A Continuous Ship Unloader (CSU) is a facility in which multiple buckets rotate to excavate cargo from a ship to land. It is typically designed to have a lifespan of 20 years. However, fatigue damage is likely to occur before the end of its designated lifespan. This study aims to examine the possibility of extending the component"s lifespan by evaluating the remaining useful life of L-holder, a part of CSU, that has been in use for 20 years. Fatigue load history was predicted by measuring the strain with or without strain at the L-holder part requiring periodic replacement. Through tensile and fatigue tests, the remaining life was evaluated when cracks were not present. In addition, the remaining life in the presence of cracks was evaluated through destructive toughness test and fatigue crack propagation test. Life prediction results based on test cycles were obtained. The proposed guidelines are expected to be helpful for preventing CSU accidents.
The CSU (continuous ship uploader) is one of the most advanced and high-tech machines among the logistics facilities. It is giant heavy equipment and has a number of driving systems compared to a general crane. In general, CSU is designed to have a life of 20 years, but recently it has been increased up to 30-50 years or is being used as a semi-permanent facility. In this study, based on the structural analysis and the elasto-plastic fracture mechanics, fracture toughness test was performed on the front tension bar, which is the main load bar of the CSU machine. The J-integral analysis was performed on the front tension bar. Based on the results of the J-integral analysis and fracture resistance test, the critical crack length without instantaneous fracture was calculated and analyzed for each operating load.
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Prediction of the Remaining Useful Life of L-holder for Continuous Ship Unloader Seung-Hun Lee, Dong-Woo Lee, Jung-Il Song Journal of the Korean Society for Precision Engineering.2023; 40(8): 647. CrossRef
This research analyzes bucket elevator roller chain pins by finite element (FE) analysis and static structural analysis for a lightweight pin design. The stress distribution of light weight roller chain pins under static load is analyzed for safety factors and damping effect. The results show that the stress distribution is higher on the plate than on the bush pin. In order to compare experimental and FE analysis results, a light weight design approach was used to produce a prototype base pin. Because the inner diameter of the pin was different, the impact damping effect was most appropriate when the inner diameter was 34.05 ㎜, and it is used as basic research data on the impact of the roller chain and sprocket.
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Suitability of Selected Diagnostic Factors for Assessing the Technical Condition of the Working Systems of Bucket Elevators Piotr Sokolski Energies.2025; 18(7): 1610. CrossRef
Prediction of the Remaining Useful Life of L-holder for Continuous Ship Unloader Seung-Hun Lee, Dong-Woo Lee, Jung-Il Song Journal of the Korean Society for Precision Engineering.2023; 40(8): 647. CrossRef
Development of lightweight fiber-reinforced composite pins for heavy load long pitch roller chains Chang-Uk Kim, Jung-il Song Composite Structures.2020; 236: 111839. CrossRef
Evaluation of Critical Crack Length of Tension Bar for Continuous Ship Uploader Keontae Park, Jang Young Chung, Chang-Sung Seok, Jung-Il Song Journal of the Korean Society for Precision Engineering.2018; 35(12): 1169. CrossRef
An Evaluation of Wear in High Load Long Pitch Roller Chain Chang Uk Kim, Jang-Young Chung, Jung Il Song Journal of the Korean Society for Precision Engineering.2017; 34(9): 647. CrossRef
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