• Title/Summary/Keyword: Tractive Stiffness

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Off-road tractive performance of tracked vehicles and the effects of soil parameters (궤도차량의 야지기동성 평가와 토지특성의 영향)

  • 김진우
    • Journal of the korean Society of Automotive Engineers
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    • v.13 no.4
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    • pp.76-84
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    • 1991
  • The off-road tractive performance of tracked vehicles can be evaluated in terms of soil thrust, motion resistance and drawbar pull. The ability to predict accurately ground pressure distribution under track is of importance since the vehicle sinkage and motion resistance are closely related to it. While the formulation of the method for predicting ground pressure distribution follows closely in spirit the ideas outlined for the terrain with linear pressure- sinkage relation case by Garber and Wong, the analysis of various terrain stiffness is magnified by numerical implementation procedure. The effects of soil parameters on tractive forces can be introduced through the terrain-track interaction such as pressure-sinkage and shearing characteristics. It is illustrated by determining the drawber pull-slip relation and corresponding ground pressure distribution for the terrains typically chosen and by comparing the results with the conventional ones based on normal ground pressure. The factorial experiment method is finally adopted for checking the sensitivity of the values of soil parameters on the drawbar pull.

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A Study on the Evaluation of Safety Stiffness from Ship's Mooring Bollards (선박 접안용 계선주의 안전 강성 평가에 관한 연구)

  • Yu, Yong-Ung;Kim, Seung-Yeon;Lee, Yun-Sok
    • Journal of Navigation and Port Research
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    • v.43 no.1
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    • pp.9-15
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    • 2019
  • Mooring bollards are the mandatory facility in ports for they are the objects used to fasten the ship to its position at the berth. All the mooring bollards were installed following suggested sizes, numbers, materials and shape of installation according to Port and Fishing Design Standards. However, Korea has no management standard for use of mooring bollards to safety in ship berthing. In this research, the installation standard for mooring bollards including the holding power applied to mooring bollards in berthing was studied. Also, the performance of mooring bollards for minimum safety guarantee in berthing based on research of various specification by their sizes was analyzed. The analysis on mooring bollards was examined by each power on mooring bollards from the applied force in berthing divided into horizontal and vertical direction in order to examine the performance of domestic mooring bollards, the limit force is calculated based on detailed specification research result. As a result, the working stress according to the towing force was found to be at least 150Mpa and it was evaluated to be 60% of the limit strength. Also, by comparing each forces, the appropriateness was examined and the specification of maximum capability calculated. This performance evaluation method based on detail specification of mooring bollards will be expected to be useful to examine the appropriateness of mooring bollards for various types of vessel in berthing and to develop maintenance and management standard through the performance change evaluation referring to mooring bollard detailed specification changes.