• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.222-225
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• 2006

The treatment objective of mandibular fracture is a return to normal function. According to Champy, a rigid fixation of mandibular angle fracture is performed by using 4 or 6 holes titanium miniplates on the external oblique ridge of mandible. However, the limitations of metal plate such as hypersensitivity, interference with the cranio-facial growth of growing child, secondary bone resorption around the plate, foreign body reaction, declination of primary callus formation, and bone atrophy due to the lack of normal stress reaction of the bone have been reported. Recently, biodegradable miniplate has been introduced and used as an alternative to the metal plate despite its lower strength than that of the titanium plate and the side effect caused by the resorption in the body. In this study, 61 patients diagnosed as mandibular angle fracture and treated from Jan. 1998 to Dec. 2004 in our department have been reviewed. Metal plate fixation was used in 50 patients and biodegradable plate fixation in 11 patients on the external oblique ridge around the fractured mandibular angle according to the principle of monocortical osteosynthesis by Champy. We compared the incidence of side effects and the degree of bony union at the mandibular inferior border in two different fixation methods. In conclusion, we have found that one miniplate regardless of matter could provide enough strength to grasp bony fragments of the tension site and compress the inferior border of mandible without any complications.

• Structural Monitoring and Maintenance
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• v.10 no.4
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• pp.315-337
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• 2023

During the design phase, it is crucial to determine the interface stresses between the reinforcing plate and the concrete base in order to predict plate end separation failures. In this work, a simple theoretical study of interface shear stresses in beams reinforced with P-FGM and E-FGM plates subjected to an arbitrarily positioned point load, or two symmetrical point loads, was presented using the linear elastic theory. The presence of pores in the reinforcing plate distributed in several forms was also taken into account. For this purpose, we analyze the effects of porosity and its distribution shape on the interracial normal and shear stresses of an FGM beam reinforced with an FRP plate under different types of load. Comparisons of the proposed model with existing analytical solutions in the literature confirm the feasibility and accuracy of this new approach. The influence of different parameters on the interfacial behavior of reinforced concrete beams reinforced with functionally graded porous plates is further examined in this parametric study using the proposed model. From the results obtained in this study, we can say that interface stress is significantly affected by several factors, including the pores present in the reinforcing plate and their distribution shape. Additionally, we can conclude from this study that reinforcement systems with composite plates are very effective in improving the flexural response of reinforced RC beams.

• Steel and Composite Structures
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• v.33 no.3
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• pp.357-373
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• 2019

Steel storage racks are slender structures whose overall behavior and the capacity depend largely on the flexural behavior of the base-plate to upright connections and on the behavior of beam-to-column connections. The base-plate upright connection assembly details, anchor bolt position in particular, associated with the high-rise steel storage racks differ from those of normal height steel storage racks. Since flexural behavior of high-rise rack base connection is hitherto unavailable, this investigation experimentally establishes the flexural behavior of base-plate upright connections of high-rise steel storage racks. This investigation used an enhanced test setup and considered nine groups of three identical tests to investigate the influence of factors such as axial load, base plate thickness, anchor bolt size, bracket length, and upright thickness. The test observations show that the base-plate assembly may significantly influence the overall behavior of such connections. A rigid plate analytical model and an elastic plate analytical model for the overall rotations stiffness of base-plate upright connections with concentric anchor bolts were constructed, and were found to give better predictions of the initial stiffness of such connections. Analytical model based parametric studies highlight and quantify the interplay of components and provide a means for efficient maximization of overall rotational stiffness of concentrically anchor bolted high-rise rack base-plate upright connections.

• Structural Engineering and Mechanics
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• v.18 no.3
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• pp.315-330
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• 2004

A four-point bending RC beam strengthened with FRP plate is investigated based on the theory of elasticity. Taking the adhesive layer into account but ignoring some secondary parameters, the analytical solutions of the normal stress and shear stress on concrete-adhesive interface are obtained and discussed. Besides, the pure bending region of the beam is analyzed and the ultimate load of the beam is predicted. The results obtained in the present paper agree very well with both the results of FEM and the experimental findings.

• Structural Engineering and Mechanics
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• v.4 no.4
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• pp.415-424
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• 1996

This paper presents a newly suggested calculation method in which an arbitrary quadrilateral element with curved sides is transformed to a normal rectangular one by mapping of coordinates, then the two-dimensional spline is adopted to approach the displacement function of this element. Finally the solution can be obtained by the least-energy principle. Thereby, the application field of Spline Finite Element Method will be extended.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.295-300
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• 2010

Metal bipolar plate applied to Polymer Electrolyte Membrane Fuel Cell is getting most attractive due to their good feasibility of mass production and low cost. But it is one of the immediate causes of performance decline because it is difficult to reduce channel pitch of metal bipolar plate. In this study, mesh was inserted in between bipolar plate and GDL to obtain uniform contact pressure without reducing channel pitch. The section measuring and performance test were carried out to confirm the mesh structure distributes contact pressure equally in reacting area. The performance of 3 type mesh structures developed in this study were higher than the normal cell at all over the current range. Especially, it showed that the mesh cell performance was increased and pressure drop was decreased with diminishing mesh gap size. The Mesh structure was more sensitive to humidification and contact pressure change than the normal cell.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1062-1068
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• 2002

In our previous study, it was proven that the mean size and the total number concentration of carbon soot particles emitted from a $C_2$H$_4$ normal diffusion flame decreased when a DC corona was discharged to pin-pin electrodes. In this work the effect of AC corona discharge on soot emission was investigated and compared with that of DC corona discharge. For the pin-pin electrodes the size of soot particles and the number concentration decreased by the AC voltage. There were only slight changes in size distribution with frequencies, while the magnitude of applied voltage was constant. When the electric field was applied to plate-plate electrodes, the size and the number concentration also decreased with the applied AC voltages. For applied voltages above 2kV the effect of frequency increase on the soot emission was effective.

• Smart Structures and Systems
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• v.9 no.2
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• pp.127-143
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• 2012

The present paper deals with the nonlinear analysis of the functionally graded piezoelectric (FGP) annular plate with two smart layers as sensor and actuator. The normal pressure is applied on the plate. The geometric nonlinearity is considered in the strain-displacement equations based on Von-Karman assumption. The problem is symmetric due to symmetric loading, boundary conditions and material properties. The radial and transverse displacements are supposed as two dominant components of displacement. The constitutive equations are derived for two sections of the plate, individually. Total energy of the system is evaluated for elastic solid and piezoelectric sections in terms of two components of displacement and electric potential. The response of the system can be obtained using minimization of the energy of system with respect to amplitude of displacements and electric potential. The distribution of all material properties is considered as power function along the thickness direction. Displacement-load and electric potential-load curves verify the nonlinearity nature of the problem. The response of the linear analysis is investigated and compared with those results obtained using the nonlinear analysis. This comparison justifies the necessity of a nonlinear analysis. The distribution of the displacements and electric potential in terms of non homogenous index indicates that these curves converge for small value of piezoelectric thickness with respect to elastic solid thickness.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.129-134
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• 1996

Bonding strength of reinforcing material has been recognized to be the most important factor which determines the strengthening effect and the durability of repair work. The properties of bonding layers affects the stress distribution at the end of the plate, therefore the behavior of bonding layer has to be investigated. In this study, the stress distribution at the end of the bonded plate has been tested and compared with Roberts' analysis. Shear stress and vertical normal stress at the end of strengtening plate are analysized and the effedts of bonding layer thickness, plate thickness and plate length on the bonding behavior are tested. The test results showed that thickness is one of the most important factor, which is the thinner the thickness, the smaller the maximum stress.

• Steel and Composite Structures
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• v.34 no.6
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• pp.795-802
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• 2020

The subject of the paper is a circular plate with symmetrically thickness-wise varying mechanical properties. The plate is simply supported and carries a concentrated force located in its centre. The axisymmetric bending problem of the plate with consideration of the shear effect is analytically and numerically studied. A nonlinear function of deformation of the straight line normal to the plate neutral surface is assumed. Two differential equations of equilibrium based on the principle of stationary potential energy are obtained. The system of equations is analytically solved and the maximum deflections and shear coefficients for example plates are derived. Moreover, the maximum deflections of the plates are calculated numerically (FEM), for comparison with the analytical results.