rope becomes more fatigued, the rate at which wires break
dramatically increases. Cold working could not be quanti-
tatively measured; however, breaking strain is a good
indicator. The decreased breaking strain indicates that
cold working reduces the ductility of the wires. The effect
of bending cycles on breaking elongation is shown in
figure 14.

Table 7 contains data from other physical measure-
ments that were made. The first two columns list the lin-
ear location and number of cycles at that location. The
third column shows the rope diameter, as measured by a
caliper, averaged from three positions around the rope.
The fourth and fifth columns are computations of the
percentage reduction in diameter and metallic area as
compared with the best pieces. The LMA is obtained
from an inhouse computer program that will be reported
in the near future. The LMA computed from caliper

readings (column 5) is compared to the LMA determined
by the average reading from the two EM NDT sensors
(column 6) in figure 15.

Figure 15 shows that the two areas are fairly close
(within approximately 2 pct of the total LMA) over the
length of the rope. This indicates that the two methods
are comparable to each other even though neither is a
panacea. EM NDT devices measure metallic mass, which
can be affected by such things as rope tension, but will
not detect such things as inner wire peenning. The caliper
readings measure outside rope diameter, which can be
used to calculate outer wire wear, but cannot detect such
things as corrosion or nonwear causes of diameter loss
such as milking, a condition resulting from the progressive
movement of strands along the axis of the rope. Despite
these shortcomings, both methods do provide an accept-
able means of determining rope condition.

Table 7.—Diameter and EM NDT measurements
Posi- Number of Rope diam ‘Area loss, pet Wire diam
tion, ft bending cycles in Loss, pet Calc EM NOT loss, pet
TEST 2
0 2.057 0.68 0.10 0.0 0.54
12,521 2.013 2.80 38 0 225
37,563 2.00 1.34 1.34 0 27.6
62,605 1.998 3.52 1.43, 0 28.3
87,647 1.987 4.06 1.97 3 32.6
87,647 1.988 4.01 1.92 1.0 32.2
100,168 1.980 4.39 2.34 1.0 35.3
100,168 1.981 435 2.29 1.0 34.9
87,647 1.999 3.48 1.39 20 27.9
87,647 1,994 3.72 1.62 25 29.9
62,605 2.007 3.09 1.05 24 24.8
37,563 2.013 2.80 83 20 22.5
12,521 2.025 2.22 56 1.0 179
° 2.055 7 12 1.0 62
Co) 2.070 ) é) 0 o
TEST 3
38. 0 2.056 0.72 011 0.0 5.8
163. 3,157 2.012 87 87 5 22.9
238. 9,471 1.984 4.20 2.13 5 33.8
288. 15,785 1.985 415 2.08 5 33.4
338. 22,099 1.979 444 2.40 1.0 35.7
363. 22,000 1.980 439 2.34 1.0 35.3
463. 25,256 1.957 5.50 3.70 20 443
488. 25,256 1.969 4.92 2.97 20 39.6
513. 25,256 1.964 5.17 3.27 2.0 415
593. 22,000 1.975 4.64 2.26 15 37.3
618 . 22,099 1.980 439 2.34 18 35.3
668. 15,785 1.993 3.77 1.67 1.0 30.3
743. 9471 1.995 3.67 1.57 1.0 20.5
793. 3,157 2.019 251 87 5 20.2
943. 0 2.066 24 0 0 19
@... () 2.070 0 0 o 0

\New condition, sample taken from shipping reel.


UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT

deg degree Ib pound

ft foot Ibf-ft pound (force) foot

fi/min foot per minute Ibf-ft/kip pound (force) foot per kip
in inch pet percent

in/min inch per minute pet in/in _ percent inch per inch

kip/in? kip per square inch psi pound (force) per square inch
ip, a



TEST ROPE DESCRIPTION

The test ropes were of 2-in-diameter 6x25 filler wire
(FW) construction, improved plow steel, with a right
regular lay of 13.13 in and an FC. In this construction
(fig. 7), there are 6 strands containing 19 wires and 6 FW’s
for spacing; the FW’s are not considered to be load

bearing. The core is composed of polypropylene fiber.
Thus, each rope is composed of 114 load-bearing wires.
The measured breaking strength for these ropes when they
were new was 348.8 kips. A rope after degradation is
shown in figure 8.

TEST PROCEDURES

BENDING FATIGUE TEST

For the bending fatigue test, the rope specimens were
reeved through the machine and wound onto the drum.
The first rope in this controlled test was run at a
conservative tension of 30 pct of breaking strength
(100,000 Ib) at a speed of 500 ft/min for a total of 12,512
machine cycles (which is equivalent to a maximum of
100,168 rope cycles) until the specimen appeared to be

Figure 7.Rope construction.

nearing failure. The second rope was run at 50 pct of
breaking strength (170,000 Ib) at a speed of 550 ft/min
vuntil the specimen broke on the machine at 3,157 machine
cycles (which is equivalent to a maximum of 25,256 rope
cycles). The test parameters are summarized in table 3.

‘Table 3.—Specifications for bending fatigue tests

Test 2 Test 3
Rope diam. . in. 2 2
Rope length sft... 878 988
Maximum fleet angle .. deg. . 2.30 100.000
Rope tension 100,000 170,000
Rope speed . 500 550

When the ropes were removed, they were cut into 25-ft
pieces. The selection of samples for further testing was
based on the number of bending cycles. These samples
were cut into three sections. Seventeen-foot-long pieces
were used for tensile destructive tests. The remaining 5-ft
pieces for wire-by-wire examination and 3-{t pieces for
metallographical analysis were stored for later testing.

Figure 8.—Test rope after degradation.


INTRODUCTION

The wire rope research laboratory is located at the U.S.
Bureau of Mines Pittsburgh Research Center in Bruceton,
PA. The laboratory was set up as part of the hoisting
system development project, which has been a continuing
effort by the Bureau for several years. The primary goal
of this project is to improve both the safety and efficiency
of hoisting systems. A major part of this effort involves
the study of the degradation of wire rope during its service
life. Personnel-carrying hoists are used for transporting
miners in hundreds of mincs; failure of the rope in a single
high-capacity hoist could result in a catastrophic accident.

The objective of the project is to enhance the safety of
hoisting systems by quantifying the degradation process.
The research approach is to develop accurate data on the
factors that reduce wire rope life, such as fatigue (both
bending and axial), wear, and corrosion, This data could
be used to improve the evaluation of current nondestruc-
tive testing equipment data for determination of rope con-
dition, Thus, it can be seen that the safety and economic
concerns are interrelated and the potential benefits of such
research are high.

EQUIPMENT DESCRIPTION

BENDING FATIGUE MACHINE

Because one of the primary modes of wire rope degra-
dation is fatigue from bending on sheaves and drums, the
principal machine in the laboratory is one designed to
cause fatigue damage in varying degrees in a long sample
of wire rope. By using a long sample, the possible var-
iation among short samples is avoided. The bending

fatigue machine is shown in figure 1 and a schematic dia-
gram of the rope path is shown in figure 2.

The "three-sheave" configuration not only shortens
the load frame, but also multiplies the number of rope-
bending cycles for each machine cycle. Thus, in a single
specimen, samples of rope at each of nine different levels
of degradation will be obtained. The cycle profiles for
these tests are shown in figure 3.

Figure 1.—Bending fatigue machine.


BENDING FATIGUE TESTS 2 AND 3 ON 2-INCH 6x25
FIBER CORE WIRE ROPE

By J. R. Bartels,’ W. M. McKewan,? and A. J. Miscoe®

ABSTRACT

The U.S. Bureau of Mines has established a wire rope research laboratory to examine the factors that
affect the life of wire rope. Two 2-in-diameter 6x25 fiber core (FC) ropes were degraded on a bending
fatigue machine. These were the second and third ropes in a series of tests on this construction and size
rope. Tensile and nondestructive tests were performed on samples of the rope to determine the
relationship between rope deterioration and rope breaking strength. The tests indicated that once a wire
rope nears the end of its service life, both deterioration and the consequent loss of rope strength begin
to increase at an accelerated rate.

1 Civil engineer.

2Metallurgist.

3supervisory physical scientist.

Pittsburgh Research Center, U.S. Bureau of Mines, Pittsburgh, PA.


TENSILE AND AXIAL FATIGUE TESTING MACHINE

The second major piece of equipment in the laboratory
is the tensile and axial fatigue testing machine shown in
figure 6.

The tensile and axial fatigue testing machine was used
to measure the actual breaking strengths of the new rope
and the degraded rope samples from the bending fatigue
test. The performance of this machine was reported in a
previous publication.®

This hydraulically actuated machine is in a horizontal
position rather than the usual vertical position to reduce
vertical height requirements and for ease of access. The
load is applied through a closed-loop servohydraulic
‘system. The controllable parameters are displacement of
the actuator, load applied to the specimen, and torque
generated by the specimen as the axial load is applied.
The system specifications are listed in table 2.

McKewan, W. M., A. J. Miscoe, and J. R. Bartels. Bending Fatigue
Test 1 on a 2-in 625 Fiber Core Wire Rope. BuMines RI 9408, 1992,
11 pp.

Table 2—Capabilities of tensile and axial
fatigue testing machine

Rope tension 800,000
Actuator spe 32
Torque .. 20,800
Rope diam . 1.2%
Sample length 233



Bending Fatigue Tests 2 and 3 on 2-Inch
6x25 Fiber Core Wire Rope

By J. R. Bartels, W. M. McKewan, and A. J. Miscoe



RESULTS

The selected samples were socketed with approximately
15 ft between socket ends. The samples were then tested
to failure on the tensile machine. The data obtained from
tensile tests on the rope samples are shown in tables 5 and
6. The position in feet in the first column is the beginning
of the sample.

Table 5.—Measured tensile test data

rope. The center section of the rope had the most degra-
dation and thus the maximum strength loss. Because the
rope broke on the machine, the most deteriorated section
in the center of rope 3 was not available for tensile testing.
Because of the machine configuration, the strength loss in
the first half of the rope is approximately a mirror image
of the second half.

Figure 11 shows the effect of the number of bending
cycles on breaking strength. As can be seen, the rope

Posi- Number of Breaking Elonga- load —_ experienced a decrease in strength with a larger number
tion, ft bending load, ton, loss, of bending cycles. There is some scatter in the data,
cycles Kips i Pct indicating that in these tests, the machine did not degrade
Test 2 ‘the rope in exact symmetry. This duplication of results is
38. 0 344.0 6.91 138 still useful in evaluating the data.
ie 12,821 340.4 S42 2a There are two major factors relating to loss of strength
38 37,563 333.2 4.76 447 . fs
288 62,605 322.9 474 7.43 considered for this test. One is LMA due to wear and the
338. 87,647 287.6 3.69 17.55 other is broken wires resulting from fatigue damage. Fig-
363 .. 87,647 283.5 3.82 18.72 —_ure 12 shows the effect of the number of bending cycles on
413. 100,168 254.7 3.10 26.98 LMA, as determined by nondestructive methods. As can
438. 100,168 254.2 3.13 27-12 be seen, initially there is a rapid LMA as the top of the
488. 87,647 2725 3.60 21.88 -
513 87,647 293.4 408 15.88 Town wires are worn, then the rate of LMA decreases as
563 .. 62,605 304.0 4.05 1284 a larger bearing area is created by the wear, and finally
613 .. 37,563 320.1 4.65 8.23 the rate of LMA increases again as the adjacent wires start
688 .. 12,521 343.9 6.21 1.40 to wear. Other factors that affect strength loss, such as
S18 .. ° wee te {8 corrosion, will be investigated separately in future tests.
O : A Figure 13 shows the effect of the number of bending
TEST 3 cycles on the number of broken wires per lay length as
38 ° 348.1 8.53 0.02 determined visually. Initially there is a very gradual
163. 3,187 342.6 5.54 178 . ,
238 ort bore tee 206 __ increase in the number of broken wires. However, as the
288 .. 15,785 342.5 4.66 1.81
338. 22,099 340.7 456 2.32 350 >
363. 22,099 333.7 4.09 4.33 rary wee
463. 25,256 268.1 2.65 23.14 .
488. 25,256 217.0 2.85 37.79 300/- 4
513 .. 25,256 275.1 3.07 21.13
593. 22,099 313.1 3.34 10.24 .
618 .. 22,099 340.7 441 2.32 °
668. 15,785 337.2 4.36 3.33 250f- 4
743. 9,471 340.9 4.76 2.26 £
793 .. 3,157 346.7 5.94 oo £ Rope 2 .
943. 0 348.2 8.27 7S oy
Oo. 0 348.8 8.67 0 S 350
TNew condition, sample taken from shipping reel, 8 . oy oe
= ° °
The configuration of the bending fatigue machine allows & 300 .° 4
a range of degradation to be achieved from a single test we
tun. The data obtained from this test are indicative of °
wire rope degradation ranging from minimal wear to a 2sof o 4
condition of imminent rope failure. The controlled lab-
oratory conditions allowed the testing of a sample with a Rope 3
30 pct loss of strength, well beyond the MSHA retirement 200

criteria of 10 pct strength loss.
Figure 10 shows the breaking load of the samples tested
versus their respective position along the length of the

© 100 200 300 400 500 600 700 800 3900
DISTANCE ALONG ROPE, ft

Figure 10.—Breaking load versus distance.


TENSILE TESTING

The locations of the samples for the tensile tests are
given in table 4. These samples were terminated with
resin-filled, standard closed sockets, resulting in a finished
specimen gauge length of about 15 ft. This length was
chosen based on the results of a baseline testing program
previously reported,’ which determined that shorter sam-
ples would show abnormally high breaking strengths.

NONDESTRUCTIVE TESTING

For these tests, extra pieces of crown (outer) wire were
imbedded between the strands, in coded order, at 50-ft
intervals, to act as permanent markers on the EM NDT
chart traces. To make a test, the rope is run through the
instrument once to properly magnetize it. The sensor

Work cited in footnote 4.

head is removed during rewinding to prevent a change in
the magnetic polarity of the rope, and then the sensor
head is remounted. The rope is then run through the
instrument while the data are being recorded. The
Magnograph nondestructive sensor was mounted on the
rope where it leaves the top of the drum. The NDT
Technologies nondestructive sensor was mounted on the
rope where it winds onto the bottom of the drum. In
these locations, 250 ft of rope that runs through the
sheaves cannot be tested by both machines. However,
with the sensors operating in opposite directions, the
maximum length of rope is covered and the two chart
traces overlap for comparison. A separate run was made
for each instrument since the polarity of the magnetic
fields is opposite with this arrangement. EM NDT tests
were run weekly until a significant number of broken wires
began to appear; then the tests were run more frequently.
Sections of the chart records for these tests are shown in
figure 9,

Table 4.—Location of tensile test samples, feet

Test 2 Test 3
Number of cycles Location, ft Number of cycles Location, ft
38- 55, 813-830 J 0 . 38- 55, 943-960
163-180, 688-705 | 3,157 163-180, 793-810
238-255, 613-630 | 9,471 238-255, 743-760
288-305, 563-580 | 15,785 . 288-305, 668-685
338-355, 513-530 22,099 . 338-355, 618-635
363-380, 488-505 | 22,099 . 363-380, 593-610
413-430, 438-455 | 25,256 . 463-480, 513-530
25,256 . 488-505

Figure 9.—Typical data from EM NDT.


Tension sheave l

cycles

aa't

6a!

Figure 2—Dlagram of rope path.

120
Rope 2
100
80
60 4
40 4
%®
2 20
g
3
& 0 100-200-300 400 500 600 700 800 900
Z 300 : 7
$ Rope 3
Fe
®B 250
200
150 4
100 4
sof 4
100 200 300 400 500 600 700 800 900 1000

DISTANCE ALONG ROPE, ft

Figure 3.—Fatigue cycle profile,

Overall control of the machine is provided by a com-
puter, The computer manages the hydraulic system as
well as the drive system. The hydraulic system, through a
ram on the center sheave, maintains constant rope tension
and compensates for stretch in the rope. The computer
also manages the braking system used for emergency shut-
down when the computer detects an abnormal operating
condition, Drum rotation is changed by an electrical
regenerative braking system in the drive; thus, the
hydraulically controlled friction brakes are a backup
system, The computer is programmed to recognize and

react to emergency situations (via a variety of sensors),
such as when the tension cylinder runs out of travel, when
the rope nears the end of the drum, or if the rope breaks.
Operations are monitored continuously throughout a test.
The bending fatigue machine is described in more detail
in a previous publication.

The current drum liner is flat, but can be replaced with
other surface materials, such as urethane-coated materials
or grooved liners, for future studies. The sheaves are
made with bolt-on segments, which are replaceable for dif-
ferent rope diameters.

The specifications for the fatigue machine are given in
table 1.

Table 1.—Specifications for bending fatigue machine

Maximum rope tension 300,000
Maximum rope speed 4,000
Maximum fleet angh 29
Maximum rope strete!

(without regripping) . 20
Rope diam . 1-2%
Rope length up to 1,100
Drum diam 10
Drum width 84
Tension sheave diam 10
Idler sheave diam . . 8

NONDESTRUCTIVE TESTING EQUIPMENT

During the test, two commercially available electro-
magnetic nondestructive testers (EM NDT’s) were used.
One was the Magnograph model MAG-1,5 which is shown
in figure 4. The other was the NDT Technologies model
LMA-250, which is shown in figure 5.

Such devices are useful because they can examine the
condition of the interior of a wire rope. However, their
use is not mandatory under the wire rope retirement regu-
lations of the U.S. Mine Safety and Health Administration
(MSHA). They operate on the principle of magnetically
saturating the test rope and then measuring any changes
in the flux level from that of the new rope. As a rope
wears, metal is lost and shows a lower level of flux
leakage. Thus, these sensors measure the loss of metallic
area (LMA). Because broken wires create magnetic
anomalies, breaks are recorded as spikes on the chart and
can be counted until the rope becomes deteriorated to the
point where individual spikes cannot be distinguished.
These breaks are known as local faults and are an
indication of fatigue in the rope.

‘McKewan, W. M., and A. J. Miscoe. Baseline Tensile Testing at the
Wire Rope Research Laboratory. BuMines IC 9255, 1990, 23 pp.

‘Reference to specific products does not imply endorsement by the
US. Bureau of Mines.


CONTENTS

Abstract .
Introduction . .
Equipment description .
Bending fatigue machine
Nondestructive testing equipment :
Tensile and axial fatigue testing machine .
Test rope description ...............05
Test procedures
Bending fatigue test .
Tensile testing .....
Nondestructive testing .
Results
Conclusions .

ILLUSTRATIONS

1, Bending fatigue machine .............00.0ee0se05
2. Diagram of rope path
3. Fatigue cycle profile
4. Magnograph nondestructive sensor

5. NDT Technologies nondestructive sensor
6.

7.

8.

Tensile and axial fatigue testing machine
Rope construction ........
. Test rope after degradation .
9. Typical data from EM NDT
10. Breaking load versus distance .
11. Breaking load versus bending cycles .
12. LMA versus bending cycles .......
13. Broken wires versus bending cycles
14, Breaking elongation versus bending cycles .
15. Calculated and measured LMA versus distance .
16. Breaking load versus broken wires .......
17. Modulus of elasticity versus bending cycles .

TABLES

Specifications for bending fatigue machine .......

Capabilities of tensile and axial fatigue testing machine
Specifications for bending fatigue tests .
Location of tensile test samples .
Measured tensile test data
Calculated tensile test data . .
Diameter and EM NDT measurements .
Broken wires data .

SAAWAYNE



10

30 T T T T T 8 T T T
2
Rope Rope 2
25F 4
6 4
20F . 4
5k . 4 ’ .
. s 4b . - 4
: Zz t
x OP . 7 8
3 5
& st . + 8, \ f fl :
o a “o 20 40 60 80 100
g 1 1 1 n at 210
go 20 "40 60 80 100 wo 6g T ' r y y
3 20 T T T , 7 3 Rope 3
Z| Rope 3 & ef 4
rot
Fd
&
15 4 et
. . 3 :
1of- . 4 4b 4
i
2 L L n L L
st 4 ° 5 10 15 20 25 30
. BENDING CYCLES, 10° —
j . Figure 14.—Breaking elongation versus bending cycles.
a L L L
° 5 10 15 20 25 30 —_ —

BENDING CYCLES, 103

Figure 13.—Broken wires ver

18 bending cycles.

The final column of table 7 shows the percentage loss
of diameter of the outer wires of the rope, which also was
determined by the previously mentioned computer
program,

Table 8 shows the tabulation of a visual count of the
number of broken wires per lay on the surface of the rope.
These are the averages for two lay lengths.

Figure 16 shows how the breaking strength decreases
with an increase in the number of broken wires.

Table 6 shows the data computed from the measure-
ments made during the tensile tests.

Breaking stress and strain are computed by the oper-
ating program when the rope specifications are inserted.
The beginning of the plastic deformation is determined by
inspection, and then yield stress and strain are computed
using the 0.2 pet offset as is customary for testing steel
samples.

The effect of the number of cycles on the modulus of
elasticity is shown in figure 17. The modulus of elasticity
increases with distance and then decreases as wires begin
to break. Again, the approximate symmetry between the
left and right halves of the rope can be seen.

6 R 2 T T T
ope
KEY
at * Measured 4
= EM NDT
ar "as |
os
3s Le ne 1 \ Le
2°
56 T T T T
Rope 3
ab . 4
ab oe wee 4
Hae !
° 200 400 600 B00 1000

DISTANCE ALONG ROPE, ft
Figure 15.—Calculated and measured LMA versus distance.

Torque K is the slope of the curve in a plot of load
versus the torque generated by a rope sample during a
tensile test. The slope is a straight line until just before
rupture. Table 6 shows that torque K is relatively insen-
sitive to increased cycling, probably because of the helical
configuration of the wires in the rope structure.


2

CONCLUSIONS

The second and third ropes in a series of tests on 2-in
6x25 FC wire ropes have indicated several important fac-
tors that will be significant in future testing at the Bureau’s
wire rope laboratory. First, higher than normal rope loads
tend to produce rope degradation primarily in the form of
fatigue and broken wires with minimal LMA. This charac-
teristic will be useful in isolating the various components
of rope degradation so that they may be studied sepa-
rately. Second, the fact that measured and calculated
LMA’s are within approximately 2 pet of total LMA indi-
cates that electromagnetic testing and diameter measure-
ments are comparable methods of measuring LMA in in

situ field applications. Finally, even though fatigue damage
was not directly measurable, the breaking strain, the
modulus of clasticity, and the broken wires provide
confirmation of its presence.

As the number of rope bending cycles increases, the
rope tends to reach a point where the combination of
LMA and number of broken wires increases at an acceler-
ated rate, This accelerated rate of deterioration results
in a rapid decrease in the breaking strength of the rope.
Further testing and analysis will be necessary to determine
the significance of this deterioration to field installations.


Library of Congress Cataloging in Publication Data:

Bartels, John R.
Bending fatigue tests 2 and 3 on 2-inch 6%25 fiber core wire rope / by J.R. Bartels,
W.M. McKewan, and A.J. Miscoe.
p. cm. — (Report of investigations; 9429)
Includes bibliographical references.
1. Mine hoisting—Equipment and supplies—Testing. 2. Wire rope—Fatigue—Test-

ing. I. McKewan, William M. II. Miscoe, Anthony J. Ill. Title. IV. Series:
Report of investigations (United States. Bureau of Mines); 9429.

TN23.U43_  [TN339] 622 s—dc20_ [622’.6]_ 92-13941 CIP



Report of Investigations 9429

Bending Fatigue Tests 2 and 3 on 2-Inch
6x25 Fiber Core Wire Rope

By J. R. Bartels, W. M. McKewan, and A. J. Miscoe

UNITED STATES DEPARTMENT OF THE INTERIOR
Manuel Lujan, Jr., Secretary

BUREAU OF MINES
T S Ary, Director


Table 6.—Calculated tensile test data

Position, ‘Number of Breaking Yield Modulus of Torque K,
bending cycles Stress, Strain, Stress, Strain, elasticity, 10° psi Ibft/kip
kip/in* pet in/in kip /in’ pet in/in
ROPE 2
0 213.0 3.68 164.8 1.68 11,24 14.4
12,521 210.8 2.89 168.9 1.74 13.41 13.0
37,563 206.4 2.54 169.6 1.40 14.08 13.6
605 199.9 2.52 166.1 1.45 13.33 13.5
87,674 178.1 1.96 158.2 1.45 13.07 13.7
87,674 175.6 2.04 182.4 1.38 13.21 13.8
100,168 157.7 1.66 145.2 1.33 13.00 14.1
100,168 157.4 1.67 146.0 1.34 12.92 14.3
87,674 168.8 1.91 151.7 1.38 12.82 14.2
87,674 181.7 2.16 155.8 1.41 13.41 14.0
605 188.2 2.16 159.6 1.41 13.63 14.1
37,563 198.2 2.47 164.6 1.50 14.02 14.1
12,512 212.9 3.30 165.9 1.45 13.58 14.3
o 212.9 4.00 160.7 1.61 11.63 14.5
ROPE 3
0 215.6 4.54 764.0 1.67 T125 46
3,157 212.2 2.94 178.8 1.51 13.75 13.8
9,471 211.6 247 184.6 1.49 14.52 13.2
15,785 212.1 2.48 184.1 1.48 14.87 13.2
22,099 209.7 2.43 182.2 1.45 15.16 13.3
22,099 206.6 217 184.6 1.46 13.21 13.3
25,256 166.0 1.41 166.6 1.43 14.31 13.6
25,256 161.3 1.51 165.7 1.60 12.19 11.6
25,256 170.1 1.63 165.1 1.45 13.58 13.6
22,009 193.9 1.78 181.3 1.46 15.04 13.3
22,009 211.0 2.35 189.7 1.51 15.06 13.3
15,785 208.8 2.31 183.7 1.50 14.52 13.5
9,471 214.1 2.53 181.6 1.48 145.50 13.6
3,157, 214.7 3.14 176.9 1.48 13.89 14.0
oO 215.6 4.40 163.3 1,70 11,18 14.7
25 T T T T T
450 T T T T T Rope 2 3
Rope 2
2.0F 2 4
400 4
Ls . . q
3505 4
’ . Lor . 4
. . . .
9 300F . . 4 a 4
2 3
o s
g 3 A 1 1 1 fl
2 1 L n 1 2
g 250 20 30 ry Bo 100 T20 ¢ ° 20 40 60 80 100 120
g 400 r 7 . = 4 T T T T T
z Rope 3 Rope 3 °
wy .
5
350 ry . : . 4 3 .
s
. . .
300 4 er 7
: , ,
.
200 " a. - - . 1 1 n 1 rn
° 5 10 15. 20 2 30 ° 5 10 5 20 23 30

a BENDING CYCLES, 103
Figure 11.—Breaking load versus bending cycles.

a __BENDING CYCLES, 103 _
Figure 12.LMA versus bending cycles.



BREAKING LOAD, kips

Table 8.—Broken wires data

Rope 2 Rope 3
Position, ft Number of Number of Position, ft Number of Number of
bending cycles _broken wires bending cycles _broken wires.
B.. 0 0 0 0
12,521 0 3,187 0
37,563 0 9.471 0
62,605 9 15,785 0
87,674 15 22,099 0
87,674 20 22,099 1
100,168, 29 25,256 "
100,168 23 25,256 19
87,674 1" 25,256 10
87,674 12 22,099 3
62,608 4 22,099 1
37,563 0 15,785 0
12,512 0 9.471 o
0 0 3,187 0
0 0
15 T T
350, — ; . ; T nme
Rope 2 val : . 4
300 . 4 isk |
. Eo 4
250 n L 1° + 5 1 1 1
° 10 15 20 25 gl 30 700 150 200
Bop geo ee
3 iok-3
Rope 3 ae ; Rope
3
3 . . .
300 4 2B al 4
2 ' ot
250-- 4 12h . 4
gooL pp f L \ \ 1
02 46 6 10 12 14 16 1820 9 5 6 20 2 30

BROKEN WIRES PER LAY LENGTH

Figure 16.—Breaking load versus broken wires.

BENDING CYCLES, 10

Figure 17.—Modulus of elasticity versus bending cycles.