• Title/Summary/Keyword: Hydrostatic pressure test

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The Design, Structural Analysis and High Pressure Chamber Test of a Thick Pressure Cylinder for 2000 m Water Depth (수심 2000m 용 두꺼운 내압용기의 설계, 구조해석과 내압시험)

  • Choi, Hyeuk-Jin;Lee, Jae-Hwan;Kim, Jin-Min;Lee, Seung-Guk;Maring, Kothilngam
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.2
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    • pp.144-153
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    • 2016
  • This paper aims to demonstrate the design, structure analysis, and hydrostatic pressure test of the cylinder used in 2000m water depth. The cylinder was designed in accordance with ASME pressure vessel design rule. The 1.5 times safety factor required by the general rule was applied to the design of the cylinder, because ASME rule is so excessive that it is not proper to apply to the hydrostatic pressure test. The finite element analysis was conducted for the cylinder. The cylinder was produced according to the design. The hydrostatic pressure test was conducted at the hyperbaric chamber in KRISO. The results of finite element analysis(FEM) and those of the hydrostatic pressure test were almost the same, which showed that the design was exact and reliable.

A Comparison of Standard Methods for Evaluating the Water Resistance of Shell Fabrics

  • Kwon, Myoung-Sook;Nam, Youn-Ja
    • The International Journal of Costume Culture
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    • v.4 no.3
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    • pp.241-248
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    • 2001
  • Re water resistance of shell fabrics intended for we in outdoor apparel was measured using three different standard test methods, ASTM D 751, hydrostatic resistance, procedure A(Mullen test -- with and without a fabric support) and Procedure B (Hydrostatic head test). A database of information on their water resistance performance was created. The data collected with different methods were correlated and the advantages and disadvantages of each method were compared. The Mullen test with a support appears to give higher and more favorable water resistance values on shell fabrics preventing fabric rupture during the test. The hydrostatic head test gave lower hydrostatic pressure values than those measured on the two Mullen tests. The Mullen test is recommended for testing the water resistance of fabrics that high a relatively high water resistance because the Mullen tester applies a wide range of pressure. The hydrostatic head test is recommended for testing the fabrics that have relatively low water resistance. The area of the fabric sample that is in contact with the water is smaller in the Mullen test, so higher pressure levels can be reached and more samples should probably be tested to get a representative value for each fabric types. Furthermore, the hydrostatic head test was deemed more repeatable than the Mullen tests in his study.

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Effects of the Hydrostatic Test and the Operating Condition on Weld Residual Stress at a Safety Nozzle of the Pressurizer (수압시험 및 운전조건이 가압기 안전노즐의 용접잔류응력에 미치는 영향 평가)

  • Lee, Kyoung Soo;Lee, Sung Ho;Kim, Wan Jae
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.8 no.1
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    • pp.19-24
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    • 2012
  • This paper presents the results of finite element analysis for the effects of hydrostatic test and operating condition on the weld residual stress at dissimilar metal weld of a pressurizer safety nozzle in a nuclear power plant. For the study, the weld residual stress at ambient condition was analyzed using ABAQUS in the first place. After the weld residual stress analysis, the hydrostatic test condition and operating condition was applied to the same model one after another. The weld residual stress was observed to change due to the successive hydrostatic test and operating condition. The axial residual stresses on inner surface of the dissimilar metal weld and HAZ region were decreased by hydrostatic test and operating condition, which gives beneficial effect on preventing primary water stress corrosion cracking.

Effect of Hydrostatic Pressure on the Elastic Work Factor of Graphite/Epoxy Composites (정수압이 탄소섬유/에폭시 복합재의 탄성일인자에 미치는 영향)

  • 이지훈;김만태;신명근;한운용;이경엽
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1390-1393
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    • 2003
  • Work factor approach is conveniently used in metal fracture mechanics to determine fracture toughness from a single fracture test. In this work, we investigated the applicability of the work factor approach in order to determine fracture toughness of thick graphite/epoxy composites in the hydrostatic pressure environment from a single fracture test. The effect of hydrostatic pressure on the elastic work factor was studied, The stacking sequence used was multi-directional, [0$^{\circ}$/${\pm}$45$^{\circ}$/90$^{\circ}$]. The hydrostatic pressures applied were 0.1 MPa, 100 MPa, 200 MPa, and 300 MPa. The results showed that the elastic work factor was not affected by the hydrostatic pressure, The elastic work factor decreased in a linear fashion with crack length.

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Experimental investigations on the failure modes of ring-stiffened cylinders under external hydrostatic pressure

  • Cho, Sang-Rai;Muttaqie, Teguh;Do, Quang Thang;Kim, Sinho;Kim, Seung Min;Han, Doo-Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.6
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    • pp.711-729
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    • 2018
  • This paper reports on the experimental investigations on the failure modes of ring-stiffened cylinder models subjected to external hydrostatic pressure. Nine models were welded from general structural steel. The shells were initially formed by cold-rolling, and flat-bar ring frames were welded to the shell. The hydrostatic pressure tests were conducted by using water as the medium in pressure chambers. The details of the preparation and main test were briefly explained. The investigation identified the consequence of the structural failure modes, including: shell yielding, local shell buckling between ring stiffeners, overall buckling of the shell together with the stiffeners, and interactive buckling mode combining local and overall buckling. In addition, the ultimate strengths were predicted by using existing design codes. Non-linear numerical computations were also conducted by employing the actual imperfection coordinates. Finally, accuracy and reliability of the predictions of design formulae and numerical were substantiated with the test results.

Winter to replace the hydraulic test and pneumatic test comparative analysis of study on the optimal pressure (동절기 수압시험을 대체하는 공기압시험의 적정압력 비교분석에 관한 연구)

  • Kwoun, Young-Hee;Hwang, Dong-Hwan;Kim, Tae-Gil;Kang, Kyung-Sik
    • Journal of the Korea Safety Management & Science
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    • v.16 no.2
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    • pp.211-216
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    • 2014
  • Using a high-rise building water piping after hydrostatic test of the reliability of the leak to be completed if the pressure is maintained until the leak is not commercially available considered. Due to the nature of high-rise buildings and the construction period will take several years from the lower levels of use of the water supply and fire fighting water pipe construction is in progress, the order of which I do most of the first pipe to the construction and more than three years. So kind of riser pipe is complete, install the valve in the basement by installing an automatic pump to maintain a constant pressure after hydrostatic test and after each floor plumbing piping is complete, the progress of the hydrostatic test without undergoing a separate branch pipe the valve is opened automatically when the number of the pressing pressure of the structure. I kind of do and keep working pressure of pipe until the completion of the construction work to keep the damage to human error when it is intended to prepare. In winter, the frost protection and an alternative to drainage water pipe is damaged or deformed, even if unaware of the finishing work to the building, the use of the damage caused by a leak in a after construction of finish work to be expected. Alternative to reduce this damage if the pressure test without fear of freezing to help maintain long-term commercial pressures may be considered.

A Study of Echo Reduction of Underwater Acoustic Material Considering Ocean Condition (수중환경을 고려한 수중 음향재료의 반향음 감소성능 연구)

  • Seo, Young Soo;Ham, Il Bae;Jung, Woo Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.377-384
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    • 2014
  • The requirement of acoustic material which is used in underwater environment more increases. The material is used to reduce acoustic signature and radiate noise for underwater vehicle. Underwater acoustic material was made by viscoelastic material such as a rubber and a polyurethane etc. The mechanical and acoustic characteristics of these material change with hydrostatic pressure. In order to increase an acoustic performance according to hydrostatic pressure, several kinds of scatterers were added to viscoelastic material. In this paper, acoustic modelling and analysis techniques of underwater acoustic material with hydrostatic pressure were introduced and proposed. The specimens for pulse tube test were made and echo reductions were calculated and measured with hydrostatic pressure. Also the characteristics of echo reduction of the specimens with hydrostatic pressure were obtained and discussed.

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A Study on the Echo Reduction Performance of Underwater Acoustic Material (수중 음향재료의 반향음 감소성능 연구)

  • Seo, Young Soo;Ham, Il Bae;Jung, Woo Jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.11
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    • pp.868-875
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    • 2014
  • The requirement of acoustic material which is used in underwater environment more increases. The material is used to reduce acoustic signature and radiate noise for underwater vehicle. Underwater acoustic material was made by viscoelastic material such as rubber and polyurethane etc. The mechanical and acoustic characteristics of these material change with hydrostatic pressure. In order to improve an acoustic performance according to hydrostatic pressure, several kinds of scatterers were added to viscoelastic material. In this paper, acoustic modelling and analysis techniques of underwater acoustic material with hydrostatic pressure were introduced and proposed. The specimens for pulse tube test were made and echo reductions were calculated and measured with hydrostatic pressure. Also the characteristics of echo reduction of the specimens with hydrostatic pressure were obtained and discussed.

Numerical studies of the failure modes of ring-stiffened cylinders under hydrostatic pressure

  • Muttaqie, Teguh;Thang, Do Quang;Prabowo, Aditya Rio;Cho, Sang-Rai;Sohn, Jung Min
    • Structural Engineering and Mechanics
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    • v.70 no.4
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    • pp.431-443
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    • 2019
  • The present paper illustrates a numerical investigation on the failure behaviour of ring-stiffened cylinder subjected to external hydrostatic pressure. The published test data of steel welded ring-stiffened cylinder are surveyed and collected. Eight test models are chosen for the verification of the modelling and FE analyses procedures. The imperfection as the consequences of the fabrication processes, such as initial geometric deformation and residual stresses due to welding and cold forming, which reduced the ultimate strength, are simulated. The results show that the collapse pressure and failure mode predicted by the nonlinear FE analyses agree acceptably with the experimental results. In addition, the failure mode parameter obtained from the characteristic pressure such as interframe buckling pressure known as local buckling pressure, overall buckling pressure, and yield pressure are also examined through the collected data and shows a good correlation. A parametric study is then conducted to confirm the failure progression as the basic parameters such as the shell radius, thickness, overall length of the compartment, and stiffener spacing are varied.

Compressive Behavior of Carbon/Epoxy Composites under High Pressure Environment-Strain Rate Effect (고압환경에서 탄소섬유/에폭시 복합재의 압축거동에 대한 연구-변형률 속도 영향)

  • 이지훈;이경엽
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.148-153
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    • 2004
  • It is well-known that the mechanical behavior of fiber-reinforced composites under hydrostatic pressure environment is different from that of atmospheric pressure environment. It is also known that the mechanical behavior of fiber-reinforced composites is affected by a strain rate. In this work, we investigated the effect of strain rate on the compressive elastic modulus, fracture stress, and fracture strain of carbon/epoxy composites under hydrostatic pressure environment. The material used in the compressive test was unidirectional carbon/epoxy composites and the hydrostatic pressures applied was 270㎫. Compressive tests were performed applying three strain rates of 0.05%/sec, 0.25%/sec, and 0.55%/sec. The results showed that the elastic modulus increased with increasing strain rate while the fracture stress was little affected by the strain rate. The results also showed that the fracture strain decreased with increasing strain rate.