Civil Engineering Reference
In-Depth Information
Table 3.3
Number of bending cycles as function of the sum of fluctuating bending and constant
stresses
Rossetti (
1975
)
lg N ¼ a
0
þ
a
1
lg
r
z
þ
r
b
r
0
(3.42)
Meeuse [in Tonghini (
1980
)]
lg N
¼
a
0
þ
a
1
lg
r
z
þ
r
b
=
2
r
0
(3.43)
lg N ¼ a
0
þ
a
1
lg
r
z
þ
r
b
þ
r
P
r
0
Pantucek (
1977
) [in Bahke et al. (
1984
)]
(3.44a)
lg N
¼
a
0
þ
a
1
lg
r
z
þ
r
b
þ
r
P
r
0
Jehmlich and Steinbach (
1980
)
(3.44b)
Rope tensile stress r
z
, wire bending stress r
b
, pressure r
q
, unit stress r
0
in N/mm
2
Number of bending cycles as a function of specific tensile force S/d
2
and of diameter
Table 3.4
ratio D/d
Woernle (
1934
)
lg N
¼
a
0
þ
a
1
lg
D
d
(3.45)
for S
=
d
2
¼
const
:
Drucker and Tachau (1944)
S
d
0
(3.46)
S
0
d
2
þ
lg
d
lg N
¼
a
0
þ
a
1
lg
D
Mebold (
1961
)
S
0
d
2
þ
lg
d
S
d
0
(3.47)
lg N ¼ a
0
þ
1
:
8
lg
D
Calderale (
1960
) Giovannozzi (
1967
)
S
d
0
(3.48)
S
0
d
2
þ
a
2
lg
d
lg N ¼ a
0
þ
a
1
lg
D
Feyrer (
1981a
,
b
)
S
d
0
(3.49)
S
0
d
2
þ
a
2
lg
D
lg N
¼
a
0
þ
a
1
lg
d
S
d
0
S
0
d
2
D
d
þ
a
3
lg
Rope tensile force S, nominal rope diameter d, sheave diameter D, unit tensile force S
0
= 1 N, unit
diameter d
0
=1mm
called the Donandt force. This force, which is the absolute limit of the usable
tensile force, will be discussed later on. First of all, a look will be taken at the
influence of the tensile force and the diameter ratio in the usable range.
A great number of researchers have tested the influence of the tensile force and
the diameter ratio D/d on the number of rope bending cycles. Some researchers
such as Klein (
1937
), Niemann et al. (
1946
) and Shitkow (
1957
) have created early
endurance equations to describe their test results.
The different equations for wire rope endurance that can be used for regression
calculation belong mainly to the two groups listed in Tables
3.3
and
3.4
. The
variables in both of these tables have been written in a uniform way so that they
can be compared more easily, but the equations are not expressed in the identical
way used by the authors.
In the equations listed in Table
3.3
, the number of bending cycles is given as a
function of a combined constant stress (from the constant tensile force) and fluctu-
ating stress (mostly from the bending and from the pressure). The number of bending
cycles is a function of these added stresses. These equations with the added stresses
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