• International Journal of Highway Engineering
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• v.9 no.1 s.31
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• pp.1-15
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• 2007

The objective of this paper is the establishment of finite element analysis frame work for pavement research. Finite element analysis results simulating various loading experiments are verified with sensor measurements obtained from the KHC Test Road. The accuracy of the finite element analysis can be supported by these efforts so that it helps spread out the finite element analysis to pavement research and design processes. The finite element model used in this research is the full 3D nonlinear model including concrete slab, lean concrete base, subbase, shoulder, dowel, and tie-bar. In order to accomplish the accurate verification, the loading condition and the pavement temperature distribution are exactly simulated with field measured data. The curling behavior and the strain distribution are compared with measured responses from the loading tests with a truck and the FWD. Strain and curling predictions from the concrete slab are matched well with measured responses but the strain prediction from the lean concrete base is not matched with measured response. In addition, the magnitude of permanent curling is evaluated with the finite element analysis.

• Journal of Korean Association for Spatial Structures
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• v.9 no.1
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• pp.61-68
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• 2009

This paper is concerned with the investigation of the structural behavior of waffle structure. Parametric variation on waffle floor thickness, main beam depth and column sizes are imposed to study the effects on mode shapes and natural frequencies of waffle structures. Comparisons between FEM models using shell and 3D-solid elements have also been made. The analysis result has shown that the mode frequencies increase with i) increase in main beam depth at level 2 and ii) decrease in waffle slab thickness at level 3. Both 3D and 2D model shown similar mode shapes. Besides, there is a consistent difference in mode frequencies between 3D and 2D model ranging from 25% to 36%.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.28-38
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• 2008

This study was to investigate the influence of composite resins with different elastic modulus, cavity modification and occlusal loading condition on the stress distribution of restored notch-shaped noncarious cervical lesion using 3-dimensional (3D) finite element (FE) analysis. The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. A notch-shaped cavity and a modified cavity with a rounded apex were modeled. Unmodified and modified cavities were filled with hybrid or flowable resin. After restoration, a static load of 500N was applied in a point-load condition at buccal cusp and palatal cusp. The stress data were analyzed using analysis of principal stress. The results were as follows: 1. In the unrestored cavity, the stresses were highly concentrated at mesial CEJ and lesion apex and the peak stress was observed at the mesial point angle under both loading conditions. 2. After restoration of the cavity, stresses were significantly reduced at the lesion apex, however cervical cavosurface margin, stresses were more increased than before restoration under both loading conditions. 3. When restoring the notch-shaped lesion, material with high elastic modulus worked well at the lesion apex and material with low elastic modulus worked well at the cervical cavosurface margin. 4. Cavity modification the rounding apex did not reduce compressive stress, but tensile stress was reduced.

• 대한치과보철학회:학술대회논문집
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• 2001.11a
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• pp.67-67
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• 2001

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.184-197
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• 2008

This study was to investigate the influence of combining composite resins with different elastic modulus, and occlusal loading condition on the stress distribution of restored notch-shaped non-carious cervical lesion using 3D finite element (FE) analysis. The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. A notch-shaped cavity was modeled and filled with hybrid, flowable resin or a combination of both. After restoration, a static load of 500N was applied in a point-load condition at buccal cusp and palatal cusp. The stress data were analyzed using analysis of principal stress. Results showed that combining method such that apex was restored by material with high elastic modulus and the occlusal and cervical cavosurface margin by small amount of material with low elastic modulus was the most profitable method in the view of tensile stress that was considered as the dominant factor jeopardizing the restoration durability and promoting the lesion progression.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.1
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• pp.11-19
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• 2001

기능경사재(FGM)는 구성 물질의 체적분율(volume fraction)이 복합재 전체에 걸쳐 연속적 그리고 기능적으로 분포되어 있어, 기존의 이종물질 접합식(bi-material-type) 복합재보다 현저히 우수한 열기계적 특성을 가진다. 하지만, 기능경사 내열복합재의 열-탄소성 거동은 체적분율의 분포형태와 경사층이 차지하는 상대두께비에 따라 절대적으로 좌우된다. 본 연구는 기능경사 내열복합재의 열-탄소성 특성의 이들 두 설계인자에 대한 파라메트릭 FEM해석을 다룬 것이다. 열-탄소성 이론과 유한요소 근사화에 따라 연구용 2차원 FEM 프로그램을 개발하고, 대표적인 3층 구조의 2차원 기능경사 내열복합재의 열-탄소성 특성을 설계변수의 다양한 조합에 따라 분석하였다.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.184-197
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• 2008

This study was to investigate the influence of combining composite resins with different elastic modulus, and occlusal loading condition on the stress distribution of restored notch-shaped non-carious cervical lesion using 3D finite element (FE) analysis. The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. A notch-shaped cavity was modeled and filled with hybrid, flowable resin or a combination of both. After restoration, a static load of 500N was applied in a point-load condition at buccal cusp and palatal cusp. The stress data were analyzed using analysis of principal stress. Results showed that combining method such that apex was restored by material with high elastic modulus and the occlusal and cervical cavosurface margin by small amount of material with low elastic modulus was the most profitable method in the view of tensile stress that was considered as the dominant factor jeopardizing the restoration durability and promoting the lesion progression.

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.427-436
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• 2006

The objective of this study was to investigate the effects of various occlusal loads on the stress distribution of the buccal cervical region of a normal maxillary second premolar, using a three dimensional fnite element analysis (3D FEA). After 3D FE modeling of maxillary second premolar, a static load of 500N of three load cases was applied. Stress analysis was performed using ANSYS (Swanson Analysis Systems, Inc., Houston, USA). The maximum principal stresses and minimum principal stresses were sampled at thirteen nodal points in the buccal cervical enamel for each four horizontal planes, 1.0 mm above CEJ, 0.5 mm above CEJ, CEJ, 0.5 mm under CEJ. The results were as follows 1. The peak stress was seen at the cervical enamel surface of the mesiobuccal line angle area, asymmetrically. 2. The values of compressive stresses were within the range of the failure stress of enamel. But the values of tensile stresses exceeded the range of the failure stress of enamel. 3. The tensile stresses from the perpendicular load at the buccal incline of palatal cusp may be shown to be the primary etiological factors of the NCCLs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.505-511
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• 2016

The aim of this study is to investigate the thermoforming characteristics of an inner case with three refrigerator cavities using three-dimensional(3D) thermoforming analyses. We perform fundamental formability analyses using a 3D model of the mould for the inner case. We carry out tensile tests at the elevated temperature to examine the properties and characteristics of the thermoformed material. Then, we design sub-processes of the thermoforming process for the inner case. In addition, we develop suitable finite-element models for different sub-processes. We investigate the deformed shapes and thickness distributions of the inner case for different sub-processes using the results of the thermoforming analysis. Finally, we discuss the formability and thermoforming characteristics of the inner case with three cavities.

• Journal of the Korean Geotechnical Society
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• v.31 no.2
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• pp.47-63
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• 2015

A fundamental study of drilled shafts subjected to lateral cyclic loading in weathered soil was carried out based on field tests and numerical analysis. The emphasis was given on quantifying the cyclic p-y curve function from lateral cyclic loading tests and three-dimensional finite element analysis. Lateral cyclic loading tests and three-dimensional finite element analysis were carried out to investigate the behavior of drilled shafts according to the direction of cyclic loading. Based on the field tests and numerical analysis, a modified lateral load transfer relationship and design chart with degradation factors were proposed by considering the characteristics of cyclic loading. It was found that the prediction by the proposed p-y curve function is in good agreement with the general trends observed by in-situ measurements, and it represents a practical improvement in the prediction of lateral displacement and bending moment distribution of drilled shafts subjected to cyclic loading.