Upload
others
View
8
Download
0
Embed Size (px)
Citation preview
NISTIR 88-3884
Static and Dynamic StrengthTests on Electrical ConductorCables Specified for AirportLanding Structures
R. J.. Fields
S. R. Low, III
D. E. Harne
U.S. DEPARTMENT OF COMMERCENational Institute of Standardsand Technology
Metallurgy Division
Gaithersburg, MD 20899
Prepared for
Navigation and Landing Division
Federal Aviation Administration
Department of Transportation
U.S. DEPARTMENT OF COMMERCERobert A. Mosbacher, Secretary
NATIONAL INSTITUTE OF STANDARDSAND TECHNOLOGYJohn W. Lyons, Director
NIST
NISTIR 88-3884
Static and Dynamic StrengthTests on Electrical ConductorCables Specified for Airport
Landing Structures
R. J.. ReidsS. R. Low, III
D. E. Harne
U.S. DEPARTMENT OF COMMERCENational Institute of Standardsand Technology
Metallurgy Division
Gaithersburg, MD 20899
Prepared for
Navigation and Landing Division
Federal Aviation Administration
Department of Transportation
October 1988
Issued September 1991
U.S. DEPARTMENT OF COMMERCERobert A. Mosbacher, Secretary
NATIONAL INSTITUTE OF STANDARDSAND TECHNOLOGYJohn W. Lyons, Director
Static and Dynamic Strength Tests on Electrical Conductor
Cables Specified for Airport Landing Structures
R. J. Fields, S. R. Low, III, D. E. Harne
Metallurgy DivisionNational Bureau of Standards
Department of CommerceGaithersburg, MD
prepared for
Navigation and Landing DivisionFederal Aviation AdministrationDepartment of Transportation
Washington, DC
1
Contents
Administrative Information
Executive Summary
Background
Static Tests
Testing Procedure
Results
Discussion
Dynamic Tests
Design and Construction of Test Apparatus
Testing Procedure
Results
Discussion
Conclusions and Recommendations
List of Tables
List of Figures
2
ADMINISTRATIVE INFORMATION
The research and measurements presented here were carried out under NBS-
FAA Interagency Agreement DTFA-01 -85-Z-02007 . The technical activities were
monitored by Stephen A. Cannistra of the Federal Aviation. This report is
the final report on conductor cables (one activity of several in the
interagency agreement) and includes all details of experimental work,
measurements, and conclusions relevant to the strength and impact behavior of
certain conductor cables specified by the FAA for landing aids. The high-
speed movies of the dynamic tests are in the possession of Stephen A.
Cannistra
.
BACKGROUND
In response to a National Transportation Safety Board Safety
Recommendation (NTSB No. A-84-36), the Federal Aviation Administration
authorized NBS to carry out a series of static and dynamic tests on
electrical conductors specified for use in landing aids on airport runways.
The structures are intended to be frangible so that they will break up
readily if impacted, thus minimizing damage to the impacting aircraft. While
the structures are frangible, they contain electrical cables which, due to
the requirement of electrical conduction, are not frangible, In an actual
impact, these cables do not break readily and tend to wrap around the
aircraft. The tests authorized by the FAA were carried out to assess the
force required to break through various types of FAA specified cables by a
simulated aircraft impact. The types studies were:
14 AWG with type THW insulation
3
12 AWG with type THW insulation
10 AWG with type THW insulation
10 AWG uninsulated
Furthermore, the effectiveness of using break-away connectors was evaluated
to determine if they would reduce the total load on a impacting aircraft.
In order to correctly design the dynamic test apparatus, it was
necessary to know the approximate, expected load levels and cable elongations
at fracture. Therefore a series of quasi-static tests were performed on the
cables and break-away connectors. This report describes these quasi-static
tests as well as the construction and application of the dynamic test
apparatus
.
STATIC TESTS
Test Procedure
Prior to testing each wire diameter was measured. The sheathing was
removed at the gripped region and the diameter of the uninsulated copper
cable was measured. The diameter of each individual strand was also measured
prior to testing. These values were used in the determination of reduction-
of-area, true stress at fracture, and tension modulus.
Tension tests on the following electrical conductor cables were carried
out
:
(a) 7 stranded, 14 gage THW- type insulation
(b) 7 stranded, 12 gage THW- type insulation
(c) 7 stranded, 10 gage THW- type insulation
(d) 7 stranded, 10 gage bare
THW refers to an industry standard type of electrical insulation. These
tests were carried out on a displacement-controlled, screw-driven testing
4
machine at 21-23°C using displacement rates between 0.005 and 50 cm/min.
Split capstan fixtures were used to grip the cables. These capstans allowed
the wire to be wound around the capstan without crimping the wire in any
manner. An initial gage length of 30.5 cm was used for each test and a
minimum of three replicate tests were performed on each gage of wire at a
given test rate. In no case did the results differ by more than 10% from the
average value for a given cable type and testing condition. However,
whenever failure of the cable occurred with 1 cm of the grip fixture, an
additional test was performed. The load and specimen elongation were
recorded digitally by a computer throughout each test. In general, at least
1000 data points were recorded per test. These data were stored on magnetic
tape for post- test analyses.
From the tension tests, the ultimate tensile load, plastic yielding
load, elongation to fracture, reduction in area, ultimate tensile strength,
true stress at fracture, tension modulus, and total energy to failure were
obtained. In addition, complete load- displacement and energy- displacement
curves were generated from these tests.
NBS was able to obtain only one type of commercial break-away connector
for these tests: Bussman 1 type HEB-AW-RCL-A fuse holders. New connectors
were tested each time in an identical fashion to that used for the copper
conductor cables. However, only failure load, failure energy, load-
displacement curves, and energy-displacement curves were recorded as results
because no true deformation ever occurred in the tests on the break-away
connectors
.
1 The use of trade names is only to fully document the research and does
not imply endorsement by the NBS
5
Results
The results are given in Tables 1 to 5 . The ultimate tensile load (Pu)
was the maximum load recorded during the test. The plastic yielding load was
determined to be the load at which elastic or linear behavior ended. the
elongation to fracture (ef ) is given by
£ - in
where £0
and £ are the initial and final gage lengths
reduction- in- area is defined as
Likewise, the
A0 - AR . A .
=
where A0
and A are the initial and final gage areas. These areas refer only
to that of the copper strands and do not consider the area of the insulation.
It is reasonable to ignore any contribution by the insulation because the
insulation is so stretchable and soft compared to the copper that it
contributes only a fraction of a percent to the strength. Nevertheless the
insulation is somewhat important in that it tends to localize the fracture in
the cable. More will be said about this in the discussion section.
The ultimate tensile strength and yield strength are calculated from
UTS = Pu /A0
and
ay = P
y/A0
where Pu and Py
are the ultimate tensile and load yielding load,
respectively
.
The true stress at fracture (af ) is calculated from
PuA
6
since Pu usually occurred at the point of failure. The tension modulus (M)
is determined as a function of the slope of the elastic line
M dP o
di A,O
The load-displacement curves show the entire
elastic, plastic, and fracture behavior. A representative selection of these
curves are given in Figures 1-4. These curves may be integrated as follows
to obtain the energy- displacement curves.
where P is the load, A is the displacement, and E(A) is the energy expended
to get to the displacement. Representative curves of energy versus
displacement are shown in Figures 5-8. The total work of fracture E(Af ) is
the energy expended to get to that displacement. Representative curves of
energy versus displacement are shown in Figures 5-8. The total work of
fracture E(Af ) is tabulated in Tables 1 to 5
.
Ultimate tensile loads and separation energy for the break-away
connectors are listed in Table 6. Typical load versus displacement and
energy versus displacement curves for the connectors are shown in Figures 9
and 1 0
.
Discussion
From the data presented in Tables 1 to 5 ,it is clear that the ultimate
tensile loads and the plastic yielding loads both increase with increasing
rate for all the types of cable tested.
The ultimate tensile strength and plastic yield strength are fairly
constant at a given rate. Therefore, this data may be used to predict the
7
yielding and breaking loads of other gages of cable at these rates providing
the initial area is known.
The reduction- in-area does not appear to depend on the gage of wire
tested or the testing rate. Its average value is 85%. The e longat ion- to
-
fracture (ef ) also seems to be fairly independent of testing rate and wire
gage .
The UTS and e f seem to depend on whether the cable is insulated or not.
The average ef
for insulated cable is 44% while that for uninsulated cable is
20.9%. The reason for this difference is due to a different failure
mechanism in the uninsulated cable as compared to the insulated cable.
Failure in both cases starts by the failure of one of the seven strands. If
the cable is uninsulated, this strand unravels rapidly from the remaining
strands, exposing the entire gage length to a 14% increase in average load.
The next weakest strand breaks and unravels, raising the average stress still
further. In the insulated case, the failure of a strand is not followed by
unravelling. Within a short distance of the failure, shear transfer permits
the broken strand to support some load. As a consequence, the fracture of
all seven strands occurs within a few millimeters of each other. This is in
contrast to the uninsulated cable in which strands break anywhere along their
305 mm gage length. This presumably at their weakest cross-sections and
results in a lower ultimate loads and shorter elongations- to- fracture
.
The failure load for the bread-away connectors also depended on rate.
This load level was much lower than that for any cable, requiring less than
one tenth the force needed to break the smallest diameter cable tested here.
DYNAMIC TESTS
Design and Construction of Test Apparatus
8
The test apparatus design consisted of an impactor, simulating an
aircraft wing, which was propelled along two guide rails to impact a test
wire until the wire is broken. The impactor was propelled using a pull cable
system, in which one end of a pull cable was attached to the impactor and the
other was rapidly wound up on a rotating flywheel. The flywheel and guide
rails were supported by a rigid steel frame which also housed the grips which
supported the test wire in the position for testing. The transient load
applied to the test wire was measured by strain gages affixed to the
connecting rods for the grips; the strain signal being monitored through a
high frequency bridge - amplifier system and recorded on a transient digital
oscilloscope
.
The apparatus for this test required a stiff test frame high enough to
test both the 6.1m (20 ft) and the 3.1 (10 ft) length test wires, and long
enough to allow sufficient travel time, prior to impact, for the impactor to
accelerate to the desired impact velocity and also to give an adequate run
off for the test wire to stretch before breaking. To properly design the
rigid test frame an approximate maximum load was needed. The rate dependence
of the ultimate tensile load determined from the quasi-static tests was used
to extrapolate the ultimate tensile load to rates expected during the dynamic
tests. The form of equation used was
UTL = (A = B log 2)' 1
ft
Where E is the strain rate and A and B are fitting constraints. This
approach predicted a maximum load of about 500 lbf. A safety factor was
further employed to assure that the test frame did not significantly deflect,
distort, or buckle during the test. The quasi-static elongation- to- failure
was used to determine the size of the test frame. This approach assured that
9
failure would occur before the impactor ran out of travel. Again a safety
factor was employed in case the dynamic ductility was significantly greater
than the quasi-static ductility.
A rectangular frame was thus designed and constructed having a height of
6.4 m (21 ft) and a length of 7.9 m (26 ft), with a vertical support in the
center as shown in Figure 11. The frame was actually two identical parallel
frames constructed of W4X13 steel beams measuring 10.5 cm by 10.2 cm (4.1 in
by 4 in) with a 0.63 cm (0.25 in) web and 0.95 cm (0.37 in) flange
thicknesses. The two frames are rigidly attached together having a 30 cm (12
in) separation for the impactor to travel between. The guide rails for the
impactor are steel channels attached to the inside of the frames, and can be
moved to the different testing heights required for various lengths of test
wires.
The impactor, shown in Figure 12, was designed to travel within the
guide rail channels on teflon sheets bolted to either side of its aluminum
plate carriage. A 11.4 cm (4.5 in) diameter aluminum tube was affixed to the
aluminum carriage to simulate the curvature of an aircraft wing. Edge stops
were added to the ends of the tube to restrain the test cable from moving off
the tube during impact with a test wire. A steel bolt was fastened through
the impactor body for attaching the nylon drag line which was, in turn,
pulled by the flywheel. A loop at the end of the drag line was attached to
the impactor by placing it loosely around the steel bolt so that the impactor
released from the drag line as it passed over the flywheel. This kept the
impactor from being destroyed by being pulled into the rotating flywheel.
The flywheel was powered by a 7 HP electric motor and was constructed of a 20
cm (8 in) diameter steel cylinder, 58 cm (23 in) long. The two ends were
10
reduced in diameter for insertion into pillow block bearings that were
mounted on a steel support shelf below the impactor guide rails. For impact
heights above the level of the support shelf, a 4.13 cm (1.62 in) diameter
steel pipe was mounted to the test frame over and in line with the flywheel.
This arrangement allowed the drag line to travel just below and parallel to
the guide rails, over the pipe and turned at a right angle down to the
flywheel
.
During an actual test, when the flywheel achieved the proper rate of
rotation, a lever mechanism (Figure 13) was pulled which attached a loop at
the end of the drag line around one of two 1.3 cm (0.5 in) diameter bolts
which were threaded into the center of the flywheel. Two bolts,
diametrically opposed to each other, were used in order to retain balance in
the flywheel. After the drag line attached, it was rapidly wound onto the
rotating flywheel, pulling the impactor down the guide rails. Because the
quantity of energy that was stored in a flywheel of this size and mass was
large compared to the energy required to pull the impactor and break the test
wire, very little reduction in impactor velocity occurred throughout the
impact event.
The rotation frequency of the flywheel was constantly monitored from the
initial start-up of the motor, until impact of the test wire occurred. This
was accomplished with a light sensitive photo diode that sensed a light pulse
reflected from a mirror mounted on the side of the flywheel (Figure 14) . The
photo diode produced a variation in voltage each time the light pulse struck
it. The voltage change triggered a frequency meter. Knowing the rotation
frequency and the diameter of the flywheel, an approximate value of the
11
resultant impactor velocity could be computed. This was used as a guide for
determining -when to engage the drag line and start the test.
The actual velocity of the impactor was determined by using
photodiodes placed at known positions along the path of the impactor and
connected in series. As the impactor passed each photodiode, a voltage pulse
was generated, and the signal was recorded on one channel of the
oscilloscope. By measuring the time intervals between pulses, the impactor
velocity was calculated at the positions of each of the photodiodes. A total
of twelve photodiodes were mounted on the guide rails at positions ahead of
the test cable, at the initial point where the impactor contacts test cable,
and at positions after the impact point.
The test cable was held in the vertical position for testing by
supporting each end of the cable with split capstan grips designed for
holding wire and cable. Connecting rods were specially designed and
constructed which exhibit a measurable elastic strain in response to the
loads experienced by the test cable during an impact. This transient strain
was measured by strain gages affixed to the surface of the rods. Two
stacked, biaxial strain gages were positioned diametrically opposed to each
other on each of the two rods such that the longitudinal and transverse
strains were measured. Two gages were used on each rod, in this manner, to
adjust for bending in the rod. The strain signals were monitored through a
bridge - amplifier system (Figure 15) specifically designed to measure dynamic
strain pulses. The strain levels were stored as voltage levels on separate
channels of a transient digital oscilloscope (Figure 16). The strain level
(or voltage level) was related to load by performing periodic calibrations of
the instrumented pull rods. This was done by connecting the two pull rods
12
with a chain hoist and dial dynamometer (a type of load measuring device).
The chain hoist was tightened and the load indicated on the dynamometer was
correlated with the output voltage of the strain gage-bridge-amplifier
system. In general, the load was calibrated in this way beyond 2227 N (500
lbf) which was considerably above the forces observed during any test. The
correlation between voltage level and load was linear and an example is shown
in Figure 17.
Film records of the tests were made. Two high speed 16 mm film cameras
were placed at 90° apart viewing positions and recorded an unobstructed view
of the impact event. One of these cameras is seen mounted on a tripod in
Figure 11. Framing speeds of 500 to 2000 frames/sec were used.
The unique nature of this test has required that much of the test
apparatus be specially designed for this program. This has resulted in a
great deal of testing and redesign in order to meet the specified test
criteria. The violent, high speed impact involved in this test also
necessitated the rebuilding of some of the test apparatus components
periodically or as often as each wire test. As a consequence, the dynamic
tests took much longer than initially estimated.
Results
A typical output of the photodiode array is shown in Figure 18. The
photodiodes were positioned as follows:
Diode # Position w.r.t. Impact (mm)
1
2
3
4
5
6
7
8
-1200-900-600
-300
0
+300+600+900
13
9 + 120010 + 150011 + 190012 +2300
Using the time at which the impactor passed a given diode (i.e., the
peak voltage) and the position of that diode, the velocity at the time was
calculated. This information is listed in Table 7. Three velocities were
determined for each test: the maximum velocity of the impactor (Vmax ), the
minimum velocity (Vmin ), and the average velocity (Vave ).
Futhermore, the deflection of the cable at anytime (and especially at
failure) was determined from the phtodiode record since the cable was always
in contact with impactor. The original length (i 0 ) of cable above (i£) and
below (i®) the impactor was combined with the deflection at failure (Axf ) to
calculate the elongation- to- failure :
e
[(l*) 2 + Axil* + fd!)2 + Ax?]*
,£ “
e
The elongations-to-failure are tabulated in Table 7. Representative
load records from the top and bottom pull-rods are shown in Figures 19-26.
Due to the dynamic loading of the cable, an oscillation is set up which is
clearly detected in these records. This oscillation makes it impossible to
measure the tension modulus or the plastic yielding load. However, the
ultimate tensile load (which is the most important design load) is easily
determined. This quantity is listed in Table 8 for the top and bottom pull
rods. The top and the bottom differ because the cable is being impacted
above its middle in both the 10 ft and 20 ft tests. Furthermore, the fact
that the forces are different in the top and bottom suggests that no slippage
of the cable around the impactor occurs. Slippage would tend to equalize the
force in the top and the bottom. Since the impact was always specified to be
14
closer to the upper grip, the force in the cable above the irapactor was
always the greatest and failure always occurred in this part of the cable.
Therefore, only the dynamic elongation- to - failure in the cable above the
impactor should be compared to that obtained in the quasi-static tests.
Using the maximum forces in the upper (F* ax ) and lower portions (F® ax )
of the cable and the deflection at failure (Axf ) ,
the resolved maximum force
on the impactor was calculated as
FIm
= F*
Ax,+
FB
Ax
,
,flH "aX
[(i?) 2 + Axf Umax max , , .4 \ 2 . * 2[(i£) z + Axf
where and are the initial lengths of cable above and below the
impactor, respectively. This is the force that an aircraft wing would
experience in a similar dynamic event. These forces are listed in Table 8
for the various cable types.
The energy expended in breaking these cables has also been calculated
from the load and position data. The energy absorbed up to any time (t)
during the impact by the upper portion of cable is given by:
t t F V2 t
A J t=0A A J t=0 [(Vt) 2 + (l£) 2
where V is the average velocity (see Table 11). A similar expression may be
written for the lower portion of cable. Representative curves of energy
consumption are shown in Figures 27-34. The total energy expended is the sum
of that absorbed by the upper and lower portions of the cable at failure.
This quantity is listed in Table 8 and represents the amount of work an
aircraft would have to do to break one of these cables.
15
The break-away connectors were tested in two configurations: a single
connector located in the middle of the upper portion of the cable and two
connectors, one located in the upper and one in the lower portion of the
cable. The two connector configuration was tried because, when only one was
used, the remaining portion of cable would wrap itself around the impactor.
To free itself, the impactor usually had to break the cable. Therefore, a
single connector would not necessarily reduce the load in a dynamic impact
situation. Typical load-time curves and energy-time curves are shown in
Figures 35 to 42. The maximum load and energy- to - failure are listed in Table
9. Clearly, multiple connectors lead to considerably reduced failure loads
and energies when compared to the cables without break-away connectors.
Discussion
The ultimate tensile strength for the four types of cables has been
plotted against displacement rates ranging from the quasi-static to the
dynamic in Figures 43-46. Curves have been drawn through these data points.
The solid lines represent the best fit regression line using all the data.
The dashed lines are the best fit regression line using only the quasi-static
data and extrapolated to the dynamic rates. The equation of these lines are
of the form
UTS = (A + B log Z)' 1
where E is the strain rate and A and B are fitting parameters. The values of
A and B determined using quasi-static data and quasi-static plus dynamic data
are listed in Table 10. While there parameters are fairly similar, using
only quasi-static data usually predicts dynamic strength which are 10-15%
lower than the observed values.
16
The elongation- to-failure in the upper portion of the cable, i.e., that
part of the total cable that experienced failure, agrees tolerably well with
that measured in quasi-static tests.
The break-away connectors require very little force or energy to
separate when compared to the cables, even at the dynamic rates applied here.
However, when the remaining cable wraps itself around the impactor, forces
equal to that required to break the cable are observed. Clearly, wrapping of
the cable around a wing could occur in actual applications. For this reason,
two connector tests were carried out. In these tests, separation of
connectors above and below the impactor took place at very low loads. If
break-away connectors are used, two or more should be employed per cable to
assure that, even in the event of cable wrapping very low forces are applied
to the impacting aircraft and very little energy is required for complete
separation.
CONCLUSIONS AND RECOMMENDATIONS
A series of quasi-static and dynamic strength tests on electrical
conductor cables specified for airport landing structures have been carried
out. The breaking loads, energies, and ductilities have been determined from
four types of cables under conditions simulating impact by an aircraft wing.
Additional quasi-static and dynamic breaking loads and energies were
determined for a commercially available break-away connector. From these
tests, the following conclusions may be drawn:
• The average 75 knot breaking loads for the 14 AWG THW, 12 AWG THW,
10 AWG THW, and 10 AWG uninsulated cable are 207, 334, 468, and 389
lbf, respectively. The energies expended breaking these cables were
234, 318, 262, and 215 ft-lbf, respectively.
17
• The 75 knot breaking load for the connectors averages 50 lbf
regardless of the cable size or type. The breaking energy is less than
1 ft - lbf
.
• The dynamic strengths of the cables are higher by 10 to 15 % than that
predicted by extrapolation of quasi-static tests.
From the tests carried out, it appears that the break-away connectors provide
for a significant reduction in loading while maintaining electrical
continuity. However, use of only one connector can lead to the remaining
cable wrapping around the impacting body. This occurrence results in
breaking loads and energies equal to that required for cable failure. To
realize the benefits of break-away connectors, at least two or more must be
strategically placed on each conductor cable.
18
List of Tables
Table 1. Results of tensile tests: testing rate = 0.005 cm/min
Table 2. Results of tensile tests: testing rate = 0.05 cm/min.
Table 3. Results of tensile tests: testing rate = 0.5 cm/min.
Table 4. Results of tensile tests: testing rate = 5 cm/min.
Table 5. Results of tensile tests: testing rate = 50 cm/min.
Table 6. Results of tensile tests on break-away connectors.
Table 7. Impactor velocities, cable deflection, and elongation- to-failure
determined from photodiode array
Table 8. Results of dynamic tests on conductor cables.
Table 9. Results of dynamic tests on break-away connectors
Table 10. Rate Dependent Strength Parameters
19
List of Figures
Figure 1. Load-displacement curve of 14 gage insulated cable determined at
displacement rate of 5 cm/min.
Figure 2. Load-displacement curvea displacement rate of 0.5 cm/min.
Figure 3. Load- displacement curvea displacement rate of 0.5 cm/min.
Figure 4. Load- displacement curveat a displacement rate of 5 cm/min
Figure 5. Energy-displacement curveat a displacement rate of 5 cm/min.
Figure 6. Energy-displacement curvedisplacement rate of 0.5 cm/min.
Figure 7. Energy- displacement curvedisplacement rate of 0.5 cm/min.
Figure 8. Energy-displacement curvea displacement rate of 5 cm/min.
Figure 9. Load- displacement curve f
displacement rate of 5 cm/min.
for 12 gage insulated cable determined at
for 10 gage insulated cable determined at
10 gage uninsulated cable determined
for 14 gage insulated cable determined
for 12 gage insulated cable tested at a
for 10 gage insulated cable tested at a
for 10 gage uninsulated cable tested at
r a break-away connector tested at a
Figure 10. Energy-displacement curve for a break-away connector tested at a
displacement rate of 5 cm/min.
Figure 11. Schematic of dynamic test apparatus and photograph showing a testcable being placed in the grips. A high speed camera can be seen on a tripodto the right of the test apparatus.
Figure 12. The impactor positioned in the guide rails prior to a test.
Figure 13. The pull cable or drag line is held in position by a levermechanism (Y-shaped arm) prior to attachment to the rotating flywheel.
Figure 14. The flywheel is the cylindrical object in the center of the
photograph. The photodiode device for monitoring the flywheel rotationfrequency is mounted to the right of the flywheel.
Figure 15. The bridge-amplifier system used to condition the strain signalsfrom the grip connecting rods. A test cable split capstan grip, andconnecting rod can be seen on the left between the two uprights of the test
apparatus
.
Figure 16. Electronic equipment used for the dynamic test.
20
Figure 17. Correlation between voltage level from strain gage conditionersand actual load.
Figure 18. Typical electrical output of photodiode array during test
Bottom peaks occur when impactor leaves a photodiode unit.
Figure 19. Load- time records for a 10 ft long, 14 gage, insulated cable.
Figure 20. Load- time records for a 10 ft long, 12 gage, insulated cable.
Figure 21
.
Load-time records for a 10 ft long, 10 gage, insulated cable.
Figure 22. Load- time records for a 10 ft long, 10 gage, uninsulated cable.
Figure 23. Load-time records for a 20 ft long, 14 gage, insulated cable.
Figure 24. Load-time records for a 20 ft long, 12 gage, insulated cable.
Figure 25. Load- time records for a 20 ft long, 10 gage, uninsulated cable.
Figure 27. Energy- time records for a 10 ft long 14 gage, insulated cable.
Figure 28. Energy- time records for a 10 ft long, 12 gage, insulated cable.
Figure 29. Energy- time records for a 10 ft long, 10 gage, insulated cable.
Figure 30. Energy- time records for a 10 ft long, 10 gage, uninsulated cable
Figure 31
.
Energy- time records for a 20 ft long, 14 gage, insulated cable.
Figure 32. Energy-time records for a 20 ft long, 12 gage, insulated cable.
Figure 33. Energy- time records for a 20 ft long, 10 gage, insulated cable.
Figure 34. Energy- time records for a 20 ft long, 20 gage, uninsulated cable
Figure 35.
connectorLoad- time records for a 10 ft long cable with one break-away
located 8.5 ft. above lower grip, i.e., at midpoint of cable aboveimpact point
Figure 36. Energy-time records for test shown in Figure 35.
Figure 37. Load- time records
Figure 38, Energy- time records for test shown in Figure 37.
Figure 39,
located 1
Load-time records for cable tested with break-away connectorsft above and 1 ft below impact point, i.e., 2 ft span.
Figure 40, Energy- time records for test shown in Figure 39.
21
Figure 41. Load-time records for cable tested with break-away connectorslocated 1 ft above bottom grip and 1 ft below top grip, i.e., 18 ft span.
Figure 42. Energy-time records for test shown in Figure 41.
Figure 43. Ultimate tensile strength as a function of strain rate for 14
AWG/THW cable.
Figure 44. UTS as a function of strain rate for 12 AWG/THW cable.
Figure 45. UTS as a function of strain rate for 10 AWG/THW cable.
Figure 46 . UTS as a function of strain rate for 10 AWG uninsulated cable
22
a> 0 Wr—^ 3•r-l 4->
C/) C/) 3 •rH
C 03 TO CO On m r“—
4
0Qj »-“l O vi) O' O' CNH CjJ as LPl Vi) co 00
CO
CO
<1>
S-i <0
4J 5-4
cn 34-1
<u O •r^
3 03 cn vO CO CN 00!-i u 5-4 CN Ov CN COH CO Ct, W CN CN CN CN
x:4-1
00TO c
0) •rH
<0 5-1 CO
»rH 4-1 co <t CO CN>< 00 CO CO CO CO
0) Xu u u03 r—I bOS'H
« II ^•U c S-I w—
1
0) ±-> X co r- o 00X H co v—' <J <t <r co
0)
5-1 <4-1
>0 3 X)b0 4J r-H
c 5-i CJ 1
•rH 0) 03 4J o- 00 o- Oe C 0 5-1 X4 m 00 CO vO\ W U til N—
'
t“H
c•r-l
C0 OCN •r^
4J<4-4 OO 3 03
TO 0) /-—
S
0) <D C 5-1 <#> t-H vf CN <t4J 02 •H < 00 OO 00 00CO
}-(
C00 Oc •r^ 0)
•rH 4-> 5-4
4J 0) 3CO bO U0) C O4-> O 03
O S-i <#> vO m r-H
03 w 4J Ci, n ' '3- <r CN
4J
03 b00 C
CO
4J 4J TO /*\r-H co —• TO <4-1
3 03 <u 03 XI 00 OO co <fco »—
4
•H O —
H
0 vO vO0) Oh >• X r-4 CN CN)-l
O a;•r^ 4J a;4J 03
03 E •r^ r~s4J •rH co TO <4-4
CO 4J C 03 X) Ov CO <3- CN1 CD O «—
1
CO CO co *“H
•i-4 33 H J r-4 CN CO COCO
03
3O' a;
5 5 3 uX X X 03
H H H 0Qr-H \ \ \ \
O U O O0) a) 3 3 3 3
r—
H
<D < < < <XI X) a03 03 to <r CN O OH <3> H «—
H
Table
2.
Quasi-static
results
at
a
testing
rate
of
2
in/min.
<D O C/3
r—\ •r^ 3•r4 4-3 «““4 ,—
V
w c/i 3 *r4 O 0 X coc C0 o C/3 *—
4
co oo uO<u *—
4
O X <r UO co 0H cu s wC/3
C/3
0)
34 03
u 3-1
cn 34J N
0) 03 •r4
3 3 C/1 Osl H «—
H
<]34 4-3 3-i A 40 00 XH C0 X CN CN CN CN
X4-3
b0"3 3 /*\—i 03 »r4
0) 3-1 c/i
•r4 4-3 x CO CO CN00 CO CO CO co
oj A4-> 03 4-1
3 <-—
4
bOE •i—
1
C ,—
s
•r4 C/3 0) •i-4
4-> C 3-1 C/3
4 03 4-3 X CN in 0 c-.
33 H oo <r <r co
03
34 C4-4
>0 3 Xb0 4-3
34 O 1
0) 3 4J
C O 34 <4-1 *—l 04 CN CMw 4-3 Cti s-/ n 00 04 X
co
•r4
u<J
3 CO
X 03
03 c 34 dP <f «—4 Xas •rH < n— 00 00 00 00
Co•r4 034J 34
Cfl 3bO 4-3
C UO CO
»—4 o 34 dP CN X 0 CMw 4—3 C*4 -O’ CO CN
bOC
1-1 •.-4
•u T3 /-N
w T3 <4-1
CO 03 CO XI 40 >0- CM 04O 4 O X 00 in
Ot >< X r-H f—
4
CN CM
03
•u 03
CO 4
E •H X-N•f4 T3 C4-1
4J c cO X X CM <f CO* " ^ 03 O CO CN CO 033 H X 'w' t-H CN CO CO
03
3 3 3 34
X X X 03
H H H CQ\ \ \ \O O CJ3 0
03 3 3 3 3«“
H
03 < < < <XI O.CO >4 CN O 0U H
05 o CO
•—
H
3•W 4J ^—4
CO co 3 •r^
c CO '
O
co in ro oQ) r—-4 o i cn «—
i
ONH W as i iO m r-
co
co
35-, 0)
4-1 5-1
co 3
05 05 •rH
3 CO CO m r^-
5-i •U 54 vT> 00 H mH c0 Et, N~' m CN m CN
xuaO
•3 Cr—
H
0) *rH
3 54 CO
•rH U m m r-H r-H
>“ CO m m m m
0) X4-> 0) 4-1
CQ aoB **-i c•H CO 05 •fH
•u C 54 CO
-—4 05 4-4 o m 003 H CO m co
35-4 cw
. 3 -43
c aO 4J *—4
*f-4 5-4 O i
e 05 CO ij CN\ c 0 54 cw O in CO mc w 4-5 Cw V
—
y <r *-H in
CN CoO *H•U
<4-1 OO 3 3
”3 305 3 C 54 <*> O' m 00 lO4J c£ >1-4 < ' 00 00 00 00CO
54
cao OC •rH 3
•r^ 4-5 544J 3 3CO ao 4J
05 C O4-) 0 3 x-s
—I o 54 <#> O CD oCO CjJ 4-1 Cl, s-/ cn <f -3- CN
4J
CO aoC5 C
CO
4-1 W TOf—
4
CO —1 ”3 4-1
3 cO 3 3 -Q in cn O cnco •—
H
O »-H O lo cO m05 CL, >4 X V-/ *-H r4 CN CN54
O 3•r^ 4-1 34-1 C\J •-HCO S »H4-1 t-l CO T3 4-1
CO ±-> c 3 o cn Osl cn1 r-H ^ 0 *—"4 co «w r-H O'
•r4 3) H X 'w' H CN co CNCO
3CO
O' 33 S 3 54
X X X 3H H H 0Q
CO \ \ \ \a O O a
0) 3 3r-H »~4 3 < < < <X X ac0 3 En <r CN o oH CJ H r-H r-H r-H r-H
05 O CO•—1 «H 3•H fa i—( /—
v
CO CO 3 <fa
C 03 03 cn LO N (J\0) —4 O -4! CO »-4 UOHUS'-' <f in fO OO
ue
Stress
acture
si)oo m -4 <f
5-1 fa S-( ^ O -fa 'XJ OMH cfl fa ^ O CM -4 -4
ield
trength
ksi
)
CM CM <f 00>> C/3 w CO CO CO CM
ltimate
ensiletrength
ksi
)p" o r- un^ t—* C/3 'w' co <t co co
(D z'—
S
c >o 3 Xi•rH b0 fa -fa
E 5-i O i\ 05 03 4_>
C C O U 4-1 -fa CM o CM•rH W fa [fa w <f m in mCMo c
• oo •fa
4-1faCJ
O 3 03
05
03 05 ^05 C fa dP 00 lOl 1"-. CM
4-)
rrtOS -fa < w OO 00 M CO
5-i
bOCo
C •fa a)•fa •fa fafa 03 3C/3 b0 fa05 C Ofa O 03
oJ
-fa O fa dP r-> *-c r- oW fa Cli —
-
CO <f «fa CM
faCfl b0
cnO C
fa fa 03*—H c/J -fa 03 4-i
3 03 05 03 X CO MO OM -faw -fa *fa O -fa O in M CO05 C4 >4 _] w fa fa CSI CM5-1
o 05•H fa 05fa Ctf »—H03 E -fa ^fa •fa co 3 faCO fa C 03 X O' vj <J1 -fa 05 O -4 -fa om o ooX H X w -fa -fa CO CMCO
303
O' 05
U3 ^ 13 UX X X 03
Efa H H oQWW05 05
o o o oX X 3 3»-H *—H (1) < < < <X x a03 03 >, <3- CM O OH U H f"H t-H t-H *-H
03 O w•M 3
•iH 4-1 »—H
w cn 3 •r-4
C c0 o cn CN rH CN03 o v£) CN r- OH S3 s«/ UO LO co O'
03
03
0)
3-i 03
•U 3-1
00 34J
03 o •r^
3 03 cn CO 0‘s CO vTi
S-i 4J 3-i CO r-H 00 COH 05 Cm csj CN r-H CN
J34->
COT3 Cr-^ 03 •rM
03 U CO
•r-4 4J r^ ct\ 00>-• CO s—
'
CSI CM CN CN
03 JC4J 03 u03 C0£ •r-4 C•rH 03 03 •r^
4-1 C S-i 03
-—4 03 4-> 00 CN COP H co ^—* m CO CO CO
03
C 3-i 4-1
•rH >o 3 X£ CO 4-3N 3-4 C3 i
C 03 03 U•M C O !-, 4^ NO CN o> co
w •U Cm CO CO co v£>
CNoo c
• oo •rH
4Jcm oO 3 cO
T3 03 /*%
03 0) c S-i dP 00 <f CO vnu Cti •rH < Nw-' oo 00 00 0003
3-(
cco oc •H 03•r^ 4J 3-1
4J 03 303 CO 4J
03 c O4-3 o 03
»—H 0 )-i dP lO O O in03 ttJ 4J Cm 'w' CO CN M CM
4->
03 coO C
03 •M •HU 4J p /-V
0) r-H "0 4h3 03 0) 03 X CO o r-4
03 *rH O 00 <r CM CO03 CL, >< J oo *—1 CM CM3-4
O 03•M M> 034-1 03 *—
1
03 £ •rH
4-1 •rH C/3 X 4-1
03 4-) c 03 X) T—
H
CO 00 «Mi 03 0 t“H r-. i--
•M P H J 'w' i-H CN CM03
303
O' 03
3 3 3 3-1
X X X CO• H H H CQ
UO \ \ \ \P P P p
03 0) 3 3 3 3r-H 03 < < < <
rO P P03 CO Pn -O’ CN O OH P H r-H rH r-H r-H
Table 6. Quasi-static results for break-away connectors.
Testing Rate Ultimate Separation( in/rain) Tens i le Energy
Load(lbf) (ft-lbf)
20 9.8 0.602 8.0 0.500.2 7.3 0.400.02 6.1 0.390.002 7.9 0.44
Table
7.
Photodiode
array
results
from
dynamic
tests.
co
u03—i ao
03 C4-> OO —I c3P
E-h U3oo r-- o r-- r-^ CM mo in <3- ro ro n <f m m <f
Co
4-1
e 03
o 00u C4-1 o ^o —i
i <*>
D3 U ^ oo n n n n 03 CN n CM mo CM CM CM
Co
•rH
4J
03
aoCa o ^
O'—i # *—i in «—i n n in <t O cm o o mo mo O 4 h oE—
1
3x3 ^ i—* CM t—4 *—4 ^ *—t CM P'3 —H —4 —
H
co
4J
0o
<4-1 U O LC3 CM m m O03 <4-1 • •
O '—
y
CO CO m co CM
>30) 4J
ao *hCO O
C/3
4-3 O rH 0 CM 03 O 0Sm 0 O MO 0 MS0; *-h c O O CM m O rH <4 03> 03
< >«—
H
00000
rH03
03 00 O«“H
00 in 00 00 OrH
-O O' CO 03 n CM 03 00 CO O 03
CO CM <f H CM CM CM CM] <-4 CO CM
<t cn 03 cm n 00 n c n o 03 mo mo Mt
co *4- -o «—
1
00 030300 in^o <t -h» co c m m m r^r^r^- co 03 oo c- 00
>3e 4-> /Na •H wE 0 4-3 in m O MO 03 00 00 T“H
•rH 0 O 00 co c-X rH c • • m <4 O 03 00 m rH 043 03 -X m m 00 03 00 rH 00 m 00 03 rHat > 00 00 03 rH rH
0 00 Mt rH CM 0 CM <4 03 in CM 0r-~ 03 m 00 03 m <4 m 00 uo CM CO00 00 00 O'- 00 00 00 00 <4 03 CO 00
E 4->
3 m-4 cn
S O 4-3
**H 0 0 1^. Mt UO O r-^
c rH c • • •
•rH 03 in MO uo <4 mOx > C' c- 00 00 r-* 03 c-
M M 03 O«-H «-M 30 00<4 r- r- o
00 im co in <f r-» ao 00 mom03 00 CM CM CM 301— mo c-
n n 03 cm mr-» i--. r-. 00 cm
\D <
—
11/3C~ C'
Test
# H CM O h cm n 4 h cm co 4 H CM CO H CM CO H CM CO .-1 CM rH CM CO
03 03
03 -C 3 3 3 3 5 S-i J-i
CL LJ X X X X X X 43 43
Sc ao H H H H H H CQ aOH C \ \ \ \ \ \ \ \
03 O a O O O U O O03 i-l 3 4J 3 4-3 3 4J 3 4J 3 u 3 4-1 3 4J 3 4J
rH-Q *0
< <4-1 < <4-4 < <4-1 < <4-4 < <4-4 < <4-1 <1 <4-1 < <4-1
03 C <r 0 M± O CM O CM O O O O O O O O OU 43 rH rH «—I CM rH rH «-H CM rH rH «-H CM rH rH rH CM
Table
8.
Force
and
energy
results
from
dynamic
tests.
T304
T3C0)
ax
4-1
>-, XLaO —i —
i
Ui ctJ i
04 AJ iJ m r—t o o CSJ L/0 OO CO rH X Q 00c c cm o 1-1 O' CO o «—
i
in 00 00 o oo csi
UJ H CSJ CN 04 «—
1
m 04 <r «—
i
<r 04 CN r— CN
-o04
~oc0)
CLXLxJ
^ E JD&0 O —
t
i-l AJ I
04 aj 4->CO 4-4
W X wco o 43 oor- oo O' x O M 4
O'' X «-J
X O vjin x
ro o''
r-i oo <r x
*0
04
"Oc04
CLXLtJ
>4 ©QO —4U I
04 Q. 4J
c o (4-1
CjJ H s-/
O «-• X 04n O' rs C4Csi o oo fi43 -3 © O 43 —
•
04 «—t CO »-o CO •—
I
CO 00co O«—I 04
O X.X O.
04
44
44 Uo oLu AJ
4)
a oj
c aa a**4 HHx03 C£ O
04 m O' o>4- O' CO CO
o o roco r- r-04 04
1/0 *"J
04 04oj <r
coO'
vj0404
00 —<r 04— Om
3 aa o o) ^1-1 AJ 4) 4-1
X AJ U XL O' 04 04 O' 00 ^4 04 co 40 o *-H 40 in O —
H
00 in X 00 <r03 o 0 in X -3 *3 co CO <3 co O' O' 04 m O' ^4 O 04 <r 04 f—
A
£ X U4 •-4 04 04 04 *“4 04 -S’ 04 CO co m co m co CN
04
4)
a h3 O
•H 4-1
X CL O oo K <r *3 o -4 O O'' n -3 X O in X O in X COcfl O —4 04 04 co 00 04 04 <3 40 X co 04 CO O' *4 X£ H 'W' *-H CNI CM CN ^4 co co co m CO >3 >3 -3 ~3 43 4f co CO CO
aj
tfl
0)
H * H OJ O H 04 O 3 H C4 CO 3 H 04 O H 04 CO rH 04 CO -A 04 04
04 0)
04 XL 3 3 3 3 3 3 iJ —4
a aj I X X X X X 03 03
>4 oO H H H H H H X XH C \ N N \ \ \ \ \
<u U O a O O O a a04 -J 3 AJ 3 AJ 3 AJ 3 AJ 3 AJ 3 3 AJ 3 aj
*"4 < <4-1 C 4j < <4-1 < <4J < 4J < AJ < 4j < 4J
XL
0
4J33 C 43 O <3 O 04 O 04 O O O O O O c oO CO *-H •—
4
«-4 04 «-H *—4 ^4 04 —i 04 o ^4 04
Table
9.
Results
of
dynamic
tests
on
connectors.
T30)
T53UaxCx]
So4jX co CN in CO <r CN CN 43
Qjj -4 _4 43 m O'' lPi <r <r co 4T lPi 03 coX co 1
<D ±J jj 43 cn 43 in 43 cn o o O o o o3 OX E—
i
4-1 in <r
33a>
"Cc0)
axXSo E O 03 0300 0 O CO in 43X jj l
a/ jj jj 43 43 403 O 4-i <—
t
lOU3 X «—
1
CO CM <—I CNI r''-P'- C\ o CO
CO <—( CO O O CM «—I UO O
43 C^ CN ooo ooo<r
•3
<u
T3c<u
34XxSo00X
4-4
X1 ro CN c- 00 ro CN O' ao co X ro
0) C4 X X o f— CN co CO CO CN cn ro CN3 0 4JX H ''w' o o o o O o o O o o o o o
s3 EE
•rH
X
0XX
03
CJ
X4jX m X CN ro in
m 00 in O' X 00
CO o o <r *—
i
-O’ O' O' O ro CN t-X in O'r aQ X m ro CO CN CN ro CN *—
h
CN CO CN CN
a)
yg X3 0E X /0-*S
4J COX a XCO o r-.
S H 'w' in
<f N 00 O CO O O in «—i in
'vOmcsir^OvO r~ vO m -o- oo *—
i
cm -o- -j- cn -d- co cn «x «-h 43 co
jjc/3
0)
H It
Co
xcO
x3oo x•x jj4-4 &0c cO 03
CJ JX CD
o <—*
X Xo CO
a) OcC "3
o cU CO
XOJJ
oa)
ccoo<u—i x00 4JC•H OC/0 H
«—i cn co <j- in 4> H CN CO CN
33 CO
CO aa ww
XX 4j4J
00CN •—1
Xo - -
X w CO
y X X0) o 03 X X3 o yo 03 a>
u C 33 3
CD O 0—J X y x y x00 4J 4-1 4Jc o 0•X o 3 O 5 O03 CM H CN H CN
Table 10. Rate Dependent Strength Parameters
**
Cable Type Fitted Parameters Predicted Parameter
A B A B
14 AWG/THW 0.0240 -0.00204 0.0246 -0.00155
12 AWG/THW 0.0226 -0.00195 0.0229 -0.00174
10 AWG/THW 0.0259 -0.00145 1.0254 -0.00187
10 AWG/THW 0.0273 -0.00095 0.0268 -0.00143
* Fitted to all data
** Fitted only to quasi-static data
LOAD
-
DISPLACEMENT
«rCM
CMC'i
CDCM
>77
VO
CM
00
VO
CM
3
© CDr- cd
lj ffl
in 'T r>CD ©©
©JO <zo ^ ^ VJ
CDCM
DISPLACEMENT
<CM>
LOAD
-
DISPLACEMENT
OJ
o
03
CD
rr
OJ
CD
LlI
LUO<L
Q_CO
CDOj
CD CDCD CD CD
03 PwCD CD CD CD CD CD•j) in t ro w ^ CD
CDi?•
J O <ZCi L3
Figure
2.
Load-displacement
curve
for
12
gage
insulated
cable
determined
at
displacement
rate
of
0.5
cm/min.
LOAD
-
DISPLACEMENT
*sD
tJ-
04
CD
CD
U3
tJ-
OJ
CD
ct
CD O00
CDrr
CD CDOJ CD CD ©—• —
< 00 >sD
JOOCCi ^ L3
<3 3tr oj CD
DISPLACEMENT
(CM)
LOAD
-
DISPLACEMENT
CD
<Ti
oo
Pw
in
rt
ro
lM
<20
o
LU
tLi
<_)
<1
Q_co*—
4
dl
GO CD00 'D
CD<r
CD '2D
OJ CD CD GOH H 05 CD
JO<IG ^ »J /*.
CDrt
CD
Figure
Load-displacement
curve
for
10
gage
uninsulated
cable
determined
at
a
displacement
rate
of
5
cm/min.
ENERGY
-
DISPLACEMENT
rrCM
CMCM
<3CVI
CO
M3
^r
cm
<3
00
M?
CM
©
O
LU
LUO<x
CLCO
CDCD CD »3— 0“, 00
G3 ® CD © Q <3 CDPw LO U0 **J* PO 0>i —4 CD
lu:Z LUOCU > <xcdcoooc;qqlucl v-.- “> O Z0 -J LU CO •
Figure
5.
Energy-displacement
curve
for
M
gage
insulated
cable
determined
at
a
displacement
rate
of
5
cm/min.
ENERGY
-
DISPLACEMENT
CM
CD
CD
CD
rr
CM
©
s—
•
UlJ
OJo<x
CL03•—
t
c<
CDCM
©CD
UJ 'Z. LU CL »JJ
CD CD CD &CD CD rf CM ©CC 03 CD O QC OQ UJ Ci 'w *"> O Z) -J UJ 03
Figure
6.
Energy-displacement
curve
for
12
gage
insulated
cable
tested
at
a
displacement
rate
of
0.5
cm/min.
ENERGY
-
DISPLACEMENT
CM
CD
CO
vo
Tt
cm
<s>
o
H-
UJ
UJO<x—Ia.O')
CDco
CD'D
CD CD CDif CM G> CD CD
ih 00 MO
<X 0Q tf> O 0C 00 UJ <2
«!D CDTf CM CD
UJ Z UJ a IJ > s^“)O3-JUJC0^
Figure
7.
Energy-displacement
curve
for
10
gage
insulated
cable
tested
at
a
displacement
rate
of
0.5
cm/min.
ENERGY
-
DISPLACEMENT
CD
<Ti
CO
U>
U")
*r
ro
CD
UJ
LtJ
O<X
a.O')
•3CD CD CD CD CD CD »3>
T. 0) N ^ If) tCD CD ©ro <M Q
crcQooaaiujCi v.UJ z: UJ QL LD >• —) O ID —l LU
Figure
8.
Energy-displacement
curve
for
10
gage
uninsulated
cable
tested
at
a
displacement
rate
of
5
cm/min.
LOAD
-
DISPLACEMENT
tr>
ro
n
in
<\j
Oi
in
in
CD
CD
u
h-
LU
SO<x
G_CO
in in Ul in
T 'T PO ro r\j c\j
-JO <xo
in
•3
Figure
9.
Load-displacement
curve
for
a
break-away
connector
tested
at
a
displacement
rate
of
5
cm/min.
ENERGY
-
DISPLACEMENT
Figure
10.
Energy-displacement
curve
fur
a
break-away
connector
tested
at
a
displacement
rate
of
5
cm/min.
LOAA CtUL
Figure 11. The d\namic test apparatus showing a test cable being placed in the grips. Ahigh speed camera can be seen on a tripod to the right of the test apparatus.
Figure 12. The impacior positioned in the guide ra
Figure 13
.
The pull cable or crag ; ine is held m rositior. tv a levs
mechanism (Y-shaped arm.'' prior to attachment to the
flywheel
.
rotating
Figure 14. The flywheel is
photograph. The
rotation frequency
the cylindricalphotodiode device
is mounted to the
obj ecfor
rich
mmoni :or
of the
center of the
.ng the flywheel
flwheel .
Figure 15. The bridge-amplifier system used to condition the strain signals from the grip
connecting rods. A test cable, split capstan grip, and connecting rod can be seen on the
left between the two uprights of the test apparatus.
Hirrrrmrr
Figure 16. Electronic equipment used for the dynamic test.
Poundsf
orce
Poundsf
orce
TOP PULL ROD CALIBRATION CJAN 19875
BOTTOM PULL ROD CALIBRATION CJAN 19875
Figure 17. Correlation between voltage level from strain gage conditioners and actual
load.
FA
A-
1
2AWG/THW-
10FT-T
IMING
GAGES-#
1
cd —
1 CD CD •a CD CD CDLU • • • • % •
>*r O C'J T <X> CD CD1 1 l »
• i
Aj LU
tn
o
mm
CD
CD
CD
ID
I
I
O O W 0)
Tins
(see)
U.OOCOUI
*£22.5
FAA-MAUOTHU-10FT-TOP-*2
Tine (see)*E-2
Figure 19. Load-time records for a 10 ft long, 14 gage, insulated cable.
<DOI
U.OttUllJ
•
>—JW
li_OQtOUJ
*E*2FAA-12AUG/THU-10FT-TOP-t2
Tin« (see)
T
i
h« (see)
Figure 20. Load-time records for a 10 ft long, 12 gage, insulated cable.
Ti«« <*ec>
IFAA-10AUG/THW-10FT-BOTTOM-I1
Figure 21. Load-time records for a 10 ft long, 10 gage, insulated cable.
IvlB
mox>o-n
-*er—
-
mox’O'n
XE + 26.0
FAA-10AWG/-BfiRE-ieFT-TOP-# 1
Tint (*ec)
Figure 22. Load-time records for a 10 ft long, 10 gage, uninsulated cable.
CD
Ol
FORCE,
lbf
CABLE. 14 AWG/THW, 20 FT
TOP GRIP
T I ME
TEST H 4
CABLE. 14 AWG/THW. 20 FT
0.0s 25.0ns 50.0ns 75.0nsTIME
TEST #4
Figure 23. Load-time records for a 20 ft long, 14 gage, insulated cable.
FORCE,
lbf
FORCE,
ibf
CABLEi 12 AWG/THW. 20 FT
TOP GRIP
TEST #3
CABLE. 12 AWG/THW. 20 FT
BOTTOM GRIP
TIME
TEST H 3
Figure 24. Load-time records for a 20 ft long, 12 gage, insulated cable.
FORCE,
lbf
CABLE. 10 AWC/THW. 20 FT
TOP GRIP
TIME
TEST #2
CABLE. 1C AWG/THW. 20 FT
BOTTOM GRIP
TEST 0 2
Figure 25. Load-time records for a 20 ft. long, 10 gage insulated cable.
FORCE.
1bf
10 AWG/BARE. 20 FT
0.0s 25.0ms 50.0ms 75.0msT I HE
TEST #3
10 AWG/BARE. 20 FT
BOTTOM GRIP
TIME
TEST M3
Figure 26. Load- time records for a 20 ft. long, 10 gage uninsulated cable.
tE *21 . €
FAA-14AUG^THW -10FT-TOP-«3
Tine (see)
Figure 27. Energy-time records for a 10 ft long 14 gage, insulated cable.
Cj
c
n
e
r
'J
t
1
bf
T 1 ne < sec *
2.4 2.9 3.4 3.9 4.4
Tine < sec '•
Figure 28. Energy-time records for a 10 ft long, 12 gage, insulated cable.
1C
Ud
T 1 H€ C sec '
Tine <szc'i
Figure 29. Energy-time records for a 10 ft long, 10 gage, insulated cable.
EHERCY
f
t
t1
bf
Tine (sec) TE-2
Tine (see)
Figure 30. Energy-time records for a 10 ft long, 10 gage, uninsulated cable.
F£h- 1 4AWC/THW -20FT-TOP-*3
Tine vsec>*E-2
Figure 31. Energy-time records for a 20 ft long, 14 gage, insulated cable.
«iu
En
er
Jy
*
t
t
1
bf
T i we < sec '/
•»
Figure 32. Energy-time records for a 20 ft long, 12 gage, insulated cable.
i\j
a*
<c
Mi
Tih« >'s«c>
Tin* (.see)
Figure 33. Energy-time records for a 20 ft long, 10 gage, insulated cable.
FAA-10MWG/BARE-20FT-TOP-t2
FAA-10«WC/'BARE-20FT-BOTTON-i2
Figure 34. Energy-time records for a 20 ft long, 10 gage, uninsulated cable.
ll>
tE*le.0
FfiA-BREnK/AUAY-ieFT-TOP-il
Tine i. sec ^
Figure 35. Load-time records for a 10 ft long cable with one break-away connectorlocated 8.5 ft. above lower grip, i.e., at midpoint of cable above impact point.
(\>
£>
l£
Vj
*E-1r. 5
FAA-BPEAK/AWAY-10FT-TOF--«i
»—
r— t-— ' r r i r r i
E
Ti
€
r
f
t
t
1
bf
FAA-BREAK/'AWAV- 10FT-6OTTOM-*!
Figure 36. Energy-time records for test shown in Figure 35.
FORCE,
lbf
BREAK-AWAY CONNECTOR. 20 FT CABLE
20.0ms 22. 5m9 25.0ms 27.5msTIME
TEST #2
BREAK-AVAY CONNECTOR. 20 FT CABLE
BOTTOM GRIP
TIME
TEST #2
Figure 37. Load-time records for 20 ft cable with one break-away connector located at
midpoint of upper portion of cable.
i£
lU
tE-1 FAA-BREAK/AWAY-20FT-TOP-II2
Tine f sec ^tE-2
* Figure 3S. Energy-time records for test shown in Figure 37.
FORCE.
1bf
FORCE,
lbf
2 BREAK-AWAY CONNECTORS. 2 FT SPAN. 20 FT CABLE
TOP GRIP
TEST #2
2 8REAK-AWAY CONNECTORS. 2 FT SPAN. 20 FT CABLE
BOTTOM CRIP
TEST #2
Figure 39. Load-time records for cable tested with break-away connectors located 1 ft
above and 1 ft below impact point, i.e., 2 ft span.
»E-13.0
FAA-2BKUY-2FT SPAM-20FT- T0P-«2
Tine < sec)
Figure 40. Energy-time records for test shown in Figure 39.
FORCE,
lbf
FORCE.
1bf
2 BREAK-AWAY CONNECTORS. 18 FT SPAN. 20 FT CABLE
TOP GRIP
TEST #2
2 BREAK-AWAY CONNECTORS. 18 FT SPAN. 20 FT CABLE
BOTTOM CRIP
TEST 02
Figure 41. Load-time records for cable tested with break-away connectors located 1 ft
above bottom grip and 1 ft below top grip, i.e., IS ft span.
•£
CL
1rti
r«
E
f
t
t
1
bf
T l n* < sec
>
Tine (.see)
Figure 42. Energy-time records for test shown in Figure 41.
UTS
VERSUS
STRAIN
RATE
FOR
14
AWG/THW
Figure
43.
Ultimate
Tensile
Strength
as
a
Function
of
Strain
Rate
for
14
AWG/TIIW
Cable
UTS
VERSUS
STRAIN
RATE
FOR
12
AWG/THW
!SN "sin
STRAIN
RATE,
in/ft/min
UTS
VERSUS
STRAIN
RATE
FOR
10
AWG/THW
Figure
45.
Ultimate
Tensile
Strength
as
a
Function
of
Strain
Rate
for
10
AWG/THW
Cable
UTS
VERSUS
STRAIN
RATE
FOR
10
AWG
UNINSULATED
IO G) LO G> LO G) LO G) LO G)r- r-* (O (O LO lo ^r CO CO
1• 'sin
STRAIN
RATE,
in/ft/min
NBS-1 14A REV. 2-8C
U.S. DEPT. OF COMM.
BIBLIOGRAPHIC DATASHEET (See instructions)
1. PUBLICATION ORREPORT NO.NISTIR 88-3884
2. Performing Organ. Report No. 3. Publication Date
October 27, 1983
4. TITLE AND SU BTITLE
Static and Dvnamic Strength Tests on Electrical Conductor Cables Specified forAirport Landing Structures
5. AUTHOR(S)
R. J. Fields, S. R. Low III, D. E. Harne
S. PERFORMING ORGANIZATION (If joint or other than NBS. see m struction s) 7. Contract/Grant No.
DTFA-01-85-Z-02007NATIONAL BUREAU OF STANDARDSU.S. DEPARTMENT OF COMMERCEGAITHERSBURG, MD 20899
9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State.
8. Type of Report 8, Period Covered
Final Report
ZIP)
Federal Aviation Administration
Department of Transportation
Washington, DC
10. SUPPLEMENTARY NOTES
Document describes a computer program; SF-185, FlPS Software Summary, is attached.
11. ABSTRACT (A 200 - word or less factual Summary of most significant information. If document includes a significantbibliography or literature Survey, mention it here)
This is a final report covering a series of static and dynamic tests on electricalconductors specified for use in landing aids on airport runways carried out by XI 51 for
the Federal Aviation Administration. The structures are intended to be frangible so
that they will break up readily if impacted, thus minimizing damage to the impactingaircraft. While the structures are frangible, they contain electrical cables which,due to the requirement of electrical conduction, are not frangible. In an actualimpact, these cables do not break readily and tend to wrap around the aircraft. Thetests authorized by the FAA were carried out to assess the force required to breakthrough various types of FAA specified cables by a simulated aircraft impact. Further-more, the effectiveness of using break-away connectors was evaluated to determine if
they would reduce the total load on an impacting aircraft.
In order to correctly design the dynamic test apparatus, it was necessary to know the
approximate, expected load levels and cable elongations at fracture. Therefore a seriesof quasi-static tests were performed on the cables and break-away connectors. Thisreport describes these quasi-static tests as well as the construction and applicationof the dynamic test apparatus.
12. KEY WORDS (Six to twelve entries; alphabetical order ;capitalize only proper names; and separate key words by semi colon s>
airport landing aids; break-away connector; cables; copperwire;
tests; frangible structures; static strength
13. availability
XX. (jnl united
For Official Distribution. Do Not Release to NTIS
dynamic strength
14. NO. OFPRINTED PAGES
81
Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.20402 .
15. Price
'rr’Ar Order From National Technical Information Service (NTIS), Springfield, VA. 22161AO 5
USCOMM-DC 6043-P80
.
1
.
•
*