT
Novo
T___7_A
tions.
Interface coding sequence
L
---. M ol..
ggg;
Figure 6.
W1
4t
used to
record
flaw loca-
-
Foam
42
End Grain Balsa
Plywood
Foam Mandrils
Shear Webs - Vertical
Figure 7.
Shear Webs - Truss
Core materials.
-
43
-
.70
-
.50
Ee
40
.30
.20
0
20
30
40
50
60
70
s0
Length on Waterline. L
Table 3.
Typical hull thickness.
90
to
-
-
44
Number of Plies or Pairs vs Larninate Thickness in Inches
Laminate
1-1/2Low
112o.Mt
Glass
Content
(Percent)J
2
3
4
5
Number of Plies or Pairs
10
9
8
7
6
11
12
13
14
15
.060 .120 .180 .240 .300 .360 .420
20 Low
High .076 .152 .228 .304 .380 .456 .532
.480
.608
.540
.684
.600
.760
.660
.836
.720
.912
.780 .940 .900
.988 1.064 1.140
.045 .090 .135 .180 .225 .270 .315
25High .061 .122 .183 .244 .305 .366 .427
.360
.488
405
.549
.450
.610
.495
.671
.540
.732
.585
.793
.630
.854
.245
.350
.280
.400
.315
.450
.350
.500.,
1.100
1.260
.900
1.070
.750
.910
.450
.610
.380
.540
.320
.480
.270
.420
.230
.380
.385
.550
1.210
1.386
.990
1.177
.825
1.001
.475
.671
.418
.594
.352
.528
.297
.462
.253
.418
.420
.600
1.320
1.512
1.080
1.284
.900
1.092
.540
.732
.456
.648
.384
.576
.324
.504
.276
.456
.455
.650.
1.430
1.638
1.170
1.391
.975
1.183
.585
.793
.494
.7012
.416
.624
.351
.546
.299
.494
.400
.701a
1.540
1.764
1.260
1.498
1.050
1.274
.630
.854
.532
.756
.448
.672
.378
.588
.322
.532
.140 .175 .210
30 Low .035 .070 .105
Il 0'0.100 .150 .200 .250 .300
30 Low .110 1220 .330 .40 .550 .660
High .126 .252 .378 .504 .630 .756
Composite Laminate
(Alternate Plies of 35 Low .090 .180 .270 .360 .450 .540
High .107 .214 .321 .428 .535 .642
1-1/2 oz. Mat and
40 Low .075 .150 .225 .300 .375 .450
24 oz. WR)
40High .091 .182 .273 .364 .455 .546
40 Low .045 .090 .135 .180 .225 .270
40High .061 .122 .183 .244 .. 305 .366
.228
45 Low .038 .076 .114 .152 .190
High .05 4 .108 .162 .216 .270 .324
Rvig 0Low .0 32 .064 .096 .128 .160 .192
24oz Wve
.048 .096 .144 .192 .240 .288
24High
.054 .081 .108 .135 .162
55 Low .027
High .042 .084 .126 .168 .210 .252
.069 .092 .115 .138
Low .023 .046
High .038 .076 .114 .152 .190 .228
Table
4.
.770 .880 .990
.882 1.008 1.134
.630 .720 .810
.749 .856 .963
.525 .600 .675
.637 .728 .819
.315 .360 .405
.427 .488 .549
.266 .304 .342
.378 .432 .486
.224 .256 .288
.336 .384 .432
.189 .216 .243
.294 .336 .378
.161 .184 .207
.266 .304 .342
.67
.915
.525
.750
1.650
1.890
1.350
1.605
1.125
1.365
.675
.915
.570
.810
.480
.720
.405
.630
.345
.570
-
-
45
Number of Plies or Pairs vs.
Laminate Weight Pounds Per Square Foot
Laminate
1-1/2 oz. Mat
Composite Laminate
(Alternate Plies of
1-1/2 oz. Mat and
24 oz. WR)
24 oz. Woven Roving
Glass
Content
(Percent)
1
2
3
20 Low .439
High .499
25 Low .345
High .405
.878
.998
.690
.810
30 Low .283
High .343
.566
.686
1.32
1.50
1.04
1.22
.849
1.03
2.47
2.74
2.10
2.37
1.82
2.09
1.21
1.29
30 Low
High
35 Low
High
40 Low
High
.823
.913
.700
.789
.606
.696
1.65
1.83
1.40
1.58
1.21
1.39
40 Low .403
High .430
.806
.860
45 Low .357
High .383
.714
.766
50 Low .320
High ..347
.640
.694
55 Low .290
High .316
.580
.632
60 Low .265
High .292
.530
.584
4
1.76
2.00
1.38
1.62
1.13
1.37
3.29
3.65
2.80
3.16
2.42
2.78
1.61
1.72
1.07 1.43
1.15 1.53
.960 1.28
1.04 1.39
5
2.20
2.50
1.73
2.03
1.42
1.72
4.12
4.57
3.50
3.95
3.03
3.48
2.02
2.15
1.79
1.92
1.60
1.74
Number of Plies or Pairs
6
7
8
10
9
2,63
2.99
2.07
2.43
1.70
2.06
4.94
5.48
4.20
4.73
3.64
4.18
2.42
2.58
2.14
2.30
1.92
2.08
.870 1.16 1.45 1.74
.948 1.26 1.58 1.90
.795 1.06 1.33 1.59
.876 1.17 1.46 1.75
Table
5.
3.07
3.49
2.42
2.84
1.98
2.40
5.76
6.39
4.90
5.52
4.24
4.87
2.82
3.01
2.50
2.68
2.24
2.43
2.03
2.21
1.86
2.04
3.51
3.99
2.76
3.24
2.26
2.74
6.58
7.30
5.60
6.31
4.85
5.57
3.22
3.44
2.86
3.06
2.56
2.78
2.32
2.53
2.12
2.34
3.95
4.49
3.11
3.65
2.55
3.09
7.41
8.22
6.30
7.10
5.45
6.26
3.63
3.87
3.21
3.45
2.88
3.12
2.61
2.84
2.39
2.63
11
12
13
14
4.39 4.83 5.27 5.71 6.15
4.99 5.49 5.99 6.49 6.99
3.45 3.80 4.14 4.49 4.83
4.05 4.46 4.86 5.27 5.67
2.83 3.11 3.40 3.68 3.96
3.43 3.77 4.12 4.46 4.80
11.5
8.23 9.05 9.88 10.7
9.13 10.0 11.0 11.9 12.8
7.00 7.70 8.40 9.10 9.80
5.89 8.68 9.47 10.3 11.0
6.06 6.67 7.27 7.88 8.48
6.9G 7.66 8.35 9.05 9.74
4.03 4.43 4.84 5.24 5.64
4.30 4.73 5.16 5.59 6.02
3.57 3.93 4.28 4.64 5.00
3.83 4.21 4.60 4.98 5.36
3.20 3.52 3.84 4.16 4.48
3.47 3.82 4.16 4.51 4.86
2.90 3.19 3.48 3.77 4.06
3.16 3.48 3.79 4.11 4.42
2.65 2.92 3.18 3.45 3.71
2.92 3.21 3.50 3.80 4.09
15
6.59
7.49
5.18
6.08
4.25
5.15
12.3
13.7
10.5
11.8
9.09
10.4
6.05
6.45
5.36
5.75
4.80
5.21
4.35
4.74
3.98
4.38