• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.311-314
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• 2006

This paper concerns about total dynamic analysis of integrated mining system. This system consists of vertical steel pipe, intermediate buffer station, flexible pipe and self-propelled miner. The self-propelled miner and buffer are assumed as rigid-body of 6-dof. Discrete models of vertical steel pipe and flexible pipe are adopted, which are obtained by means of lumped-parameter method. The motion of mining vessel is not considered. Instead, the motion of mining vessel is taken into account in form of various boundary conditions (e.g. forced excitation in slow motion and/or fast oscillation and so on). A terramechanics model of extremely soft cohesive soil is applied to the self-propelled miner. The hydrodynamic forces and moments are included in the dynamic models of vehicle and lifting pipe system. Hinged and fixed constraints are used to define the connections between sub-systems (vertical steel pipe, buffer, flexible pipe, miner). Equations of motion of the coupled model are derived with respect to the each local coordinates system. Four Euler parameters are used to express the orientations of the sub-systems. To solve the equations of motion of the total dynamic model, an incremental-iterative formulation is employed. Newmark-b method is used for time-domain integration. The total dynamic responses of integrated mining system are investigated.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.315-318
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• 2006

This paper concerns about coupled dynamic analysis of the deep-seabed mining system in launching operation. The dynamic behavior of mining system consisting of lifting pipe, buffer station, flexible conduit and self-propelled miner is simulated in time domain. The launching operation is divided into four critical phases: (1) deployment of miner and flexible conduit, (2) deployment of lifting pipe, flexible conduit and miner, (3) touch-down of miner, (4) final launching. The dynamic responses of sub-systems - miner, flexible conduit, buffer and lifting pipe - are analyzed in each launching phase. According to the changing periods of forced excitation at the top, the dynamic responses of sub-systems are diverse in their characteristics. It has been shown that the total integrated responses of sub-systems are strongly affected by the design parameters. Especially, the principal dimensions of flexible conduit seem to be significant in determining of the global response. Based on the simulation results, safe operation conditions are investigated.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.73-78
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• 2004

The deep seabed mining system is generally composed of surface vessel, lifting system, buffer, flexible pipe and miner. The milling system is regarded as a large-scale system in which each subsystem is interconnected to other one. In order to control a large-scale system, a decentralized control approaches have been proposed recently. In this paper, as a basic study on application of decentralized control, firstly, the mining system is simplified modeled, where the lifting system and buffer is regarded as a spherical pendulum and tile flexible pipe is as a two-dimension linear spring. Based on the derived model, the system characteristics and the feasibility of decentralized control are analyzed.

• 대한기계학회논문집A
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• 제39권12호
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• pp.1213-1220
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• 2015

망간단괴를 채집하는 심해저 통합 채광시스템은 채광선, 수직양광관, 중간버퍼, 유연관, 채광로봇으로 구성되어 있다. 최근 심해저 통합 채광시스템 연구에서는 생산성을 극대화하기 위한 다수의 채광로봇으로 구성되는 새로운 다중로봇 통합 채광시스템의 개념이 소개되었다. 본 논문에서는 다중로봇 통합 채광시스템 해석의 효율성을 향상시키고, 다중로봇 시스템의 확장이 이하도록 부분시스템 합성방법이 적되었다. 또한 유연 다물체 동역학이 적된 부분구조로 나눔으로써 수직양광관과 유연관의 대변위가 고려되었다. 일반적인 해석방법과 부분시스템 합성방법의 산술 연산 횟수를 비교함으로써 통합 채광시스템의 부분시스템 합성방법의 이론적인 효율성 연구가 수행되었다.

• 한국항해항만학회지
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• 제34권3호
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• pp.195-203
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• 2010

본 논문은 통합채광시스템의 동력학 해석을 다루고 있다. 통합채광시스템은 채광선, 수직양광관, 중간 저장 장소인 버퍼, 유연관, 자항식집광기로 구성되어 있다. 자항식집광기와 버퍼는 6자유도의 강체로 가정하였으며, 수직양광관과 유연관의 동적거동 해석을 위해 집중질량 매개방법을 이용한 이산화 모델을 적용하였다. 채광선에 대한 운동은 포함시키지 않았지만 경계조건을 통하여 채광선의 움직임을 표현하였다. 연약한 해저면을 주행하는 차량에는 연약지반 역학 모델을 적용시켰다. 수직양광관-버퍼, 버퍼-유연관, 유연관-자항식집광기의 연결에는 회전구속과 볼 구속조건을 사용하였다. 연성 동력학 모델의 운동방정식을 유도하기 위해 국부좌표계를 사용하였으며, 4개의 오일러 매개변수를 사용하여 각 시스템의 자세를 표현하였다. 통합 채광시스템의 운동 방정식 해를 구하기 위해서 증분-반복법을 적용하였으며, 시간영역 적분기는 newmark-${\beta}$를 사용하였다. 통합 채광시스템의 동적 거동 해석을 수치해석을 통해 분석하였다.

• 한국전산구조공학회논문집
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• 제20권2호
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• pp.105-111
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• 2007

본 논문에서는 극한 해상상태나 돌발적인 환경하중에서 양광시스템의 진수와 인양이 이루어질 때 발생할 수 있는 파이프의 점핑현상과 이에 의해 유발되는 파이프의 장력변화 및 위해도를 위한 해석기법을 제시하였다. 동적 과도응답 해석은 본 논문에서 제시된 기법에 의하여 여러 가지 형식의 임펄스에 대해 수행되어졌으며, 해석을 위한 모델로 KT-Submarine에서 사용하고 있는 '세계로호' 양광시스템의 진수, 인양 시스템을 선정하였다. 결과적으로 양광시스템관련 해상작업을 위한 지침이 제시되었다. 정성적인 해석기법의 검증과 비교를 위하여 ROV진수 시 발생 가능한 케이블장력 과도응답을 해석하였으며 이를 통하여, 본 연구에서 시도한 수학적 모델링과 이상화된 임펄스에 대한 파이프의 과도 응답과정이 충분한 정성적인 기초자료를 제공해 줄 수 있다는 점을 파악하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.652-669
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• 2014

This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI) method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.376-386
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• 2020

The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.

• 대한조선학회논문집
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• 제56권2호
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• pp.143-151
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• 2019

This study describes a method for analyzing log data generated in a process using process mining techniques. A system for collecting and analyzing a large amount of log data generated in the process of manufacturing an offshore plant piping material was constructed. The analyzed data was visualized through various methods. Through the analysis of the process model, it was evaluated whether the process performance was correctly input. Through the pattern analysis of the log data, it is possible to check beforehand whether the problem process occurred. In addition, we analyzed the process performance data of partner companies and identified the load of their processes. These data can be used as reference data for pipe production allocation. Real-time decision-making is required to cope with the various variances that arise in offshore plant production. To do this, we have built a system that can analyze the log data of real - time system and make decisions.