Wire Ropes Under Tensile Load - Wire Ropes: Tension, Endurance, Reliability - page 58

Chapter 2
Wire Ropes Under Tensile Load

2.1 Stresses in Straight Wire Ropes

2.1.1 Global Tensile Stresses

The wires in straight wire ropes under tensile load are mainly strained by tensile
stresses. The real tensile stress in the wires will not be considered in most cases.
Instead of this the stress condition will be normally characterised globally by the
rope tensile stress (nominal tensile stress). This global rope tensile stress is

r z ¼ S

A :

In this, S is the rope tensile force and A is the wire rope cross-section, that
means the sum of the cross sections of all wires in the rope with the diameters d i is
A ¼ p
4

X d i :

A very practical form for the tensile rope stress is the diameter related tensile
rope force

S = d 2 :

S is again the tensile rope force and d is the nominal rope diameter. This
diameter related tensile rope force S/d 2 has the advantage that both factors S and d
are well defined and well known for the rope maker and rope user. A further
advantage is that in most cases the calculation result encludes in its deviation the
deviation of the rope diameter.