• Korean Journal of Computational Design and Engineering
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• v.17 no.5
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• pp.324-332
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• 2012

In this paper, a method for calculating the contact force and the frictional force caused by contacts between the wire rope and the rigid body is introduced based on multibody dynamics. And the method is applied to a simulation of contacts between the wire rope and the shell plate of a block that can occur during shipbuilding. The wire rope is composed of a number of lumped masses and the wire rope segments that connect the masses. After calculating the position of interference, we inserted a contact node into the wire rope. We then derived the equations of motion of the wire rope and the rigid body using augmented formulation based on multibody dynamics taking into account the constraints between the contact node and the rigid body. Using the equations, we were able to obtain the constraint force between the contact node and the rigid body, and calculate the contact force and the frictional force, based on which the position of the contact node was corrected. Finally, we applied our results to perform simulation of contacts between the wire rope and the shell plate of a block in order to verify the efficacy of the method proposed in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.150-155
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• 2013

We present a kevlar rope based Non-Explosive Actuator(NEA) device which has simple structure and is activated by burning Ni-Cr wire. Through performance test, we find it can be operated under various pre-load by simply changing turn number of Ni-Cr wire. It shows release time of 680ms and shock level of 110G under pre-load of 6.0kN. Launching environment and space environment tests are planned to verify performance of the NEA based on European Satellite Agency test manual. Conclusively, we expect the proposed NEA can be applicable to release solar panel and fairing separation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1758-1764
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• 2012

A large number of wire rope has been used in various inderstiries as Cranes and Elevators from expanding the scale of the industrial market. But now, the management of wire rope is used as manually operated by rope replacement from over time or after the accident.It is caused to major accidents as well as economic losses and personal injury. Therefore its time to need periodic fault diagnosis of wire rope or supply of real-time monitoring system. Currently, there are several methods has been reported for fault diagnosis method of the wire rope, to find out the feature point from extracting method is becoming more common compared to time wave and model-based system. This method has implemented a deterministic modeling like the observer and neural network through considering the state of the system as a deterministic signal. However, the out-put of real system has probability characteristics, and if it is used as a current method on this system, the performance will be decreased at the real time. And if the random noise is occurred from unstable measure/experiment environment in wire rope system, diagnostic criterion becomes unclear and accuracy of diagnosis becomes blurred. Thus, more sophisticated techniques are required rather than deterministic fault diagnosis algorithm. In this paper, we developed the fault diagnosis of the wire rope using probability density estimation techniques algorithm. At first, The steady-state wire rope fault signal detection is defined as the probability model through probability distribution estimate. Wire rope defects signal is detected by a hall sensor in real-time, it is estimated by proposed probability estimation algorithm. we judge whether wire rope has defection or not using the error value from comparing two probability distribution.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.57-64
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• 2019

A man-made slope has been increased due to the construction of road. This slope lies at risk of rock falling, induced mostly by heavy rainfall. The MOLIT (Ministry of Land, Infrastructure and Transport) recommends the specific dimension of rockfall protection fence (post, wire-rope, and mesh) which should resist 48~61 kJ. However, the energy absorption capacity of each component of rockfall protection fence is not clearly presented. Hence, this study made an effort to compute the energy absorption capacity of each component in analytical and numerical method, and compared with each other.

• Journal of the Korean GEO-environmental Society
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• v.23 no.2
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• pp.5-12
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• 2022

In this study, a field test was conducted to present a test method for performance evaluation of a rock fall prevention fence, centering on the vertical drop test among the existing test methods of the rock fall prevention fence. A test to determine the support capacity of a rockfall prevention fence in Korea is usually conducted using a combination of wire mesh, poles, and wire rope, and the location of the impact of falling rocks has been conducted centered on the center of the wire mesh. However, in the case of domestic papers and test data, there is no data on direct hit of post. Therefore, the amount of displacement and weak section were analyzed when the impact on 100kJ class rock energy was hit on the post, centering on the Rockfall Protection fence (highway type No. 2).

• Journal of the Korean GEO-environmental Society
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• v.23 no.3
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• pp.5-13
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• 2022

In this study a test was conducted to identify weak section using 100kJ class rock energy to find out the protection performance of rockfall prevention fences in Korea. Performance rating of the rockfall protection fences is very low (48~61kJ) compared to that of foreign countries and it is necessary to determine whether it can function properly if high rock energy is generated. Furthermore, a reinforcing technology that can improve to 100kJ energy on the existing rockfall protection fences should be developed. Therefore, this study confirmed the protection performance using 100kJ rock energy in the existing rockfall protection fence system (for national road, for highway) and identified weak section of post, wire ropes and nets. Furthermore, it will be used as basic data for developing 100kJ class reinforcement technology without dismantling the existing rockfall protection fence (48-61kJ).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.423-436
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• 2003

Submarine optical fiber cable construction consists of marine survey, PLGR(Pre Lay Grapnel Run), shore-end-work, laying order. PLGR is the work process which removes the oceanic contaminations(ropes, wires, nets etc.) in the route before laying the submarine optical cable. This PLGR is work to ease the cable lay safely in seabed, improve the performance of Plough and ROV((Remotely-Operated Vehicle) laying work, and protect laying equipment. This paper presents the optimization algorithm implementation of KP(Kilometer Post) and XTE(Cross Track Error) to manage marine survey and PLGR work efficiently. In this paper, we composes overall PLGR work, and proposed optimization algorithm of KP and XTE. For the validity evaluation of this paper, KP and XTE decision algorithm are implemented and tested.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.113-119
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• 2002

Recently, an automatic crane control system is required with high speed and rapid transportation. During the operation of crane system in container yard it is necessary to control the crane trolley position and loop length so that the swing of the hanging container is minimized We can do development of unmanned automation control system using automation travel control technique and anti-sway technique in crane system. Therefore, we designed a controller for Automation travel control to control the transfer crane system. Analyzed crane system through simulation, and proved excellency of control performance than other conventional controllers.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.53-59
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• 2014

It has been generally recognized that the conventional rockfall protection nets have several problems to actual field application in the aspect of shock absorption, lack of pullout bearing capacities, and net damages. Because of the recognition, authors have tried to develop a new rockfall protection system consisted of shock absorption parts and hexagonal net configuration. In the previous research by the authors, the performance of the newly developed rockfall protection system has been investigated through the laboratory tests and the full-scale testing. In this study, subsequently, numerical analysis program is organized to make a confirmation of the structural stability and performance. For the correct design procedure of the hexagonal net system, it is essential to understand the various mechanical behavior of the entire system. It is also important to be reproduced the systematic characteristics of the system acquired by laboratory and full-scale testing by numerical analysis in order to carry out the numerical experiment to understand various mechanical behavior of the system. As a conclusion, the hexagonal net has better performance in mechanical and physical behavior compared with that of the rectangular net. Furthermore, due to the hexagonal net shows a good performance in aspect of the load distribution, it gives a good alternative in long-term management of the rockfall protection net.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.63-70
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• 2017

In this paper, a magnetic flux leakage(MFL) based steel bar damage detection was first researched to quantify the signals from damages on the wire rope. Though many researches inspecting damages using a MFL method was proceeded until the present, the researches are at the level that diagnose whether damages are or not. This has limitation to take measures in accordance with the damage level. Thus, a MFL inspection system was modeled using a finite element analysis(FEM) program dealing with electromagnetism problems, and a steel bar specimen was adopted as a ferromagnetic object. Then, an experimental study was also carried out to verify the simulation results with a steel bar which has same damage conditions as the simulation. The MFL signals was nearly not affected by the increase of the inspection velocity, and the magnitudes of the signals are not identical according to the change of the defect width even the defects have same depth. On the basis of the analysis, the signal properties from the damages were extracted to classify the type of damages, and it could be confirmed that classification of damages using extracted signal properties is feasible.