• Geomechanics and Engineering
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• 제16권4호
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• pp.449-461
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• 2018

The load sharing ratio (${\alpha}_{pr}$) of piles is one of the most common problems in the preliminary design of piled raft foundations. A series of 3D numerical analysis are conducted so that special attentions are given to load sharing characteristics under varying conditions, such as pile configuration, pile diameter, pile length, raft thickness, and settlement level. Based on the 3D FE analysis, influencing factors on load sharing behavior of piled raft are investigated. As a result, it is shown that the load sharing ratio of piled raft decreases with increasing settlement level. The load sharing ratio is not only highly dependent on the system geometries of the foundation but also on the settlement level. Based on the results of parametric studies, the load sharing ratio is proposed as a function of the various influencing factors. In addition, the parametric analyses suggest that the load sharing ratios to minimize the differential settlement of piled raft are ranging from 15 to 48% for friction pile and from 15 to 54% for end-bearing pile. The recommendations can provide a basis for an optimum design that would be applicable to piled rafts taking into account the load sharing characteristics.

• International Journal of Contents
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• 제2권1호
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• pp.39-44
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• 2006

Load sharing is a critical resource in computer system. In sender-initiated load sharing algorithms, the sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. Meanwhile, in the receiver initiated load sharing algorithms, the receiver continues to send an unnecessary request message for load acquisition until a sender is found while the system load is light. These unnecessary request messages result in inefficient communications, low CPU utilization, and low system throughput in distributed systems. To solve these problems, we propose a genetic algorithm based approach for improved sender-initiated and receiver-initiated load sharing in distributed systems. And we expand this algorithm to an adaptive load sharing algorithm. Compared with the conventional sender-initiated and receiver-initiated algorithms, the proposed algorithm decreases the response time and task processing time.

• Steel and Composite Structures
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• 제12권6호
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• pp.523-540
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• 2012

It was clear from the former researches on reinforced concrete filled tubular steel (RCFT) structures that RCFT structures have different performance than concrete filled steel tubular (CFT) structures. However, despite of that, load-sharing ratio of RCFT is evaluating by the formula and range of CFT given by JSCE. Therefore, the aim of this investigation is to study the load-sharing ratio of RCFT columns subjected to axial compressive load by performing numerical simulations of RCFT columns with the nonlinear finite element analysis (FEA) program - ADINA. To achieve this goal, firstly proper material constitutive models for concrete, steel tube and reinforcement are proposed. Then axial compression tests of concrete, RC, CFT, and RCFT columns are carried out to verify proposed material constitutive models. Finally, by the plenty of numerical analysis with small-sized and big-sized columns, load-sharing ratio of RCFT columns was studied, the evaluation formulas and range were proposed, application of the formula was demonstrated, and following conclusions were drawn: The FEA model introduced in this paper can be applied to nonlinear analysis of RCFT columns with reliable results; the load-sharing ratio evaluation formula and range of CFT should not be applied to RCFT; The lower limit for the range of load-sharing ratio of RCFT can be smaller than that of CFT; the proposed formulas for load-sharing ratio of RCFT have practical mean in design of RCFT columns.

• International Journal of Contents
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• 제4권2호
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• pp.13-18
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• 2008

A load sharing algorithm is one of the important factors in computer system. In sender-initiated load sharing algorithms, when a distributed system becomes to heavy system load, it is difficult to find a suitable receiver because most processors have additional tasks to send. The sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. Because of these unnecessary request messages it results in inefficient communications, low cpu utilization, and low system throughput. To solve these problems, we propose a self-adjusting evolutionary algorithm for improved sender-initiated load sharing in distributed systems. This algorithm decreases response time and increases acceptance rate. Compared with the conventional sender-initiated load sharing algorithms, we show that the proposed algorithm performs better.

• 전력전자학회논문지
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• 제16권1호
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• pp.50-57
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• 2011

본 논문에서는 마이컴(ATmega-2560) 기반의 디지털 통신 방식을 이용한 새로운 부하분담(Load-sharing) 알고리즘(Algorithm)을 제안한다. 기존의 아날로그 방식과 달리 고속 통신과 디지털 제어를 수행하고 실시간 제어를 위한 시분할 토큰버스 방식을 적용함으로서 효율적인 부하분담 및 리던던시(Redundancy)를 구현하였다. 또한 자동 ID 설정 알고리즘을 적용함으로서 시스템 비용을 낮추었으며, 제어기의 전압 및 전류 적분값을 공유하는 새로운 알고리즘으로 시스템의 속응성을 향상시켰다. 제작된 병렬 시스템은 각 모듈마다 독립된 제어기가 구성되어 있으며, 마스터(Master) 모듈의 지령치에 따라 슬레이브(Slave) 모듈이 부하분담을 수행한다. 본 논문에서는 PSIM을 통한 시뮬레이션과 시작품 제작을 통해 제안된 알고리즘의 타당성을 검증하였다.

• Journal of Biosystems Engineering
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• 제41권3호
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• pp.145-152
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• 2016

Purpose: This study aims to establish the effect of pinhole position errors in the planet carrier of a planetary gear set (PGS) on load sharing among the planet gears in the hydromechanical transmission (HMT) system of an agricultural tractor. Methods: A simulation model of a PGS with five planet gears was developed to analyze load sharing among the planet gears. The simulation model was verified by comparing i ts r esults w ith those of a model developed in a previous s tudy. The verified simulation model was used to analyze the load-sharing characteristics of the planet gears with respect to the pinhole position error and the input torque to the PGS. Results: Both simulation models had identical load magnitude sequences for the five planet gears. However, the load magnitudes on the corresponding planet gears differed between the models because of the different stiffnesses of the PGS components and the input torques to the PGS. The verified simulation model demonstrated that the evenness of load sharing among the planet gears increases with decreasing pinhole position error and increasing input torque. Conclusions: The geometrical tolerance of the pinhole position should be properly considered during the design of the planet carrier to improve the service life of the PGS and load sharing among the planet gears.

• 한국생산제조학회지
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• 제25권2호
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• pp.97-104
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• 2016

In this study, the qualitative effects of the positional error of carrier pin holes on the planet load sharing characteristics of the three-point suspension gearbox of wind turbines were investigated experimentally. A 35-kW gearbox comprising two planetary gear stages and a parallel gear stage and size one-fourth of that of a 2-MW three-point suspension gearbox was used as the test gearbox. The strain gauges attached to the ring gear teeth of the input planetary gear stage were used for the purpose of this study. The applied loading conditions were 50%, 75%, and 100% of the rated torque, and the mesh load factor was used as the load sharing index. The experimental results indicated that both the magnitude and direction of the positional error of pin holes had a significant effect on the planet load sharing characteristics of the three-point suspension gearbox. In addition, an increase in the applied torque results in uniform load sharing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1775-1780
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• 2003

A hybrid finite element analysis was used to analyze the influence of ring gear rim thickness and spline number on the static properties of an epicyclic gear system with manufacturing errors. Both of these parameters affected the bearing force and critical stress. The effect of changes in the rim thickness on the load sharing between the gears depended on the type of manufacturing error. Ring flexibility improved the load sharing between planetary gears only in systems with planet tooth thickness or planet tangential errors; for other types of error, ring flexibility worsened the load sharing. To improve load sharing, rim thickness and spline number should be controlled within a specific range. The effect of the ring gear boundary condition was more apparent in a system with errors than in a normal system.

• Journal of Biosystems Engineering
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• 제43권4호
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• pp.263-272
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• 2018

Purpose: The load on the planet gear of a planetary gear set is uniformly distributed. However, manufacturing and assembly errors cause uneven load sharing in the planetary gear set. To solve this problem, most studies have suggested applying a floating sun gear to the planetary gear set. However, the effect of the floating ring gear and floating carrier has not been extensively studied. This study aimed to investigate the effect of the floating ring gear. Methods: Two models were developed; one was the fixed ring gear model, and the other was the floating ring gear model. In the fixed ring gear model, the clearance between the ring gear and the housing was $0{\mu}m$, and in the floating ring gear model, the clearance was from $10{\mu}m$ to $100{\mu}m$. The load sharing of the planetary gear set was evaluated by the load sharing factor. Results: Our study showed that with increase in clearance, the load sharing factor of the planetary gear set approached unity. In addition, when the clearance increased above a certain level by which a fully floating ring gear was achieved, the load sharing factor was not affected by the clearance. Conclusions: This indicates that the fully floating ring gear increased the power density of the planetary gearbox by uniformly dividing the load of the planetary gear set. For this reason, the size of the gearbox could be decreased by using a fully floating ring gear.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1949-1957
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• 2003

A hybrid finite element analysis was used to analyze the influence of ring gear rim thickness and spline number on the static properties of a planetary gear system with manufacturing errors. Both of these parameters affected the bearing force and critical stress. The effect of changes in the rim thickness on the load sharing between the gears depended on the type of manufacturing error. Ring flexibility improved the load sharing between planetary gears only in systems with planet tooth thickness or planet tangential errors; for other types of error, ring flexibility worsened the load sharing. To improve load sharing, rim thickness and spline number should be controlled within a specific range. The minimum rim thickness limit should be determined considering not only the critical stress but also the load sharing. The effect of the ring gear boundary condition was more apparent in a system with errors than in a normal system.