Views: 0 Author: Site Editor Publish Time: 2023-05-13 Origin: Site
Depending on the place of use, the wire rope must meet different requirements.The main uses are:
Running rope (stranded rope) bends on pulleys and drums.Therefore, they are mainly subjected to bending stress and secondarily to tensile stress.
Fixed ropes, stay cables (spiral ropes, mostly full locks) have to withstand tension and are therefore mainly subject to static and fluctuating tensile stresses.The rope used for hanging is often called a cable.
Track ropes (locked ropes) must be used as tracks for cabin rollers or other loads in aerial ropeways and cable cranes.Unlike running ropes, track ropes do not have the curvature of a roller. Under the action of the roller force, the so-called free bending radius of the rope occurs. This radius increases with tension (decreasing bending stress) and decreases with roll force.
Wire rope slings (stranded ropes) are used for lifting various cargoes.These slings take tension, but above all the bending stress when the more or less sharp edges of the cargo are bent.
The technical regulations apply to the design of rope drives for cranes, elevators, ropeways and mining installations.Factors considered in the design include:
The number of duty cycles allowed before the rope is replaced or broken
Donandt force (pull force for a given bend diameter ratio D/d) - strictly limited.The nominal rope pull S must be less than the Donandt force SD1.
Rope Safety Factor, the ratio between the breaking strength of the rope and the expected maximum load
Allowable number of broken strands before replacement
Optimum rope diameter for a given sheave diameter for optimum working life
The calculation of the rope drive limit depends on:
Data of the wire rope used
Rope tension S
Diameter D of the pulley or roller
Simple bending wsim for each duty cycle
Reverse bending wrev per duty cycle
Combined fluctuating tension and bending wcom per duty cycle
Relative fluctuating pull force ΔS/S
Rope bend length
Wire ropes are stressed by wave forces, abrasion, corrosion and, in rare cases, extreme forces.The life of the steel wire rope is limited. Only by detecting faults such as broken wires and section loss of the reference wire rope can safety be ensured, and the steel wire rope can be replaced before a dangerous situation occurs.The design of the device should facilitate the inspection of the wire rope.Passenger lifting equipment requires a combination of methods to prevent the car from falling.Elevators must have redundant carrying ropes and safety devices. Ropeways and mine hoists must be permanently supervised by the responsible manager and ropes must be checked by magnetic methods capable of detecting internal wire breaks.
A rope is a group of yarns, strands, fibers or strands that are twisted or woven together to form larger and stronger forms.The rope has tensile strength so it can be used for dragging and lifting. Rope is thicker and stronger than similarly constructed rope, twine, and twine.
Ropes can be made of any long, sticky fibrous material, but are usually made of certain natural or synthetic fibers.Synthetic fiber ropes are significantly stronger than natural fiber ropes, they have higher tensile strength, are more resistant to decay than ropes made from natural fibers, and can float on water.  But synthetic ropes have some disadvantages, including slipping, and some are more easily damaged by UV rays.Common natural fibers for rope are abaca, hemp, flax, cotton, coir, jute, straw and sisal. Synthetic fibers used in rope include polypropylene, nylon, polyester (such as PET, LCP, Vectran), polyethylene (such as Dyneema and Spectra), aramid (such as Twaron, Technora and Kevlar), and acrylics (such as Dralon) .Some ropes are constructed from a blend of several fibers or use copolymer fibers.Wire ropes are made of steel or other metal alloys. Ropes were made from other fibrous materials such as silk, wool, and hair, but these were not commonly used.Rayon is a recycled fiber used to make decorative rope.The twisting of the strands in a stranded or braided rope not only serves to hold the rope together, but also allows the rope to distribute tension more evenly among the individual strands.If the rope does not have any twist, the shortest strands will always support a higher proportion of the total load.