• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.353-358
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• 2004

Tracing the study of the burst test of steam generator tube, few studies have been reported to effect of external pressure acting on secondary-side in service condition. In this study the burst tests of Inconel 690TT were conducted in order to evaluate burst strength characteristics under the effect of external pressure. We obtained the result that the burst strength of Inconel 690TT increased when external pressure increased while both total circumferential elongation and uniform burst elongation were not affected. Also, according to the increased of external pressure, the size of the burst opening became smaller and the tear was getting severe.

• 품질경영학회지
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• 제48권4호
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• pp.597-608
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• 2020

Purpose: The purpose of this paper is to present a probability distribution of the burst pressure of API 5L X65 pipes for the reliability assessment of corroded gas pipelines. Methods: Corrosion is a major cause of weakening the residual strength of the pipe. The mean residual strength on the corrosion defect can be obtained using the burst pressure code. However, in order to obtain the pipe reliability, a probability distribution of the burst pressure should be provided. This study is concerned with estimating the burst pressure distribution using Monte Carlo simulation. A response surface method is employed to represent the distribution parameter as a model of the corrosion defect size. Results: The experimental results suggest that the normal or Weibull distribution should be suitable as the probability distribution of the burst pressure. In particular, it was shown that the probability distribution parameters can be well predicted by using the depth and length of the corrosion defect. Conclusion: Given a corrosion defect on the pipe, its corresponding burst pressure distribution can be provided at instant. Subsequently, a reliability assessment of the pipe is conducted as well.

• 한국안전학회지
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• 제18권4호
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• pp.16-22
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• 2003

Generally the rupture of steam generator tubes proceeds from significant plastic deformation before failure. In this study, the burst pressures of damaged steam generator tubes were calculated from the plastic instability analysis with the finite element method. Two wear types, flat and circumferential types were considered. An equation for the burst pressure was proposed by using the strength reduction factor and the Svensson equation. The analysis results were compared with the experiment data from published references and they showed a good agreement with the experiment data.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.666-676
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• 2021

This paper presents numerical estimation of burst pressures of axial cracked U-bend tubes, considering the U-bending process analysis. The validity of the FE simulations is confirmed by comparing with published experimental data. From parametric analyses, it is shown that existing EPRI burst pressure estimation equations for straight tubes can be conservatively used to estimate burst pressures of the U-bend tubes. This is due to the increase in yield strength during the U-bending process. The degree of conservatism would decrease with increasing the bend radius and with increasing the crack depth.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.435-451
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• 2015

Evaluation of the performance of aging structures is essential in the oil and gas industry, where the inaccurate prediction of structural performance can have significantly hazardous consequences. The effects of structure failure due to the significant reduction in wall thickness, which determines the burst strength, make it very complicated for pipeline operators to maintain pipeline serviceability. In other words, the serviceability of gas pipelines and elbows needs to be predicted and assessed to ensure that the burst or collapse strength capacities of the structures remain less than the maximum allowable operation pressure. In this study, several positions of the corrosion in a subsea elbow made of API X42 steel were evaluated using both design formulas and numerical analysis. The most hazardous corrosion position of the aging elbow was then determined to assess its serviceability. The results of this study are applicable to the operational and elbow serviceability needs of subsea pipelines and can help predict more accurate replacement or repair times.

• Composites Research
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• 제34권4호
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• pp.257-263
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• 2021

복합재료는 높은 비 강성 및 비 강도 특성으로 인해 기체 혹은 액체 연료를 저장하기 위한 압력 용기의 설계 및 제작에 널리 활용되고 있다. 이에 따라, 압력용기의 파열압력 또는 파단 변형률의 기계적 특성의 보다 정확한 측정은 상용화 전에 필수적 요소이다. 그러나, 기존의 시험방법을 활용한 복합재료 압력 용기의 안전성 검증은 하중 전달 매체의 변형으로 인한 추가적인 에너지 손실의 발생과, 불필요한 하중 및 모멘트의 발생 등의 한계가 있다. 따라서 본 연구에서는 수직기둥의 이론적인 하중전달 정도와 적용 가능한 수직방향 변위를 고려하여 세그먼트형 링 버스트 시험장치를 설계하였다. 또한, 세그먼트 형 링 버스트 시험장치의 균일한 압력분포를 검증하기 위해 수치해석을 활용하였고, 수압 시험방법과 링 시편의 원주방향 응력 및 변형률 분포를 비교하였다. 복합재료 압력용기의 파괴 거동을 모사하기 위해 Hashin 파손 기준을 적용하였고, 실험적으로 파단 변형률을 측정하여 이를 수치해석 결과와 비교하였다.

• 한국기계가공학회지
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• 제17권6호
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• pp.151-157
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• 2018

In this study, we have developed a composite pressure vessel that is compact and can store refrigerant at high pressure to increase the refrigerant volume. The composite pressure vessel is made of aluminum-based duralumin, which has high rigidity and excellent elongation in the inner liner, considering the characteristics of products in the aerospace and defense industry, where the safety of the applied product is considered as a priority. High strength carbon fiber was applied to the outside. In order to evaluate the performance of the developed product, burst test and cycling test were carried out. In burst test, an excellent safety margin equivalent to 2.7 times the operating pressure was obtained. In cycling test, a stable failure mode in which 'pre-burst leak' occurs is proved and the soundness of the product is proved.

• Composites Research
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• 제23권3호
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• pp.37-42
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• 2010

섬유 방향 강성과 강도는 복합재 압력 용기의 성능과 밀접한 관계를 갖기 때문에, 압력 용기 구조 설계시에 다른 물성들보다 중요 설계 인자가 된다. 즉 복합재 압력 용기의 내압 변형 및 파열 압력은 섬유 물성에 의해 큰 영향을 받는다. 그러므로 정확한 섬유 방향 물성을 측정할 수 있는 기법을 확립하는 것이 복합재 압력 용기 설계 전에 우선되어야 한다. 그러나 복합재 압력용기의 섬유 방향 물성은 제작 공정 변수(와인딩 장비, 작업자, 작업환경 등)와 크기 효과에 의해 큰 영향을 받으므로 기존의 시편 시험 방법으로는 정확한 섬유 방향 물성 측정이 어렵다. 섬유 물성을 측정하는 가장 이상적인 시험 방법은 실물 압력용기 파괴시험이지만 많은 비용이 소요되어, 제품으로부터 다량의 링 시편을 채취, 내압 시험을 할 수 있는 Hoop ring 시험 방법이 제시되었다. Hoop ring 시험과 실물 압력용기의 수압 파괴 시험으로부터 구한 섬유 방향 물성들은 근접된 좋은 일치를 나타내었다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.224-227
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• 2004

A computer program for composite pressure vtlssel design is developed. In-puts are : material-property(young's modulus, shear modulus, tensile strength, poisson's ratio, density), operating pressure, burst pressure, liner thickness, boss diameter, boss weight and number of helical angles. Out-puts are; thickness of each layer, weight of the vessel, dimension of the vessel, inner volume, dome-shape and helical winding angle. Also filament winding angles can be selected various kinds of utilizing virtual boss diameter.

• Structural Engineering and Mechanics
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• 제27권3호
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• pp.277-292
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• 2007

Based on the composite finite element simulation and a series of hydrostatic pressure and burst tests, autofrettage effects on strength and deformation of fiber reinforced pressure vessel with metallic liners have been studied in the paper (autofrettage: during the course of one pressure taking effect, the increasing internal stress in metallic liner can surpass the yielding point and the plastic deformation will happen, which result in that when there is no internal pressure, there are press stress in liner while tensile stress in fiber lamination). By making use of a composite finite element Ansys code and a series of experiments, the autofrettage pressure is determined in order to make the aluminium liner be totally in elastic state, under given hydrostatic test pressure. The stress intensity factors of the longitudinal crack in aluminum liner end under internal pressure and thermal loads have been computed and analyzed before and after the autofrettage processing. Through numerical calculation and experiment investigations, it is found that a correct choice for autofrettage pressure can improve the gas-tightness and fatigue strength of FRP vessel.