• Nuclear Engineering and Technology
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• v.19 no.1
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• pp.1-9
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• 1987

The fracture toughness of SA 533 Grade B Class 1 steel has been studied with the Charpy impact test specimens in a range of temperature between -4$0^{\circ}C$ and 288$^{\circ}C$. The dynamic fracture toughness is measured by the instrumented precracked Charpy impact test while the static fracture toughness is by the 3-point bend test based on the unloading compliance method. The results are compared with the data obtained from the large specimens. It is known through the studies that temperature dependence of the appropriate (a low bound) value of the fracture toughness can be estimated by taking the static fracture toughness above the transition temperature and the dynamic fracture toughness below the temperature and it is also shown that the tests are satisfied with the requirements of ASTM E 813 when the side-groove is more than 14%.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.6
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• pp.607-614
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• 2015

In this research, the structural analysis and safety evaluation for Sungnyemun -No.1 national treasure of Korea- was performed. Roof loads were calculated in detail, and structural analysis model was constructed using Midas Gen ver.820. Static structural analysis under vertical loads was performed and safety of main structural members and serviceability of main horizontal members were evaluated. To evaluate dynamic characteristics of Sungnyemun, both field measurements by impact hammer test and eigenvalue analysis by structural analysis software were performed and the results were compared. Sungnyemun showed rooms in their structural capacity.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.250-257
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• 2002

Pseudo dynamic test is an on-line computer control method to achieve the realism of shaking table test with the economy and versatility of the conventional quasi-static approach Pseudo dynamic tests of six full-size RC bridge piers have been carried out to investigate their seismic performance. For the purpose of precise evaluation, the experimental investigation was conducted to study the seismic performance of the real size specimen, which is constructed for highway bridge piers in Korean peninsula. Since it is believed that Korea belongs to the moderate seismicity region, five test specimens were designed in accordance with limited ductility design concept. Another one test specimen was nonseismically designed according to a conventional code. Important test parameters were transverse reinforcement and lap splicing. Lap splicing was frequently used in the plastic hinge region of many bridge columns. Furthermore, the seismic design code is not present about lap splice in Korean Roadway Bridge Design Code. The results show that specimens designed according to the limited ductility design concept exhibit higher seismic resistance. Specimens with longitudinal steel lap splice in the plastic hinge region appeared to significantly fail at low ductility level.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.688-696
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• 1995

Cemented carbides, best known for their superior mechanical properties such as high strength, high hardness and high wear resistance, have a wide range of industrial applications including metal working tools, mining tools, and wear resistance components. The cobalt has been used as a binder in the WC-based hard composites due to its outstanding wetting and adhesion characteristics even though its expensiveness. Therefore many studies attempted to find a better substitute for cobalt as binder to decrease production costs. This investigation is a pre-step to study dynamic fracture characteristic evaluation of a WC-Co hardmetal were evaluated by using the instrumented Charpy impact testing procedures. It was found that the dynamic characteristics of used strain amplifier were very important experimental factors to extract valid dynamic fracturing data in WC-Co specimens. It was suggested by showing some experimental examples that when we wished to evaluate dynamic fracture toughness for cemented carbide composites by using the instrumented Charpy impact testing procedure, a careful attention must be given to obtain valid results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.74-81
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• 2005

The purpose of this study is to suggest a proper analysis model that can evaluate seismic stability for local rock foundation of nuclear power plant. Sliding Analysis, Pseudo-static Analysis and Danamic Analysis methods are used for analysing NPP rock foundation with the conditions like acting directions of input earthquake, boundary conditions, width and depth of analysing model, and modeling methods of weakness fault zones. As the results of study, Pseudo-static Analysis for lateral roller and dynamic analysis for transfer boundary condition showed good results, and analysing ranges of width and depth were 5 times of structure width and over 2 times of structure depth.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.261-270
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• 1999

This paper presents how to evaluate the accuracy and uncertainty of the measuring techniques and the measurement systems, and establish their accreditation procedures. There are largely static error and dynamic error in the measurement error. In particular, the static error which always remains in the measurement systems is obtained by proposed error equations. In addition, the accreditation procedures are proposed.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.89-98
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• 2006

This paper describes signal attenuation characteristics as splicing the output on LVDT for stability and reliability of switching mechanism, which is developed to use common signal between FLCC and EDFLCC, on T-50 aircraft. The method of test is classified a Pspice simulation and an actual hardware evaluation. The difference of error margin for two methods is 10times, the latter higher. The result in this experiment shows that the signal attenuation as splicing the output on LVDT doesn't affect and the static error margin is 53% for develope the EDFLCC.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.2
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• pp.19-28
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• 2018

The progressive collapse resistance performance of a steel structure constructed using the moment frame with the WUF-B connection and the composite slabs was evaluated. GSA 2003 was adapted for the evaluation. Additionally the structural robustness and the sensitivity against the progressive collapse were analyzed. In the numerical analysis, a reduced model comprised of the beam and spring elements for WUF-B connection was adapted. The composite slab was modeled using the composite-shell element. Instead of the time-consuming dynamic analysis for the effect of the sudden column removal, the equivalent energy-based static analysis was effectively applied. The analysis results showed that the structure was the most vulnerable to in the case of the internal column removal, however it satisfied the chord rotation criterion of GSA 2003 due to the contribution of the composite slab which improved the stiffness of structure. In the robustness evaluation, the structural performance showed more than 2.5 times of the requirement according to GSA 2003, and the structural sensitivity analysis indicated the decrease of 33% of the initial structural performance.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.338-346
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• 2001

Evaluation of microstructural changes is important for process control during open die forging of heavy ingots. The control of forging parameters, such as shape of the dies, reduction, temperature and sequence of passes, is to maximize the forging effects and to minimize inhomogeneities of mechanical properties. The hot working die steel is produced by using the multistage open die forging. The structure is altered during forging by subsequent Precesses of plastic deformation, recrystallization and grain growth. A numerical analysis using an rigid visco-plastic finite element model was performed to predict microstructural evolution of hot working die steel.

• Journal of KIISE:Software and Applications
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• v.26 no.8
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• pp.1018-1027
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• 1999

속성 문법은 언어의 정적인 의미구조를 표현하는 형식적인 표기법으로 동적인 의미구조를 표현하기는 부적절하다. 동적 의미구조를 잘 명세하고 명세된 언어를 구현하기 위해서 기존의 속성 문법을 확장하여 언어 구현에 필요한 동적인 작용들(actions)을 잘 표현해야 한다. 본 논문에서는 속성 문법을 확장하여 정적이고 동적인 의미구조를 잘 표현할 수 있는 새로운 작용 식(action equation)을 제시한다. 제시된 작용 식(action equation)의 동적인 의미 구조로 부터 SIMP 언어의 점진 해석기(incremental interpreter)를 설계하고 구현한다. 점진 해석기는 언어 기반의 프로그래밍 환경에서 수정된 부분만을 번역하여 프로그램의 전체 실행 결과를 얻는 해석기를 의미한다. 본 해석기는 SUN 1000에서 Lex와 Yacc을 사용해서 C 언어로 설계하고 구현하였다. 예제 프로그램을 실행시켰을 때 배정 문이나 IF문의 경우는 매우 효율적이었고 Loop의 경우는 재실행될 필요가 있는 영향받는 명령문들이 적을수록 점진 해석이 더 효율적으로 수행된다.Abstract Attribute grammars are a formal notation which expresses the static semantics of programming languages, but they are not suitable for expressing dynamic semantics. To describe dynamic semantics and implement a specified language, we extend attribute grammars and present new action equations which describe static and dynamic semantics. The incremental interpreter of a SIMP language is designed and implemented from the dynamic semantics of presented action equations. The incremental interpreter is to translate only modified part in the language-based programming environments and have results of whole program.Our interpreter is implemented in C with Lex and Yacc on SUN 1000. When we execute example programs, the incremental evaluation of any assignment and IF statements executes efficiently. But in the case of loop, we execute efficiently when the effected statements to be reexecuted in the loop are of small number.