• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.35-38
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• 2003

The wire rope, one of the component of the elevator, is extremely important for the sage operation of the elevator. That is why the wire rope is replaced at a specific interval regradless of the operating conditions or the degree of damage to prevent the breakage of the wire rope. This is the waste of resources, causing economic and environmental loss. This paper has surveyed and analyzed and analyzed the status of replacing wire-rope by buildings that use elevators, in order to compare the replacement cycles of the wire rope under each operating conditions.

• Composites Research
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• v.28 no.6
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• pp.378-382
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• 2015

With increasing population density and high-rise expansion of buildings in recent years, elevators have become to play a pivotal role in our everyday lives as most people take an elevator several times even in a day. The elevator penetration and distribution rates in Korea have increased dramatically every year, and the emergence of skyscrapers leads to accelerating the development of elevator industry. Carbon-fiber-reinforced plastics (CFRPs) exhibit better mechanical and thermal properties than steel suitable for uses as elevator wire ropes. In this paper, in order to analyze the properties of CFRPs, the tensile strength of unidirectional (UD) CFRP wire ropes was characterized and finite element analysis was conducted for bending simulation. Simulation results were compared.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.17-21
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• 2020

Over 60% of South Korea's land consists of mountainous topography, and recently, due to earthquakes, localized heavy rains and road development, the risks of rockfalls are getting higher. As of now, rockfall prevention facilities are being constructed in 70% of Korean roads cut slope and rockfall protections account for about 20% of them. Rockfall protection's supporting capacity is defined by combining performance of wire mesh, pillars and wire ropes. For the existing constructed rockfall protection, standards of pillars that can absorb 48~61 kJ amount of energy, wire ropes and wire mesh are presented in Guidelines for the installation and management of traffic safety facilities, Rockfall prevention facilities by Ministry of Land, Transport and Maritime Affairs (2008). However, each factor's correlation of absorption energy is not presented so it is uncertain. This study will conduct vertical drop test and identify adequacy of rockfall protection net of displacement quantity calculation factor which is delta and evaluate rockfall protection net's absorbable energy through standards of overseas performance evaluation criteria.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.1
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• pp.35-46
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• 2018

In this paper, safety analysis of the process of installing offshore structures such as manifolds and jacket-type substructures using floating cranes and barges in waves is performed. The safety analysis consists of three components. First, the dynamic responses of the offshore structure, cranes, and barge, all of which are moored and connected using wire ropes, are analyzed. Second, tensions in the wire ropes connecting the cranes and the offshore structures are calculated. Finally, any collision between the offshore structure and the cranes or the barge that transports the offshore structure is detected. Equations of motion of the offshore structure, cranes, and barge are formulated based on multibody dynamics, as well as considering the hydrostatic, hydrodynamic, and mooring forces. Additionally, proportional-derivative control of the tagline between the cranes and the offshore structure is performed to verify the safety of the installation process, as well as for reducing the dynamic response and collisions among them.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.173-179
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• 1998

The piping system of a power plant suffers not only thermal expansion according to the temperature variation, but also many kinds of load: steady state vibrations due to the equipment operation or fluid flow, and transient vibrations due to the earthquake or explosion, etc. The snubbers are usually installed on the piping system to allow thermal expansion, and to reduce dynamic responses. Most snubbers are kinds of hydraulic and mechanical type, which can be degraded by leakage and abrasion, and required much cost for maintenance and replacement. Recently the wire rope type snubbers are developed and applied to the power plant, and proved as effective to reduce piping system vibration. Wire rope type snubber uses the bending rigidity and energy dissipation properties of ropes. This paper presents the procedure of design, and the method to apply hysteresis curve to the dynamic response analysis. Experiments were also conducted to confirm design results.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.179-184
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• 2003

This study focuses on an analytical approach to calculate crane lifting forces for a sunken ship in consideration oj elongation of crane ropes. The method takes into account the relation of lifting forces acting in wire rope slings to the inclination of the ship's hull including the effect of lug positions. For lifting analysis, the Euler angles are defined to represent the inclination of a sunken ship in developing the static force and moment equations. An additional compatability condition is introduced in order to solve an indeterminate lifting analysis problem with 4 cranes and a set of lifting forces along the 4 crane ropes is calculated. A 3-dimensional example of the G/T 1500 oil tanker is analyzed and the results show that the information obtained by the method could be useful to engineers to conduct salvage work.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.56-63
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• 2018

The present study examined the reversal cyclic flexural behavior of walls with jacket section approach for seismic strengthening through forming the boundary elements at both ends of the wall. The prestressed wire ropes were used for the lateral reinforcement to confine the boundary element of the wall. The main parameter investigated was the height of the jacket section for strengthening. The limit height of the strengthening jacket section was determined by comparing the moment distributions between the existing and strengthened walls. Test results showed that the examined jacket section approach was significantly effective in enhancing the flexural resistance of walls, indicating 46% higher stiffness at peak strength and 210% greater work damage indicator, compared with the flexural performance of the unstrengthened wall. The ductility of the strengthened walls was insignificantly affected by the height of the jacket section when the height is greater than twice the wall length. The flexural capacity of the strengthened walls was 22% higher than the predictions obtained using the equivalent stress block specified in ACI 318-14.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.127-134
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• 2001

Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and composed of single or multi-layer strands. It is difficult to find out the characteristics of a strand or wire rope because of complicated geometry and contact condition. In this study, the axial stiffness is evaluated using finite element method and reliable finite element analysis model is presented, taking into consideration the convergence on the length. The axial stiffness predictive equation of a strand is developed using analysis of variance, which can be applicable for characterizing the relationship between load and displacement when the strand configuration is determined.

• Steel and Composite Structures
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• v.28 no.2
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• pp.139-147
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• 2018

Moment frames have considerable ductility against cyclic lateral loads and displacements; however, sometimes this feature causes the relative displacement to exceed the permissible limits. This issue can bring unfavorable hysteretic behavior on the frame due to the reduction in the stiffness and resistance against lateral loads. Most of common bracing systems usually control lateral displacements through increasing stiffness while result in decreasing the capacity for energy absorption. This has direct effect on hysteresis curves of moment frames. Therefore, a system that is capable of both having the capacity of energy absorption as well as controlling the displacements without a considerable increase in the stiffness is quite important. This paper investigates retrofitting of a single-storey steel moment frame using a delayed wire-rope bracing system equipped with the ductile middle steel plate. The steel plate is considered at the middle intersection of wire ropes, where it causes cables to be continuously in tension. This integrated system has the advantage of reducing considerable stiffness of the frame compared to cross bracing systems as a result of which it could also preserve the frame's energy absorption capacity. In this paper, FEM models of a delayed wire-rope bracing system equipped by steel plates with different geometries have been studied, validated, and compared with other researchers' laboratory test results.

• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.3-10
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• 1994

This study examines fracture characteristics of wire rope of 6$\times$37+FC 14mm B degree, Which has been widely used for the strength support for machinery, cranes and shipping. The examination Is based on the fellowing experimental conditions. Firstly, this study analyzes the effect of the strength of wlre rope. When number of broken wires is occuring at the level of 5%, 10% and 15% degree respectively in the following two cases：1) Case of broken down to each strand equally. 2) Case of broken down to one strand only. Secondly, this study analyzes the effect of corrosion on the strength of wire rope. Corrosion times are 72hours, 144hours and 216hours corrosion respectively under following conditions. 1) Case of only a corrosion without wire breaking. 2) Case of corrosion after 5% degree wire breaking to each strand equally. Some outcomes of these experiment are as follows. 1) From the of tension test, We can find that the ratio of strength reduction case of wire broke down to one strand concentrically is greater than that ratio case of broke down to each strand equally. 2) From the corrosion test, We can also find that the ratio of strength reduction case of corroded after 5% degree wire breaking to each strand equally Is greater than that ratio case of corroded without wire breaking. 3) After comparing theoretical fracture load of wires with experimental fracture load of wires, we can find the fracture load of the case of broken down to each strand equally is most similar to theoretical fracture load. 4) It is proposed that safety rules on wire rope in the Industrial safety and healthy labor of law have to change “breaking over 10% of number of wires in one strand of wire rope(excluded filler wire )”has to be replaced by“breaking over 10% of number of all wires in all strand of wire rope(excluded filler wire)”