• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2282-2291
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• 2024

In this work we study the effects of different factors of dislocation loop on its obstacle strength when interacting with an edge dislocation. At first, the interaction model for dislocation and dislocation loop is established and the full and partial absorption mechanism is obtained. Then, the effect of temperature, size and burgers vector of dislocation loop are investigated. The relation between the obstacle strength and irradiation dose has been established, which bridges the irradiation source and microscale properties. Except that, the obstacle strength of C, Cr, Ni, Mn, Mo and P decorated dislocation loop is studied. Results show that the obstacle strength for dislocation loop decorated by alloy element decreases in the sequence of Cr, Ni, Mn, C, P and Mo, which could be used to help parameterize and validate crystal plasticity finite element model and therein integrated constitutive laws to enable accounting for irradiation-induced chemical segregation effects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.3-20
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• 1995

Advanced ceramics have excellent thermal resistance, wear resistance, corrosion resistance, and other properties, and are promising materials as structural materials. Over the past decade, they have been applied to some machine parts, for example, glow plugs and turbochargers of automotive engines. In the case where the advanced ceramics are used as these structural parts, te low-dimensional accuracy of sintered bodies requires secondary machining.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.137-144
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• 2003

Recently, the interest in a complex building increases rapidly in Korea. High-rise complex is not simply the combination of a residential apartment and a business office as previous but a building with the object of the convenience of the residents familiar with city-life style through adapting the high class life style and new residential culture to the business space, and the efficiency in using the limited building site in the town. This study presents an exploratory analysis focusing the structural system with the help of the extensive survey of the construction site in Korea, and aims a guideline for the structural design and construction of high rise complex. Through the survey, change and development in the design and the construction can be seen as the height and size of the complex grow. It is almost indispensable to design a structural system against lateral forces like earthquake or wind, which is usually measured by story drift ratio or story displacement. Improvement of the structural materials and their usages is also included for the efficiency of the structural system. Useful slab-beam system contributing to the decrease of the story height is still a concern.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.81-85
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• 2022

In this study, we conducted a structural design and analysis of air intake of aircraft engine using composite materials. First, an investigation on structural design requirement of target structure was carried out. The distributed pressure load and acceleration condition was applied to structural design. To evaluate the structural design result, finite element analysis was carried out. The stress, deflection and buckling analysis for structural safety evaluation was performed. Finally, it was confirmed that the air intake through structural analysis is safety.

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.423-432
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• 2005

Japanese activities on fusion structural materials R&D have been well organized under the coordination of university programs and JAERI/NIMS programs more than two decades. Where, two categories of structural materials have been studied, those are; reduced activation martensitic/ferritic steels (RAFs) as reference material and vanadium alloys and SiC/SiC composite materials as advanced materials. The R&D histories of these candidate materials and the present status in Japan are reviewed with the emphasis on materials behavior under radiation damage. The importance of IFMIF and technology development for blanket R&D including ITER-TBRG activity is emphasized and the current status of those activities in Japan is also presented.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.701-707
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• 2008

This study examined the creation mechanism of free volume during homogeneous deformation induced by the elastostatic compression at room temperature. Experiments demonstrated that amorphous alloys subjected to the elastostatic compression underwent structural disordering, during which densely packed polyhedra breakdown to form new, loosely packed ones, resulting in the creation of excess free volume. A combination of experiments and molecular dynamics simulations are used to explore fundamental issues on how free volume is created during elastostatic compression.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.865-870
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• 2012

CFRP of the advanced composite materials as structure materials for vehicles has a widely application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness compared with conventional materials. This study is to investigate the energy absorption characteristics and collapse mode of CFRP single and double hat shaped structural member under the axial static collapse test. The CFRP single and double hat shaped structural members stacked at different angles (${\pm}15^{\circ}$, ${\pm}45^{\circ}$, ${\pm}90^{\circ}$, $90^{\circ}/0^{\circ}$ and $0^{\circ}/90^{\circ}$ where the direction on $0^{\circ}$ coincides with the axis of the member). The axial static collapse tests were carried out for each member. Collapse mode and energy absorption characteristics of the each member were analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.147-154
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• 2001

The prestressed concrete containment is one of the most important structures in nuclear power plants, which is required to prevent release of radioactive or hazardous effluents to the environment even in the case of a severe accident. Numerical analyses are carried out by using the ABAQUS finite element program to assess the ultimate pressure capacity of the Y prestressed concrete containment with light water reactor at design criteria condition and aging condition considering varied properties of time-dependant materials respectively. From the results, it is verified that the structural capacity of the Y prestressed concrete containment building under the present, aging condition is still robust. In addition, the parameter studies for the reduction of the ultimate pressure capacity of containment building according to the degradation levels of the main structural materials are carried out. The results show that when the degradations of each materials are considered as individual and combined forms, the influence is large in the order of tendon, rebar and concrete degradation, and tendon-rebar, tendon-concrete and rebar-concrete degradation respectively.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.1-10
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• 2009

The safe and reliable performance of fusion and fission plants depends on the choice of suitable materials and an assessment of long-term materials degradation. These materials are degraded by their exposure to extreme conditions; it is necessary, therefore, to address the issue of long-term damage evolution of materials under service exposure in advanced plants. The empirical approach to the study of structural materials and fuels is reaching its limit when used to define and extrapolate new materials, new environments, or new operating conditions due to a lack of knowledge of the basic principles and mechanisms present. Materials designed for future Gen IV systems require significant innovation for the new environments that the materials will be exposed to. Thus, it is a challenge to understand the materials more precisely and to go far beyond the current empirical design methodology. Breakthrough technology is being achieved with the incorporation in design codes of a fundamental understanding of the properties of materials. This paper discusses the multi-scale, multi-code computations and multi-dimensional modelling undertaken to understand the mechanical properties of these materials. Such an approach is envisaged to probe beyond currently possible approaches to become a predictive tool in estimating the mechanical properties and lifetimes of materials.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.148-154
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• 2010

It is necessary to develop new methods to prevent catastrophic failure of structural material in order to avoid accidents and conserve natural and energy resources. Design of intelligent materials with a self-diagnosing function to prevent fatal fracture of structural materials was achieved by smart composites consisting of carbon fiber tows or carbon powders with a small value of ultimate elongation and glass fiber tows with a large value of ultimate elongation. The changes in electrical resistance of CF-GFRP/GFRP (carbon fiber and glass fiber-reinforced plastics/glass fiber-reinforced plastics) composites increased abruptly with increasing strain, and a tremendous change was seen at the transition point where carbon fiber tows were broken. Therefore, the composites were not to monitor damage from the early stage. On the other hand, the change in electrical resistance of CP-GFRP/GFRP (carbon powder dispersed in glass fiber-reinforced plastics/glass fiber-reinforced plastics) composites increased almost linearly in proportion to strain. CP-GFRP/GFRP composites are superior to CF-GFRP/GFRP composites in terms of their capability to monitor damage by measuring change in electrical resistance from the early stage of damage. However, the former was inferior to the latter as an application because of the difficulties of mass production and high cost. A method based on monitoring damage by measuring changes in the electrical resistance of structural materials is promising for improved reliability of the material.