• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1999.03a
• /
• pp.73-76
• /
• 1999

• Transactions of Materials Processing
• /
• v.13 no.6 s.70
• /
• pp.479-483
• /
• 2004

• Magazine of the Korea Concrete Institute
• /
• v.11 no.2
• /
• pp.167-175
• /
• 1999

Many composite girder bridges have been constructed for about thirty five years. Nowadays they are aged or deteriorated because of the increase in traffic and vehicle loads. In this study, the effect of strengthening with glass fiber sheet is investigated to estimate the possibility for applying to damaged prestressed concrete bridges. One normal and eight cracked specimens which had been preloaded were tested. The cracked specimens were strengthened with either external prestressing or bonding glass fiber sheet, or using both methods. The results showed that the maximum loads are almost same for both methods. So it seems that the strengthening with glass fiber sheet can be used for strengthening damaged prestressed concrete girders. It is important that proper devices should be selected to prevent glass fiber sheet from premature bonding failure below its maximum load, which is similar to end anchorage problem in external prestressing method. It is proved that the devices proposed in this paper have sufficient anchoring capability to increase load carrying capacity.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.4
• /
• pp.1281-1293
• /
• 2013

A sophisticated finite element model is illustrated to analyze the behavior of Prefabricated Parallel Wire Strand(PPWS) sockets for main cables of suspension bridges. An orthotropic model is proposed for the casting material by considering both effects of individual wires and a casting alloy, and the contact between surfaces of a socket and a casting alloy is idealized by using the Coulomb friction and the surface-based contact model. The proposed FE model is verified by comparing the strain distributions obtained from the tensile test and FE analysis. The mechanical behavior of a socket is investigated with respect to the variation of the frictional coefficient. The result shows that the friction between surfaces significantly diminishes the stress concentration of a socket and a casting alloy, and the normal stress from the design equation represents the averaged value of the upper and lower quartiles in the distribution of contact stresses between a socket and a casting alloy.

• Journal of Yeungnam Medical Science
• /
• v.10 no.2
• /
• pp.400-408
• /
• 1993

During the period from March 1990 to November 1993, 22 children with diplaced supracondylar fracture of humerus were treated by closed reduction and percutaneous K-wire fixation at department of Orthopaedic surgery in Yeungnam University. All fracture were treated with closed reduction under the general anesthesia and percutaneous pinning. After the fracture was internally fixed, intraoperative anteroposterior reontgenograms of each distal humerus were compared. Only anatomical reduction ensured good result, because the main cause of late cubitus varus was medial tilting of distal fragment. We could follow up 10 patients more than one year. By Flynn's criteria, satisfactory result were obtained in 9 of the 10. Unsatisfactory one had a limitation in flexion of elbow joint, but had no problem in cosmetic feature. In short term follow up of 7 patients, 5 patients had a satisfactory result, too. There were no neurovascular complication and hospitalization was shortened to 11.4 days. Closed reduction and percutaneous pinning provided stabillity, vascular safety, simplified management, reduced hospital stay. This is safe and reliable technique for obtaining and maintaining an excellent reduction.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.8
• /
• pp.897-904
• /
• 2012

The rifling design problem has continuous-type shape variables and an integral number of riflings. In addition, it requires considerable time for analysis because its behavior should be described by a nonlinear finite element model (FEM). Therefore, this study presents an efficient design process for rifling based on a design of experiment (DOE) approach. First, Bose's orthogonal array is used to represent 25 runs for four design variables including three shape variables and one integer variable. Then, nonlinear FE analyses are performed. Next, to minimize the bullet resistance without affecting the bullet velocity and bullet rotational angle immediately before a bullet leaves the gun barrel, a what-if design is performed. In the proposed what-if design, a functional including the design objective and constraints is constructed and effect analysis is performed by using the functional. It is found that the new design obtained from the what-if design shows better results than the current one.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2002.11a
• /
• pp.101-105
• /
• 2002

FRP(Fiber glass reinforced plastics) is compound with materials, which are created to combine each other materials, of which nature of mechanical and chemical are different. Even though the weight and the thickness are identic, its physical figure of characteristic changes with consisting of lay-up and work situation. It is also a method of creating after manufacturing of mould. It has feature that manufacturing of FRP runs parallel design of material with design of structure simultaneously. The rule of FRP structure is distinguished from the length of a ship and it is hard to catch the feature of structure mechanics due to identical formula and figure used for it regardless of the shape of a ship or the speed. This studying, basing on a small FRP ship, will show te fundamental data needed to design of structure analysing the feature of intensity with direction, the method of Lay-up, and the characteristic of materials of FRP.

• Land and Housing Review
• /
• v.1 no.1
• /
• pp.67-73
• /
• 2010

Method of protruding steel bar embedded in PHC pile for connecting with foundation plate is an intermediate form of fixed and hinged connection and has often been used in architectural structures such as apartment complex. However, mechanical properties of this method have not been proved and its construction process is not simple. In this study, therefore, by analyzing previous research and by considering ratio of steel bar and concrete in PHC pile, which is minimum reinforcement of rebar, the newly optimized method of reinforcing joint of PHC pile and foundation plate is suggested with respect to PHC pile type (PHC 450, PHC 500, and PHC 600). To assess mechanical properties (ultimate tensile and shear strength) of joint of PHC pile and foundation plate, full scale experimental tests are performed. As a result, all cases are satisfied with required design criteria and can be practically applied. Our results indicate that reduction of rebar reinforcement compared to previous method would lead cost saving in PHC pile construction.

• Journal of Trauma and Injury
• /
• v.28 no.2
• /
• pp.55-59
• /
• 2015

Purpose: To compare clinical and radiographic outcomes of between two and three Kirschner wire(K-wire) intramedullary fixation for fractures in the neck of the metacarpal bone. Methods: A single institutional retrospective review identified 28 cases of metacarpal fractures between March 2010 and August 2014. Each of the cases met the inclusion criteria for closed, extra-articular fractures of the neck of the metacarpal bone. The patient groups were divided by the number of K-wire. Outcomes were compared for range of motion of the metacarpophalangeal joint, radiographic parameters, and period until union. Results: The fractures were treated with either 2 Kirschner wire fixation (n=10) or 3 Kirschner wire fixation (n=18). The active range of motion of metacarpophalangeal joint and radiographic result showed no statistically significant difference between the two groups. The mean union period was 5.9 weeks. However, four cases suffered distal head perforation in 2 K-wire fixation group and one case in 3 K-wire fixation group. Conclusion: Multiple retrograde intramedullary Kirschner wire fixation is a good treatment of choice for fractures in the neck of the metacarpal bone. To prevent metacarpal head perforation, it is preferred to use three K-wires than two K-wires.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.6
• /
• pp.540-545
• /
• 2021

A transverse fracture is the most common type of displaced patella fracture requiring surgery. These fractures are commonly fixed with parallel Kirschner wires or screws that cross the fracture line, often with an additional tension band. Nevertheless, conventional fixation methods of patella fractures have prevalent complications caused by the protrusion of wires or pins. These complications necessitate additional surgery for hardware removal, increase medical cost, and can limit the function of the knee joint. This paper reports cases treated with a minimally invasive load-sharing percutaneous suture of the patella tendon. The procedure provides reliable fixation for transverse patella fractures, minimizes soft tissue injuries, preserves blood flow, and reduces postoperative pain. In addition, the procedure also reduces the irritation and pain caused by the internal fixture, thereby reducing the risk of restricted knee joint movement.