• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.109-122
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• 1984

The purpose of this study was to analyze the magnitude and mode of the stress distribution induced in the supporting alveolar bone and periodontal ligament and, to determine the displacement of abutment teeth and telescope denture base by applying chewing force to the telescope denture quantitatively and qualitatively. Two finite element models of telescope denture that were restored the missing mandibular second molar with two abutment teeth which were constructed. In two different models, parallel and tapering type telescope crowns were constructed. These finite element models of two cases used for these experiment were a two-dimensional mesiodistal section of the mandibular second bicuspid and first molar. Chewing force of 25Kg that was devided in the ratio of 45/155 (29%) in bicuspid and 55/155 (35.5%) in molars was applied to telescope denture and abutment teeth respectively. The displacement of the telescope denture base and abutment teeth and the stress distribution in the periodontal ligament and alveolar bone were analized to investigate the influence of chewing force acting on the telescope denture and abutment teeth. The results were as follows: 1. Abutment teeth displaced mesially and the magnitude of displacement of abutment teeth in vertical direction were more than that of horizontal direction in two cases. The displacement of abutment teeth on the telescope denture treated with tapering type telescope crown were less than that of the parallel type crown. 2. The displacement of the telescope denture base that were treated with parallel type telescope crown were less than that of treated with tapering type telescope crown. 3. The stress induced in the alveolar bone and periodontal ligament on abutment teeth that treated with parallel type telescope crown were more than that of treated with tapering type telescope crown and more stress induced in the alveolar bone than in the periodontal ligament. 4. In the telescope denture, the magnitude of displacement of abutment teeth and stress induced in the periodontal ligament and alveolar bone were within physiologic limit.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.549-557
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• 2021

In this study, it is aimed to analyze the bending of porous sandwich plates using the four-variable shear deformation theory. The core of the sandwich plate is assumed to be functionally graded, and face sheets are assumed to be isotropic. The pore distribution of the sandwich plate is considered even and uneven type of porosity distribution. Displacement fields are defined with four variable shear deformation theory. Equilibrium equations of porous sandwich plates are derived from virtual displacement principle. An analytical solution is obtained by Navier's approach. Results are presented for uniformly and sinusoidally distributed loaded porous sandwich plates. Face sheet -core thickness ratio, porosity distribution, amount of porosity is investigated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.623-628
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• 2007

The accurate peak response estimation of a seismically excited structure with frictional damping system(FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated that by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In the case that an earthquake load is defined with probabilistic characteristics, the corresponding response of the structure with FDS has probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake loads generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Finally, coefficients of the proposed PDF are obtained by regression analysis of the statistical distribution of the time history responses. Finally the correlation between PDFs and statistical response distribution is presented.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.6
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• pp.291-299
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• 2014

There has been an increasing demand for introducing a base isolation system to secure the seismic safety of a nuclear power plant. However, the design criteria and the safety assessment methodology of a base isolated nuclear facility are still being developed. A performance based design concept for the base isolation system needs to be added to the general seismic design procedures. For the base isolation system, the displacement responses of isolators excited by the extended design basis earthquake are important as well as the design displacement. The possible displacement response by the extended design basis earthquake should be limited less than the failure displacement of the isolator. The failure of isolators were investigated by an experimental test to define the ultimate strain level of rubber bearings. The uncertainty analysis, considering the variations of the mechanical properties of isolators and input ground motions, was performed to estimate the probabilistic distribution of the isolator displacement. The relationship of the displacement response by each ground motion level was compared in view of a period elongation and a reduction of damping. Finally, several examples of isolator parameters are calculated and the considerations for an acceptable isolation design is discussed.

• The korean journal of orthodontics
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• v.15 no.1
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• pp.43-54
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• 1985

Recently, rapid palatal expansion technique is widely used for the correction of the skeletal imbalance in Cl III malocclusion patients. There were many studies about the cephalometric changes to rapid palatal expansion but quantitative analysis were small. The purpose of this study was to analysis the stresses and displacement of the maxilla in human dry skull to rapid palatal expansion. The results were as follows: 1. The anterior portion of palate show more lateral and inferior displacement than the posterior portion. But the posterior portion show more anterior displacement. 2. In transpalatal suture area, the medial portion show more anterior and inferior displacement than the lateral portion. But the lateral portion show more lateral displacement than the medial portion. 3. In mid-sagittal plane, the lower portion (palatal area) of maxilla show more anterior, lateral, inferior displacement than the upper portion (frontamaxillary stuture area). 4. In zygomatic arch, the adjacent area to maxilla show tonsil. stresses and the adjacent area to frontal bone show compressive stresses. 5. The sequence of stress bearing area to R.P.E. is upper retromolar area, upper 1st molar, 1st premolar, 2nd premolar, anterior segment of teeth.

• Tunnel and Underground Space
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• v.11 no.2
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• pp.167-173
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• 2001

The joint model has influence on the results of discontinuum analysis. In this study the results of discontinuum analysis with Barton-Bandis joint model(BB model) and with Mohr-Coulomb joint model(MC model) are compared. The results of continuum analysis under the same condition are compared with the results of discontinuum analysis to investigate the behavior of rockmass around tunnel. The result of continuum analysis and that of discontinuum analysis with BB model show similar distribution of displacement and stress. On the other hand, the discontinuum analysis with MC model shows different displacement distribution and stress distribution. Moreover, the displacement and minor principal stress of the discontinuum analysis with MC model are smaller than those of continuum analysis, although the joints are explicitly considered in the discontinuum analysis. These results are originated from the limitation of MC model in simulating joint deformation behavior, especially the assumption of constant dilation jingle independent of it)int 7hear displacement.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.833-841
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• 2001

Abstract In this work, we analyze the Levy mutation operations based on the Levy probability distribution in the evolutionary programming via the mean square displacement and the distinctness. The Levy probability distribution is characterized by an infinite second moment and has been widely studied in conjunction with the fractals. The Levy mutation operators not only generate small varied offspring, but are more likely to generate large varied offspring than the conventional mutation operators. Based on this fact, we prove mathematically, via the mean square displacement and the distinctness, that the Levy mutation operations can explore and exploit a search space more effectively. As a result, one can get better performance with the Levy mutation than the conventional Gaussian mutation for the multi-valued functional optimization problems.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.98-129
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• 1995

The purpose of this study was to evaluate how mandibular implant-supported fixed complete prosthesis, implant and mandible responded mechanically, according to curvature of arch, number and location of fixture, and amounts of load. The shape of mandibular arch was tapered or square form and, 4 or 6 fixtures were implanted in each arch model. A vertical load of 10kg was applied at the center of prosthesis and a vertical load of 20kg was applied at the location of the 10mm or 20mm cantilever posterior to the most distal implant. Three-dimensional finite element analysis was performed for stress distribution and deflection using commercial software(ABAQUS program) for Sun-SPARC Workstation. The results were as follows : 1. The case square arch form was more stable to compare with that of tapered arch form in respect of stress distribution and displacement under vertical load on the center of prosthesis. 2. 6-implants cases were more stable than 4-implants cases for decreasing bending torque under vertical load on the center of prosthesis. 3. Under vertical load on cantilever extension, the case of 10mm long cantilever was more stable than that of 20mm long cantilever in respect of stress distribution and displacement. 4. Under vertical load on cantilever extension, 6-implants cases had a tendency to reduce displacement and to increase the reaction force of supporting point due to increasing of the bending stiffness of the prosthesis than 4-implant case. 5. When the ends of 10mm or 20mm long cantilever were loaded, the most distal implant was under compressive stress but the second most distal implant was under the highest tensile stress and the remaining implants were under varying tensile stress. 6. Because 6-implants cases had smaller displacement than 4-implants cases, 6-implants cases were more favorable in respect of prevention of screw loosening under repeated loadings.

• Korean Journal of Optics and Photonics
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• v.17 no.2
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• pp.136-142
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• 2006

This paper presents irradiance distribution model of light radiated from a step-index multimode optical fiber. The model is important in analysis of displacement response characteristics for intensity modulation type optical fiber sensors. The induced model was verified by experimental results. And the displacement response analysis result induced by using the irradiance distribution model was verified by experimental results and compared with using existing irradiance distribution models such as the constant model or the gaussian model. The experiment has better agreement with the analysis result using the induced model in this study than with the others models.

• Membrane Journal
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• v.27 no.3
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• pp.263-272
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• 2017

There are several different methods to characterize membrane pore size distribution, however, it is yet difficult to accurately measure pore size range of 10-50 nm. In this work, we employed gas-liquid displacement porometer (GLDP) and liquid-liquid displacement porometer (LLDP) to characterize in-house alumina hollow fiber membrane (K-100) and commercial membranes (A-100, A-20) that exhibit pore sizes between 10-100 nm. GLDP method was more suitable for measuring the maximum pore size, and the measured mean pore size of the membranes by LLDP were better correlated with water permeability and solute rejection. It was determined that LLDP is effective for measuring pore sizes between 10-50 nm; however, the method holds intrinsic disadvantages such as low precision and high sensitivity compared to that of GLDP. Nevertheless, it is expected that the recently commercialized LLDP technique can provide useful data that other methods cannot.