NISTIR 88-3884

Static and Dynamic Strength

Tests on Electrical Conductor

Cables Specified for Airport

Landing Structures

R. J.. Fields

S. R. Low, III D. E. Harne

U.S. DEPARTMENT OF COMMERCE

National Institute of Standards

and Technology

Metallurgy Division

Gaithersburg, MD 20899

Prepared for

Navigation and Landing Division

Federal Aviation Administration

Department of Transportation

U.S. DEPARTMENT OF COMMERCE

Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS

AND TECHNOLOGY

John W. Lyons, Director

NIST

NISTIR 88-3884

Static and Dynamic Strength

Tests on Electrical Conductor

Cables Specified for Airport

Landing Structures

R. J.. Reids

S. R. Low, III D. E. Harne

U.S. DEPARTMENT OF COMMERCE

National Institute of Standards

and 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 COMMERCE

Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS

AND TECHNOLOGY

John 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 Division

National Bureau of Standards

Department of Commerce

Gaithersburg, MD

prepared for

Navigation and Landing Division

Federal Aviation Administration

Department 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 NBSFAA 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 highspeed 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 reductionof-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: Bussman1 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, loaddisplacement 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 (e f ) is given by

£ - in

where £ 0 and £ are the initial and final gage lengths

reduction- in- area is defined as

Likewise, the

A0- A

R . 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

a

y = P

y /A0 where Pu and P

y are the ultimate tensile and load yielding load,

respectively

.

The true stress at fracture (a f ) is calculated from

Pu

A

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 (e f ) 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 e f 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)

12

3

4

5

6

7

8

-1200

-900

-600

-300

0

+300

+600

+900

13
9 + 1200

10 + 1500

11 + 1900

12 +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 (V ave ).

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

F

Im

= F*

Ax, +

F

B

Ax

,

, fl

H "aX

[(i?) 2 + Axf U

max 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 V

2 t

A J t=0

A 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 curve

a displacement rate of 0.5 cm/min.

Figure 3. Load- displacement curve

a displacement rate of 0.5 cm/min.

Figure 4. Load- displacement curve

at a displacement rate of 5 cm/min

Figure 5. Energy-displacement curve

at a displacement rate of 5 cm/min.

Figure 6. Energy-displacement curve

displacement rate of 0.5 cm/min.

Figure 7. Energy- displacement curve

displacement rate of 0.5 cm/min.

Figure 8. Energy-displacement curve

a 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 test

cable being placed in the grips. A high speed camera can be seen on a tripod

to 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 lever

mechanism (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 rotation

frequency is mounted to the right of the flywheel.

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

.

Figure 16. Electronic equipment used for the dynamic test.

20
Figure 17. Correlation between voltage level from strain gage conditioners

and 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.

connector

Load- 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 above

impact 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 connectors

ft 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 connectors

located 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 W

r—^ 3

•r-l 4->

C/) C/) 3 •rH C 03 TO CO On m r“—

4

0

Qj »-“l O vi) O' O' CN H CjJ as LPl Vi) co 00

CO

CO

<1> S-i <0 4J 5-4 cn 3

4-1 <u O •r^ 3 03 cn vO CO CN 00

!-i u 5-4 CN Ov CN CO H CO Ct, W CN CN CN CN

x:

4-1 00

TO c

0) •rH

<0 5-1 CO »rH 4-1 co <t CO CN

>< 00 CO CO CO CO

0) X

u u u

03 r—I bO S'H

« II ^

•U c S-I w —

1

0) ±-> X co r- o 00 X 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- O

e C 0 5-1 X4 m 00 CO vO \ W U til N—

t“H c

•r-l C 0 O

CN •r^ 4J

<4-4 O

O 3 03 TO 0) /-—

S

0) <D C 5-1 <#> t-H vf CN <t

4J 02 •H < 00 OO 00 00

CO

}-( C

00 O c •r^ 0)

•rH 4-> 5-4 4J 0) 3

CO bO U

0) C O

4-> O 03 O S-i <#> vO m r-H

03 w 4J Ci, n ' '3- <r CN

4J

03 b0

0 C

CO 4J 4J TO /*\

r-H co —• TO <4-1 3 03 <u 03 XI 00 OO co <f

co »—

4

•H O —

H

0 vO vO

0) Oh >• X r-4 CN CN

)-l O a;

•r^ 4J a; 4J 03

03 E •r^ r~s 4J •rH co TO <4-4 CO 4J C 03 X) Ov CO <3- CN

1 CD O «—

1

CO CO co *“H

•i-4 33 H J r-4 CN CO CO

CO

033

O' a; 5 5 3 u X X X 03 H H H 0Q

r-H \ \ \ \ O U O O

0) a) 3 3 3 3 r—

H

<D < < < <

XI X) a

03 03 to <r CN O O

H <3> H «—

H
Table

2.

Quasi-static

results

ata

testing

rate

of2

in/min.

<D

O C/3 r—\ •r^ 3

•r4 4-3 «““4 ,—V w c/i 3 *r4

O 0 X co c C0 o C/3 *—4

co oo uO

<u *—4 OX <r UO co 0 H cu s w

C/3

C/3 0)34 03 u 3-1 cn 3

4JN

0) 03 •r4 3 3 C/1 Osl

H «—

H

<]

34 4-3 3-i

A 40 00

X

H 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 CN

00 CO CO CO co

oj

A 4-> 03 4-1 3 <-—4

bO E •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

0334 C4-4 >0 3 X b0 4-3 34 O 1 0) 3 4J C O 34 <4-1 *—l 04 CN CM w 4-3 Cti s-/ n 00 04 X co

•r4 u

<J3 CO X 03

03 c 34 dP <f «—4 X

as •rH < n— 00 00 00 00 Co

•r4 03 4J 34

Cfl 3

bO 4-3 C U O CO »—4 o 34 dP CN

X 0 CM

w 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 04 O 4 O X 00 in

Ot ><

X r-H f—4CN 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 0 33 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 0 U H
05 o CO

•—

H

3

•W 4J ^—4

CO co 3 •r^ c CO '

O

co in ro o

Q) r—-4 o i cn «—

i

ON H W as i iO m rco

co3

5-, 0)

4-1 5-1 co 3

05 05 •rH 3 CO CO m r^-

5-i •U 54 vT> 00 H m

H c0 Et, N~' m CN m CN x

u

aO

•3 C

r—

H

0) *rH 3 54 CO •rH U m m r-H r-H >“ CO m m m m

0) X 4-> 0) 4-1 CQ ao B **-i c

•H CO 05 •fH •u C 54 CO -—4 05 4-4 o m 00 3 H CO m co

3

5-4 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 m

c w 4-5 Cw V

y <r *-H in

CN C

o O *H

•U

<4-1 O

O 3 3

”3 3

05 3 C 54 <*> O' m 00 lO

4J c£ >1-4 < ' 00 00 00 00

CO54 c

ao O

C •rH 3

•r^ 4-5 54 4J 3 3

CO ao 4J

05 C O

4-) 0 3 x-s —I o 54 <#> O CD o

CO CjJ 4-1 Cl, s-/ cn <f -3- CN

4J

CO ao

C5 C

CO

4-1 W TO

f—

4

CO —1 ”3 4-1 3 cO 3 3 -Q in cn O cn

co •—

H

O »-H O lo cO m

05 CL, >4 X V-/ *-H r4 CN CN

54O 3

•r^ 4-1 3

4-1 C\J •-H

CO S »H

4-1 t-l CO T3 4-1

CO ±-> c 3 o cn Osl cn

1 r-H ^ 0 *—"4 co «w r-H O'

•r4 3) H X 'w' H CN co CN

CO3

CO O' 3 3 S 3 54 X X X 3 H H H 0Q

CO \ \ \ \ a O O a

0) 3 3 r-H »~4 3 < < < < X X a c0 3 En <r CN o o

H 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 UO HUS'-' <f in fO OO

ue

Stress

acture

si) oo m -4 <f

5-1 fa S-( ^ O -fa 'XJ OM H cfl fa ^ O CM -4 -4

ield

trength

ksi )

CM CM <f 00

>> C/3 w CO CO CO CM

ltimate ensile trength

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 m

CMo c • o o •fa

4-1 fa

CJ O 3 03

05 03 05 ^ 05 C fa dP 00 lOl 1"-. CM

4-)

rrt OS -fa < w OO 00 M CO

5-i bO C

o C •fa a)

•fa •fa fa fa 03 3

C/3 b0 fa

05 C O

fa O 03

oJ

-fa O fa dP r-> *-c r- o W fa Cli —

CO <f «fa CM

fa

Cfl b0

cn O C

fa fa 03

*—H c/J -fa 03 4-i 3 03 05 03 X CO MO OM -fa w -fa *fa O -fa O in M CO

05 C4 >4 _] w fa fa CSI CM

5-1 o 05 •H fa 05 fa Ctf »—H

03 E -fa ^ fa •fa co 3 fa

CO fa C 03 X O' vj <J

1 -fa 05 O -4 -fa om o oo X H X w -fa -fa CO CM

CO3

03 O' 05 U3 ^ 13 U X X X 03 WEfa H WH oQ

05 05 o o o o

X X 3 3 »-H *—H (1) < < < < X x a 03 03 >, <3- CM O O H 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 CN

03 o v£) CN rO H S3 s«/ UO LO co O'

03

03

0)

3-i 03 •U 3-1 00 3

4J

03 o •r^ 3 03 cn CO 0‘s CO vTi

S-i 4J 3-i CO r-H 00 CO H 05 Cm csj CN r-H CN

J3

4-> CO

T3C

r-^ 03 •rM

03

U CO

•r-4 4J r^ ct\ 00

>-• CO s—

CSI CM CN CN

03 JC

4J 03

u

03 C0 £ •r-4 C

•rH 03 03 •r^

4-1

C S-i 03 -—4 03 4-> 00 CN CO P H co ^—* m CO CO CO

03

C 3-i 4-1

•rH >o 3 X £ CO 4-3 N 3-4 C3 i C 03 03 U

•M

CO !-, 4^ NO CN o> co

w •U Cm CO CO co v£> CNoo c • o o •rH 4J cm o O 3 cO T3 03 /*%

03 0) c S-i dP 00 <f CO vn u Cti •rH < Nw-' oo 00 00 00

03

3-( c

co o c •H 03

•r^ 4J 3-1 4J 03 3

03 CO 4J

03 c O

4-3 o 03

»—

H 0 )-i dP lO

O

O in

03 ttJ 4J Cm 'w' CO CN

M CM

4-> 03 co O C

03 •M •H U 4J p /-V

0) r-H "0 4h 3 03 0) 03 X CO o r-4

03 *rH

O 00 <r CM CO

03 CL, ><

J oo *—1 CM CM

3-4 O 03 •M M> 03

4-1 03 *—1 03 £ •rH

4-1 •rH C/3

X 4-1

03 4-) c 03 X) T—HCO 00 «M i 03 0 t“H r-. i-- •M P H J 'w' i-H CN CM

033

03 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 3 r-H 03 < < < <

rO P P

03 CO Pn -O’ CN

OO

H 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 0.60

2 8.0 0.50

0.2 7.3 0.40

0.02 6.1 0.39

0.002 7.9 0.44
Table

7.

Photodiode

array

results

from

dynamic

tests.

c

ou

03 —i ao

03 C

4-> O

O —I c3P E-h U3 oo r-- o r-- r-^ CM mo in <3- ro ro n <f m m <f

C

o

4-1 e 03 o 00 u C

4-1 o ^

o —i <*> D3 U ^ oo n n n n 03 CN n CM mo CM CM CM

C

o

•rH 4J

03aoC

a o ^

O'—i # *—i in «—i n n in <t O cm o o mo mo O 4 h o

E—

1

3x3 ^ i—* CM t—4 *—4 ^ *—t CM P'3 —H —4 —

H

c

o

4J0o

<4-1 U O LC3 CM m m O

03 <4-1 • • O '—

y

CO CO m co CM

>3

0) 4J ao *h

CO O

C/3 4-3 O rH 0 CM 03 O 0

Sm 0 O MO 0 MS

0; *-h c O O CM m O rH <4 03 > 03 < >

«—

H

00 0

00

rH

03

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

>3 e 4-> /N a •H w

E 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 0

43 03 -X m m 00 03 00 rH 00 m 00 03 rH

at > 00 00 03 rH rH

0 00 Mt rH CM 0 CM <4 03 in CM 0

r-~ 03 m 00 03 m <4 m 00 uo CM CO

00 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 mO x > C' c- 00 00 r-* 03 cM M 03 O

«-H «-M 30 00

<4 r- r- o

00 im co in <f r-» ao 00 mom

03 00 CM CM CM 30

1— mo c- n n 03 cm m

r-» i--. r-. 00 cm

\D <

11/3 C~ 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 aO H C \ \ \ \ \ \ \ \ 03 O a O O O U O O

03 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 O

U 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.

T3

04 T3C

0)ax

4-1

>-, XL

aO

—i —i

Ui ctJ i 04 AJ iJ

m r—t o o CSJ L/0 OO CO rH

X

Q 00 c 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

-o

04 ~oc

0)CLX

LxJ^ E JD

&0

O

—t

i-l AJ I 04 aj 4-> CO 4-4 W X w

co o 43 oo r- oo O' x

O

M 4

O''X «-J

X

O vj

in

x

ro o''

r-i oo <r

x

*0

04 "Oc

04CLX

LtJ>4

©

QO —4 U I 04 Q. 4J c o (4-1 CjJ H s-/

O «-•

X 04

n O' rs C4

Csi o oo fi

43 -3

©O 43

—

04 «—t CO »-o CO •—I

CO 00

co

O «—I 04

O X. X O.

0444

44

U o o

Lu AJ

4)

a oj c a a a

**4 HH x

03

C £ O

04

m O' o >4- O' CO CO o o ro

co r- r- 04 04

1/0 *"J 04 04

oj <r

co

O'

vj04

04

00

—

<r 04 — Om 3 a a 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 <r

03 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

h 3 O

•H 4-1 X CL

O oo

K <r *3 o -4

O O''

n -3

X

O in

X

O in

X CO

cfl

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

OH 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 X H C \ N N \ \ \ \ \

<u

U

O

aO

OO

a

a

04 -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

4J

33

C 43

O <3O 04O 04

OOO

O

OO c o O CO *-H •—4

«-4 04 «-H *—4 ^4 04 —i 04 o ^4 04
Table

9.

Results

of

dynamic

tests

on

connectors.

T3

0) T53

U

a

x

Cx]So

4jX co CN in CO <r CN CN 43

Qjj -4 _4 43 m O'' lPi <r <r co 4T lPi 03 co X co 1 <D ±J jj 43 cn 43 in 43 cn o o O o o o

3 O X E—

i

4-1 in <r

33

a> "Cc

0)a

xX

So E O 03 03 00 0 O CO in 43 X jj l a/ jj jj 43 43 40 3 O 4-i <—

t

lO

U3 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

<u34X

x

So

00X

4-4 X

1 ro CN c- 00 ro CN O' ao co X ro

0) C4 X X o f— CN co CO CO CN cn ro CN 3 0 4J X H ''w' o o o o O o o O o o o o o

s

3 E

E

• rHX

0X

X

03CJX

4jX 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)y

g X

3 0

E X /0-*S 4J CO X a X

CO 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

jj

c/3 0) H It

C

ox

cOx

3

oo x •x jj

4-4 &0 c c

O 03 CJ J

X CD o <—* X X

o CO

a) O

c

C "3 o c U CO

X

O

JJo

a)c

c

oo

<u —i x

00 4J C

•H O

C/0 H

«—i cn co <j- in 4> H CN CO CN 3

3 CO

CO a

a w

w X

X 4j

4J

00 CN •—1 X

o - - X w CO y X X

0) o 0

3 X X

3 o y

o 03 a> u C 3

3 3

CD O 0 —J X y x y x

00 4J 4-1 4J c o 0

•X o 3 O 5 O

03 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

CM

C'i

CD

CM

>77

VO

CM

00

VO

CM

3

© CD

r- cd

lj ffl in 'T r>CD ©

©©

JO <zo

^ ^

VJ

CD

CM

DISPLACEMENT

<CM>
LOAD

-

DISPLACEMENT

OJ

o

03

CD

rr

OJ

CD

LlI LUO

<L

Q_

CO

CD

Oj

CD CD

CD CD CD

03 Pw

CD CD CD CD CD CD

•j) in t ro w

^

CD

CD

i?•

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

tJ04

CD

CD

U3

tJOJ

CD

ct

CD O

00

CD

rr

CD CD

OJ CD CD © —• —< 00 >sD JOOCCi ^

L3

<3 3

tr oj CD

DISPLACEMENT

(CM)
LOAD

-

DISPLACEMENT

CD

<Ti

oo

Pw

in

rt

ro

lM

<20

o

LU

tLi

<_) <1

Q_

co

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4

dl

GO CD

00 'D

CD

<r

CD '2D OJ CD CD GO H H 05 CD

JO<IG ^ »J /*.

CD

rt

CD

Figure

Load-displacement

curve

for

10

gage

uninsulated

cable

determined

ata

displacement

rate

of

5

cm/min.
ENERGY

-

DISPLACEMENT

rrCM

CM

CM

<3

CVI

CO

M3

^r

cm

<3

00

M?

CM

©

O

LU

LUO

<xCL

CO

CD

CD CD »3 — 0“, 00

G3 ® CD © Q <3 CD

Pw 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

ata

displacement

rate

of

5

cm/min.
ENERGY

-

DISPLACEMENT

CM

CD

CD

CD

rr

CM

©

s—

UlJ OJ

o

<xCL

03

•—

t

c<

CD

CM

©

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

ata

displacement

rate

of

0.5

cm/min.
ENERGY

-

DISPLACEMENT

CM

CD

CO

vo

Tt

cm




o

HUJ

UJO

<x

—Ia.

O')

CD

co CD

'D

CD CD CD

if CM G> CD CD

ih 00 MO

<X 0Q tf> O 0C 00 UJ <2

«!D CD

Tf CM CD

UJ Z UJ a IJ > s^“)O3-JUJC0^

Figure

7.

Energy-displacement

curve

for

10

gage

insulated

cable

tested

ata

displacement

rate

of

0.5

cm/min.
ENERGY

-

DISPLACEMENT

CD

<Ti

CO

U>

U")

*r

ro

CD

UJ

LtJ O

<Xa.

O')

•3

CD CD CD CD CD CD »3> T. 0) N ^

If) t

CD CD ©

ro <M Q

UJ z: UJ QL LD >• crcQooaaiujCi v. —) O ID —l LU

Figure

8.

Energy-displacement

curve

for

10

gage

uninsulated

cable

tested

ata

displacement

rate

of

5

cm/min.
LOAD

-

DISPLACEMENT

tr> ro

n

in

<\j

Oi

in

in

CD

CD

u

hLU

S

O

<x

G_

CO

in in Ul in

T 'T PO ro r\j c\j

-JO <xo

in

•3

Figure

9.

Load-displacement

curve

fora

break-away

connector

tested

ata

displacement

rate

of

5

cm/min.
ENERGY -

DISPLACEMENT

Figure

10.

Energy-displacement

curve

fura

break-away

connector

tested

ata

displacement

rate

of5

cm/min.
LOAA CtUL

Figure 11. The d\namic test apparatus showing a test cable being placed in the grips. A

high 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 cylindrical

photodiode device

is mounted to the

obj ec

for

rich

m

moni :or

of the

center of the

.ng the flywheel

fl wheel .
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

A1

2AWG/THW10FT-T

I

M

ING

GAGES-#

1

cd —

1 CD CD •a CD CD CD

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o

mm CD

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CD

ID

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Tins

(see)
U.OOCOUI

*£2

2.5

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

•

>— J

W

li_OQtOUJ

*E*2 FAA-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 + 2

6.0

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 75.0ns

TIME

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.

1

fb

10 AWG/BARE. 20 FT

0.0s 25.0ms 50.0ms 75.0ms

T 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 *2

1 . €

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

1b

f

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.
E

H

ER

C

Y

f

tt

1b

f

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

E

n

e

rJy

*

tt

1b

f

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*l

e.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 connector

located 8.5 ft. above lower grip, i.e., at midpoint of cable above impact point.

(\>

£>
l£

Vj

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r. 5 FAA-BPEAK/AWAY-10FT-TOF--«i

» — r — t-— ' r r i r r i

E

Ti€

r

ft

t

1b

f

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 27.5ms

TIME

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£

Ul

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.

1

fb

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-1

3.0

FAA-2BKUY-2FT SPAM-20FT- T0P-«2

Tine < sec)

Figure 40. Energy-time records for test shown in Figure 39.
FORCE,

lbf

FORCE.

1

fb

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

1

rti

r«E

f

tt

1b

f

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

asa

Function

of

Strain

Rate

for

14

AWG/TIIW

Cable
UTS

VERSUS

STRAIN

RATE

FOR

12

AWG/THW

! S N "sin

STRAIN

RATE,

in/ft/min
UTS

VERSUS

STRAIN

RATE

FOR

10

AWG/THW

Figure

45.

Ultimate

Tensile

Strength

asa

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 DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT 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 for

Airport 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-02007

NATIONAL BUREAU OF STANDARDS

U.S. DEPARTMENT OF COMMERCE

GAITHERSBURG, 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 significant

bibliography or literature Survey, mention it here)

This is a final report covering a series of static and dynamic tests on electrical

conductors 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 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. Furthermore, 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 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.

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. OF

PRINTED 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. 22161

AO 5

USCOMM-DC 6043-P80
. 1 . • *