REDWIRE The basic facts about wire-rope stretch from Bergen Cable

January 2, 2018 REDWIRE is news you can use from leading suppliers. Powered by FRASERS.

Posted by Bergen Cable Technology, Inc


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Wire-rope stretch is an important factor and easy to calculate.

When selecting wire rope for a workplace application, or inspecting wire rope that the workplace is using, an important trait to take into consideration is the stretch. Occupational safety standards generally recommend regular checks of the stretch of wire rope under load.

As one of the top providers of innovative solutions for cable assemblies in North America’s aerospace sector, Bergen Cable prides itself on its expertise on cable products, including wire-rope stretch.

Two different components

According to Bergen, there are two basic factors that affect the stretch of a wire rope:

  • Structural stretch – the stretch caused by the lengthening of the rope lay, the compression of the core, and the adjustment of the wires and strands to the load that the rope is holding; and
  • Elastic stretch – the stretch caused by the elongation of the wires.

A wire rope’s structural stretch depends upon the size of the core, the length of the lays, and the rope’s construction. The loads and the amount of bending that one imposes on the rope also affect the structural stretch. The quantitative value of this stretch can be estimated by multiplying the length of the rope by 0.005 when it is under load – although it may be preferable to multiply by 0.0025 if the load is light or 0.01 if the load is heavy.

For loads that do not exceed a wire rope’s elastic limit, the elastic stretch is proportional to both the weight of the load and the length of the rope at the time it is loaded. It is also inversely proportional to the wire rope’s metallic area and its modulus of elasticity. A user can calculate a wire rope’s elastic stretch in feet with this formula: multiply the load weight (in pounds) by the length of loaded rope (feet), then divide that figure by the metallic area (square inches) multiplied by the modulus.

The elastic limit of a galvanized wire rope tends to be about half of its breaking strength, while that of a stainless-steel rope is usually about 60 per cent of its breaking strength.

To learn more, contact Bergen.


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Posted by Bergen Cable Technology, Inc


Mfr Mechanical Cable, Cable Assemblies & Push-Pull Controls. Original Mfr Of Safety Cable, A Patented Fastener Reten... Read more

Contact supplier