• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1813-1819
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• 2001

Partial penetration welding Joint defines that groove welds without steel backing, welded from on side, and groove weeds welded from both sides but without back gouging, that is. it has an unwelded portion at the root of the weld. In this study we analysed fur residual stress and displacement distribution on partial penetration welding condition of thick plate metal. For 25.4mm thick plate, theoretical residual stress and displacement analysis by finite element method using ABAQUS was carried out and compared with the experimental result using hole-drilling method. In results of the condition of partial penetration, it appeared that longitudinal stress at welding area was a little difference and transverse stress did not have any effect by partial penetration multi-pass welding. From a point of welding distortion in partial penetration multi-pass welding, it seemed to be better to control root face smaller than 6.35mm.

• Journal of Power System Engineering
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• v.16 no.4
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• pp.66-73
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• 2012

본 연구는 횡방향 TIG 용접된 Al6013-T4 알루미늄 합금 용접부의 피로균열전파거동에 미치는 용접후열처리(PWHT)의 영향을 조사하는 것이 주목적이다. 기초적으로 인장시험, 경도 및 미세조직이 조사되었으며, 피로균열전파거동을 고찰하기 위한 피로 시험은 모두 중앙균열인장(CCT) 시험편에 대하여 수행되었다. T82열처리에 있어서 시효시간은 피로균열전파율, 인장강도 및 경도에 대단히 민감함을 나타내었으며, 모재와 열영향부재의 경우가 용접재보다 기계적 성질이 우수하였다. 횡방향 TIG 용접한 Al6013-T4 시험재의 용접후열처리 조건에 따라서 피로균열전파 저항에는 차이가 나타났으며, 본 실험의 조건하에서 24시간 인공시효 PWHT-82 시험편이 피로균열전파 저항이 가장 우수한 결과를 나타내었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.249-257
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• 1999

A three dimensional finite model of a human neck has been developed in an effort to study the mechanics of cervical spin while subjected to vertical impact. This model consisting of the vertebrae from C1 through C7 including posterior element and ligaments was constructed by 2mm thick transverse CT cross-sections and X-ray film taken at lateral side. Geometrical nonlinearity was also considered for the large deformation on the disc. ABAQUS package was used for calculation and its results were verified comparing with responses of a model under static loading condition with published in-vitro experimental data. There were more cervical fracture in the restrained (compression) mode than in the nonrestrained (flexion-compression and extension-compression) mode. Upper cervical(C1-C2) injuries were observed under compression-extension modes, while lower cervical injuries occurred undjer compression-flexion modes. Posterior ligament distraction without bony damage at the upper cervical spin(C1-C2) were observed secondary to C5-C7 trauma in compression-flexion modes.

• Ocean Systems Engineering
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• v.1 no.1
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• pp.73-93
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• 2011

Large deck openings of ultra large container ships reduce their torsional stiffness considerably and hydroelastic analysis for reliable structural design becomes an imperative. In the early design stage the beam model coupled with 3D hydrodynamic model is a rational choice. The modal superposition method is ordinary used for solving this complex problem. The advanced thin-walled girder theory, with shear influence on both bending and torsion, is applied for calculation of dry natural modes. It is shown that relatively short engine room structure of large container ships behaves as the open hold structure with increased torsional stiffness due to deck effect. Warping discontinuity at the joint of the closed and open segments is compensated by induced distortion. The effective torsional stiffness parameters based on an energy balance approach are determined. Estimation of distortion of transverse bulkheads, as a result of torsion and warping, is given. The procedure is illustrated in the case of a ship-like pontoon and checked by 3D FEM analysis. The obtained results encourage incorporation of the modified beam model of the short engine room structure in general beam model of ship hull for the need of hydroelastic analysis, where only the first few natural modes are of interest.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.143-148
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• 2019

Although many patients who undergo bunion repair do well and have satisfactory results, a critical evaluation of these results shows the potential for improvement. Metatarsal deformity of the hallux valgus is a 3-dimensional deformity, including rotation in the coronal plane. Theoretically, it is important to understand the 3-dimensional displacement of the first metatarsal for correcting the deformities of valgus rotation in the frontal plane. Yet the current methods of metatarsal osteotomy principally attempt to correct the deformity in the transverse plane. The modified technique for the Lapidus procedure can be used in a variety of hallux valgus conditions and severities, and the early results suggest that a powerful correction can be maintained. In addition, efforts have been made to correct the 3-dimensional deformity by performing metatarsal shaft osteotomy. In the case of degenerative arthritis, first metatarsophalangeal joint arthrodesis is a good option to correct the 3-dimensional deformation. Correction of the 3-dimensional deformity, including a rotational deformity in the frontal plane of the metatarsals, should be considered when selecting surgical treatment and is essential for achieving a good prognosis for patients with hallux valgus. This article reviews the classification and treatment of hallux valgus for correction of the 3-dimensional deformity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.315-321
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• 2010

Co-cured single lap joints under cyclic tensile loads fail initially at the tip of the interface corner between the two adherents. The failure mechanism is complex because it is related to corrosion fatigue. Corrosion behavior at the interface affects the failure of the joints because corrosion deteriorates fatigue resistance. In this study, we clarified the cause of interfacial corrosion in co-cured single lap joints under cyclic tensile loads. The failure mechanism was also analyzed by observing the failed surfaces of specimens and the stress distribution along the interface. The surface roughness at the interface and the stacking sequence of the composite adherent were examined to investigate their effects on failure of the joint.

• Korean Journal of Applied Biomechanics
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• v.32 no.4
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• pp.134-140
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• 2022

Objective: This study aims to verify effect of 1-RM direct measurement method of back squat on beginners. Method: Total of 8 healthy adults were recruited for this study (age: 29 ± 3.81 yrs., height: 174 ± 3.83 cm., body mass: 74 ± 11.63 kg., 1RM: 96 ± 19.78 kg). All participants performed the back squat with 80%, 90% and 100% of the pre-measured 1RM. A three-dimensional motion analysis was performed with 8 infrared cameras and 3 channels of EMG were used for this study. One-way ANOVA with repeated measure was used for the statistical analysis with the significant level set to α=.05. Results: The ankle joint ROM in the transverse plane was significantly increased as the weight increased during the concentric contraction phase 2 (p < .05). In addition, the erector spinae and the gluteus maximus, which are synergist for the motion, showed a significant difference according to the increased weight (p < .05). Conclusion: Our results revealed that beginners increase potential dynamic knee valgus as weight increased. Therefore, it is thought that field coaches should pay attention to this to minimize and prevent injuries when measuring 1-RM for beginners.

• Archives of Craniofacial Surgery
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• v.25 no.2
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• pp.85-89
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• 2024

Postoperative atlantoaxial rotatory subluxation (AARS) is a rare complication that develops almost exclusively in children following oropharyngeal and otologic surgeries, proposing that oropharyngeal inflammatory responses and excessive head rotation are responsible factors. However, there have been no reports of AARS after excision of a nevus on the head and neck. Here, we present two cases of AARS following limited head rotation during simple nevus excision. Patient 1, a 9-year-old girl, complained of neck pain and limited range of motion after excision of the nevus on the neck. After 2 months, computed tomography and magnetic resonance imaging finally revealed AARS with a ruptured transverse atlantal ligament. A month of halo traction was required for the treatment. Patient 2, an 11-year-old girl, presented with immediate pain and limited neck extension after tissue expander insertion under the upper chest and excision of the nevus on her left cheek. The diagnosis was promptly made using cervical spine radiography. A cervical collar was applied for 1 month. Both patients recovered without any complications after treatment. This report highlights the importance of suspicion for AARS after surgery regardless of surgical duration or amount of head rotation.

• International Journal of Highway Engineering
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• v.1 no.1
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• pp.107-119
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• 1999

The joints in the jointed concrete pavement provide a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random cracks cause more serious distresses and result in structural or functional failure of pavement system. However, joints nay cause distresses due to its inherent weakness in structural integrity. Thus, the evaluation at joint is very important. and the joint-related distresses should be evaluated reasonably for economic rehabilitation. The purpose of this paper was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis program, ILLI-SLAB, and nondestructive testing device. FWD. To develop an evaluation system for JCP, a sensitivity analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. An evaluation charts were made for jointed concrete pavement by adopting the field FWD data. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP are 300pci. 500,000 lb/in. respectively. Using these variables and FWD test, a charts of load transfer ratio versus surface deflection at joints were made in order to evaluate the performance of JCP. Practically, Chungbu highway was evaluated by these evaluation charts and FWD field data for jointed concrete pavement. For Chungbu highway, only one joint showed smaller value than limiting criterion of the modulus of dowel/concrete interaction(G). The rest joints showed larger values than limiting criteria of the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G).

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.120-123
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• 2001

Purpose : We used transparent flexible tube which had provided the good visual field of median nerve when it was used in endoscopic release of transverse carpal ligament and evaluated the safety of that technique. Materials and Methods : We evaluated the 12 patients(20cases) who had been diagnosed as carpal tunnel syndrome and performed by endoscopic carpal tunnel release between Mar. 1997 and Mar. 2000. We used two portal technique and released the transverse carpal ligament with direct supervision of median nerve. Results : 14 cases$(70\%)$ were revealed excellent or good results and 6 cases$(30\%)$ were fair. No serious complications were shown such as nerve injury. Conclusion : We could avoid the complications of endoscopic carpal tunnel release using the transparent flexible tube which had provided tire good circumferential vision around the median nerve and it is unnecessary to maintain the wrist Joint hyperextension state during operation. Also that tube was easily obtainable in hospital so we need not to purchase the expensive operation apparatus.