• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3703-3716
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• 2022

Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1726-1746
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• 2022

This paper presents fracture mechanics analysis results for various cracks located at pressurized water reactor pressure vessel nozzle crotch corners taking into consideration constraint effect. Technical documents such as the ASME B&PV Code, Sec.XI were reviewed and then a fracture mechanics analysis procedure was proposed for structural integrity assessment of various nozzle crotch corner cracks under normal operation conditions considering the constraint effect. Linear elastic fracture mechanics analysis was performed by conducting finite element analysis with the proposed analysis procedure. Based on the evaluation results, elastic-plastic fracture mechanics analysis taking into account the constraint effect was performed only for the axial surface crack of the reactor pressure vessel outlet nozzle with cladding. The fracture mechanics analysis result shows that only the axial surface crack in the reactor pressure vessel outlet nozzle has the stress intensity factor exceeding the low bound of upper-shelf fracture toughness irrespectively of considering the constraint effect. It is confirmed that the J-integral for the axial crack of the outlet nozzle does not exceed the ductile crack initiation toughness. Hence, it can be ensured that the structural integrity of all the cracks is maintained during the normal operation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.149-154
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• 2002

An analytical fracture mechanics approach was used to investigate the fracture behavior of reinforced concrete beams. By use of this approach based on fracture mechanics concepts, the crack width and length as well as the strength and cracking stability of reinforced concrete beams were investigated. The results obtained from the analytical studies were also discussed in terms of the minimum reinforcement ratio and crack width specified in design code provisions. The analytical approach based on fracture mechanics concepts are very useful to predict the fracture behavior of reinforced concrete beams.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 1996년도 정기총회 및 학술발표회
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• pp.1-10
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• 1996

Fracture toughness of rock materials, which generally violate the fundamental assumptions of LEFM, often depends on the specimen size and test method employed. Hence, a standardized procedure for testing and data interpretation for determining fracture toughness of rock materials is required. Special attention has been given by the International Society for Rock Mechanics (ISRM) to the difficulties in obtaining true fracture mechanics parameters for the wide variety of rock materials. (omitted)

• 대한수학회지
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• 제38권2호
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• pp.385-408
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• 2001

This is an introduction to a stochastic version of E. Cartan′s symplectic mechanics. A class of time-symmetric("Bernstein") diffusion processes is used to deform stochastically the exterior derivative of the Poincare-Cartan one-form on the extended phase space. The resulting symplectic tow-form is shown to contain the (a.e.) dynamical laws of the diffusions. This can be regarded as a geometrization of Feynman′s path integral approach to quantum theory; when Planck′s constant reduce to zero, we recover Cartan′s mechanics. The underlying strategy is the one of "Euclidean Quantum Mechanics".

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.419-419
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• 2006

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.723-723
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• 2006

• Structural Engineering and Mechanics
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• 제10권3호
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• pp.289-298
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• 2000

Based on the two-dimensional constitutive relationship of the piezoelastic material, this paper derived an analytic solution to the elastic beam with the piezoelectric layer under the electric field, presented the explicit expressions of its displacement and stress. It is helpful for understanding the electrical and mechanical behavior of piezoelectric materials as actuators and the validation of the numerical methods such as FEM.

• Coupled systems mechanics
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• 제9권1호
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• pp.5-28
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• 2020

Despite a widely-held belief that the finite element method is the method for the solution of solid mechanics problems, which has for 30 years dissuaded solid mechanics scientists from paying any attention to the finite volume method, it is argued that finite volume methods can be a viable alternative. It is shown that it is simple to understand and implement, strongly conservative, memory efficient, and directly applicable to nonlinear problems. A number of examples are presented and, when available, comparison with finite element methods is made, showing that finite volume methods can be not only equal to, but outperform finite element methods for many applications.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.131-133
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• 2006

A high efficiency half bridge converter for PDP in whole operation load range is proposed in this paper. The ZVS(Zero Voltage Switching) in whole load range and high efficiency in low load range is achieved because the proposed converter is switched by fixed frequency asymmetrical duty ratio and resonant operation.