• Title, Summary, Keyword: displacement distribution

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A STUDY ON THE MECHANICAL BEHAVIORS OF ABUTMENT TEETH AND SUPPORTING TISSUE OF THE TELESCOPE DENTURE BY THE FINITE ELEMENT METHOD (유한요소법(有限要素法)에 의(依)한 Telescope Denture의 지대치(支臺齒) 및 지지조직(支持組織)의 역학적(力學的) 반응(反應)에 관(關)한 연구(硏究))

  • Kim, Moon-Ki;Choi, Boo-Byung
    • 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.

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A Study on transverse Behavior of Lifeline System Due to Liquefaction-induced Permanent Ground Displacement (액상화 영구지반변형에 의한 라이프라인 구조물의 횡방향 거동에 관한 연구)

  • 김문겸
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.369-376
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    • 1998
  • The purpose of the present study is to analyze the response of pipelines subjected to liquefaction-induced permanent ground displacement and to discuss the failure prediction of domestic waterway pipelines. Initially here, characteristics of liquefaction are reviewed and then permanent ground displacement is investigated base on previous earthquake hazard cases. Next, considering the distribution of the transverse permanent ground displacement and equivalent spring constant effect, formulas obtained by a beam theory are established to analyze continuous pipelines. This analysis was performed without consideration of axial effects. So the finite element analysis was used in order to consider the axial stiffness of soil. As a result, degree of liquefaction, width of deformed ground and axial stiffness are crucial points for evaluation the failure of pipelines subjected to permanent ground displacement.

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Particle displacement distributions of energy-trapped thickness shear vibrations in the piezoelectric substrate (압전체 기판에서 에너지 포획된 두께 전단진동의 변위분포)

  • 이개명
    • Electrical & Electronic Materials
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    • v.9 no.9
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    • pp.954-963
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    • 1996
  • Particle displacement distributions of the fundamental thickness shear vibration mode and overtone modes in an energy-trapped single resonator and an energy-trapped double acoustically coupled filter were calculated. The effects of the width of a pair of partial eletrodes and the magnitude of the plate back of the resonator on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated. And the effects of the width of a pair of partial eletrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back of the filter on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated.

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Design and Performance Evaluation of Retraction-Type Actuators with Displacement Amplification Mechanism Based on Thermomechanical Metamaterial

  • Cho, Yelin;Lee, Euntaek;Kim, Yongdae
    • Journal of Aerospace System Engineering
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    • v.14 no.2
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    • pp.28-35
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    • 2020
  • In this paper, we present a design for a retraction-type actuator (ReACT) that has the characteristics of both thermomechanical metamaterials and displacement amplification mechanisms. The ReACT consists of an actuating bar, a diamond-shaped displacement amplification (DA) structure, and a slot for loading thin-film heaters formed through the actuating bar. When power is supplied to the thin film heater, the actuating bars contacting the heater thermally expand, and the diamond-shaped DA structures retract in the longitudinal direction. The performance characteristics of the ReACT, such as temperature distribution and retracting displacement, were calculated with thermomechanical analysis methods using the finite element method (FEM). Subsequently, the ReACTs were fabricated using a polymer-based 3D printer that can easily execute complex structures, and the performance of the ReACT was evaluated through repeated tests under various temperature conditions. The results of the performance evaluation were compared with the results of the FEM analysis.

Probability Distribution of Displacement Response of Structures with Friction dampers Excited by Earthquake Loads Generated Using Kanai-Tajimi Filter (Kanai-Tajimi 필터 인공지진 가진된 마찰형 감쇠를 갖는 구조물의 변위 응답 확률분포)

  • Youn, Kyung-Jo;Park, Ji-Hun;Min, Kyung-Won;Lee, Sang-Hyun
    • 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.

Analysis of the Levy Mutation Operations in the Evolutionary prograamming using Mean Square Displacement and distinctness (평균변화율 및 유일성을 통한 진화 프로그래밍에서 레비 돌연변이 연산 분석)

  • Lee, Chang-Yong
    • 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.

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A Comparison of Barton-Bandis Joint Model and Mohr-Coulomb Joint Model for Tunnel Stability Analysis with DEM (개별요소법을 이용한 터널 안정성 해석에 있어 Barton-Bandis 절리 모델과 Mohr-Coulomb절리 모델의 비교)

  • 이성규;김치환
    • 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.

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A STUDY ON THE THREE DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE STRESSES ACCORDING TO THE CURVATURE OF ARCH AND PLACEMENT OF IMPLANTS (악궁의 만곡도 및 임플랜트 위치에 따른 삼차원적 유한요소 응력분석)

  • Lee, Don-Oh;Chung, Chae-Heon;Cho, Kyu-Zong
    • 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.

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Modeling of Transmitting Light Irradiance Distribution of Step-index Multimode Optical Fiber (스텝 인덱스 멀티모드 광섬유의 투광 조도분포 모델링)

  • Shin, Woo-Cheol;Hong, Jun-Hee
    • 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.

A FINITE ELEMENT ANALYSIS OF THE STRESS DISTRIBUTION AND DISPLACEMENT IN HUMAN MAXILLA TO RAPID PALATAL EXPANSION (상악골 급속 확장시 상악골의 응력 분산과 변위에 대한 유한요소법적 분석)

  • Joe, Bong-Jea;Sohn, Byung-Hwa
    • 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.

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