Wire Ropes Under Tensile Load - Wire Ropes: Tension, Endurance, Reliability - page 81

Fig. 2.10 Reference value
for rope elasticity modules of
locked coil ropes, DIN18809

1,8-10 5

1,7-10 5

E p

1,6-10 5

1,5-10 5

E g

E A

1,4-10 5

E B
between
E g and E A

1,3-10 5

1,2-10 5

1,1-10 5

1,0-10 5

0,5 0,6 0,7 0,8 0,9 1,0

˃ g
˃ g + ˃ p

mean value

limits

Wyss ( 1957 ) and Jehmlich ( 1985 ) have made series of measurements. They
distinguished between a total rope elasticity module starting from the stress 0 (first
loading) and the rope elasticity module between two stresses after a longer rope
working time. An important contribution to what is known about the rope elasticity
module was made by Hankus ( 1976 , 1978 , 1989 ). He measured the elongation of
many ropes of different constructions with fibre and steel cores with the first
loading as well as after loading repeatedly in an up-and-down direction. He used
these measurements to evaluate the rope elasticity module as secant starting from
the stress r z = 0 with multi-dimensional linear regression calculations. He also
evaluated the rope elongation after it had been loaded for a long time.
The following remarks about the rope elasticity module relate mostly to the
Stuttgart tests conducted by Feyrer and Jahne ( 1990 ). These tests were done with
nearly all types of construction for round stranded wire ropes. A lot of the tests
were carried out by the students listed in the previous article.

2.2.3.1 Stress-Extension Curves

The measurements of stress-extension curves—which form the basis of the eval-
uation for rope elasticity modules—have always been taken in the same manner.
The rope elongation DL is measured for a rope length of L = 2,000 mm with two
inductive elongation meters on the right and left of the rope as seen in Fig. 2.11 .
The results of these measurements are recorded for the first loading cycle up to