Papers by Keyword: Ropes

Abstract: Stainless steel reinforcement in the form of prestressing wires and ropes, commonly used to reinforce prestressed concrete structures [1], is also used for suspension strips of footbridge bridges. After the accident of some of them, these structures became the subject of an examination of their current state and analyses of the origin and development of corrosion of the prestressing reinforcement used. The issue of the service life of prestressed structures is related, among other things, to their structural arrangement and the construction procedure used. As with most existing prestressed structures, the anti-corrosion protection of the reinforcement has traditionally been ensured primarily by the alkalinity of the environment, ie by concreting or grouting prestressed elements in the pipeline [2].

Abstract: The relationship between the structure parameters and the mechanical properties of two-dimensional braided polyester ropes were studied. 22 times of polyester ropes were braided with different pitch length and different yarns, and their tensile properties were tested, then the relationship between the mechanical properties of the rope and braiding pitch was obtained. The results showed that the breaking strength of 2D braided ropes increased with the increase of pitch length, but after achieving certain length, the strength began to decline, and the breaking elongation decreased along with the increase of unit length.

Abstract: Early defect detection and monitoring of rope systems constitute important safety requirements for equipment that employs ropes as single driving component, e.g. lifts, rope trains, etc. Quality characteristics of ropes are regulated by procedures of safety standards and are prescribed in safety standards of transportation machines, which are particularly stringent in the case of human elevating equipment. Many types of rope quality control are applied in practice but standard control procedure of such nonhomogeneous structures as ropes with electromagnetic methods are still not fully reliable, particularly in the case of broken wires in rope strands. The paper presents a method for detection of the aforementioned rope defects using dynamic properties of a rope that is treated as a dynamic system. The proposed method enables to measure dynamic characteristics of a rope system and, based on obtained results, evaluate rope quality, determine the presence of broken strands and define cross-section of the defects. Analysis of dynamic properties is used in order to establish existence of a defect. Aim of such analysis is to determine some characteristic natural frequencies corresponding to broken strand and change of the lowest natural frequencies that represent the rope as a constrained system. The paper also addresses the issues of equipment and methodology required for defect detection in ropes together with the necessary conditions. Final conclusions are formulated with regard to possibility of implementing the proposed method in real working conditions.

Abstract: This paper deals with recent developments in non-destructive tests on operating steel wire ropes, with the aim of analyzing their conditions and residual resistance. The instruments for executing magneto-inductive tests on wire ropes - employed in cableways, chairlifts, mine elevators and, occasionally, in equipment for handling material in harbours (e.g. gantry cranes and portainers) – are commonly composed of three parts: the revealing device (detector); power supply; and a recorder, equipped with an amplification apparatus and paper rolls for printing the results. The system proposed in this work is composed of an innovative magnetic detector where the traditional paper recording system is substituted with a software interface that allows a digital recording of the signal. The performances in terms of accuracy and linearity of the proposed detector are tested through proper laboratory set up and are presented and discussed.

Abstract: Traction drive elevator installations employ ropes of variable length as a mean of car and counterweight suspension. The inertial and elastic characteristics of elevator suspension systems depend on the rope construction and vary slowly during the elevator travel. The system suffers from vibrations caused by various sources of excitation. This paper presents the analysis of the dynamic response of the suspension system employing traditional steel wire ropes as well as ropes constructed of aramid fibers. The equations describing the lateral response of the system subjected to a boundary periodic excitation are solved numerically. The results show that the entire rope is subjected to repetitive low frequency transient resonances. Consequently, the structural integrity of the suspension ropes is compromised. The issue of active vibration control and the feasibility of the integration of shape memory alloy elements within the suspension rope design are discussed.