• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.191-200
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• 2001

This paper presents buckling analysis of the cylindrical shell subjected to axial loads using numerical method. The modeling method, appropriate element type, and number of element are recommended by comparing with analytical solution. Based on the parametric study, buckling stress decreases significantly as the diameter-thickness ratio increases. These results are different from those obtained from buckling analysis of columns. The number of buckling half-wave in circumferential direction decreases as the diameter-height ratio increases. Buckling stress increases 1~2% as the thickness of base plate increases. Therefore the effect of base plate on buckling strength for cylindrical shell can be disregarded. Buckling stress significantly decreases as the amplitude of initial geometric imperfection used for calculating buckling stress is developed and it shows a good agreement with numerical results.

• Transactions of Materials Processing
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• v.29 no.3
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• pp.157-162
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• 2020

Blind rivet nuts are increasingly used in automotive for the joining of sheets. Their application, however, requires appropriate design guides to prevent catastrophic events arising from the failure of joints. In this study, the shaft shape of a frequently used M8 blind rivet nut is optimized based on 3D numerical analysis of the blind rivet nut considering the characteristics of thread. The thread needs to be modeled to suitably consider the fastening of the M8 bolt after the crimping process. FE analysis showed that while the friction in the contact between crimp flange and plate has no significant effect on the crimp geometry, shaft thickness (t) and shaft height (h) are the most significant design variables. The parameter study including various combinations of t and h reveals that they affect the gap (the distance between the crimped flange and the plate that develops through riveting) and the load acting on the plate. The gap is an indicator of the tightening force. It is found that t is inversely proportional to the gap, and proportional to the load, whereas h is proportional to the gap and inversely proportional to the load. Based on our FE analysis results, we propose the range 0.062 < t/h < 0.1 to ensure sufficient fastening (high clamping load, small gap) of the M8 blind rivet nut. The design guide for determining the t/h ratio proposed in this study can be used for general quantitative analysis of the size and the t/h ratio of blind rivet nuts.

• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.143-149
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• 2013

Purpose: Open reduction and internal fixation of calcaneal fracture using plate has been used. While numerous plates have been manufactured, most of the conventional plates are designed for westerners, realistically the size is larger for Korean. The domestic products, on the other hand, often have the undesirable screw holes and path. Therefore, we measured the radiologic parameter of Korean calcaneus for providing the plate and screw hole placements. Materials and Methods: We measured the outer lines and angles with over the 20 years old 291 females and 322 males. A: Length of inferior plane of calcaneus, B: Length of anterior plane of calcaneus, C: Length from line A to sinus tarsi, D: Length from line A to posterior point of posterior facet, E: Length from line A to calcaneal tuberosity, F: Length of posterior facet, G: Length from anterior point of line A to C, H: Length from line C to line D, a: Angle between A and B, b: Gissane angle, c: Bohler angle, d: Calcaneal pitch angle using Marosis m-view$^{(R)}$. Results: Mean A, B, C, D, E, F, G, H were 63.6, 26.4, 23.2, 43.7, 40.5, 26.9, 12.8, 18.1 mm. Mean a, b, c, d angle were 105.8, 122.4, 32.4, $20.5^{\circ}$. Male's calcaneus is significantly bigger than female's (p<0.001). Conclusion: AP calcaneus length 63.6 mm, maximal height 43.7 mm is considered to be helpful in making the Korean calcaneal plate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.311-318
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• 2005

Periodically perforated slot structure in the upper wall of the parallel plate waveguide is analyzed with main interest focusing on the diffraction Properties. The Periodic slot array is of infinite extent in one direction and of finite extent in the other direction. Various numerical results for reflection from the slotted section and transmission beyond the slotted section, and the radiation through the slotted section into the upper half space are presented with the height of feeding parallel plate waveguide, single slot size, and the periodicity between slots as parameters. This study is thought to be helpful to the design of the ventilation hole in the TFT-LCD and PDP.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.3
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• pp.217-226
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• 2003

This study is focused on the finding out load transfer mechanism in the ground near the tunnel during tunnel excavation in the jointed sandy ground. Laboratory model tests were performed on various cases of the overburden heights above tunnel crown, location, and degree of discontinuity planes. For model tests, a movable plate was installed in the midst of the bottom of sandy ground. This plate, moving downwards, was intended to model the stress relaxation during tunnel excavation. The load transfer was measured at the fixed separated bottom plates adjacent to the movable plate. As the result, the loosening zone and the load-transfer form around the tunnelling site were affected by the overburden height and the characteristics of discontinuous planes. And large loosening zone was developed along the discontinuous planes which were close to the tunnel.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.211-219
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• 2017

Objective : This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). Methods : From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2-7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. Results : The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. Conclusion : This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.247-258
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• 2007

This paper describes the results of an experimental study on the new type of encased composite beams that use deep deck plates, which could reduce the story height of buildings by controlling the bottom flange of steel beams. The profiled steel beam was thus developed. It was advantageous to the long span of the buildings. Seven full-scale specimens were constructed, and simply supported bending tests were conducted on the encased composite beams with different steel plate thicknesses, with and without shear studs, reinforcing bars, and web openings. The test results showed that the encased composite beams that were developed in this study had sufficient composite action without additional shear connectors due to their inherent shear-bond effects between the steel beams and concrete.

• The Journal of Pediatrics of Korean Medicine
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• v.19 no.2
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• pp.165-174
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• 2005

Objectives : The purpose of this study was to suggest a new method for measurement of children's growth development Ultrasound transonic velocity of inferior radiocarpal joint has some advantages that it is harmless to human body and apply a new analysis algorithm, it can be used for the diagnosis of bone age. Methods: This clinical study have been carried out with the 117 case(male 68, female 49) of the children aged 5 to 16 years old who visited in Department of Pediatrics, ${\bigcirc}{\bigcirc}$ university Oriental Hospital. Bone maturity is measured by Ultrasound transonic velocity and X-ray image of growth plate in inferior radiocarpal joint. This study were designed to investigate the relationship of the bone age by Ultrasound transonic velocity and X-ray image. Result & Conclusion : The maturity of growth plate of inferior radiocarpal joint was correlated with age, height, weight, BMI in this study(P<0.001). The Ultrasound transonic velocity of inferior radiocarpal joint are sufficient diagnostic worth as an index to predict bone maturity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.295-300
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• 2011

Ship are a box-shaped structure. It is used often fore and aft parts, bilge strake, deck with camber of ship structures. When this structure is compared with flat plate structure, it different to behaviour. Generally, if it subjected to axial compressive load, ultimate strength depend on the change of curvature. Also, In this paper, stiffened curved plate with 1/2+1+1/2 bay model subjected to compressive load carried out the elasto-plastic large deflection series analysis. and parameter effect considered slender ratio, web height/thickness as well as change of curvature and investigated collapse mode for analysis model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.254-261
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• 2021

This study was intended to develop an inspection method to detect defects in closed-cell steel members in steel girder bridges. The ultrasonic pulse velocity method was selected as a rapid and effective method to identify thickness changes of steel specimens caused by corrsion. This study developed an algorithm to expedite the process and improve the accuracy in the prediction of steel plate thickness. Also, both static and continuous scanning methods were compared to each other to identify the difference in accuracy, but the results revealed that both methods produce almost the same results. This study also provided the idea to calculate the height of water contained in the closed-cell steel member and results of laboratory experimental results. The water heights which is thicker than the steel plate thickness were detectable and predicted using the idea suggested by this study, but the water heights lower than the steel plate thickness were not possible. However, the results showed whether the steel member contains water or not.