• Title/Summary/Keyword: elastic-plastic fracture toughness

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A study on the fracture toughness evaluating method for cryogenic structural material (극저온용 구조재료의 파괴인성평가법에 관한 연구)

  • Kwon, Il-Hyun;Chung, Se-Hi
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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    • pp.64-72
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    • 1998
  • This paper was undertaken to develop the fracture toughness testing method using small and single specimen compared to the conventional method in evaluating elastic-plastic fracture toughness of the superconducting magnet structural material at cryogenic temperature. The elastic-plastic fracture toughness test was conducted by using the unloading compliance method recommended by ASTM E813-89 to accomplish the above purpose. And, the 20% side-grooved 0.5TCT and 1TCT specimens were used to evaluate the fracture toughness by using as possible as miniaturized CT specimen. The unloading compliance method was a very useful method in evaluating elastic-plastic fracture toughness at cryogenic temperature. It could be taken valid fracture toughness values by using 20% side-grooved 0.5TCT specimen recommended by ASTM E813-89.

Effects of Specimen Size in Evaluation of Elastic-Plastic Fracture Toughness by Ultrasonic Method (초음파법을 이용한 탄소성 파괴인성치 평가에 있어서 시험편 크기의 영향)

  • 강동명;함경춘;우창기
    • Journal of the Korean Society of Safety
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    • v.13 no.4
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    • pp.19-24
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    • 1998
  • Elastic-plastic fracture toughness($J_{IC}$) by ultrasonic method is evaluated in terms of width and thickness. Widths of specimen in 6061-T6 aluminum alloy are 50mm and 100mm, thicknesses of those are 20mm and 25mm, respectively. Elastic-plastic fracture toughness by ultrasonic method is independent of specimen thickness and side groove. Angle beam probe which are placed on the end of the compact specimen detect the maximum crack extension effectively. Comparing with elastic-plastic fracture toughness by ultrasonic method and that of unloading compliance method, $J_{IC}$ of ultrasonic method are underestimated to that of unloading compliance method. Elastic-plastic fracture toughness of width 100mm specimen are underestimated to that of width 50mm specimen about 20%.

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Effect of Side Groove on the Elastic Plastic Fracture Toughness of Gas Piping Material (가스배관재의 탄소성파괴인성에 미치는 측면홈 영향)

  • 임만배;차귀준;윤한기;공유식;김정호
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.63-68
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    • 2001
  • SG-365 steel is an important material and used for manufacturing a pressure vessel which the gas piping. In this investigation, the elastic plastic fracture toughness of this material is evaluated by the an unloading compliance method according to the ATM E813-97 method on the smooth and side groove 1CT specimens. The effect of smooth and side groove is studied on the elastic plastic fracture toughness. The side grooved specimen is very useful in estimation of the $J_IC. Because it is much easier than the smooth specimen to the onset of the ductile tearing by the R curve method. Besides, it improves the accuracy of toughness values, decreases the scattering of them and tunneling and shear lip by the side groove.

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Effect of Side Grooved on the Elastic Plastic Fracture Toughness of Gas Piping Meterial (가스배관재의 탄소성파괴인성에 미치는 측면홈영향)

  • 임만배;차귀준;윤한기;김정호
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.350-356
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    • 2001
  • SG-50 steel is an important material and used for manufacturing a pressure vessel which the gas piping. In this investigation, the elastic plastic fracture toughness of this material is evaluated by the an unloading compliance method according to the ASTM E813-97 and E1152-97 method on the smooth and side groove 1CT specimens. The effect of smooth and side groove is studied on the elastic plastic fracture toughness. The side grooved specimen is very useful in estimation of the J$_{IC}$. Because it is much easier than the smooth specimen to the onset of the ductile tearing by the R curve method. Besides, it improves the accuracy of toughness values, decreases the scattering of them and tunneling and shear lip by the side groove.e.

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A Study on HIGH TEMPERATURE FRACTURE TOUGHNESS of Pressure Vessel Steel SA516 at High Temperature. (압력용기용강의 고온파괴인성에 관한 연구)

  • 박경동;김정호
    • Proceedings of the KWS Conference
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    • 2001.05a
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    • pp.228-231
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    • 2001
  • Elastic-plastic fracture toughness $J_{1c}$ can be used as an effective design criterion in elastic plastic fracture mechanics. Most of these systems are operated at high temperature and $J_{1c}$ values are affected by temperature. therefore, the $J_{1c}$ valuse at high temperature must be determined for use of integrity evaluation and designing of such systems. Elastic-plastic fracture toughness $J_{1c}$ tests were performed on SA516 carbon steel plate and test results were analyzed according to ASTM E 813-8, ASTM 1813-89. Safety and integrity are required for reactor pressure vessels vecause pthey are operated in high temperature. there are single specimen method, which used as evaluation of safety and integrity for reactor pressure vessels. In this study, elastic-plastic fracture toughness$(J_{1c})$ and $J-\Delta{a}$ of SA 516/70 steel used as reactor pressure vessel steel are measured and evaluated at room Temperature, $150^{\circ}C$, $250^{\circ}C$ and $370^{\circ}C$ according to unloading compliance method.

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Evaluation on High Temperature Fracture toughness of Pressure Vessel SA516/70 Steel (압력용기용 SA516/70강의 고온파괴인성평가)

  • 박경동;김정호;윤한기;박원조
    • Journal of Ocean Engineering and Technology
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    • v.15 no.2
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    • pp.99-104
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    • 2001
  • Elastic-plastic fracture toughness $J_{lc}$ can be used as an effective design criterion in elastic plastic fracture mechanics. Most of these systems are$J_{lc}$ $J_{lc}$ value at high temperature must be determined for use of integrity evaluation and designing of such systems. Elastic-plastic fracture toughness $J_{lc}$ tests were performed on SA516/70 carbon steel plate and test results were analyzed according to ASTM E 813-87, ASTM E 813-89 and ASTM E 1152-87.safety and integrity are required for reactor pressure vessels because, they are operated in high temperature. There are single specimen method, which used as evaluation of safety and integrity for reactor pressure vessels. In this study, elastic-plastic fracture toughness($J_{lc}$) and J-$\Delta$a of SA 516/70 steel used as reactor pressure vessel steel are measured and evaluated at room temperature, 150$^{\circ}C $, 250$^{\circ}C $ and 370$^{\circ}C $ according to unloading compliance method.

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A Study on the Fracture Resistance Curve and Effect of Side Grooves of SG365 Material (SG365강의 파괴저항곡선과 측면홈효과에 관한 연구)

  • 임만배
    • Journal of the Korean Society of Safety
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    • v.16 no.4
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    • pp.14-21
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    • 2001
  • SG-365 steel is an important material End used for manufacturing a pressure vessel and gas piping. In this investigation, the elastic plastic fracture toughness of this material is evaluated by the unloading compliance method according to the ASTM E8l3-97 and E1152-97 method on the smooth and side groove In specimens. The effect of smooth and side groove is studied on the elastic plastic fracture toughness. The side grooved specimen is very useful in estimation of the $J_{IC}$. Because it is much easier than the smooth specimen to the onset of the ductile tearing by the R curve method. Besides. it improves the accuracy of toughness values, decreases the scattering of them and crack tunneling effect and shear lip by the side groove.

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Elastic Plastic Finite Element Calculation of Standard Fracture Toughness Specimens (표준 파괴인성시험편에 대한 탄소성 유한요소해석)

  • 박용걸
    • Computational Structural Engineering
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    • v.7 no.4
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    • pp.113-118
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    • 1994
  • The purpose of this study is elastic plastic finite element analysis for standard fracture toughness specimens. The principles of elastic-plastic fracture mechanics are shortly summarized and the special requirements for computational tools are derived. Possibilities to model the crack tip singularities are mentioned. The relevant fracture parameters like J-Integral and COD and their correlation are evaluated from elastic plastic finite element calculations of standard fracture toughnes specimens. The size and form of the plastic zone are shown. The comparion between experiment and caculation is discussed as well as the application of the limit load analysis.

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DETERMINATION OF FRACTURE TOUGHNESS BY UNIAXIAL TENSILE TEST

  • Oh, Hung-Kuk
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1994.05a
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    • pp.2-7
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    • 1994
  • The dynamic fatigue life equation is applied to uniaxial tensile test. The resultant equations far the surface energy and fracture toughness are calculated with the data from the tensile test and compared with the ones from ASTM E399 test. During the crack propagation under model loading, the material of the crack tip undergoes the process of the elastic-plastic deformation in the uniaxial tensile test. The surface energy per unit area is proportional to the ratio of plastic and elastic elongations. The calculated fracture toughness of the metals are very well coincident to the ASTM E399's test results.

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An Experimental Study on the Evaluaiton of Elastic-Plastic Fracture Toughness under Mixed Mode I-II-III Loading Using the Optical PSD (PSD를 이용한 혼합모드 하중하에서 탄소성 파괴인성평가에 관한 실험적인 연구)

  • Kim, Hei-Song;Lee, Choon-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.1263-1274
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    • 1996
  • In this paper, as elastic-plastic fracture toughness test under mixed mode loading was proposed using a single edge-cracked specimen subjected to bending moment(M), shearing force(F), and twisting moment(T). The J-integral of a crack in the specimen is expressed in the form J=$J_I$+ $J_II$$J_III$, where $J_I$, $J_II$ and $J_III$ are the components of mode I, mode II and mode III deformation, respectively. $J_I$, $J_II$ and $J_III$ can be estimated from M-$\theta$ ($\theta$;crack opening angle), F-U(U; crack shear displacement) and T-$\alpha$ ($\alpha$;crack twisting angle). In order to obtain the the M<-TEX>$\theta$, F-U and T-$\alpha$ diagram inreal time, a new deformaiton gage for mixed mode loading was proposed using the optical position sensing device(PSD). The elastic-plastic fracture toughness test was carried out with an aluminum alloy. The loading apparatus was designed and manufactured for this experiment. For the loading condition of the crack initatio in the mixed mode, the MMT -3(mode I+ mode II+ mode III) has the lowest values out of the all specimens. This implies that MMT-3 is possible of the crackinitation at lower load, if the specimen acts on together with the torque under the same loading condition. An elastic-plastic fracture toughness test using the PSD brings a successful experimentation in measuring the crack deformation(mode I+ mode II+ mode III).