Study On Theory And Life Estimation Of The Non-rotating Rope Used In Crane

Wire ropes are the important parts of the hoisting equipments, are widely used in actualapplications such as the tourism, transportation, mining, port engineering, and so on. In thehoisting cases, the general wire ropes are ususally used, but the general wire ropes could berotating aroud themselves when hoisting, which bring dangerous, life threatening andproperty security to the works.Therefore, in some circumstances required for working with ahigh speed, large travel, quiet operation, and carrying by a single rope, etc, were mainly usethe non-rotating wire ropes gradually. However, compared with the general steel wire ropes,the non-rotating ropes have the inevitable disadvantages of the wires' abrasion, fatigue andbroken that localed in the inner strands, which reduced the ropes' life expectancy sharply. Atpresent, it is ture that there are lack of the effective measures to make detections for the innnerwires' abrasion, fatigue and broken damage in these ropes, so the non-rotating ropes were ofgreat security risks in application. Due to their structural complexity, the mechanical analysisfor the non-rotating ropes were very difficult. So far, there were exiguous research about thenon-rotating ropes at present. As the non-rotating ropes are used more and more, so thestudies on their mechanics, friction and abrasion, fatigue life were in need urgently.Firstly, the dynamic loads of the non-rotating wire rope were obtained when the cranecarrying goods by simulation. Then, according to the differential geometry and spacecoordinate transform principle, the spatial spiral equations that express the wires' spatialpositions in the rope accurately, when it carry straightly or bend over a pulley, were deduced.Based on the space spiral equations, an entity model of the non-rotating rope is set up usingthe three-dimension CAD software ProE, and the calculation method for the wires' curvatureand contact angles were developed. According to the Costello theory for the genneral rope, amechanical model of the non-rotating wire rope under straight tension was established, basedon which the inner wires' stresses were analysed for a single strand wire rope, non-rotatingwire rope with steel core and the fiber core non-rotating rope respectively. The entity model isintroduced in ANSYS to carry out mechanical analyses for the verification of the mechanicalmodel. By calculating and analysing the internal stresses and bending stresses in anon-rotating wire rope, the influence and relationships between the stresses' distribution andthe lay lengths of the side wires, the inner and outer strands,and the diameter of pulley wereresearched. Which can provide guidances for improving the strengths and lifes of thenon-rotating ropes.Sencondly,by analyzing the contact status of the wire rope and pulley, A new modle for caculating the contact stress between the rope and pulley is proposed, by which the outercontact stress and wear between the wire rope and pulley are analysed. A wear model for theinternal contact wires in non-rotating rope is established, based on this model, the inner wearproblem was studied deeply, and inner wires' wear behavior of the non-rotating rope weresimulated by using the typical Archard wear theory. The ferrographic analysis test of wearparticles from the inner of the non-rotaing rope used in the port crane were made detailedly, aswell as the detach-strands experiment. The friction and wear mechanism of the non-rotatingwire rope were studied by these experiments. Based on the inner wires' friction and wearsimulation, a new standard for the rope's retirement that take the wear wire's section lossfactor as the judgment is put forward. And the investigation data from the applied experienceverifys the feasibility of this standard. As can be provided a new approach for the guidance ofwhen to change the non-rotating ropes in cranes.Finally, considering the wear and fatigue damages of the non-rotating rope, according tothe proposed mechanical model and wear model, on the hypothesis that the rope's fatiguedamages were the superposition of the tension-tension fatigue in straight and the bendingfatigue caused by the pulley, a life estimation method for the non-rotating rope based on itsmost frail wire is put forward. The actual fatigue load spectrums of the most frail wire in thenon-rotating rope are established by the theoretical analysis and measurement test for thelifting system of the crane. Adopt this load spectrums and the linear fatigue accumulatingtheory to estimate the life of the non-rotating rope, and the related experimental resultsvalidate the veracity and feasibility of the proposed life estimation model and method, whichwould have a good guidance for life prediction of the wire rope. And, the laws that the safetyfactors and diameter of the pulley influence on the rope's lifes are studied, to providetheoretical guides for the safety use of the non-rotating rope. The main failure reasons of thenon-rotating wire rope are found from the mechanical perspective by the research on itsmechanical characteristics, wear and fatigue, it conclued that the non-rotating rope shouldfracture from its interior firstly in service.