• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.230-238
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• 2018

Purpose: Metacarpal fractures are common injuries of the hand. They are treated using closed reduction (CR) or open reduction (OR) techniques. The management strategy depends on fracture site characteristic and fixation methods. In this study, we evaluated pre- and postoperative fracture angulation, when metacarpal fractures bad been treated using two different techniques: CR with parallel transverse pinning and OR with plate fixation. Methods: Forty-six patients undergoing anatomic reduction to treat extra-articular metacarpal fractures were recruited. They were included in one of two therapeutic groups: Group 1, CR with parallel transverse pinning (n=21); Group 2, OR with plate fixation (n=25). Fracture angulation values have been measured on pre- and postoperative radiologic images. Values were compared between pre- and postoperative states, and between corresponding measurements of each group. Results: All extra-articular metacarpal fractures were successfully treated without wound related complications or the limit of joint motion. Both groups demonstrated adequate reduction at immediate postoperative period (postoperative angulation of group 1, $20^{\circ}{\pm}7^{\circ}$; group 2, $19^{\circ}{\pm}5^{\circ}$). During the observation at follow-up period, Group 1 exhibited slight recurrence (follow-up angulation of group 1, $24^{\circ}{\pm}10^{\circ}$). Nonetheless, Group 2 showed adequate reduction state in both immediate postoperative and long-term follow-up periods (follow-up angulation of group 2, $18^{\circ}{\pm}6^{\circ}$). Conclusion: Extra-articular metacarpal fractures were successfully restored without functional complications. CR with parallel transverse pinning method exhibited recurrence after pin removal, which necessitates cautious postoperative exercise and monitoring.

• Journal of Korean Foot and Ankle Society
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• v.19 no.4
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• pp.151-155
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• 2015

Purpose: The purpose of this study was to analyze the frequency and patterns of intra-articular lesions detected during ankle fracture surgery using ankle arthroscopy. Materials and Methods: Thirty patients (31 ankles) who underwent open reduction and internal fixation combined with ankle arthroscopy for acute ankle fracture at Inje University Busan Paik Hospital from June 2011 to September 2013 were evaluated. The ankle fractures were classified according to the AO/OTA (AO Foundation and Orthopaedic Trauma Association) classification and the intraarticular injuries were identified by ankle arthroscopy. Osteochondral lesions of the talus were divided into nine subtypes based on their locations, and the ligament injuries were classified according to avulsion fracture and rupture. Results: Using arthroscopy, abnormality in the distal tibiofibular ligament was found in 21 cases and osteochondral lesions and defects of the talus larger than 5 mm were detected in 26 cases. Among ligament injuries, anterior inferior tibio-fibular ligament injury was found in 14 cases, posterior inferior tibio-fibular ligament injury was found in two cases, deep deltoid ligament injury was found in three cases, and deep transverse tibio-fibular ligament injury was found in five cases. The locations of the osteochondral lesions were on the antero-lateral, antero-medial, centro-medial, centro-central, centro-lateral, and postero-lateral talus in 11, one, two, one, two, and nine cases, respectively. Conclusion: With early diagnosis and treatment arthroscopy performed at the time of intra-articular fracture surgery is expected to result in a good outcome.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.461-465
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• 2007

Purpose: Nasal bone fracture may be the most common fracture among facial trauma. However, diagnosis and treatment tend to be overlooked while the reduction and maintenance of fragments remain complicated. Thus, the results are plagued with high rate of nasal deformity which leads cosmetic and functional discomfort. We took advantage of the fact that the nasal bone is one of the thinnest facial bone while at the same time being located close to the skin and utilized ultrasound in performing reduction of nasal bone. Methods:This method was performed on 25 patients with nasal bone fracture. The CL 15-7 linear array transducer (10-15MHz) ultrasound which provides a total of 7 views (3 axial views and 4 transverse views) of the elevator under the bony fragments was enough for the surgeon to accurately perform the reduction. Results: In our class, an accurate and precise reduction has been made possible by real time images before, during, and after the procedure with the help of ultrasound while reducing the exposure to radiation. Conclusion: Compared to previous methods, satisfaction of patients has increased in the nasal tip, minimal fracture of the side wall and secondary reduction cases. Therefore, the incorporation of ultrasound in the closed reduction of nasal bone may prove to be a useful method.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.157-165
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• 2019

Recently, lean duplex stainless steel, STS329FLD with less nickel (reduced to 0.5~1.5%) has been developed as a substitute of austenitic stainless steel (8%~10.5% nickel in STS304) and included in Korean standards (KS). This paper investigates the block shear behavior of cold-formed duplex stainless steel (STS329FLD, nominal plate thickness of 1.5mm) fillet-welded connection with base metal fracture. Main variables are weld lengths in the longitudinal and the transverse directions of applied force ranged from 20mm to 50mm. As a result, specimens failed by typical block shear facture (the combination of gross section tensile fracture and shear fracture or shear yielding) and ultimate strength of the specimens got higher with the increase of weld length. Block shear fracture strengths predicted by current design specifications (KBC2016/AISC2016 and EC3) and existing proposed equations for welded connections by Topkaya, Oosterhof & Driver and Lee et al. were compared with test strengths. KBC2016/AISC2016 and EC3 design specifications underestimated block shear strength of STS329FLD welded connections by on average 24%, 29%, respectively and Oosterhof & Driver, Topkaya and Lee et al's equations overestimated the ultimate strength of the welded connection by the range of 3% to 44%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.25-32
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• 1989

A finite element program for material nonlinear fracture analysis of reinforced concrete shell was developed. This method can be used to trace the load-displacement response and crack propagation through the elastic and inelastic ranges. A layered isoparametric flat finite element considering the coupling effect between the in-plane and the bending action was developed. Mindlin plate theory taking account of transverse shear deformation was used. The validity of the present program was proved by comparing the numerical results with Hedgren's experimental data.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.3
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• pp.31-39
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• 1996

The objective of this study is to investigate the influence of welding residual stresses on the fatigue crack growth behavior of cracks located transverse to the weld bead. For this purpose, G. T. A (Gas Tungsten Arc) welding was performed on hte Al alloy 1100-O plate and the same initial crack is made on HAZ(Heat Affected Zone), weld metal and base meta respectively. Specimens were used CT(Compact Tension) specimens. Initial welding residual stresses were measured by using strai gage sectioning method. All specimens were tested under constant amplitude load with stress ratio R=0.1, It is possible to predict fatigue crack growth behaviors and the fatigue life, using numerical analysis together with distribution of initial residual stress and the values of C and m obtained from $da/dN-{\Delta}K$

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1218-1222
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• 2006

The bolts fixing the valve cover to the engine were often reported to be failed in a wheel loader model. Recently this failures were continually repeated in the specified equipment. In order to identify the fatigue fractures of the bolts, various vibration tests were carried out. From these tests, it was found out that the failure was due to the resonance between the excitation force of engine and the transverse mode of engine valve cover. So, the several modifications for the bolts were considered to avoid the resonance. Finally, the bolt failure problem was clearly resolved.

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.189-191
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• 2001

This study introduces the new way for the evaluation criteria of the Mash-Seam Tailored Blank weldability, The materials used are low carbon automotive galvanized and high strength steels and the evaluation of weldability are examined with various thickness. Welding tests were conducted for both similar thickness and dissimilar thickness cases. The criteria developed for optimum welding conditions were based on the relationship among results of die press forming test, weld transverse tensile test, Erichsen test and microhardness measurements. The application of the developed criteria(fracture ratio, strength ratio, etc) in obtaining optimum welding condition revealed that a weld which satisfied ant of the criteria did not fracture during actual die press test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.4
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• pp.141-148
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• 2000

Recently the Carbon Fiber Sheet(CFS) is widely used for strengthening damaged RC structures. Strengthening compression members such as column can increase ductility and strength due to the confinement effect. In this experiment, the behavior of concrete cylinders confined by CFS was examined. The confinement pressure is increased linearly as axial stress is increased in low axial stress, and the confinement effect of CFS was rapidly developed after near maximum axial stress, thus axial strength and ductility was improved. As the ratio of CPS is increased, concrete cylinders failed due to local fracture of CFS. The confinement effect of circular section is more efficient than that of rectangular section. And significant improvement of axial strength, axial strain, transverse strain at failure is observed in circular section. This is because in rectangular section the local fracture of CFS near corner may be occured, thus the strain efficiency ratio must be considered for RC structures with CFS.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.6
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• pp.68-74
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• 2002

This research covers the development of axi-symmetric plastic elements for injection molding with insert steel such as high stiffness Sabot. The functional requirements of sabot are concentricity and fracture resistance about vertical and horizontal forces. For these, an analysis of characteristics of PEI(polyetherimide) polymer is performed by standard test specimen with accordance of ASTM test guidance. Moldflow analysis and simulation of injection molding process are carried out in order not only to estimate of the warpage but also to predict the characteristics of residual stresses which both product and structure of mold may have. A new vertical side injection machine and transverse mold have been constructed. Results of the measuring concentricity and fracture test after molding of sabot are satisfied to design specification over Cp $ratio{\geq}1.33$. Finally, this technique needs more research application to others axi-symmetric elements having different radius with insert steel md structure analysis from now on.