• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1185-1191
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• 2014

Gas turbine blades that have complex geometry of the cooling holes and cooling passages are usually subjected to cyclic and sustained thermal loads due to changes in the operating characteristic in combined power plants; these results in non-uniform temperature and stress distributions according to time to gas turbine blades. Those operation conditions cause creep or thermo-mechanical fatigue damage and reduce the lifetime of gas turbine blades. Thus, an accurate analysis of the stresses caused by various loading conditions is required to ensure the integrity and to ensure an accurate life assessment of the components of a gas turbine. It is well known that computational analysis such as cross-linking process including CFD, heat transfer and stress analysis is used as an alternative to demonstration test. In this paper, temperatures and stresses of gas turbine blade were calculated with fluid-structural analysis integrating fluid-thermal-solid analysis methodologies by considering actual operation conditions. Based on analysis results, additionally, the total lifetime was obtained using creep and thermo-mechanical damage model.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.419-431
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• 2001

This study was to investigate structural behavior of composite structure beams composed of end-RC. center-Steel according to respective reinforcing method for connection zone composed of different materials (SRC) while attaching main bars on steel-flange by welding. The main reinforcing methods are as follows ; non-reinforcing, vertical shear reinforcing (type-stirrup), inclined reinforcing(type-x), horizontal reinforcing(type-web, 0.3L), double horizontal reinforcing (type-web, 0.3L), vertical reinforcing (type-flange, 0.3L). Consequently, It showed little difference in structural properties like ductility and strength according to the attaching method of main bars. For Maximizing the structural properties of composite beam, the most effective methods were vertical reinforcing one and double horizontal reinforcing one.

• Polymer(Korea)
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• v.26 no.1
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• pp.80-87
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• 2002

A comparative study using electron-beam(EB) and thermal curing techniques was carried out to determine the effect of cure behavior and thermal stability of epoxy resins. In this work, benzylquinoxalinium hexafluoroantimonate(BQH) was used as a latent cationic catalyst for an epoxy resin. According to the thermogravimetric analysis(TGA), the decomposed activation energy based on Coats-Redfern method was higher in the case of thermal curing technique. This could be interpreted in terms of slow thermal diffusion rate resulted from high crosslink density of the thermally cured epoxy resin. However, the increase of hydroxyl group in the epoxy resin cured by EB technique was observed in near-infrared spectroscopy(NIRS) measurements, resulting in improving the stable short aromatic chain structure, integral procedural decomposition temperature, and finally ductile properties for high impact strengths.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.19-25
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• 2004

The linear analysis for the balance of linear momentum of a structure is relatively easy to perform, but the error becomes large when the structure experiences large deformation. Therefore, the material and geometric nonlinearity need to be considered for the precise calculations in that case. The plastic flow of a ductile steel-like metal mainly transforms its dissipated mechanical energy into heat, which transfers under the first and second law of thermodynamics. This heat increases the temperature of the material and the strength of the material decreases accordingly, which affects mechanical behavior of the given structure. This paper presents a finite-strain thermo-elasto-plastic steel model. This model can handle large deformation and thermal load simultaneously, which is common during earthquake periods. Two 3-dimensional finite element analyses verify this formulation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.265-268
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• 2011

하중 속도에 따른 콘크리트 재료의 역학적 특성은 구조물의 동적파괴거동에 영향을 미친다. 본 연구는, rigid-body-spring network를 이용하여 파괴해석을 수행하고, 거시적 시뮬레이션에서 속도효과를 표현하기 위하여 점소성 파괴모델을 적용하였다. 보정을 위해서 Perzyna 구성관계식의 점소성 계수들이 다양한 하중속도에 따른 직접인장실험을 통해서 결정되었다. 동정상승계수를 이용하여 하중 속도가 증가함에 따른 강도 증가를 표현하였고 이를 실험결과와 비교하였다. 다음으로 느린 하중속도와 빠른 하중속도에 따라 단순 콘크리트 보와 철근 콘크리트 보에 대한 휨 실험을 수행하였으며, 하중 속도에 따라서 서로 다른 균열 패턴을 관찰할 수 있었다. 빠른 하중은 보의 파괴가 국부적으로 나타나게 만드는데, 이는 속도 의존적 재료의 특성 때문이다. 구조적인 측면에서, 보강재는 느린 하중속도에서 균열의 크기를 줄이고 연성을 높이는 데 큰 영향을 미친다. 본 논문은 속도 의존적 거동에 대한 이해와 동적하중에 대한 보강효과를 제시한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.367-372
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• 2006

When we design a linear motor, the thermal behavior investigation is one of great important considerations with respect to uniform thrust force and thermal deformation of a linear motor. In this study, we conduct the research for the structural design of the linear motor for LMTT(Linear Motor-based Transfer Technology) which is the next generation of container horizontal transfer system in order to automate a container terminal. After the dimensions of main parts for a linear motor were set up, we carried out the thermal-structural analysis of the linear motor considering the thermal analysis of the stator module.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.410-419
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• 2016

With the aim of reducing greenhouse gas emissions by 20 percent by 2020 and by 50 percent by 2050 from their 2005 level, International Maritime Organization (IMO) regulated the emissions of SOx and NOx by setting the emission control area in 2012. Since these environmental regulations have been reinforced, demands for the LNG fuel ships are expected to increase dramatically. Accordingly, the worldwide shipbuilding companies spur the development of the LNG fueled ships. Therefore, it is essential to carry out the research on the development of LNG fuel tank, which is one of the important components of the LNG fuel supply system. In this study, the deliberate finite element analysis of type-B LNG fuel tank for 10,000 TEU containership was carried out to evaluate structural safety and provide the process for analyzing stress levels and evaluating fatigue life of target structural. In particular, thermo-structural analysis and fatigue analysis were carried out using the databases on materials and structures of LNG fuel tank.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.191-198
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• 2014

In this paper, structural integrity evaluation of reactor pressure vessel bottom head without penetration nozzles in core melting accident has been performed. Considering the analysis results of thermal load, weight of molten core debris and internal pressure, thermal load is the most significant factor in reactor vessel bottom head. The failure probability was evaluated according to the established failure criteria and the evaluation showed that the equivalent plastic strain results are lower than critical strain failure criteria. Thermal-structural coupled analyses show that the existence of elastic zone with a lower stress than yield strength is in the middle of bottom head thickness. As a result of analysis, the elastic zone became narrow and moved to the internal wall as the internal pressure increases, and it is evaluated that the structural integrity of reactor vessel is maintained under core melting accident.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.15-24
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• 2010

In the case of underground power utilities pipe such as circular pipe, the most difficult problem is low compaction efficiency of the bottom of pipe inducing the failure of utilities. To overcome this problem, various studies have been performed and one of these is CLSM(Controlled Low Strength Materials) accelerated flow ability. But underground power utilities pipe backfill materials is also needed to have good thermal property that can dissipate the heat as rapidly as it is generated. So, in this study, we performed thermal resistancy test for various materials such as sand, weathered soil, clay and mixed soil to analyze the thermal characteristics of CLSM(Controlled Low Strength Materials) with accelerated flow ability for various conditions(water content, unit weight, void ratio, curing time) and to evaluate the applicability for backfill material of underground power utilities pipe. The test results of 16 specimens for thermal resistancy test showed good thermal property that maintained below $85^{\circ}C\;cm/W$.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.97-97
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• 2011

현대사회에서 화재에 의한 물적 피해는 물론 인적피해가 현저하게 증가하고 있으며 희생자의 사망원인이 종래에는 화재시 발생한 열에 의한 화상을 중심으로 하는 소사였지만, 최근에는 화염보다 독성가스로 인하여 사망하는 경우가 많아졌고, 희생자는 거의 화상을 확인할 수 없거나 화상자이더라도 혈액 중에서 일산화탄소를 중심으로 한 유독가스가 확인되기 때문에 이들 유독가스의 흡입으로 인하여 행동불능상태 이후 열의 영향으로 사망한 것으로 추정되는 사례가 증가하는 추세이다. 따라서 대규모 건축물에 있어서는 화재발생시 유독가스가 건물 전체로 연소 확대되는 것을 방지하기 위하여 넓은 면적을 일정한 면적으로 구획하거나 계단실 등과 다른 부분 또는 층별 등으로 구획하고 있으며, 국내의 방화구획은 크게 다른 층으로 화재전파를 막기 위한 층간 방화구획, 연소면적을 제한하기 위한 면적별 방화구획, 다른 용도로 인한 화재 위험성 감소를 위해 용도별 방화구획으로 3가지를 법에서 채택하고 있다. 방화구획은 방화문 또는 자동방화셔터를 이용하거나, 내부구조의 바닥, 벽, 각종 방화문으로 구획할 것을 정하고 있다.(피난방화규칙 제14조) 본 연구에서는 철제방화셔터 대체용으로 직물방화셔터용의 실리카 소재를 이용하여 제직한 직물에 내열/차연 기능성 코팅의 공정 조건을 변화하여 최종 방화시험을 거치기 전 내열성 테스트중 하나인 불꽃열 통과량 실험을 실행하여 방화 직물의 내열성을 비교 분석하였다. 이러한 결과를 토대로 본 연구는 고내열/차연성 방화 제품 기술을 개발하는데 필요한 연구를 수행하는데 목적이 있다.