• Journal of Advanced Marine Engineering and Technology
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• 제12권3호
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• pp.57-67
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• 1988

Although handicapped by the inability to bridge the size gap between small laboratory sample and large engineering component, the V charpy test sample method does possess certain advantages, such as each of preparation, simplicity of test method, speed, low cost in test machinery, and low cost per test. On the other hand, the COD test method does posses advantages, which reduce the size gap between the laboratory sample and actual engineering component. Consequently, the correlation between V charpy absorbed energy and the critical COD value is required for estimating critical COD value from the simple V charpy test results. In this paper, the high tensile strength steel AH36 plate specimens having a single edge cracked notch were investigated to find out the correlation between V charpy absorbed energy and critical COD value in the welded parts under such various welding methods as shielded metal arc welding, the submerged arc welding and the electro gas welding by means of V charpy impact test and static 3-point bending test. Main results obtained are as follow ; 1. The relationships between V charpy absorbed energy Wc' and critical COD value ($\delta_c$)show; $\delta_c$=0.0065 Wc'+0.1906. 2. Ductile- brittle transition behaviours can be estimated by means of fracture appearance and general yielding behaviours. 3. The V charpy absorbed energy of SMAW is higher than that of SAW, EGW and similar relationships are obtained in the COD tests.

• Nuclear Engineering and Technology
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• 제19권1호
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• pp.1-9
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• 1987

원자로 압력용기 재료인 SA 533 Grade B Class 1강의 파괴인성에 대하여 -4$0^{\circ}C$~288$^{\circ}C$의 온도 구간에서 Charpy 충격시편을 이용하여 연구하였다. 동적 파괴인성은 계장화 충격시험으로, 정적 파괴인성은 unloading compliance 방법에 따라 3-point bend test로 수행되었으며, 결과는 큰 시편에 의한 자료와 비교하였다. 온도에 대한 재료의 적절한 파괴인성치(하한값)는 천이온도 이상에서는 정직 파괴인성을, 그 이하의 온도에서는 동적 파괴인성을 택함으로써 유추할 수 있음을 알게 되었으며 side-groove가 14%이상일 때 시험은 ASTM E 813의 조건을 만족함을 보였다.

• 한국강구조학회 논문집
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• 제23권4호
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• pp.483-491
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• 2011

본 연구에서는 구조용강재의 샤르피 충격시험(Charpy Impact Test)을 통해 저온에서의 충격 인성(Impact Toughness) 평가를 실시하여 사용 가능 온도를 파악함으로써 강재의 극한지 적용성을 검토하였다. 본 시험에 사용된 강재는 용접구조용강 중 현재 가장 널리 쓰이는 강종인 SM490B와 TMCP (Thermo-Mechanical Control Process)법에 의해 제조된 고강도 강재인 SM570-TMC이다. 또한, 본 시험결과와의 비교를 위해 남극 세종기지 건설시 사용실적이 있는 일반구조용강인 SS400에 대해서도 시험을 수행하였다. 대부분의 강구조물은 용접에 의해 제작되므로, 강재의 극한지 적용성 검토를 위해 용접시험판을 제작하여 모재(Base Metal), 용접금속(Weld Metal) 및 열양향부(Heat Affected Zone)에 대해서 충격시험을 실시하였다. 단, SS400의 경우에는 용접구조용강재가 아니므로 모재에 대해서 충격시험을 실시하였다. 대상 강재의 샤르피 충격시험을 통해서 저온에서의 충격흡수에너지 값을 구하고 이를 강재의 항복응력에 따른 충격흡수에너지의 기준값과 비교함으로써 강재의 사용온도를 결정하였으며, 이를 통해서 구조용강재의 극한지 적용성을 검토하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.706-711
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• 2007

Numerical studies were performed to examine the effects of notch location of impact specimens on the failure behavior of HAZ (heat affected zone) when Charpy V-notch impact test were made at a low temperature ($1^{\circ}C$). Carbon steel plate (SA-516 Gr. 70) with thickness of 25mm for pressure vessel was welded by SMAW (shielded metal-arc welding) and specimens were fabricated from the welded plate. Charpy tests were then performed with specimens having different notch positions of specimens varying from the fusion line through HAZ to base metal. A series of finite element analysis which simulates the Charpy test and crack propagation initiating at the tip of V-notch was carried out as well. The finite element analysis takes into account the irregular fusion line and non-homogenous material properties due to the notch location of the specimen in HAZ. Results reveals that the energies absorbed during impact test depend significantly on the notch location and direction of specimen. Finite element analysis also demonstrates that the notch location of specimens, to a great extent, influences the reliability and consistency of the test.

• 한국안전학회지
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• 제16권4호
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• pp.39-46
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• 2001

It is noted that KS D 3507 pipe steel has several problems when it is used as a city gas pipe at medium pressure. So new pipe steel, KS D 3631, was developed in order to be used as a pipe for medium and low pressure and now it is being substituted for D 3507. In this study, several mechanical tests, such as tensile test, microhardness test, and Charpy impact test were conducted to get material properties of D 3507 and D 3631 pipe steels. And also microstructures at the weld and heat affected zones were observed for the two materials. From the Charpy test results $K_{IC}/$ was estimated for the upper and lower shelf and the critical crack length is calculated for supposed axial semi-elliptical surface cracks. And the burst pressure is estimated as a function of wear depth for a defective D 3631 pipe by using the finite element method. The burst pressure is also calculated for pipes with an axial crack by using the published equations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.101-106
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• 2003

In order to investigate the mechanical behavior of newly developed materials, the evaluation of mechanical properties using small-size specimen is essential. For those purposes, an instrumented impact testing apparatus, which provides the load-displacement curve under impact loading without oscillations, was devised. To develop the test procedure with the setup, the impact behaviors of various kinds of structural materials such as S45C, SCM4, Ti alloys (Ti-6V-4Al) and Zr-based bulk amorphous metal, were investigated through the instrumented Charpy V-notch impact tests. The calibrations of the dynamic load and displacement that was calculated based on the Newton' second law were carried out through the quasi-static load test and the comparison of a directly measured value using a laser displacement meter. Satisfactory results could be obtained. The crack initiation and propagation processes during impact fracture could be well divided on the curve, depending on the intrinsic characteristic of specimen tested; ductile or brittle. The absorbed impact energy in Zr-basd BAM was largely used for crack initiation not for crack propagation process. The fracture surfaces under impact loading showed different feature when compared with the static cases.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1520-1526
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• 2002

The Charpy and Izod impact tests are the most prevalent techniques used to characterize the effects of high impulse loads on ploymeric materials. An analysis method for rubber toughened PVC is suggested to evaluate critical dynamic strain energy release rates(G$\_$c/) from the Charpy impact energy measurements. An instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture energies and maximum critical loads. The dynamic stress intensity factor Kid was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well.

• 한국가스학회지
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• 제12권1호
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• pp.1-6
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• 2008

샤피충격시험은 동적하중 하에 있는 고분자 재료의 거동을 이해하는데 가장 널리 사용되고 있는 방법이다. 본 연구에서는 샤피충격시험장치에서 얻어지는 파단에너지를 사용하여 나일론 소재 샤피 시편의 노치각도에 따른 에너지 해방율을 구하는 방법을 제시하였다. 또한 샤피충격시험장치를 계장화하여 최대 하중과 파단 시까지 소요되는 에너지 등의 파손인자들을 산출하였다. 그리고 노치각도에 따른 동적파괴 인성치와 유한요소법을 사용하여 중앙집중 하중 하에서 사피 시편의 노치각도에 따른 응력분포를 산출하였다.

• 대한토목학회논문집
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• 제14권6호
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• pp.1319-1327
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• 1994

레일강에 있어서 피로균열은 레일의 파괴와 그에 따른 열차탈선의 근본적인 요인으로서 실험실시험의 분석 결과에 의한 피로거동 및 파괴특성의 정량적 평가는 피로수명 추정 및 안전조사 주기설정의 기본이 된다. 따라서 본 연구에서는 살피충격시험의 결과로부터 레일강의 샬피거동 및 파괴인성거동을 평가하고 일정진폭하중하에서 피로시험의 분석 결과로부터 피로균열성장거동에 미치는 균열의 방향성, 온도, 그리고 응력비 R의 효과를 파괴역학적 수법을 도입하여 평가하였다.

• Journal of Welding and Joining
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• 제26권3호
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• pp.37-44
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• 2008

Charpy V-Notch test is commonly used to evaluate fracture toughness. However, since the region to be evaluated is limited to bulk material due to the specimen size required, individual evaluation of micro-structures on weldment is very difficult. In this study, ASP(Advanced Small Punch) test was carried out to evaluate material degradation and fracture toughness on the B.M, W.M and each micro-structures of HAZ for X20CrMoV121 and 2.25Cr1Mo steels with artificial aging time. In addition, to evaluate fracture toughness and material degradation of B.M and W.M of X20CrMoV121 steels with aging times, CVN (Charpy V-notch) test was performed. And then the correlation between ASP and CVN test on X20CrMoV121 steels was obtained. Furthermore, through this correlation, material degradation property of each micro-region of the HAZ in weldment, which was impossible to be evaluated by the CVN test, can be estimated and determined.