• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.41-49
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• 2007

In general, the curved structures have the engineering efficiency as well as a fine view compared with straight member. Also, composite materials are composed of two or more different materials to produce desirable properties for structural strength as compared to single ones. Shell structures with composite materials have many advantages in strength and weight reduction. Therefore, composite laminated conical shells are analyzed in this study. To solve differential equations of conical shells, this paper used finite difference method. Various parametric study according to the change of radius ratio, vertex angle and subtended angle are examined. The change of radius ratio, vertex angle and subtended angle mean the change from conical shells to cylindrical shells, conical shells to circular plates and open shells closed shells, respectively.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.81-86
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• 2014

Composite materials have high specific stiffness, specific strength than existing concrete or steel materials. It has superior dynamic properties when utilizing advantages of material such as Non-corrosive, light weight, non-conducting and it has superior mold ability which can make variable shapes. Thus, in the construction, for using composite materials as construction materials, the study carried out static strength of fiber right angle direction and fatigue performance of FRP deck member. The study is going to deduct S-N curve by analyzing the results comparatively and estimate long-term durability. From now on, the study is going to provide interpretation of FRP member and basic data of design basis, furthermore providing foundation technique of composite materials' application of structural frame is the goal of this study.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.613-620
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• 2005

This research is experimental paper to prepare the structural safety of the upper bridge for support type on tunnel and the effect of settlement. Unit weight test and uni-axial compression test have been performed to simulate the physical property of foundation on the tunnel. Tunnel model of slip form type for centrifuge model has been developed to performed the tunnel excavation while field stress is activated. And the support type of tunnel such as umbrella arch method and large diameter steel pipe reinforce method has been tested for the centrifuge model. After the analysis of experiment, results show that internal displacement of large diameter steel pipe reinforce method is smaller than that of the umbrella arch method.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.142-147
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• 1999

Formwork is a temporary structure that supports its own weight and that of the freshly placed concrete as well as construction live loads including materials, equipments, and workmen. In designing and building formwork, the contractor should plan for economical construction without sacrificing quality or safety. But these temporary structures sometimes collapse during the concrete placing. Among the accidents and failures that occur during concrete construction, many are formwork failures, which usually happen at the time concrete is being placed. Generally some unexpected events cause one member to give way, then others become overloaded or misaligned and the whole formwork structure collapses. In this study, formwork failure events from 1994 to 1997 are analyzed using the structural analysis program. So the causes of the respective formwork failure are explored. Therefore, the present study provides a firm base to design the temporary structures such as formwork.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.660-665
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• 2007

This Study is a structure analysis about twin lift telescopic Spreader that usually loading and unloading a container in harbor. Applied load is assumed by lifting 65tons that is the maximum weight of real container. The finite element analysis for 3D model is performed by ABAQUS/Standard. We made an estimate of safety by evaluating the results of the finite element analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.399-406
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• 2007

Structural vibrations of generator sets with medium speed diesel engine mainly come from the resonance between the excitations of engine and natural modes of system. The countermeasures to reduce the vibration or to avoid the resonance are fairly well known to workers. However these processes which are applied after the completion of system need much time consumption and additional cost. In this paper, the vibration measurement results collected for about 8 years were compiled as Database. Based on the database, the change of vibration was predicted with respect to variation of system such as engine type, generator weight, mount stiffness, and etc. As results of study, this paper presents the anti-vibration design procedures of newly composed generator sets using Database in the initial design stage and their effects.

• Journal of the Korean Society of Combustion
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• v.7 no.3
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• pp.23-31
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• 2002

Processes in an iron ore sintering bed can characterized as a relatively uniform progress of fuel, cokes combustion and complicated physical change of solid particles. The sintering bed was modelled as an unsteady one-dimensional progress of the fuel layer, containing two phases: solid and gas. Coke added to the raw mix, of which the amount is about 3.5% of the total weight, was assumed to form a single particle with other components. Numerical simulations of the condition in the iron ore sintering bed were performed for various parameters: moisture contents, cokes contents and air suction rates, along with the various particle diameters of the solid for sensitivity analysis. Calculation results showed that the influence of these parameters on the bed condition should be carefully evaluated, in order to achieve self-sustaining combustion without high temperature section. The model should be extended to consider the bed structural change and multiple solid phase, which could treat the inerts and fuel particles separately.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.360-365
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• 2003

최적화의 개념은 목적에 따라 다양하겠으나 수치해석에서는 기본적으로 설계변수를 움직여 목적함수를 최소화 혹은 최대화하는데 있다. 열전달에서는 최소온도, motor를 설계할 때는 최대토크 등이 있고, 구조물설계에 있어서는 최소무게(Weight or Volume) 혹은 최대의 Frequency를 구하는데 최적화 수치해석이 이용되고 있다. 오늘날 컴퓨터하드웨어의 발달과 더불어 전산수치해석의 영역이 급속히 높아져가고 있으며 PC에서의 계산처리능력이 90년대의 work station급을 초가 함으로써 보다 쉽게 전산수치해석이 가능하게 되었다. (중략)

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.319-325
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• 2007

Preload of critical engine bolts affects the performance and durability of engines. In modern engines that pursue higher power outputs and which are of lighter weight, it becomes more difficult to select an optimal target preload in consideration of various factors such as the role and structural characteristics of joint members, joint load, and fatigue durability of bolts and joint members. A procedure to select the bolt preload using computer-aided engineering technology, especially the finite element method, has been developed. The procedure is illustrated with connecting-rod bolts for which an appropriate preload is known. The selection criteria of target preload and the finite element modeling technique for connecting-rod bolts are also explained.

• Journal of Fashion Business
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• v.12 no.4
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• pp.131-142
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• 2008

One of the major fashion trends is the naturalism and ecology-conscious trend. The natural looks required in the trend require somewhat random distribution of yarn linear density, which results in irregular appearance along the yarn. This is a technically challenging work of producing yarns that look natural far from being artificial yet maintaining the intricately aesthetic randomness without causing process disturbances. This study focused on the characteristics of fabrics made of natural cellulosic fibers including hemp, ramie, flax, and polyester fabrics. Image analysis of the fabric samples included area measurement of yarn specimen, FFT and inverse FFT. Measurements of bending resistance, thickness, air permeability, and weight were also implemented to interpret the structural differences.