• Title/Summary/Keyword: CT 시험편

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Fracture Study due to Various Core at Compact Tension Specimen Made of Carbon Fiber Reinforced Plastic (탄소성유강화플라스틱으로 만들어진 소형 인장 시험편에서 여러 종류의 심재에 따른 파손 연구)

  • Kim, Jae-Won;Cho, Jae-Ung
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.8 no.3
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    • pp.589-596
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    • 2018
  • Transportation or structure has the important role at clothing, food, and housing at modern society. If even the small crack happens and propagates at transportation or structure, the parts are fractured and they can cause a disaster. CT specimen was used in order to investigate the damage trend due to the crack propagation at this study to prevent this situation. As the material of CT specimen, the unidirectional carbon fiber reinforced plastic of the composite material in the limelight nowadays. The laminate angle designated in order of [60/-60/60/-60] was applied to the specimen model with the unidirectional fiber. As the analysis condition, the forced displacement was applied to the hole of upper part after fixing the hole of lower part. At the result of this study, the equivalent stress and shear stress was shown to be higher in order of the structural steel, copper, titanium and aluminum. This study result is thought to be utilized usefully at verifying the damage of CT specimen made of inhomogeneous material.

An Analytical Study on Crack Behavior Inside Standard Compact Tension Specimen with Holes (구멍들을 가진 표준 CT 시험편 내에서의 크랙 거동에 대한 해석적 연구)

  • Lee, Jung Ho;Cho, Jae Ung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.6
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    • pp.531-537
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    • 2016
  • The damage and fracture of machine or structure are caused by the crack happened from the defect existed at the inside of material. The properties of crack propagation and growth characteristic must be considered because there are many cases at which these cracks are densely existed. Therefore, this study investigates the fracture property due to the position of crack and hole inside the standard compact tension (C. T.) specimen. When the concentrated load is applied eccentrically at the standard C. T. specimen, the fracture mechanical behavior due to the existence or non-existence and the position of hole near crack is investigated. As the result of analysis study, model 3 (in case of the distance of 2mm on the horizontal direction between the end part and hole as the specimen model existed with one hole near the crack) has the maximum deformation, stress and deformation energy of the most values among three models. As the distance between the crack and hole inside the specimen becomes nearer, the maximum stress becomes higher in cases of three models. Apart from the number of holes, it is seen that the maximum stress becomes higher near the crack when the hole exists near the crack inside the specimen. If the hole inside the machine or the mechanical structure is punctured by using the result of this study, it is thought that the occurred breakage or breakdown can be prevented by reducing the fracture stress happened at the specimen.

JIC Evaluation of the Smooth and the Side-Grooved CT Specimens in the Reactor Pressure Vessel Steel(SA508-3) (원자력압력용기강 (SA508-3)의 평활 및 측면홈 CT시험편을 이용한 J$_{IC}$ 평가)

  • Oh, Sae-Wook
    • Journal of Ocean Engineering and Technology
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    • v.8 no.2
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    • pp.173-184
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    • 1994
  • 원자력 압력용기강의 탄소성 파괴인성값 $J_IC$를 CT형 시험편을 이용하여 검토하였으며, 평활 시험편 및 측면홈 시험편의 두께는 각각 $B_O$=25.4mm, $B_N$=20.4mm 이다. 측면홈의 깊이는 19.7% 이며, 홈의 각도는 90 .deg.로 가공하였다. 탄소성 파괴인성시험은 ASTM E813-81과 JSME S001-81의 추천방법에 따라 실시하였다. 두 추천방법으로 실험한 결과 ASTM 방법에 의한 $J_IC$값이 과대평가됨으로써 부대조건에 만족되지 못하였지만 JSME방법은 만족되었다. 측면홈 시험편은 R고선법에 의한 ductile tearing의 결정이 평활 시험편보다 용이하였으며, 이에 따른 $J_IC$값의 정확성을 배가 할 수 있었다. 또한 임계 스트레치존 폭($SZW_C$)은 측면홈에 의한 높은 3축응력이 발생되어 평활시험편보다 적게 나타났으며, 이러한 복합적인 원인에 기인하여 스트레치존법에 의한 $J_IC$평가는 R곡선법에 의한 평가보다 약간 과대평가됨을 알 수 있었다.

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Estimation of the Fracture Resistance Curve for the Nuclear Piping Using the Standard Compact Tension Specimen (표준 CT시험편을 이용한 실배관 파괴저항 곡선 예측)

  • Park, Hong-Sun;Heo, Yong;Koo, Jae-Mean;Seok, Chang-Sung;Park, Jae-Sil;Cho, Sung-Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.9
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    • pp.930-937
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    • 2009
  • The estimation method of the fracture resistance curve for the pipe specimen was proposed using the load ratio method for the standard specimen. For this, the calculation method of the load - CMOD curve for the pipe specimen with the common format equation(CFE) was proposed by using data of the CT specimen. The proposed method agreed well with experimental data. The J-integral value and the crack extension were calculated from the estimated load - CMOD data. The fracture resistance curve was estimated from the calculated J-integral and the crack extension. From these results, it have been seen that the proposed method is reliable to estimate the J-R curve of the pipe specimen.

Effect of Specimen Orientation on Fatigue Crack Growth Behavior in Friction Stir Welded Al7075-T651 Joints (마찰교반용접된 Al7075-T651 용접부의 피로균열전파 거동에 미치는 시험편 채취방향의 영향)

  • Jeong, Yeui Han;Kim, Seon Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1317-1323
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    • 2014
  • The aim of this paper is to investigate the effects of crack orientation on fatigue crack growth behavior in friction stir welded (FSWed) Al 7075-T651. Fatigue crack growth testing was conducted on compact tension (CT) specimens machined from the friction stir welds and the base metal under constant stress intensity factor range control. Tests were performed with the crack propagating nominally perpendicular to the weld line (termed the TL specimen) and the crack propagating in a parallel direction of the weld line (termed the LT specimen), and with three different constant stress intensity factor ranges. Both these specimen orientations were found to have a considerable effect on the fatigue crack growth behavior. Paris's law was adopted for the analysis of experimental results; the exponent m of the WM-LT specimen was determined to be 3.56, which was the largest value in this experimental conditions.

Measurement of Stress Intensity Factor Using Strain Gage Methods (스트레인게이지법을 이용한 응력확대계수 측정)

  • 김재훈;문순일;이현철;김덕희
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.1
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    • pp.53-64
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    • 2000
  • Strain gage method is investigated to evaluate the mode I stress intensity factor. Two types of specimens for CT and three point bend specimen are used. Sharp notch of specimens is manufactured by wiring discharge machining. Strain gages signal from the crack tip region are used to calculate stress intensity factors. The results are compared with those of the ASTM E399 method and finite element analysis. The present experimental results coincide well with the data obtained from finite element analysis. Attached position of strain gage should be seriously considered during the application of this method.

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$J_{IC}$ Evaluation of Smooth and Side-Grooved CT Specimens in Structural Steel SB 41 (SB41 강의 평골 및 측면홈 CT시험편의 $J_{IC}$평가)

  • 오세욱;안광주;윤영재
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.4
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    • pp.494-503
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    • 1986
  • 본 연구에서는 저강도.고연성재인 일반구조용압연강 SB41의 평골 CT 시험편과 양측면홈이 있는 CT시험편을 사용하여 ASTM R유선법, JSME R유선법,SZW법, 초음파법 및 전입차법에 따라 J$_{IC}$를 종합적으로 평가하였다. 복수시험편법인 ASTM 및 JSME 및 JSME R유선법을 상호 비교고찰하므로써 저강도.고연성재에 대한 파환인성평가 의 적용한계를 명확히 하였으며 단일시험편법인 초음파 및 전입차시험법은 효율적이고 간편한 J$_{IC}$평가법임을 확인하였다.

Evaluation of Shape Parameter Effect on the J-R Curve of Curved CT Specimen Using Limit Load Method (한계하중법을 이용한 Curved CT 시험편의 파괴저항곡선에 미치는 형상변수 영향 평가)

  • Shin, In Hwan;Park, Chi Yong;Seok, Chang Sung;Koo, Jae Mean
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.7
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    • pp.757-764
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    • 2014
  • In this study, the effect of shape parameters on the J-R curves of curved CT specimens was evaluated using the limit load method. Fracture toughness tests considering the shape factors L/W and $R_m/t$ of the specimens were also performed. Thereafter, the J-R curves of the curved CT specimens were compared using the J-integral equation proposed in the ASTM (American Society for Testing and Materials) and limit load solution. The J-R curves of the curved CT specimens were also compared with those of the CWP (curved wide plate), which is regarded to be similar to real pipe and standard specimens. Finally, the effectiveness of the J-R curve of each curved CT specimen was evaluated. The results of this study can be used for assessing the applicability of curved CT specimens in the accurate evaluation of the fracture toughness of real pipes.

A Study on Evaluation of J$_{IC}$ for SB41 Steel with Measured Bluntion Line (실측 둔화직선을 이용한 SB41 강의 J$_{IC}$평가에 관한 연구)

  • 허정원;오세욱;유재환;김득진;차재준
    • Journal of Ocean Engineering and Technology
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    • v.8 no.2
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    • pp.38-46
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    • 1994
  • The method of JSME S001-83 and ASTM E813-87 have been adapted for evaluation of the elastic-plastic fracture toughness J sub(IC) of SB41 steel. This SB41 steel have the characteristics of low-stength CT specimens. The test results obtained have been considered and compared on the basis of resulted data from two kinds of methods(JSME S001-83, ASTM E813-87) and two kinds of specimen configurations(smooth, side-grooved). On the basis of results from consideration and comparison, the difficulties for its application were presented in case when the standard ASTM E813-87 method was employed for the measurement of J sub(IC) in SB41 steel. A modified method was applied for measuring J sub(IC) in SB41 steel that it used the blunting line real-measured by experiment instead of the standard blunting line theoretically determined, and the result from that procedure was analyzed and the usefulness of that method was examined and considered.

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