Wire Rope Properties

Stainless steel wire rope is made up of individual wires spun into a strand. A number of outer strands are closed over a central core. The number of strands around this core gives different construction of wire their unique characteristics.

Constructional Stretch

Wire rope is made up of individual wire strands formed around a central core. When load is first applied to a wire rope, the individual strands bed in. This settlement leads to elongation, referred to as permanent construction extension (Constructional Stretch).

Elastic Stretch

The elastic extension of wire rope (Elastic Stretch) occurs when a load is applied to the end of a rope. “Hookes Law” defines that this stretch is proportional to the load applied, i.e stress is proportional to strain.

This applies as long as the yield point is not exceeded, after which permanent deformation takes place.

The modulus of elasticity or resistance to stretch, for wire rope will vary upon the wire rope construction. The following stretch calculation can be used as a guide.

There are different international standards for calculating the Modulus of Elasticity (E), this should be verified by your structural engineer.

 

Elastic Stretch = W x L / E x A

 

Where:

W= Applied Load (kN)
L – Cable Length (mm)
E = Strand modulus of elasticity (kN/mm2)
A = Cross section area of wire rope = Π r²

Where r = diameter of rope/2.

 

1×19

The 1×19 construction is suitable for all types of general applications due to its low elasticity and high braking load.

Compacted Strand

Compacted Strand wires feature high strength and very low stretch, providing this wire with excellent longevity and performance.

7×7

The 7×7 construction wire provides high flexibility but it is the stronger of the flexible wire rope.

7×19

The 7×19 construction is the most flexible of the multi-strand wire ropes.

PVC Covered

Found where a covering is needed for functional or aesthetic purposes.