Effect of implant- and occlusal load location on stress distribution in Locator attachments of mandibular overdenture. A finite element study

Alvarez-Arenal, Angel,Gonzalez-Gonzalez, Ignacio,deLlanos-Lanchares, Hector,Martin-Fernandez, Elena,Brizuela-Velasco, Aritza,Ellacuria-Echebarria, Joseba The Korean Academy of Prosthodonitics 2017 The Journal of Advanced Prosthodontics Vol.9 No.5

PURPOSE. The aim of this study is to evaluate and compare the stress distribution in Locator attachments in mandibular two-implant overdentures according to implant locations and different loading conditions. MATERIALS AND METHODS. Four three-dimensional finite element models were created, simulating two osseointegrated implants in the mandible to support two Locator attachments and an overdenture. The models simulated an overdenture with implants located in the position of the level of lateral incisors, canines, second premolars, and crossed implant. A 150 N vertical unilateral and bilateral load was applied at different locations and 40 N was also applied when combined with anterior load at the midline. Data for von Mises stresses in the abutment (matrix) of the attachment and the plastic insert (patrix) of the attachment were produced numerically, color-coded, and compared between the models for attachments and loading conditions. RESULTS. Regardless of the load, the greatest stress values were recorded in the overdenture attachments with implants at lateral incisor locations. In all models and load conditions, the attachment abutment (matrix) withstood a much greater stress than the insert plastic (patrix). Regardless of the model, when a unilateral load was applied, the load side Locator attachments recorded a much higher stress compared to the contralateral side. However, with load bilateral posterior alone or combined at midline load, the stress distribution was more symmetrical. The stress is distributed primarily in the occlusal and lateral surface of the insert plastic patrix and threadless area of the abutment (matrix). CONCLUSION. The overdenture model with lateral incisor level implants is the worst design in terms of biomechanical environment for the attachment components. The bilateral load in general favors a more uniform stress distribution in both attachments compared to a much greater stress registered with unilateral load in the load side attachments. Regardless of the implant positions and the occlusal load application site, the stress transferred to the insert plastic is much lower than that registered in the abutment.

Effect of implant- and occlusal load location on stress distribution in Locator attachments of mandibular overdenture. A finite element study

Angel Alvarez-Arenal,Ignacio Gonzalez-Gonzalez,Hector deLlanos-Lanchares,Elena Martin-Fernandez,Aritza Brizuela-Velasco,Joseba Ellacuria-Echebarria 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.5

PURPOSE. The aim of this study is to evaluate and compare the stress distribution in Locator attachments in mandibular two-implant overdentures according to implant locations and different loading conditions. MATERIALS AND METHODS. Four three-dimensional finite element models were created, simulating two osseointegrated implants in the mandible to support two Locator attachments and an overdenture. The models simulated an overdenture with implants located in the position of the level of lateral incisors, canines, second premolars, and crossed implant. A 150 N vertical unilateral and bilateral load was applied at different locations and 40 N was also applied when combined with anterior load at the midline. Data for von Mises stresses in the abutment (matrix) of the attachment and the plastic insert (patrix) of the attachment were produced numerically, color-coded, and compared between the models for attachments and loading conditions. RESULTS. Regardless of the load, the greatest stress values were recorded in the overdenture attachments with implants at lateral incisor locations. In all models and load conditions, the attachment abutment (matrix) withstood a much greater stress than the insert plastic (patrix). Regardless of the model, when a unilateral load was applied, the load side Locator attachments recorded a much higher stress compared to the contralateral side. However, with load bilateral posterior alone or combined at midline load, the stress distribution was more symmetrical. The stress is distributed primarily in the occlusal and lateral surface of the insert plastic patrix and threadless area of the abutment (matrix). CONCLUSION. The overdenture model with lateral incisor level implants is the worst design in terms of biomechanical environment for the attachment components. The bilateral load in general favors a more uniform stress distribution in both attachments compared to a much greater stress registered with unilateral load in the load side attachments. Regardless of the implant positions and the occlusal load application site, the stress transferred to the insert plastic is much lower than that registered in the abutment.

공동주택의 세대위치별 열부하 특성 분석

윤성환(Yoon Seong-Hwan),장희경(Jang Hee-Kyung),김영탁(Kim Young-Tag) 대한건축학회 2009 대한건축학회논문집 Vol.25 No.10

This study is focused on analysis of the characteristics of thermal load using dynamic heat load simulation according to building exterior thermal performance and direction classified by each household in apartment house. The conclusion of the study is as follows. 1) The characteristics of thermal load classified by each household in a view of the story showed that the mean heating and cooling load at the top floor was the highest(371MJ/㎡yr), the second highest at the ground floor(339MJ/㎡yr) and the lowest at the center floor(281MJ/㎡yr). The heating load of each household in the same story was increased by 10%(side wall of center floor)∼52%(side wall of ground floor) than the center household of center floor which has the lowest in heating load. In the case of cooling load small change occurred except the ground floor. 2) As a result of investigating the characteristics of thermal load according to the change of direction, apartment block which has 25th floor and one hundred of household showed that the south(232MJ/㎡yr) was the most advantageous direction for heating load and the northeast(290MJ/㎡yr) was the most disadvantageous. In the case of cooling load, the south and north(51MJ/㎡yr) was the most advantageous direction and the east(63MJ/㎡yr) was the most disadvantageous. 3) As improving building exterior thermal performance by 10% against the legal standards of building, the mean heating load of one hundred household showed a increased by 22∼23MJ/㎡yr as the mean thermal disadvantage factor was increased by 0.1W/㎡K. Mean heating load and the mean thermal disadvantage factor showed liner correlations. As improving building exterior thermal performance, the mean cooling load of one hundred household showed a constant pattern.

상재하중의 재하위치 및 매설심도를 고려한 지중 매설관의 구조거동 평가

류연선(Ryu Yeon Sun),조현만(Cho Hyun Man),김영빈(Kim Young bin) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.2

지중매설관은 산업의 각종분야 및 지하 기반시설에 널리 사용되고 있다. 지중 매설관에 작용하는 하중으로는 토압, 차량하중, 온도, 지진 하중, 부양하중 등이 있다. 특히 다수의 매설관은 도로 포장아래에 매설되어 있고, 과도한 차량하중이나 예상치 못한 하중을 받는 경우가 있다. 본 논문에서는 매설관의 상부 및 인근에 상재하중이 작용할 때 나타나는 매설관의 구조적 거동을 상재하중의 재하위치, 매설관의 매설깊이, 매설관의 크기를 고려하여 평가하였다. 이를 위해 수치모델을 구성하고 유한요소해석을 수행하였다. 매설깊이와 재하위치에 따라 매설관의 변위와 응력의 변화를 산정하고, 그 결과로부터 거동특성을 파악하였다. Buried pipes have been applied in a wide range of industry and the subsurface infrastructures. The loads acting on buried pipes include soil pressure, traffic load, seismic load, flotation. Many underground pipes are buried under the road pavement and subjected to excessive vehicle load or unexpected load. In this paper, the structural behavior of the buried pipe under the surcharge load is evaluated considering load location, buried depth and dimension of pipe. Finite element analysis was perform for the assessment of the displacement and stress of buried pipe. The results showed the effect of the load location and buried depth on performance of the underground pipe.

Sex differences of cognitive load effects on object-location binding memory

박진식,신가인,박영민,김인영,장동표 대한의용생체공학회 2017 Biomedical Engineering Letters (BMEL) Vol.7 No.4

In this study, we investigated where the sexdifferences of object-location binding memory performancewere influenced by the cognitive load. We used thefractal objects version of the ‘What was where?’ task tomeasure object memory, location memory and objectionlocationbinding memory. Cognitive load was controlled bytask difficulty presented two sessions: one session randomlydisplayed three or four fractal objects (Session 34)and the other session four or five objects (Session 45). Theresults showed that females outperformed males on objectlocationbinding memory. Interestingly, even when the fourobject trials were compared between Session 34 and Session45, in which we believed that the level of difficultywas similar while cognitive load varied, the swap error ofmales was significantly increased in Session 45 comparedto females. In conclusion, there may be sex differences inobject-location binding memory and the males could bemore sensitive about the cognitive load than females.

A Location-Based Deterministic Load Balancing for Cluster Routing Protocol in Wireless Sensor Networks

강상혁,최혜경 한국통신학회 2024 韓國通信學會論文誌 Vol.49 No.1

Wireless sensor networks (WSN) play an important role in Internet of Things (IoT). Routing protocols are essential for energy-efficient WSN with battery powered sensor nodes. Cluster-based hierarchical routing protocols are renowned for its simplicity and efficiency in WSN. However, stochastic cluster formation in conventional schemes often suffer from high energy drain. We suggest a location-based load balancing scheme with a deterministic cluster formation approach. Our proposed scheme features the location phase which is carried out once before the first round starts in the beginning. In the location phase, the sensor nodes exchange greeting messages to measure the distance between every pair of nodes. The distance information is forwarded to the base station (BS) node. The BS node calculates the exact coordinate of every sensor node and then constructs a deterministic process for cluster head selection and transmission scheduling in clusters. Our proposed scheme is evaluated through computer simulations and is shown to outperform existing schemes with or without location information, in terms of network/node lifespan.

유전자알고리즘을 이용한 정적풍하중의 추정에 관한 연구

황재승,이충남 한국풍공학회 2009 한국풍공학회지 Vol.13 No.2

In this study, a procedure to estimated static wind loads on building structures using a real-code genetic algorithm is provided. In the process, the effect of the location and number of sensors on the accuracy of the estimation is profoundly investigated through numerical analysis. With actual static wind loads evaluated according to the KBC 2005 code, displacement responses of a thirty-story building are calculated and some of the displacement responses are used to identify the static wind loads. From the numerical results, it is shown that the accuracy of the estimation is sensitive to the performance index of the genetic algorithm and the accuracy can be enhanced when the location of sensors is uniformly distributed over the building. 본 연구에서는 실수코딩 유전자알고리즘을 이용하여 정적풍하중을 추정하는 과정에서 중요한 요소인 측정센서의 개수와 위치가 미치는 영향을 분석하는 것을 목적으로 하였다. 영향을 분석하는 방법은 수치적인 방법을 이용하며 실수코딩 유전자알고리즘을 이용한 해석후의 실제 풍하중 추정정도의 정확도에 따라 측정센서의 개수와 위치에 의한 영향을 평가하였다. 첫 단계로써 코드에 따른 정적풍하중을 생성하여 30층 구조물에 대한 각 층의 풍하중, 전단강성행렬, 정적변위를 구한 후 다음 단계로써 유전자알고리즘을 이용하여 센서의 개수와 위치에 따라 구조물의 응답을 사용하여 풍하중을 추정하였다. 유전자알고리즘의 목적함수는 실제풍하중과 또는 실제풍하중과 유사하게 생성한 풍하중을 이용하여 만들 수 있다. 본 연구에서는 센서의 개수와 위치에 따른 각 변수의 최단시간 도출에 대한 내용을 분석하는데 중점을 두어 실제풍하중을 목적함수로 이용하였다.

로드셀 기반의 실내 위치추적 보완 기법

이남수 ( Nam-su Yi ),문승진 ( Seung-jin Moon ) 한국인터넷정보학회 2016 인터넷정보학회논문지 Vol.17 No.6

기존의 실내 침입 탐지 및 대상 객체의 이동 경로 추정은 객체가 수신 장치를 갖고 있어야 하는 문제점과 단일 셀(약 100cm ^* 100cm)의 공간 내에 객체의 수와 이동 범위를 파악할 수 없는 문제가 지적되어 왔다. 이러한 방법을 해결하기 위해 보편적으로 사용되는 기술인 CCTV를 이용한 방법은 환경적인 변수로 인하여 상당히 제한적일 뿐만 아니라 음영 지역에서(e.g., 상황인식 시스템이 설치되지 않은 곳, 광량이 현저히 낮아 환경의 상황을 파악할 수 없을 경우) 서비스를 받을 수 없다. 이에 본 논문은 센서 네트워크(Sensor Network) 시스템 기반의 객체 탐지 및 대응의 범위 확대가 가능함과 동시에 대상 객체의 이동경로 추적을 능동적으로 대응할 수 있는 실내 보안감시 시스템을 제안한다. 제안된 시스템은 가상의 시나리오에 기반을 두어 구현되었으며, 기존 시설에서 발생할 수 있는 환경적인 단점인 신호의 단절 및 사물의 위치 추정에 대한 손실을 보완하며, 위급한 상황 및 객체에 대한 행동 패턴의 신속한 분석이 가능케 되어, 비상시 사고 예방 및 발생된 상황에 대한 유연한 대처가 가능하리라 사료된다. Current indoor intrusion detection and location tracking methods have the weakness in seamless operations in tracking the objective because the object must possess a communicating device and the limitation of the single cell size (approximate 100cm ^* 100cm) exits. Also, the utilization of CCTV technologies show the shortcomings in tracking when the object disappear the area where the CCTV is not installed or illumination is not enough for capturing the scene (e.g. where the context-awarded system is not installed or low illumination presents). Therefore, in this paper we present an improved in-door tracking system based on sensor networks. Such system is built on a simulated scenario and enables us to detect and extend the area of surveillance as well as actively responding the emergency situation. Through simulated studies, we have demonstrated that the proposed system is capable of supplementing the shortcomings of signal cutting, and of estimating the location of the moving object. We expect the study will improve the better analysis of the intruder behavior, the more effective prevention and flexible response to various emergency situations.

Experimental study on the performance of compensation grouting in structured soil

Zheng, Gang,Zhang, Xiaoshuang,Diao, Yu,Lei, Huayang Techno-Press 2016 Geomechanics & engineering Vol.10 No.3

Most laboratory test research has focused on grouting efficiency in homogeneous reconstituted soft clay. However, the natural sedimentary soils generally behave differently from reconstituted soils due to the effect of soil structure. A series of laboratory grouting tests were conducted to research the effect of soil structure on the performance of compensation grouting. The effects of grouting volume, overlying load and grouting location on the performance of compensation grouting under different soil structures were also studied. Reconstituted soil was altered with added cement to simulate artificial structured soil. The results showed that the final grouting efficiency was positive and significantly increased with the increase of stress ratio within a certain range when grouting in normally consolidated structured clay. However, in the same low yield stress situation, the artificial structured soil had a lower final grouting efficiency than the overconsolidated reconstituted soil. The larger of normalized grouting volume could increase the final grouting efficiency for both reconstituted and artificial structured soils. Whereas, the effect of the overlying load on final grouting efficiencies was unfavourable, and was independent of the stress ratio. As for the layered soil specimens, grouting in the artificial structured soil layer was the most efficient. In addition, the peak grouting pressure was affected by the stress ratio and the overlying load, and it could be predicted with an empirical equation when the overlying load was less than the yield stress. The end time of primary consolidation and the proportion of secondary consolidation settlement varied with the different soil structures, grouting volumes, overlying loads and grouting locations.

골유착성 임플랜트 보철물의 캔틸레버 위치와 길이변화에 따른 삼차원 유한요소법적 응력분석

장복숙,김창회,김영수,Jang, Bok-Sook,Kim, Chang-Whe,Kim, Yung-Soo 대한치과보철학회 1996 대한치과보철학회지 Vol.34 No.3

This study investigated the effects of cantilever length, location and load condition on stress distribution developed in the implants, prostheses and supporting tissues. The osseointegrated prostheses with two 10mm Branemark implants at 2nd premolar and 1st molar sites with cantilever extensions at 1st premolar, 2nd and 3rd molar sites were constructed. Under 100N, 200N of vertical and $45^{\circ}$ oblique loads at the cantilever pontics, stress distribution patterns and displacement were analyzed with three dimensional finite element method. The results were as follows : 1. The stress was concentrated at the joint of the cantilever pontic and implant superstructure, the neck of implant and the ridge crest near the cantilever But there was little load transfer to the lower supporting tissues of implants. 2. The implant near the cantilever was displaced inferiorly while the implant far from the cantilever was displaced superiorly. In horizontal direction the implants were displaced to the direction where the loads were applied, except the apexes of the implants. 3. In case of anterior cantilever, the stress and displacement were higher than the prosthesis connected with natural tooth. 4. The stress developed in the posterior cantilevered type was higher than in the anterior cantilevered type. The greastest stress was concentrated at the ridge crest near the posterior cantilever. 5. The longer the cantilever, the more the stress was developed and was concentrated at the joint of the cantilever pontic and implant superstructure. 6. Under oblique load, the stress was concentrated at the necks of implants and the ridge crests, but decreased at the joint of the cantilever pontic and implant superstructure than under vertical load.