GRAVITY GOODS ROPEWAY
Tensile test
Tensile test must cover the measurement of the
tensile strength, the proportional limit (elasticity
limit), the plastic limit, elongation of the rod
(thread) of 200 mm in length at the breaking
point and the Young’s modulus. Most important
of all is the tensile strength which is determined
by the Amsler testing machine with application
of breaking forces of 500, 5000 and 10,000
kgs. On completion of this test, it is necessary to
discard the following:
Wires in which the breaking strength differs
by more than eight per cent from that of the
average strength of the wires
Wires which fail to comply with the reverse
bend and torsion tests
Wires in which the elongation is 20 per cent
lower than the average elongation or which
fail to reach the required elongation
The rope should be rejected if the tensile strength,
determined from the Amsler testing machine,
does not reach the required value.
The proportional limit of round wires lies between
39 to 53 per cent and of cross-sectional wires
from 27 to 42 per cent of tensile strength. The
elongation close to the breaking point is from 2.5
to 3.7 per cent.
Reverse bend tests
These tests should be carried out on 100 mm
long samples tensioned by a longitudinal force of
1 to 6 kg (according to diameter) and bent in
the vice jaws, over a radius equal to 5 times the
wire diameter. The wires are bent back and forth
through 180 degree until fracture occurs.
The test should comply with the relevent IS code
(IS 1608).
Torsion tests
The test should be carried out in the test piece of
length equal to 100 times to diameter of the wire
in a manner laid out in the relevent IS code.
B) Test on ropes
The test assesses the technical properties and
strengths of ropes.
Technical tests usually examine:
the wire arrangement in the strand and
of the strands in the rope
the rope diameter
the length and direction of lay
the method of stranding
the length of the rope and the condition
of the wire
the coating with lubricants
the strand production
the wire diameter and the number of
wires in the layer
the grade of the fibre and construction of
the core
tensile strength of wires through tensile,
torsion and reverse bends tests and
the breaking strength of the rope
Tests to examine the position of wire arrangement
in the strand and the strands in the rope, the
rope diameter, the length and direction of lay
and method of rope stranding are carried out on
a rope winded on a drum. Similarly, examination
of the condition of wires, the state of lubrication,
the production of strands, the wire diameter and
number of wires in a layer and the constitution of
the core are carried out with the sample cut from
the rope and un-stranded. The sample should
have the length of 30 to 70 rope diameters.
Strength tests examine the measurement of the
breaking load, the elongation at breaking point,
the kind of fracture and the values of Young’s
modulus, the proportional limit, and the plastic
limit.
Breaking strength of rope
To examine the strength of a completed rope,
a piece with a minimum length of 30 rope
diameters (usually 5 to 7 metres in practice) is
cut off from the bundle of rope. To examine the
actual breaking load of the rope, the length of
the test piece should not be less than 70 rope
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