• 수산해양기술연구
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• 제35권1호
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• pp.50-53
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• 1999

In this paper, the mechanical movement of lip seal-ring which plays the most important function in stern-tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. By the finite element method for axial symmetry object which receives the torsional bending load, the displacement and stress analysis of the seal-rings are executed for products of several representative manufacturers of seal-rings, and also the possibility of crack occurance are checked by theoretical analysis. A sample seal-ring id designed and manufactured using the program of displacement and stress analysis developed in this study and made an experimental apparatus to test the sampling seal-ring. The sampling seal-ring functioned excellently, but it had its durability and this problem may be solved by using the Viton instead of NBR.

• Computers and Concrete
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• 제16권1호
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• pp.1-16
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• 2015

The proposed techniques to strengthen concrete members such as steel plates, polymers or concrete have important deficiencies in adherence and durability. The use of UHPFC plates can overtake effectively these problems. In this paper, the possibility of using UHPFC to strengthen RC beams under torsion is investigated. Four specimens of concrete beams reinforced with longitudinal bars only were tested under pure torsion. One of the beams was considered as the baseline specimen, while the others were strengthened by ultra-high-performance fiber concrete (UHPFC) on two, three, and four sides. Finite element analysis was conducted in tandem with experimental work. Results showed that UHPFC enhances the strength, ductility, and toughness of concrete beams under torsional load, and that finite element analysis is in good agreement with the experimental data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1098-1100
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• 2001

In the industrial motor drive system which is composed of a motor and load connected with a flexible shaft, a torsional vibration is often generated because of the elastic elements in torque transmission. To solve this problem, $H_{\infty}$ controller was designed. In this paper, $H_{\infty}$ control of 2-mass system using $H_{\infty}$ filter for compensating shaft torque is proposed. Pole-zero maps show the validity of proposed controller.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.442-447
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• 2003

The actual behavior of the railroad track structure is suspected to be a complex interaction between the vertical, lateral, longitudinal, and torsional behaviors. A FE program are developed in the present study to be used for extensive nonlinear analysis of the track structures subjected to thermal load. Using the rigorous study on the deformed shape of the rail and tie, and stress resultants, characteristics of the three dimensional behavior are investigated. It is found that the flexural rigidity of the tie and the rotational stiffness of pad-fastener can be affect the behavior of the track structure and the postbuckling behavior in each rail, except lateral behavior, is not same.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.815-817
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• 1999

In the two-mass system driving a load through a flexible shaft or transmission system, a shaft torsional vibration is often generated. In this case, it's difficult to control only by conventional PI controller. To solve this problem. the two-mass speed control system with PID controller is designed by using pole assignment method, and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. Simulation results show the validity of the proposed PID controller and this controller is compared with the conventional PID controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.481-484
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• 2000

Practical structures are subject not only to tension but also to shear and torsional loading. Even under uniaxial loading, when the load is not perpendicular to the crack plane, mixed mode crack can occur. Hence, it is necessary to evaluate the fatigue behavior under mixed mode loading. In this study, the propagation behavior of the fatigue crack of the STS304 steels under mixed mode loading condition was investigated. The mode I and II stress intensity factors of CTS specimen were calculated using elastic finite element method with experimental results. The fatigue crack propagation under mixed mode was evaluated by the effective stress intensity factor proposed by Tanaka.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.359-368
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• 2006

The trend on marine diesel engine productions and refinements has led to a higher mean effective pressure and thermal efficiency. These resulted in increased maximum combustion pressure within the cylinder and vibratory torque in crankshaft. In view of this. the crankshaft should be able to withstand the dynamic stresses caused by load variations. Different factors including size, material and stress concentration factors should also be considered to ensure the reliability of the shafting system. As such, crankshaft must be designed and compacted within its fatigue strength. In this paper, the strength analysis of crankshaft Is carried out by: simplified method recommended by IACS(International Association Classification Societies) M53 and a detailed method with the crankshaft assumed as a continuous beam and bearing supported in its flexibility. The results of these two methods are then compared.

• Steel and Composite Structures
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• 제9권3호
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• pp.275-301
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• 2009

The long-term behaviour of simply supported composite steel-concrete beams with deformable connectors subjected to skew bending and torsion is presented. The problem is dealt with by recurring to the displacement method, assuming the bending and torsional curvatures and the longitudinal deformations of each sectional part as unknowns and obtaining a system of differential and integro-differential equations. Some solving methods are presented, in order to obtain exact and approximate solutions and evaluate the precision of the approximate ones. A case study is then presented. For the sake of clearness, the responses of the composite beam under loads applied in different directions are studied separately, in order to correctly evaluate the effects of each load condition.

• 콘크리트학회논문집
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• 제12권5호
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• pp.13-23
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• 2000

In this study, an flexural test on half-scale spliced PSC-I girder was conducted to verify the efficiency of the long span spliced girder as suggested by the Korean Highway Design Specification. The experimental results showed that the specimens developed a complex failure mode due to flexural-compression and torsional stress. The cracking moment of each girder was higher the experiment than was calulated by the ACI and the ultimate strength were the almost same. To estimate the safety and the structural efficiency of the spliced girder, the proposed Yielding Resistance Index(YRI) and ductility index by American Concrete Institutes were used based on the energy concept. The proposed YRI defined the ratio of crack resisting energy and the total energy calculated from load-displacement relationship. Based on the analysis of YRI and ductility index, the flexural behavior of the spliced girder was found to be efficient. Through the experimental results, the structural behavior of proposed spliced PSC I-type girder for long span bridge was found to be more efficient than the exsisting PSC I-type girders.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.515-517
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• 1997

In the industrial motor drive system, a shaft torsional vibration is often generated when a motor and a load are connected with a flexible shaft. This paper treats the vibration suppression control of such a system. In this paper, two-degree-of-freedom(TDOF) control of the two-mass resonant system using the $H_{\infty}$ filter is proposed. TDOF control method satisfies the command following property and the internal stability at the same. The $H_{\infty}$ filter is robust in noise and disturbance. Simulation results show the validity of the proposed control method.