• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4295-4306
• /
• 2023

The vibration of fuel rods in axial flow is a universally recognized issue within both engineering and academic communities due to its significant importance in ensuring structural safety. This paper aims to thoroughly investigate the stability and nonlinear vibration of a fuel rod subjected to axial flow in a newly designed high temperature gas cooled reactor. Considering the possible presence of thermal expansion and large deformation in practical scenarios, the thermal effect and geometric nonlinearity are modeled using the von Karman equation. By applying Hamilton's principle, we derive the comprehensive governing equation for this fluid-structure interaction system, which incorporates the quadratic nonlinear stiffness. To establish a connection between the fluid and structure aspects, we utilize the Galerkin method to solve the perturbation potential function, while employing mode expansion techniques associated with the structural analysis. Following convergence and validation analyses, we examine the stability of the structure under various conditions in detail, and also investigate the bifurcation behavior concerning the buckling amplitude and flow velocity. The findings from this research enhance the understanding of the underlying physics governing fuel rod behavior in axial flow under severe yet practical conditions, while providing valuable guidance for reactor design.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.1
• /
• pp.21-26
• /
• 2013

In recent study, infiltration analysis considering rainfall intensity is more economical and practical than existing analysis method. Revised construction slope design standard is also stated to full-fill infiltration analysis considering rainfall for practical stability review. Infiltration analysis considering rainfall for practical stability review. But, to infiltration analysis, the process is complicated by ground impermeability and rainfall intensity. In this study, we perform infiltration analysis to charge infiltration conditions, soil type and rainfall characteristics, for more pratical stability review. Using the result, we can suggest construable condition on the assumption that soil is saturated up to surface zone.

• Journal of the Korean Magnetic Resonance Society
• /
• v.26 no.4
• /
• pp.66-70
• /
• 2022

Protein structure determination using NMR spectroscopy requires a suite of heteronuclear 3-D NMR experiments that can take a couple of weeks for completion. During the experiments, protein samples may suffer from slow degradation due to co-purifying proteases, which complicates and slows down the assignment procedure. Here we describe a practical protocol to avoid unwanted proteolysis during the experiment.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.6
• /
• pp.437-443
• /
• 1987

Due to the recent development of microprocessor, the digital control is now in use for the practical structure of the control systems, but it leaves the problem of controlling delays caused by computation time when it is applied to the realization problems, such as application method of the control law and controlling effect of continuous control, etc. This paper deals with robust stability of the digital regulator which compensates for the controlling delays by applying prediction values of state.

• Proceedings of the KIEE Conference
• /
• 2005.11b
• /
• pp.362-364
• /
• 2005

In abroad, thousands of generator testing were accomplished because of importance about generator stability parameters. But it was introduced TWBP and processing in Korea. In addition to, related rules of generator testing had been weaken. Without guidelines, practical uses are much limited. So, it studied compliance life cycle about generator facility parameters for stability analysis. This paper presents security scheme and working rules using generator testing and disturbance recordings, considering domestic circumstance.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.420-423
• /
• 1995

The stability of system is one of the important aspects and to judge system's stability is another complicated problem. Previously, new technique derived from relaxing Lyapunov conditions has been already introduced and in this paper, this proposed technique applies to the practical dynamic systems. This utility of numerical procedures prove the comparable improvements of the estimation of robustness for dynamic systems having structured (bounded) perturbations.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.270-270
• /
• 2000

Input delay is frequently encountered in the practical systems since measurement delay and computational delay can be represented by input delay. In this viewpoint, this paper deals with the robust control problem of input delayed systems with structured uncertainty. Robust stability conditions are provided in terms of linear matrix inequalities(LMIs) and it is shown that the proposed conditions can give less conservative maximum bound of input delay guaranteeing robust stability.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.167-174
• /
• 2000

Profiles of discontinuities through scanline method were investigated for the analysis of rock slope stability. Lower hemispheric projection method was used to evaluate the geometric stability and failure potential of these discontinuities. Also, safety factor was evaluated for the discontinuities of failure potential using by limit equilibrium analysis. Then, displacements of rock block due to the discontinuities were displayed by using the program UDEC(Universal Distinct Element Code) which applied the Distinct Element Method. When we determine the cut-slope in design, the characteristics of discontinuities is not represented only by strength parameters of intact rock. Therefore it is more reasonable method in assuring stability that first, construction would be preceded by the cut-slope of preliminary design, and then, cut-slope would be redetermined by elaborate site investigation in processing construction.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.207-215
• /
• 2005

This paper presents a case history of a geosynthetics-reinforced segmental retaining wall, which collapsed during a sever rainfall immediately after the completion of the wall construction. In an attempt to identify possible causes for the collapse, a comprehensive investigation was carried out including physical and strength tests on the backfill, stability analyses on the as-built design based on the current design approaches, and slope stability analyses with pore pressure consideration. The investigation revealed that the inappropriate as-built design and the bad-quality backfill were mainly responsible for the collapse. This paper describes the site condition including wall design, details of the results of investigation and finally, lessons learned. Practical significance of the findings from this study is also discussed.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1224-1226
• /
• 1999

When electrical engineers get started with the design of main electrical system of a complex petrochemical plant along with chemical and mechanical engineers, they are usually confronted with lack of power system data. This paper presents a procedure how to perform power system stability analysis for the purpose of design studies within the limited system data given and to verify the given data to get reliable convergence in dynamic simulation as well as to apply the stability analysis result on practical system design. The power system stability analysis on the Cadereyta petrochemical plant in Mexico is provided as a study case.