• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.189-197
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• 2017

In the design of an automotive structural component, one of the more important tasks for a design engineer is to determine the life of the component and to ensure that the component will not fail prematurely. In order to accomplish this, a design engineer will first use simple section analysis to come up with a section shape in the concept design stage and use more advanced analysis for stress level. At this stage, the analysis should focus on understanding overall behavior in terms of load paths and gross stress levels. A model that is adequate for a stiffness analysis of the structure will usually provide an adequate level of stress information in the design process. To perform a detailed stress analysis, the structure models must have the detailed local areas such as stress concentrations or force(or displacement) distributions. This paper is to present the design considerations for the stress analysis of automotive structure.

• Macromolecular Research
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• v.12 no.6
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• pp.564-572
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• 2004

Modem applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal, or mechanical properties, especially when coupled with locally controlled distribution of the directional response. Such materials are difficult to engineer by conventional methods, but the electric field-aided technology presented herein is able to locally tailor electroactive composites. Applying an electric field to a polymer in its liquid state allows the orientation of chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixtures of pre-polymers and cross-linking agents. Upon curing, a 'created composite' results; it consists of these 'pseudofibers' embedded in a matrix. One can also create oriented composites from embedded spheres, flakes, or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of the field-aided self-assembled composites. The strength and duration of exposure of the electric field control the degree of anisotropy created. Results of electromechanical testing of these modified materials, which are relevant to sensing and actuation applications, are presented. The materials' micro/nanostructures were analyzed using microscopy and X-ray diffraction techniques.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2225-2229
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• 2011

Squirrel cage induction motor is the main driving system of industrial field and familiar with its use in a large variety of applications. However, many engineer are unfamiliar with the induction generator, even though no difference exists between both machines except for the mode of operation. But an induction generator is commonly used for micro & small hydro power applications due to its simplicity, reliability, low cost and robustness. Input and output of induction motor has turned against at the induction generator operation. Rotation speed of induction generator is small faster than induction motor. As output of induction machines increases with the increasement of speed, so loss is same. Actually, generator efficiency is lower than motor at this condition. If induction generator is connected with mechanical load, total efficiency is decreased. In this paper, we analyzed that input, output, torque and efficiency is different from each other above and below synchronous speed.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.164-169
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• 2001

A comprehensive extension of functions and efficiency of the software system, DS/Block, developed earlier for the purpose of simulation of the motion of a ship block during lifting and turnover operation. A viewpoint change used in 3D-CAD is utilized and saves the time for displays of a series of configurations for the motion. The Euler parameters are adopted to convert 3 rotational degrees of freedom about global coordinate system to those about local coordinate system defined in Pro/ENGINEER. DS/Block provides FEM input data for stress and strain analyses. Several functions are incorporated for user-friendliness. DS/Block is to be tested and installed in a shipyard.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.339-344
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• 2001

In recent engineering, the designer has become more and more dependent on the computer simulations such as FEM (Finite Element Method) and BEM (Boundary Element Method). In order to optimize such implicit models more efficiently and reliably, the meta-modeling technique has been developed for solving such a complex problems combined with the DACE (Design and Analysis of Computer Experiments). It is widely used for exploring the engineer's design space and for building meta-models in order to facilitate an effective solution of multi-objective and multi-disciplinary optimization problems. Optimization of a train suspension is performed according to the minimization of forty-six responses that represent ten ride comforts, twelve derailment quotients, twelve unloading ratios, and twelve stabilities by using the Kriging meta-model of a train suspension. After each Kriging meta-model is constructed, multi-objective optimal solutions are achieved by using a nonlinear programming method called SQP (Sequential Quadratic Programming).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1113-1118
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• 2004

This paper presents the dynamic analysis method for an electromechanical system. The engineer has at his disposal a variety of software simulation tools. However, difficulties arise when the study of the behavior of complex electromechanical systems in combination with coupling element is required. Typical examples of such systems are machines for factory automation, home automation, and office automation. Dynamic systems analysis packages or electronic systems analysis packages offer the restrictive to simulate these mixed systems such electromechanical product. Electronic circuit analysis algorithm is easily incorporated into a multi-body dynamics analysis algorithm. The governing equation of electronic circuit is formulated as a differential algebraic equation form including both electrical and mechanical variables and is simultaneously solved in every time step. This analysis method clearly demonstrates the application potential for mixed electromechanical simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.878-884
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• 2015

In this paper, Power Management System(PMS) simulator for Liquid Nature Gas Carrier(LNGC) is developed. Major components of power system for LNGC, such as generator, diesel engine and governor, transformer, circuit breaker, and 3 phase loads models are built based on MATLAB/SIMULINK. With these designed major parts, PMS simulator modeling is carried out. Based on MATLAB/Graphical User Interface, PMS simulator control for LNGC, and Human Machine Interface for monitoring is designed. PMS simulator for LNGC carries out simulation according to sequence of characteristics analysis. By comparing results of predicted simulation for each sequence to that of characteristics analysis, the reliability of PMS simulator for LNGC will be verified.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.267-271
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• 1993

Developed in this paper is a feature based modeling of welded plate construction(WPC) which is composed of flat or bended plates represented as reference plane with a constant thickness. First, the necessity and the characteristics of the feature based modeling of WPC as compared with the assemblies of mechanical parts are investigated. Second, feature library for the assemblied of WPC is shown which contains several types of features like joint feature, groove feature, materialfeature and precision feature. Third, the assembly procedures are presented whichmainly consist of both the assembly transformation and the correct assembly checking. Fourth, weld lines generated in the assembled WPC are defined so that those can be used in the process planning or the manufacturing stage. Finally, A prototype system isdeveloped by using a geometric modeling software Pro/Engineer, a graphic software GL(Graphic Library), and C language on a CAD workstation IRIS.

• Journal of the KSME
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• v.18 no.4
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• pp.13-19
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• 1978

산업계에서 용접의 역할은 근년에 와서 그 중요성이 날로 더해 가고 있다. 산업계의 발전과 동승 해서 용접이 차지하는 비중이 확대되고 여러 분야에서 금속을 결합하는 수단으로 응용되고 있는 것은 이미 알고 있는 것으로 매일매일 용접기술은 개발이 되여 현재 사용되고 있는 용접법만 하 더라도 30여종이나 된다고 하며 금속합금은 이 용접법에 의해서 만족하게 처리되고 있다고 보겠 다. 여기서 생각해 보고 싶은 것은 어떤 금속합금을 용접하여 접합할 때 여러가지 용접법중에서 어떤 방법을 어떻게 채용된 용접법의 장단점을 충분히 고려한 후에 용접작업에 들어가지 않으면 안된다. 그런데 비교적 역사가 짧은 원자력공업은 재료를 접합하는데 여러가지로 어려운 문제점 을 제공하고 있는데 이것은 비단원자력공업 뿐만이 아니고 사람들이 금속을 처음으로 만들기 시 작했을 때부터라고 생각이 든다. 이 산업의 발전은 용접기술자가 여러가지로 복잡한 문제를 어떻 게 빨리 안전하게 해결할 수 있느냐에 달려 있다고 본다. 그러므로 용접기술자는 신기한 특성을 가지고 있는 금속의 접합기술을 개발하지 않으면 안되겠지만 원자력공업에서 적용되는 아주 높은 온도에서도, 높은 압력에서도 견딜 수가 있고 중성자 충격에도 손상을 받지 않는 성질이 요구된 다. 또 실험장치등도 운전중에는 방사성이 강하기 때문에 용접의 완전성이 절실히 요구된다.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.2
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• pp.107-114
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• 2000

Recently the studies on the vibration and the noise of a helical gear transmission have been focused on the many researchers. The manufacturing error and the deformation of the tooth profile, which generates the vibration and the noise of the gear transmission, are main factors. The major purpose of this study is to develop an optimal design program for reducing the vibration and the noise of the helical gear. To obtain the these results, we restrain the helical gear from the deformation of the tooth profile and increase the contact ratio within the optimal design program. Furthermore we made the three-dimensional solid modeling of the helical gear from the AutoCAD and the Pro/Engineer. This model will be available to generate the finite element model and the NC code.