Simplified calculation of dynamic and static stresses
in a conductor with regard to the suspension clamp
(1973)Аннотация
Under the assumption that the equation for an elastic
cable y" = -~~ applies, and with a simple approximation
of the deformation y, the bending moment Mx at the
support can be calculated. The stresses can then be
calculated using stress-strain curves for steel and
aluminium respectively. Static tension stresses, due
to the line-span's vertical load, must then he ~dded
to these static bending stresses. For a 593 mm~ FeAlc
on duct o r o f " Curl e w ~ t y p e , t h i s re s u 1 t e d i n s t r e s r; 0
values of ·.· 12 kp/mm - for aluminium and ,_., 100 kp/mmc.
for steel2 These high values decre~se to about
6. 4 kp/mm for aluminium and 80 kp/mm" for steel shortly
after stringing, owing to creep in the line.
The dynamic stresses owing
using the impulse the~rem.
for aluminium and ~ - 2. 3
supports.
to ?sci~lation¥ are
This
2
g1 v es r::. - 1 • 3
kg/mm for steel at
calcu~ated
kg/mm -
the
By inserting these values in a Smith-diagram it is found
that the conductor can withstand 108 load-cycles.
The nominal stresses for the entire conductor are thus:
- shortly after stringing
- after 24 hours creep
2 2 I 2
2. kp mm
14.8 kp/mm 2·
With the sheave (D = 400 mm) which at present ts used
for stringing in Sweden, the conductor will hold despite
the high stresses ( 0 80 % of HS). lt would be desireable,
from the point of view of safety, to reduce these
stresses. This could suitably be arranged by using a
sheave either with a larger diameter or in the form of
a tandem wheel.
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