• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.78-85
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• 2020

The scaffolding system, which is a construction workbench of the cargo containment for a membrane LNG carrier, is a large truss structure composed of various members. To shorten the installation period and process of the scaffolding system, it is effective to enlarge the mounting unit from the existing two stages to eight stages. Owing to the increase in lifting load according to the large size of the module, the stresses around the pin and hole will be increased significantly. In this study, a tensile strength test and contact stress analysis were performed to confirm the structural safety. The relatively large hole deformation was observed visually near the average load generated in the vertical pipe at the top through tensile strength tests. A contact stress calculation confirmed the stress distribution around the hole. The contact problem was dealt with in terms of the Herzian contact stress. The possibility of 8-stage loading was examined by comparing the yield strength and contact stresses of failure critical locations. As a result, the 8-stage loading method of the existing scaffolding material was inadequate, and a new loading method with proper safety is proposed.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.224-228
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• 1997

Rolling contact fatigue tests were performed for two types silicon nitrides using disk- type specimens. Materials showed a fatigue behaviour similar to that typically found in metallic materials From the fractographic and metallographic observations, it has been found that the crack initation in the silicon nitrides subjected to rolling contact fatigue is to be induced by cyclic subsurface shear stress, as is known in steel bearing. On the mid-sections of the specimens, many subsurface cracks which lay parallel to the contact surface can be found at a depth where fluctuation of the Herzian shear stress was the maximum.

• Tribology and Lubricants
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• v.16 no.1
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• pp.9-14
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• 2000

It has been cleared in previous author's paper that the fatigue life before the pitting on the rolling contact surface with lubricant are influenced by the wear amount. In this study, the wear type has been clarified when wear amount is extremely large such as the case without lubricant. The test of rolling contact fatigue has been conducted under two different of herzian pressures and three different of slide ratios without lubricant. In addition, residual stress and half-value breadth using X-ray diffraction on worn surface have been measured as well as the wear amount. The results show that the pitting type wear by rolling contact fatigue has not been occurred when the wear amount is considerably large. Thus this type of wear has been deduced by the fatigue wear depending on delamination theory.