EFFECT OF NUMBER OF IMPLANTS AND CANTILEVER DESIGN ON STRESS DISTRIBUTION IN THREE-UNIT FIXED PARTIAL DENTURES: A THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS

Park, Ji-Hyun,Kim, Sung-Hun,Han, Jung-Suk,Lee, Jai-Bong,Yang, Jae-Ho The Korean Academy of Prosthodonitics 2008 대한치과보철학회지 Vol.46 No.3

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.

3차원 유한요소법적 분석을 이용한 5종의첨형 임플랜트에 발생하는 응력의 비교연구

변상기,박원희,이영수,Byun, Sang-Ki,Park, Won-Hee,Lee, Young-Soo 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.5

Statement of problem : Dental implant which has been developed gradually through many experiments and clinical applications is presently used to various dental prosthetic treatments. To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately of load support. Therefore, it is essential to give the consideration about the stress analysis of supporting tissues for higher successful rates. Purpose : Recently, many implant manufacturing company produce various taper design of root form implant, the fixture is often selected. However, the stress analysis of taper form fixture still requires more studies. Material and method : This study we make the element models that five implant fixture; Branemark system(Nobel Biocare, Gothenberg, Sweden), Camlog system(Altatec, Germany), Astra system(Astra Tech, Sweden), 3i system(Implant Innovations Inc, USA), Avana system(Osstem, Korea) were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the three-dimension finite element analysis under two loading condition. Results : This study compares the aspect of stress distribution of each system with the standard of Von mises stress, among many resulted from finite element analysis so that this research gets the following results. 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and type of system, cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. under the vertical loading, maximum Von mises stress is more higher in order of Branemark, Camlog, Astra, 3i, Avana. under the horizontal loading, maximum Von mises is more higher in order of Camlog, Branemark, Astra, 3i, Avana.

충돌 접촉에 있어서의 차체와 승객의 손상

한문식(Moon-Sik Han),조재웅(Jae-Ung Cho) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.3

This study investigates the durability of car body and the safety of passenger inside car body in the case of the impact contact at passenger and car body. In case of front impact contact, maximum von Mises equivalent stress and principal stress become 3240.7㎫ and 1634㎫ respectively at the rear part of car body and the neck of dummy. And maximum total deformation occurred with 14.145㎜ at the hand of dummy. In case of side impact contact, maximum von Mises equivalent stress and principal stress become 7687.9㎫ and 1690.7㎫ respectively at the front part of car body and the lap of dummy. And maximum total deformation occurred with 16.414 ㎜ at the foot of dummy. In case of rear impact contact, maximum von Mises equivalent stress and principal stress become 2366.6MPa and 1447㎫ respectively at the front part of car body and the neck of dummy. And maximum total deformation occurred with 7.548㎜ at the rear part of car body. As the maximum von-Mises stress at side impact is shown with more than 700㎫ as over two times at front or rear impact the danger of car body is increased. The great possibility of damage is shown at neck and hand of dummy with more than total displacement of 10㎜.

프레스에 의한 블랭킹 판재의 응력 해석

조재웅(Jae-Ung Cho),한문식(Moon-Sik Han) 한국기계가공학회 2008 한국기계가공학회지 Vol.7 No.2

The data of the deformation and the stress according to time are studied at upper model of press and lower model of the blanking plate applied by press with the width, length and height of 0.4 m and 0.6 m respectively. The press is pushing downward on the plate fixed at the lower floor. These data are compared and investigated through this study. By using these results, there is the maximum deformation at 4 comers in the lower plate model of aluminium alloy fixed at lower floor. This deformation incase of elapsed time of 0.6 second becomes 4 times as much as in case of elapsed time of 0.2 second. The quantity of deformation at the lower plate model becomes more than at the upper press model to the extent of 10%. At the lower plate model of aluminium alloy, there is the maximum Von-Mises equivalent stress at 4 comers and both sides of middle area on the lower plate model of aluminium alloy. This stress in case of elapsed time of 0.6 second becomes 6 times as much as in case of elapsed time of 0.2 second. The Von-Mises equivalent stress of lower plate model becomes 2 times as much as that of upper press mode.

정지궤도복합위성 추진계 배관망 구조해석

정규,임재혁,채종원,전형열 항공우주시스템공학회 2018 항공우주시스템공학회지 Vol.12 No.1

In this paper, the structural analysis of the Geostationary Korea Multi-Purpose Satellite-2 (GEO-KOMPSAT-2) tubing system is discussed, and the structural integrity of the tubing system is assessed by comparative analysis with the results of overseas partner AIRBUS. Securing structural reliability of the tubing system is a very important key element of the propulsion system of the GEO-KOMPSAT-2 satellite. Therefore, FE modeling of the propulsion tubing was carried out directly using the CAE program, and structural analysis was performed to evaluate the stress state under launch conditions. Hoop stress, axial stress, bending stress, and torsion stress were calculated according to diverse load conditions by using pressure stress analysis, thruster alignment analysis, sine qualification load analysis, and random qualification load analysis. From the results, the Margin of Safety (MoS) of the tubing system is evaluated, and we can verify the structural integrity of the tubing system when subjected to various launch loads. 본 논문에서는 정지궤도복합위성 추진계 배관망의 독자적인 구조해석을 실시하였고, AIRBUS의 구조해석결과와 비교분석을 통해 추진계 배관망의 구조적 건전성 및 해석방법의 신뢰성을 평가하였다. 추진계 배관망의 구조적 신뢰성 확보는 정지궤도복합위성 추진계의 매우 중요한 핵심요소이다. 따라서 CAE 프로그램을 통해 직접 추진계 배관망 모델링을 수행하였고, 발사환경에서 구조해석을 실시하여 응력을도출하였다. 내압응력해석, 조립정렬해석, 정현파진동해석, 랜덤진동해석의 하중조건에 따라 Hoop stress, Axial stress, Bending stress, Torsion stress를 구하였고, 이를 모두 고려한 von Mises 응력 계산 후 안전여유 결과 값을 도출함으로써 추진계 배관망의 구조적 건전성을 판단하였다.

폴리머 콘크리트 포장을 적용한 강바닥판의 피로응력에 관한 해석적 연구

한범진,윤상일,최병진,최진웅,박선규 한국구조물진단유지관리공학회 2014 한국구조물진단유지관리공학회 논문집 Vol.18 No.5

본 연구에서는 초박층 교면포장으로 폴리설파이드 에폭시 폴리머 콘크리트 포장을 선정하여, 에폭시 아스팔트 포장, SFRC 포장과의 비교 분석을 통해 폴리머 콘크리트 포장이 강바닥판의 피로응력범위에 어떠한 영향을 미치는 지 분석하였다. 강바닥판의 피로응력범위를 산정하기 위해 Abaqus를 사용한 유한요소해석을 사용하여 비교평가하였으며, 용접부에 교축방향 및 교축직각방향의 다축응력이 발생하는 점을 감안하여 Signed Von-Mises 응력을 도입하여 피로 검토에 활용하였다. 강바닥판의 피로응력범위를 산정하기 위해 Abaqus를 사용한유한요소해석을 사용하여 포장 재료 및 두께에 따라 비교평가하였으며, 용접부에 교축방향 및 교축직각방향의 다축응력이 발생하는 점을 감안하여 Signed Von-Mises 응력을 도입하여 피로 검토에 활용하였다. In this study, polysulfide epoxy polymer concrete was chosen as an ultra thin bridge deck overlay, and the effect of polymer concrete pavement on the fatigue stress range of the orthotropic steel deck was analyzed through the comparative analysis with epoxy asphalt pavement and SFRC pavement. Abaqus was used to estimate the fatigue stress range, and signed von-mises stress was used to estimate fatigue stress range according to pavement materials and thickness, considering there were multi axis stresses which have longitudinal and lateral direction on the welded parts of the steel deck.

승용 A-IMS 모듈의 토크 변경에 따른 응력 분포특성

민세훈,서현규 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.6

This study was performed for the optimizations of A-IMS assembly by analyzing the stress distributions under the different torque conditions. In order to achieve this, the numerical simulation was performed by SOLIDWORKS commercial code and the torque range that applied on the A-IMS assembly was increased from 10 N·m to 40 N·m. The simulation results were analyzed and compared in terms of Von-mises stress, principal stress, and displacement characteristics. The maximum stress distributions was observed on the contact surface of needle bearing which is located between tubular and solid shaft. It was found that the fracture of A-IMS assembly won’t occur until 30 N·m of torque. Therefore, it was concluded that there is no problem for the manufacturing of A-IMS assembly.

Optimal torso design selection for dual 7-DOF robot arm using von Mises stress and workspace analysis

Hamza Khan,Saad Jamshed Abbasi,이민철 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.9

This paper presents a unique optimal torso design selection technique for the dual seven-degree-of-freedom robot arm. This optimal design enhances the robot endeffector's workspace with less operational stress. The selection procedure incorporates the von Mises stress and robot workspace analysis in different robot-torso mounting configurations. The torso design selection strategy includes the von Mises stress calculation numerically and by using SolidWorks static analysis for robot arm considered as bolted-fixed end cantilever beam. Followed by robot end-effector workspace analysis using inverse kinematics, which determines the maximum area covered by manipulated robot end-effector in 2-dimensional (2D) and 3-dimensional (3D) space. Subsequently, introducing a selection function for torso design. This selection function is calculated based on weighting coefficients (priority given to stress and workspace), von Mises stress, and workspace area. The selection technique concludes that the torso design with upper-arm mounting configuration is optimal for current robot application, i.e., assembly.

폴리머 콘크리트 포장을 적용한 강바닥판의 피로응력에 관한 해석적 연구

한범진,윤상일,최병진,최진웅,박선규 한국구조물진단유지관리공학회 2014 한국구조물진단유지관리공학회 논문집 Vol.18 No.5

In this study, polysulfide epoxy polymer concrete was chosen as an ultra thin bridge deck overlay, and the effect of polymerconcrete pavement on the fatigue stress range of the orthotropic steel deck was analyzed through the comparative analysis withepoxy asphalt pavement and SFRC pavement. Abaqus was used to estimate the fatigue stress range, and signed von-mises stresswas used to estimate fatigue stress range according to pavement materials and thickness, considering there were multi axis stresseswhich have longitudinal and lateral direction on the welded parts of the steel deck. 본 연구에서는 초박층 교면포장으로 폴리설파이드 에폭시 폴리머 콘크리트 포장을 선정하여, 에폭시 아스팔트 포장, SFRC 포장과의 비교 분석을 통해 폴리머 콘크리트 포장이 강바닥판의 피로응력범위에 어떠한 영향을 미치는 지 분석하였다. 강바닥판의 피로응력범위를 산정하기 위해 Abaqus를 사용한 유한요소해석을 사용하여 비교평가하였으며, 용접부에 교축방향 및 교축직각방향의 다축응력이 발생하는 점을 감안하여 Signed Von-Mises 응력을 도입하여 피로 검토에 활용하였다. 강바닥판의 피로응력범위를 산정하기 위해 Abaqus를 사용한유한요소해석을 사용하여 포장 재료 및 두께에 따라 비교평가하였으며, 용접부에 교축방향 및 교축직각방향의 다축응력이 발생하는 점을감안하여 Signed Von-Mises 응력을 도입하여 피로 검토에 활용하였다.

A Study on the Thermal Stress Analysis of Thick Plate Structures in Post Weld Heat Treatment

김용래,김재웅 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

Post weld heat treatment (PWHT) is carried out to improve the capacity of weld structures and to relieve welding residual stress. During the PWHT process, however, a cracking or deformation may occur in a weldment due to the formation of thermal stress and the redistribution of residual stresses. The aim of this study is to analyze the formation of thermal stress during PWHT and then to find the solution which decreases the thermal stress. In regard of the tensile stress, one of the causes of a cracking, the parametric studies are performed in detail through the numerical analysis. Simulations are carried out in the FE software MSC.Marc. PWHT experiments were performed to verify the reliability of the numerical analysis. On the basis of that, the numerical analyses of the thermal stress were carried out for the plate and nozzle shape in many cases such as change of thickness, PWHT temperature history and nozzle shape.