• Journal of Welding and Joining
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• v.21 no.1
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• pp.72-79
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• 2003

Fatigue behaviour of partially penetrated butt-welded joints in high strength steel plates, in which crack-like structural defect, i.e. lack of penetration(LOP), is inevitably introduced during welding processes, was investigated. Fatigue lives of two types of welded joints, namely X-grooved and K-grooved joints, were experimentally determined first. Observed fatigue crack propagation behaviours of the partially penetrated butt-welds were interpreted through considering 3-dimensional semi-elliptical crack shape in front of the LOP. Based on such interpretation, a fracture mechanical method to estimate stress intensity factors at the crack tip was proposed. Since the fatigue lift of the partially penetrated butt-welds was strongly influenced by the ratio of size of the LOP to thickness, D/t, the D/t was used as a main parameter to calculate the fatigue lift by using the proposed method. Comparison of the fatigue lift obtained experimentally and analytically agreed well with each other. Hence it is suggested that the method used in this work to predict fatigue lift of the partially penetrated butt-welds can be applied to real cases with improved lift-prediction capability.

• Journal of Chest Surgery
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• v.31 no.2
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• pp.190-193
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• 1998

We experienced a case of primary sternal tuberculosis with destroyed midsternum and bony defect. An 22-year-old female was admitted to our hospital two times for severe sternal pain and spontaneous fracture without history of trauma. On hospital admission, chest X-ray and chest CT showed destruction of midsternum and soft tissue swelling. Fine needle aspiration cytology revealed tuberculous osteomyelitis with cold abscess. And the patient was treated with usual anti-tubeculosis medication for preoperative preparation. At operation, we confirmed midsternal destruction with cold abscess and multiple sinus tracts. After removal of diseased sternal segment and cold abscess, we performed sternal reconstruction with autologus iliac bone graft. The pathologic report was compatible with tuberculous osteomyelitis and caseous necrosis The postoperative course was smooth and uneventful, and she remains well without sternal instability two months later.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2246-2251
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• 2000

Adhesive bonding repair methods has been used for a number of decades for construction of damaged structures. In order to evaluate the life of cracked aging aircraft structures, the repair technique which uses adhesively bonded boron/epoxy composite patches is being widely considered as a cost-effective and reliable method. But, this repair method contains many shortcomings. One of these shortcomings, debonding is major issue. When the adhesive shear stress increases, debonding is caused at the end of patch and plate interface. And this debonding is another defect except cracks propagation. In this paper, we assess safety at the cracked AI-plate repaired by Br/Epoxy composite patch. Firstly, from the view of fracture mechanics, reduction of stress intensity factors is determined by the variety of patch feature. Secondly, using the elastic analysis and finite element analysis, the distribution of adhesive shear stresses is acquired. Finally, The problem of how to optimize the geometric configurations of the patch has been discussed.

• Archives of Reconstructive Microsurgery
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• v.17 no.1
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• pp.7-13
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• 2008

Popliteal artery injury in blunt trauma of knee joint is not common but poses high rate of amputation due to anatomical characteristics or delayed diagnosis and treatment. The aim of the present study is to review the authors' experiences with this condition and identify factors contributing to disability. We reviewed 7 cases of popliteal artery injury in trauma around knee. Injury mechanism, type of vessel damage, associated injuries, mangled extremity severity scores (MESS), ischemic time and additional treatments were analyzed. Tibial fracture, distal femoral fracture and serious soft tissue defect were combined. Mean MESS was 9.9 point and mean time of revascularization was 7.1 hours. Transfemoral amputation was performed in 2 cases due to vascular insufficiency and devastating infection, and 4 patients were able to walk without any support at the last follow up. Age, the severity of soft tissue injury, ischemic time and MESS are thought to be related to prognosis, and young patients with short ischemic time show best results, but authors experienced one exceptional case. We have to consider multiple factors related to the prognosis in popliteal artery injury with fractures around knee, and careful decision is needed regarding to early amputation.

• Archives of Plastic Surgery
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• v.41 no.5
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• pp.480-485
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• 2014

Background The objective of this article is to evaluate clinical outcomes of combined orbital floor and medial wall fracture repair using a three-dimensional pre-bent titanium implant in an East Asian population. Methods Clinical and radiologic data were analyzed for 11 patients with concomitant orbital floor and medial wall fractures. A combined transcaruncular and inferior fornix approach with lateral canthotomy was used for the exposure of fractures. An appropriate three-dimensional preformed titanium implant was selected and inserted according to the characteristics of a given defect. Results Follow-up time ranged from 2 to 6 months (median, 4.07 months). All patients had a successful treatment outcome without any complications. Clinically significant enophthalmos was not observed after treatment. Conclusions Three-dimensional pre-bent titanium implants are appropriate for use in the East Asian population, with a high success rate of anatomic restoration of the orbital volume and prevention of enophthalmos in combined orbital floor and medial wall fracture cases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.5
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• pp.353-357
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• 2020

Fractures of the orbital floor and walls are among the most frequent maxillofacial fractures. Virtual three-dimensional (3D) planning and use of patient-specific implants (PSIs) could improve anatomic and functional outcomes in orbital reconstruction surgery. The presented case was a victim of a terrorist attack involving improvised explosive devices. This 58-year-old female suffered severe wounds caused by a single piece of metal from a bomb, shattering the left orbital floor and lateral orbital wall. Due to remaining hypotropia of the left eye compared to the right eye, late orbital floor reconstruction was carried out with a personalised 3D printed titanium implant. We concluded that this technique with PSI appears to be a viable method to correct complex orbital floor defects. Our research group noted good aesthetic and functional results one year after surgery. Due to the complexity of the surgery for a major bony defect of the orbital floor, it is important that the surgery be executed by experienced surgeons in the field of maxillofacial traumatology.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.447-450
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• 2023

Traumatic abdominal wall hernia is a rare presentation, most commonly reported in the context of motor vehicle accidents and associated with blunt abdominal injuries and handlebar injuries in the pediatric population. A 13-year-old boy presented with multiple traumatic injuries and hemodynamic instability after a high-speed motor vehicle accident. His injuries consisted of massive traumatic abdominal wall hernia (grade 4) with bowel injury and perforation, blunt aortic injury, a Chance fracture, hemopneumothorax, and a humeral shaft fracture. Initial surgical management included partial resection of the terminal ileum, sigmoid colon, and descending colon. Laparostomy was managed with negative pressure wound therapy. The patient underwent skin-only primary closure of the abdominal wall and required multiple returns to theatre for debridement, dressing changes, and repair of other injuries. Various surgical management options for abdominal wall closure were considered. In total, he underwent 36 procedures. The multiple injuries had competing management aims, which required close collaboration between specialist clinicians to form an individualized management plan. The severity and complexity of this injury was of a scale not previously experienced by many clinicians and benefited from intrahospital and interhospital specialist collaboration. The ideal aim of primary surgical repair was not possible in this case of a giant abdominal wall defect.

• Journal of Welding and Joining
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• v.13 no.2
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• pp.42-52
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• 1995

In the evaluation of aging degradation on the structural materials based on the fracture mechanics, the detection and size prediction of defect are very important. Aiming at nondestructive detection and size prediction ol defect with high accuracy and resolution, therefore, an lnduced Current Focusing Potential Drop(ICFPD) technique has been developed. The principle of this technique is to induce a focusing current at an exploratory region by an induction wire flowing an alternating current(AC) that is a constant ampere and frequency. Defects are assessed with the potential drops that are measured the induced current on the surface of metallic material by the potential pick-up pins. In this study, the lCFPD technique was applied for evaluating the location and size of the surface crack and blind crack made in plate specimens, and also for detecting the defects existing in valve, a field component, that were developed by SCC etc. during the service. The results of this present study show that surface crack and blind crack are able to defect with potential drop. these cracks are distinguished with the distribution of potential drop, and the crack depths can be estimated with each normalized potential drop that are parameters estimating the depth of each type crack. In the field component, the defects estimated by experiment result correspond with those in the cutting face of the measuring point within a higher sensitivity.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.553-569
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• 2000

Many natural medicines have been studied for their capacity and effects of antibacterial, anti-inflammatory and regenerative potential in periodontal tissues. Safflower seed has been traditionally used as a drug for treatment of bone fracture in oriental medicine. The purpose of the present study was to compare the effects of safflower seed extract and bone substitute on bone formation and regeneration in artificial defects in mongrel dogs. The bony defects were made with round bur at mandible and tibia. Extracts of safflower seed and bovine bone were placed directly at each defect for experimental group, and the defect of control group was sutured without any other treatment. Experimental animals were sacrificed at 8 weeks. And then histopathologic reading and histomorphometric study was done. There was not significant differences between control and experimental groups in osteoclastic activity and infiltration of inflammatory cells. However, new capillary proliferation, fibrosis and new bone formation were prominent in safflower seed extract group. The mandibular defects of safflower seed extract group were healed with dense connective and bony tissues, and endochondral bone formation was observed in tibial defect of safflower seed extract group only. New bone area of safflower seed extract group was more significantly increased than that of control and that of bone substitute group. These results indicate that direct local application of safflower seed extracts on bony defects seems to reduces the early inflammatory response and to promotes the bone regeneration.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1078-1085
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• 2011

Prediction of a minimum crack size for growth, which is defined as a crack size that grows fast enough to keep ahead of its removal by contact wear and periodic grinding, is the most demanding work to prevent rail from fatigue failure and develop cost effective railway maintenance strategy In this study, we investigated the wheel load increment due to a rail defect during a train ran over it, and its effect on the minimum crack size for growth. For this purpose, we developed simulation software based on the Fletcher and Kapoor's "2.5D" model and measured wheel load increment during a train passed over a defect. A maximum contact pressure and contact patch size were calculated by 3D FEM and crack growth analyses were performed by varying two of dominant contact contributors; surface friction coefficient(0.1, 0.2, 0.3 and 0.4) and crack aspect ratio. The minimum crack sizes for growth were calculated from 0.29 to 1.44mm depending on the contact conditions. They were decreasing with increasing surface friction coefficient and decreasing with crack aspect ratio(a/b).