• 한국기계가공학회지
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• 제20권3호
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• pp.83-91
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• 2021

A crawler crane, which consists of a lattice boom, a driving system, and a movable vehicle, is widely used on construction sites. The crawler crane often traverses rough terrain at these sites; as a result, an overload limiter needs to be installed on the crane to prevent it from overturning and breaking. In this paper, we studied the distributed load change in relation to boom length and the angle of rotation of the roller that comes in direct contact with the grounded track shoe. First, we developed a 3D model of a crawler crane and meshed it for finite elements. Then, we performed finite element analysis to derive the load on the roller. Finally, we graphed and examined the roller distributed load data of the case according to boom length and rotation angle. By detecting the load on the roller of the crawler crane, we can predict the potential for the crane to overturn before it happens.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.77-78
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• 2023

As large logistics buildings have high floor heights and long spans, these buildings are designed as PC structures, and large cranes are used to lift PC members. PC erection planning can generally cause errors depending on the field engineer's experience. To solve this problem, a basic analysis method is needed to establish a systematic PC member erection plan. Crane work can be minimized if the trajectory is easily and quickly calculated according to the location of the crane and applied to the site. Therefore, the objective of this study is a basic study of crane trajectory distance calculation for sustainable PC members erection of large logistic building. In this study, a crawler crane commonly used for lifting PC members is limited. The trajectory distance for the PC erection plan was automatically calculated using the algorithm.

• 한국기계가공학회지
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• 제10권4호
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• pp.44-49
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• 2011

The crawler crane, which consists of a lattice boom, a driving system, and movable vehicle, is widely used in a construction site. It needs to be installed an overload limiter to prevent the overturning accident and the fracture of structure. This research is undertaken to provide the relation formula for designing the overload limiter as follows: First the relation formulas between the wire-rope tension and the hoisting load or the overturning ratio according to the luffing angle and length of a lattice boom are established. Secondly the derived formulas are corrected by using the compensated angle considering the deflection of boom through the finite element analysis. The stiffness analysis is carried out for 30-kinds of models as a combination of 6-kinds of luffing angle and 5-kinds of length of boom. Finally the shape design of a stick type load cell, which is the device to measure the wire-rope tension, is performed. 5-kinds of notch radius and 5-kinds of center hole radius are adopted as the design parameter for the strength analysis of the load cell.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.81-85
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• 2024

• 플랜트 저널
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• 제8권2호
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• pp.59-69
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• 2012

This study focuses on avoiding the failures from the wrong selections by experiences as simulation programs is not available, and suggests the methods which effectively select the alternatives when the selected model is not appropriate for the original plan. First, CC8800-1K of DEMAG has the longest boom whose length is 216 m at the maximum. The combination of the boom is feasible to second level except for MANITIWOC M 2250 (M-1200 RINGER) which is possible to third level. Second, the angle of boom is from 20 degrees to 82 degrees. Suitable angle to work is in the 55-78 degrees. The working load of crawler type and hydraulic one to be applied is 75-85% in the critical loads capacity. As increasing operating radius, crawler type is a favorable position over hydraulic one. Lastly, related problems were verified through examination by suggestions for the design of the selection methods for the case analysis. The major problems are stemming from the selection based on its experiences, unreasonable demand for the existing facility and repeated selections by the designer who accumulates his experiences via same or similar projects.

• 한국전산구조공학회논문집
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• 제25권2호
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• pp.119-127
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• 2012

와이어 로프(wire rope)는 여러 가닥의 얇고 긴 철사를 감아서 밧줄과 같이 만든 것으로 굽힘과 비틀림 하중에 비해 축 하중에 더 크게 저항할 수 있는 특징을 가지고 있다. 해상 크레인, 갠트리 크레인, 크롤러 크레인 등과 같이 선박 또는 해양 구조물의 탑재를 위해 사용되는 조선용 탑재 크레인은 이러한 와이어 로프를 이용해 큰 중량의 블록들을 들거나 내리고 있다. 따라서 블록의 안전한 탑재를 위해서는 와이어 로프에 대한 동역학적 특성을 잘 파악해야 한다. 본 연구에서는 블록 탑재 시 크레인의 와이어 로프에 작용하는 장력과 비틀림 모멘트에 대한 계산식을 유도하고, 이를 기반으로 한 조선용 탑재 크레인의 동역학 시뮬레이션을 수행하였다. 그 결과, 개발된 시뮬레이션 방법이 실제 조선소의 안전한 블록 탑재 과정에 충분히 적용할 수 있음을 확인하였다.

• 한국산림과학회지
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• 제82권2호
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• pp.195-206
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• 1993

본 연구는 임업기계화(林業機械化)의 전제조건인 지역별(地域別) 산림수종체계(山林收種體系)를 수립하기 위한 기초연구로 시도되었다. 이를 위하여 산림수확방법(山林收穫方法)과 집재방법(集材方法)들을 제어(制御)하는 인자들이 무엇인가를 특히 지형적(地形的)인 관점에서 조사하고 분석하였다. 주요한 산림수확방법은 단재수확법(短材收穫法), 장재수확법(長材收穫法) 및 전목수확법(全木收穫法)이다. 단재수확법은 지형조건(地形條件)이 열악(劣惡)한 산림(山林)에, 전목수확법은 양호(良好)한 산림(山林)에, 그리고 장재수확법은 중간조건(中間條件)의 산림(山林)에 적용됨이 조사되었다. 집재방법(集材方法)에 대해서는 육상집재법(陸上集材法)을 중심으로 검토하고 주요 집재법으로는 축력집재(畜力集材), 인력(人力) 및 중력(重力) 집재(集材), 차량집재(車輛集材), 그리고 강선집재(鋼線集材) 등이다. 강선집재 중 케이블 크레인에 의한 집재는 집촌거리(集村距離)에 따라 단거리(短距離)(300 혹은 400m까지), 중거리(中距離)(700 혹은 800m까지) 및 장거리(長距離)(700 혹은 800m 이상) 등으로 구분한다. 집재작업범위(集材作業範圍)를 제어하는 인자는 경사(傾斜)와 집재거리(集材距離)이다. 차량집재(車輛集材)는 산림에 큰 부하(負荷)를 주며, 중력집재(重力集材) 중 log-line과 강선집재(鋼線集材) 중 케이블 크레인에 의한 집재법은 산림훼손(山林毁損)을 최소화(最小化)한다. 차량집재는 경사가 급할수록 어려워지고 케이블 크레인 집재는 120%까지 가능하다(상향집재(上向集材)).

• 한국산림과학회지
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• 제100권2호
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• pp.154-164
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• 2011

본 연구는 우리나라 험준한 급경사 지형의 단목중심의 목재생산시스템 등에 적합하고 사방사업, 임도사업 등의 다양한 산림작업에 유용하게 활용할 수 있는 다목적의 반궤도식 산림작업차 개발을 목적으로 실시하였다. 산림작업차량의 기본 차체는 최소회전반경 설계기준과 작업도 폭을 고려하여 차체프레임부의 총길이는 5,750 mm, 차체의 폭은 1,900 mm, 적재부의 적재용량은 약 $2.5m^{3}$으로 설계 제작하였다. 동력원은 3,400 rpm의 최대 96마력 출력의 엔진을 선정하였으며, 유압펌프는 2개의 주펌프와 2개의 보조펌프로 나누어 선정하고, 주펌프는 전후좌우 4개의 주행용 유압모터에 사용하고, 보조펌프는 각종 작업기에 사용하도록 설계 제작하였다. 동력전달방식은 HST(Hydro-Static Transmission) 시스템을 적용하였고, 주행부는 조향가능한 전방 고무바퀴와 무한 궤도형으로 회전하는 후방 크롤러로 설계 제작하고, 조향방식은 애커만 조향방식을 채택하였다. 주행조작부는 일반 자동차의 운전 및 운전석 형태로 설계 제작하였으며, 보조장치로 윈치와 로그그래플 및 아웃트리거를 장착하였다. 시작기의 공차시 임도의 주행속도는 저속 5.3 km/hr, 고속 7.7 km/hr로 나타났다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.87-92
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• 2003

Generally, in jack up rig design for harsh environment, its leg height is a major factor for achieving a sufficient serviceability & operability in terms of the worst environment and the workable depth. Due to difficulties in constructing such a high-slender leg, inaccessibility of yard fabrication equipment, etc. the construction of Jack up rig fur harsh deep sea has not been common. Method using heavy crawler crane, fabrication tower or extension by the floating crane vessel is still conventional construction but, considering high cost fur mobilizing heavy lift vessel (HLV) or additional marine work for implementing preload / full height test at sea, the ground-base construction is much advantageous. Air skidding method (ASM hereafter) is ground-based construction methodology, newly developed due to such requests. ASM could also be extended to similar engineering fields. This paper presents the operating sequence, design parameters and procedure which were verified through successful operation at the end of May 2002.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.699-722
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• 2019

It is difficult to observe the potential risks of lifting or turn-over operations in the early stages before a real operation. Therefore, many dynamic simulations have been designed to predict the risks and to reduce the possibility of accidents. These simulations, however, have usually been performed for predetermined and fixed scenarios, so they do not reflect the real-time control of an operator that is one of the most important influential factors in an operation; additionally, lifting or turn-over operations should be a collaboration involving more than two operators. Therefore, this study presents an integrated method for a collaborative simulation that allows multiple workers to operate together in the virtual world. The proposed method is composed of four components. The first component is a dynamic analysis that is based on multibody-system dynamics. The second component is VR (virtual reality) for the generation of realistic views for the operators. The third component comprises the control devices and the scenario generator to handle the crane in the virtual environment. Lastly, the fourth component is the HLA (high-level architecture)-based integrated simulation interface for the convenient and efficient exchange of the data through the middleware. To show the applicability of the proposed method, it has been applied to a block turn-over simulation for which one floating crane and two crawler cranes were used, and an offshore module installation for which a DCR (dual-crane rig) was used. In conclusion, the execution of the proposed method of this study is successful regarding the above two applications for which multiple workers were involved.