• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4647-4658
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• 2023

In this paper, elastic-plastic fracture mechanics analysis is performed to determine the critical crack sizes of the multipurpose canister (MPC) manufactured using austenitic stainless steel under dynamic loading conditions that simulate drop accidents. Firstly, dynamic finite element (FE) analysis is performed using Abaqus v.2018 with the KORAD (Korea Radioactive Waste Agency)-21 model under two drop accident conditions. Through the FE analysis, critical locations and through-thickness stress distributions in the MPC are identified, where the maximum plastic strain occurs during impact loadings. Then, the evaluation using the failure assessment diagram (FAD) is performed by postulating an external surface crack at the critical location to determine the critical crack depth. It is found that, for the drop cases considered in this paper, the principal failure mechanism for the circumferential surface crack is found to be the plastic collapse due to dominant high bending axial stress in the thickness. For axial cracks, the plastic collapse is also the dominant failure mechanism due to high membrane hoop stress, followed by the ductile tearing analysis. When incorporating the strain rate effect on yield strength and fracture toughness, the critical crack depth increases from 10 to 20%.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.314-317
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• 2004

The aim of this study was to evaluate the susceptibility from landslides in the Lai Chau region of Vietnam, using Geographic Information System (GIS) and remote sensing data, focusing on the relationship between tectonic fractures and landslides. Landslide locations were identified from an interpretation of aerial photographs and field surveys. Topographic and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS data and image processing techniques, and a scheme of the tectonic fracturing of the crust in the Lai Chau region was established. In this scheme, Lai Chau was identified as a region with low crustal fractures, with the grade of tectonic fracture having a close relationship with landslide occurrence. The factors found to influence landslide occurrence were: topographic slope, topographic aspect, topographic curvature, distance from drainage, lithology, distance from a tectonic fracture and land cover. Landslide prone areas were analyzed and mapped using the landslide occurrence factors employing the probability-likelihood ratio method. The results of the analysis were verified using landslide location data, and these showed a satisfactory agreement between the hazard map and existing landslide location data.

• Structural Engineering and Mechanics
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• 제33권5호
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• pp.543-560
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• 2009

The rotating Rayleigh-Timoshenko beam element based on B-spline wavelet on the interval (BSWI) is constructed to discrete short shaft and stiffness disc. The crack is represented by non-dimensional linear spring using linear fracture mechanics theory. The wavelet-based finite element model of rotor system is constructed to solve the first three natural frequencies functions of normalized crack location and depth. The normalized crack location, normalized crack depth and the first three natural frequencies are then employed as the training samples to achieve the neural networks for crack diagnosis. Measured natural frequencies are served as inputs of the trained neural networks and the normalized crack location and depth can be identified. The experimental results of fatigue crack in short shaft is also given.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.423-428
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• 2000

This Study was conducted to evaluate structural integrity and crack source location of RC structures strengthened with Carbon Fiber Reinforced Plates using acoustic, Four pont bending tests were carried out RC reinforced with C.F.R.P for the several strengthening specimens, the process of fracture was monitored by Acoustic Emission and duration and energy in AE parameters were analyzed. The location and propagation of crack could be easily determined by monitoring AE, which concluded that AE technique could be a very useful tool to evaluate structural integrity of reinforced RC structure.

• 한국공작기계학회논문집
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• 제15권5호
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• pp.104-113
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• 2006

The main objective of this study is to investigate the effect of compounded welding by using acoustic emission (AE) signals and doing a source location for weld heat affected zone (HAZ) through tensile testing. This study was carried out an SWS 490A high strength steel for electric shield metal arc welding, SMAW; $CO_2$ gas metal arc welding, GMAW($CO_2$); and gas tungsten arc welding, GTAW/TIG. Data displays are based on the measured parameters of the AE signals, along with environmental variables such as time and load. For instance, Gutenberg-Richter magnitude-frequency relationship (G-R MFR) offers useful b-value in data analysis. Namely event identification, source location gives the X- and Y-coordinates of the AE source. And K-means clustering analysis by Euclidean distance confirmed that was powerful to source location. Generally, strength of welded metal zone was stronger than strength of base metal. As the result, confirmed certainly that fracture is produced in HAZ instead of welded metal zone from source location.

• Journal of Korean Neurosurgical Society
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• 제59권4호
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• pp.368-373
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• 2016

Objective : Delayed hinge fracture (HF) that develops after cervical open door laminoplasty can be a source of postoperative complications such as axial pain. However, risk factors related to this complication remain unclear. We performed a retrospective clinical series to determine risk factors for delayed HF following plate-only open-door cervical laminoplasty. Methods : Patients who underwent plate-only open-door laminoplasty and had available postoperative computed tomography (CT) scans (80 patients with 270 laminae) were enrolled. Hinge status, hinge gutter location, open location, hinge width, number of screws used, operation level, and open angle were observed in the CT to determine radiographic outcome. Demographic data were collected as well. Radiographic and clinical parameters were analyzed using univariate and multivariate logistic regression analysis to determine the risk factors for HF. Results : Univariate logistic regression analysis results indicated poor initial hinge status, medially placed hinge gutter, double screw fixation on the elevated lamina, upper surgical level, and wide open angle as predictors for HF (p<0.05). Initial hinge status seemed to be the most powerful risk factor for HF (p=0.000) and thus was collinear with other variables. Therefore, multivariate logistic regression analysis was performed excluding initial hinge status, and the results indicated that medially placed hinge gutter, double screw fixation on the elevated lamina, and upper surgical level were risk factors for HF after adjustment for other confounding factors. Conclusion : To prevent HF and to draw a successful postoperative outcome after cervical laminoplasty, surgical and clinical precautions should be considered.

• Archives of Plastic Surgery
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• 제32권1호
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• pp.55-59
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• 2005

The proper management of the pediatric facial bone fracture is critical in the facial bone development. This study characterizes the surgically treated patient population suffering from facial bone fractures by the use of current data from a large series consisting of 201 cases. The data was gathered through a retrospective chart review of patients surgically treated for facial bone fractures at the department of plastic and reconstructive surgery, Sanggye Paik hospital, Inje university medical center, collected over 10-years period from January, 1993 to December, 2002. Data regarding patient demographics(age, sex), seasonal distribution, location of fractures, and the causes of injury with admission periods, were collected. In total, there were 201cases of pediatric facial bone fractures. Male patients outnumbered female patients by a 5.48: 1 ratio and were found to engage in a wider range of behaviors that resulted in facial bone fractures. Physical violence was the leading cause of pediatric facial bone fractures(27.9%), followed by sports-related mechanisms (22.9%) and falling down(17.9%). The most prevalent age group was 11-15 years-old(71.1%) and there was a 14.3% prevalence in March. Among the location of fractures, the nasal bone was the most prevalent, accounting for 82.3% of injuries, followed by the orbit(9.95%), and the mandible fractures(7.5%). Most patients(59.7%) were treated within 6-9 days after trauma and the mean hospitalization period was 8-11 days. We should follow up the surgically treated patients, and they will be further evaluated about postoperative sequele and effect on the facial bone development. These studies demonstrate differences in the demographics and clinical presentation that, if applied to patients, will enable a more accurate diagnosis and proper management.

• 비파괴검사학회지
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• 제19권1호
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• pp.25-33
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• 1999

콘크리트는 다상(multi-phase)의 재료로서 구성되어지는 복합재료의 일종으로써 준취성(quasi-brittle)적인 재료적 특성을 가지고 있기 때문에 실제 복잡한 미시적 파괴특성을 나타낸다. 따라서 콘크리트 구조물의 안전성 확보를 위해서는 먼저 하중의 증가에 따른 콘크리트 내부의 변형특성 및 미시적 파손기구를 파악하여야 하며, 특히 실제 구조물에 있어서는 이들 특성들을 비파괴적으로 상시 (on-line) 모니터링 하여야 할 필요가 있다. 따라서 본 연구에서는 3점 굽힘 하중을 받는 콘크리트 부재의 미시적 파손기구 및 각 파손기구에 대한 AE 특성을 명확히 함으로써 콘크리트 부재의 미시적 손상 및 파괴 특성을 비파괴적으로 평가하고 AE 발생원 위치 추정 기법을 이용하여 균열 발생 및 진전거동을 평가하였다.

• Archives of Plastic Surgery
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• 제40권6호
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• pp.721-727
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• 2013

Background One of the main concerns in orbital blowout fracture repair is a narrow operation field, due mainly to the innate complex three dimensions of the orbit; however, a deep location and extensive area of the fracture and soft tissue edema can also cause concern. Swelling of the orbital contents progresses as the operation continues. Mannitol has been used empirically in glaucoma, cerebral hemorrhage, and orbital compartment syndrome for decompression. The authors adopted mannitol for the control of intraorbital edema and pressure in orbital blowout fracture repair. Methods This prospective study included 108 consecutive patients who were treated for a pure blowout fracture from January 2007 to October 2012. For group I, mannitol was administered during the operation. Under general anesthesia, all patients underwent surgery by open reduction and insertion of an absorbable mesh implant. The authors compared postoperative complications, the reoperation rate, operation time, and surgical field improvement between the two groups. Results In patients who received intraoperative administration of mannitol, the reoperation rate and operation time were decreased; however, the difference was not statistically significant. The total postoperative complication rates did not differ. Panel assessment for the intraoperative surgical field video recordings showed significantly improved vision in group I. Conclusions For six years, mannitol proved itself an effective, reliable, and safe adjunctive drug in the repair of orbital blowout fractures. With its rapid onset and short duration of action, mannitol could be one of the best methods for obtaining a wider surgical field in blowout fracture defects.

• 대한정형외과학회지
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• 제56권2호
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• pp.150-156
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• 2021

목적: 제5 중족골 기저부 골절의 위치와 전위, 관절 침범, 분쇄 등의 특징이 조기 체중부하 치료의 결과에 어떤 영향을 미치는지 알아보고자 하였다. 대상 및 방법: 2013년 1월부터 2017년 7월까지 인제대학교 부산백병원에 내원하여 제5 중족골 기저부 제1, 2 구역 골절로 진단 받은 총 34명의 34예를 대상으로 하였다. 평균 추시 기간은 13개월(6-15개월)이었다. 동 기간 동안 수술적 치료를 시행한 경우는 없었고 1명의 경우 추시 기간 중 이전 골절 부위와 다른 부위의 재골절로 제외되었으며 총 33예 모두 보존적 치료를 시행하였다. 족부의 전후면, 측면 및 경사 방사선 촬영 및 컴퓨터 단층 촬영을 시행하여 골절의 위치와 전위, 관절 침범, 분쇄의 정도를 평가하였다. 33명의 모든 환자에게 있어서 수상 직후부터 단하지 석고고정 혹은 탈착 가능한 부츠형 보조기를 선택하여 착용 후 통증이 허용되는 범위 내에서 부분적인 체중부하를 허용한 뒤 통증이 소실되면 일반 신발 또는 수술 후 신발을 착용 후 전 체중부하를 시행하게 하였다. 임상적 결과로 최종 추시 시에 American Orthopedic Foot and Ankle Society (AOFAS) score를 평가하였다. 외래 추시 시 족부의 단순 방사선 촬영을 하여 방사선적 골유합 시기와 업무로의 복귀 시기를 확인하였다. 결과: 총 33명의 환자가 본 연구에 참여하였고(남자 9명, 여자 24명), 환자들의 평균 나이는 48.7세(16-80세)였다. 제1 구역이 24명, 제2 구역이 9명이었고 전체 33명의 환자 중 22명에서 2 mm 이상의 골절 전위가 관찰되었고 관절 침범은 9명, 분쇄 골절은 5명에서 관찰되었다. 제1 구역에서 제2 구역에 비하여 통계적 의미 있는 업무로의 복귀를 보였고 최종 추시 시 AOFAS score는 우수한 결과를 보였고 통계적 차이는 없었다. 골절의 전위 정도, 관절 침범 여부, 분쇄 정도를 분류, 비교하였을 때 방사선적 유합 시기, 업무 복귀 시기에 있어 통계적 차이는 없었으며 모든 경우에 있어 최종 추시 시 만족할 만한 결과를 보였다. 결론: 제5 중족골 기저부 골절에서 골절의 위치, 전위, 관절 침범, 분쇄 여부에 관계없이 조기 체중부하를 허용하여도 만족할 만한 임상적 결과를 얻을 수 있다. 제5 중족골 기저부 골절에서 조기 체중부하하 보존적 치료는 우수한 임상 결과를 얻을 수 있는 좋은 치료 방법이라 생각된다.