• Journal of Ocean Engineering and Technology
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• v.21 no.4
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• pp.28-33
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• 2007

The objective of this paper is to investigate the relationship between the short-term creep rupture time and the creep rupture properties at three different elevated temperatures in STS304 stainless steel. Uniaxial constant stress creep rupture tests were performed on the steel to observe the creep rupture behaviors at the elevated temperatures of 600, 650 and 700, according to the testing matrix. It is very important to predict creep life in practical creep design problems. As one of the series of studies on the statistical modelling of probabilistic creep rupture time and the development of creep life prediction techniques, the relationship between applied stress and creep rupture behaviors, such as creep strain rate and rupture time, were investigated. In addition, the Monkman-Grant relationship was observed between the steady-state creep rate and the creep rupture time. The creep rupture surfaces observed by SEM showed up dimple phenomenon at all conditions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1182-1189
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• 1995

Several methods have been developed to predict the creep rupture time of the steam pipes in thermal power plant. However, existing creep life prediction methods give very conservative value at operating stress of power plant and creep rupture strain cannot be well estimated. Therefore, in this study, creep rupture time and strain prediction method accounting for material damage and grain boundary sliding is newly proposed and compared with the existing experimental data. The creep damage evolves by continuous cavity nucleation and constrained cavity growth. The results showed good correlation between the theoretically predicted creep rupture time and the experimental data. And creep rupture strain may be well estimated by using the proposed method.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.56-62
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• 2010

This paper is concerned with the stochastic nature of elevated temperature tensile strength and creep rupture time in 18Cr-8Ni stainless steels. The Weibull statistical analysis using the NRIM data sheet has been performed to investigate the effects of variability of the elevated temperature tensile strength and creep rupture time on the testing temperature. From those investigations, the distributions of temperature tensile strength and creep rupture time were well followed in 2-parameter Weibull. The shape parameter and scale parameter for the Weibull distribution of tensile strength were decreased with increasing the testing temperature. For the creep rupture time, generally, the shape parameter were decreased with increasing the testing temperature.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2812-2822
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• 2000

Several methods have been developed to predict the rupture time of the boiler tubes in thermal power plant. However, existing life prediction methods give very conservative value at operating stress of power plant and rupture strain cannot be well estimated. Therefore, in this study, rupture time and strain prediction method accounting for creep, corrosion and heat transfer is newly proposed and compared with the current research results. The creep damage evolves by continuous cavity nucleation and constrained cavity growth. The corrosion damage evolves by steam side and fire side corrosion. The results showed good correlation between the theoretically predicted rupture time and the current research results. And rupture strain may be well estimated by using the proposed method.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.273-278
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• 1997

In order to investigate the punch properties of some vegetables-cucumber, radish, garlic, ginger and potato-force, distance, and time were measured with a texturometer, and the correlations between compositions and cell characteristics of samples were characterized. Many reflection and rupture points on the force-distance and distance-time curve were observed, and these points appeared when the cells of sample were resisted and yielded against the applied force. They were big and clear at the slow crosshead speed. The regression analysis for force-time and distance-time to the rupture point showed $R^{2}>0.95$. The rupture time and rupure force were 5.63 sec, 4.88 N in ginger and 4.15 sec, 2.00 N in cucumber. The rupture forces become large values at the fast crosshead speed. As cell sizes were increased, the moisture content and rupture distance were increased, while the viscosity of juice, density, regularity of cell, and slope of force-time were decreased. Rupture force, time and distance were decreased at the large specific gravity of samples. The slopes of distance-time curve were inversely proportional to slope of force-time curve.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.6
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• pp.301-308
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• 2014

A suspension bridge is a type of bridge in which the beam is suspended by load-bearing cables. There are two classifications: the self-anchored suspension bridge has the main cable anchored to the bridge girders, and the earth-anchored suspension bridge has the main cable anchored to a large anchorage. Although a suspension bridge is structurally safe, it is prone to be damaged by various actions such as hurricanes, tsunamis and terrorist incidents because its cables are exposed. If damage to a cable eventually leads to the cable rupture, the bridge may collapse. To avoid these accidents, studies on the dynamic behavior of cable bridges due to the cable rupture have been carried out. Design codes specify that the calculated DAF (dynamic amplification factor) should not exceed a certain value. However, it has been difficult to determine DAFs effectively from dynamic analysis, and thus no systematic approach has been suggested. The current study provides a guideline to determine DAFs reliably from the dynamic analysis results and summarizes the results by applying the method to an earth-anchored suspension bridge. In the study, DAFs were calculated at the location of four structural parts, girders, pylons, main cable and hangers, with variations in the rupture time.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2454-2465
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• 2023

Film boiling may lead to burnout of the heating element. Even though burnout does not occur, the heating element is subject to deformation because it is not sufficiently strong to withstand external loads. In particular, the ballooning and rupture of a tube under film boiling are important phenomena in the field of nuclear reactor safety. If the tube-type cladding of nuclear fuel ruptures owing to high internal pressure and thermal load, radioactive materials inside the cladding are released to the coolant. Therefore, predicting the ballooning and rupture is important. This study presents numerical simulations to predict the ballooning behavior and rupture time of a horizontal tube at high internal pressure under saturated film boiling. To do so, a multi-step coupled simulation of conjugated film boiling heat transfer and ballooning using creep model is adopted. The numerical methods and models are validated against experimental values. Two different nonuniform heat flux distributions and four different internal pressures are considered. The three-step simulation is enough to obtain a convergent result. However, the single-step simulation also successfully predicts the rupture time. This is because the film boiling heat transfer characteristics are slightly affected by the tube geometry related to creep ballooning.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.473-480
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• 1998

This study was performed to analyze the variation of various physicochemical factors related to the freshness of apple and tomato during post-harvest period. The total soluble solids content, uronic acid content, cell surface roughness. density, rupture deformation and rupture force were measured for 39 days at 7-day intervals for apple and for 11 days at 2-day intervals for tomato. respectively. The cell surface roughness of apple increased with the elapsed time, while the rupture force decreased. In case of tomato, uronic acid content, density and rupture deformation increased with the elapsed time whereas the rupture force decreased. Both apple and tomato exhibited the significant correlations among those physicochemical factors.

• Journal of Chest Surgery
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• v.21 no.4
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• pp.778-781
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• 1988

With the advent of widespread mechanization and high-speed era, the incidence of traumatic rupture of the tracheobronchial tree has been increased considerably. Rupture of the bronchus is an unusual result of nonpenetrating trauma to the chest. This case was a 30 years old male who was a worker in the mine. The patient had sustained a compression chest injury with multiple rib fracture. At the time trauma, he was suffered from dyspnea, hemoptysis and hemopnemothorax of both side were noted. After tracheostomy, corrective surgery was performed with end-to-end anastomosis on the 8th time after trauma. Postoperative course was uneventful and good result of bronchogram with hypaque on the 16th day after operation.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.58-63
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• 2008

The short-term high temperature creep rupture behavior of Ni-based Alloy718 steels jointed by friction welding wasinvestigated at the elevated temperatures of 550 to $700^{\circ}C$ under constant stress conditions. The creep rupture characteristics such as creep stress, rupture time, steady state creep rate, and initial strain were evaluated. Creep stress has a quantitative correlation between creep rupture time and steady state creep rate. The stress exponents (n, m) of the experimental data at 550, 600, 650 and $700^{\circ}C$ were derived as 26.1, -22.4, 22.5, -18.5, 17.4, -14.3 and 6.9, -8.1, respectively. The stress exponents decreased with increasing creep temperature. The creep life prediction was derived by the Larson-Miller parameter (LMP) method and the result equation obtained is as follows: T(logtr+20)=-0.00148${\sigma}^2$-3.089${\sigma}$+23232. Finally, the results were compared with those of the base metal for Alloy718.