• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 춘계학술대회논문집; 전남대학교, 19 May 1995
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• pp.223-230
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• 1995

본 연구에서는 선박소음해석을 수행하기 위한 기초작업으로서 실선 선박모델을 크게 3가지 경우로 구분하여 모델링 하였으며, SEA법을 적용하여 고체소음의 전달손실을 이론적으로 예측할 수 있는 방법을 제시하였으며, 또한 STL을 도입하여 각 요소간의 에너지 흐름 및 구성판요소의 재료별 방진효과를 알아보았다. 이 방법의 결과 다음과 같은 결론을 얻을 수 있었다. 1) 내장판의 종류에 따른 전달특성은 고주파 대역에서는 plywood, 저주파 대 역에서는 rockwool이 높은 손실값을 보였으며, glasswool은 전 주파수 대역에서 고른 손실값을 가짐을 확인하였다. 2) 기진원으로부터의 거리가 멀어짐에 따라 내장판의 효과가 크게 나타나며, 기진원의 근방 요소에서는 내장판의 효과보다는 강판의 두께의 영향이 두드 러짐을 알 수 있었다. 3) 내장판 요소중 plywood의 방진효과가 가장 크게 나타남을 알 수 있었다. 4) 본 SEA법에 의한 연구에서는 구성 판요소의 재질과 두께에 따른 고쳇음 의 전달특성을 이론적으로 해석하였으며, 차후 실험을 통한 검증이 요구되어 진다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1723-1728
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• 2000

This paper deals experimentally with the effect of the sound-damping sheet on building wall system; brick wall, light wall panel, and gypsum board. Experimental results show that when the sound-damping sheet is attached on wall systems, the mass and/or damping effects result in increasing of STL of wall system depending on the characteristics of the original partition. It is pointed out that the performances of sound damping sheets must be presented with specific wall structures that applied, not by the sound transmission loss of the sheet itself.

• 한국정밀공학회지
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• 제17권5호
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• pp.76-83
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• 2000

Shape reconstruction is considered as a new technology to be useful and important in many areas such as RPD (Rapid Product Development) and reverse engineering, compared with the conventional design and manufacturing. In shape reconstruction, it becomes possible to reconstruct objects not by their measured shape data but those data extracted from the original shape. The goal of this research is to realize 3D shape construction by showing a possible way to analyze the input image data and reconstruct that original shape. The main 2 steps of the reconstructing process are getting cross-section data from image processing and linking loops between one slice and the next one. And the reconstructed object in this way is compared with the other object using a laser scanner and modelled by an commercial software.

• 대한기계학회논문집A
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• 제29권6호
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• pp.895-903
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• 2005

In this paper, we present a cutter location (CL) surface deformation approach for constant scallop height tool path generation from triangular mesh. The triangular mesh model of the stereo lithography (STL) format is offset to the CL surface and then deformed in accordance with the deformation vectors, which are computed by the slope and the curvature of the CL surface. In addition, the tool path which is computed by slicing the deformed CL surface is inversely deformed by those same deformation vectors to a tool path with a constant scallop height. The proposed method is implemented, and a tool path generated by the proposed method is tested by simulation and by numerical control (NC) machining. The scallop height was found to be constant over the entire machined surface, demonstrating much better quality than that of mesh slicing, under the same constraints for machining time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1862-1864
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• 2002

In this study, micro-ohm shunts with rated ac current of 2, 20, 80kA intended for use as an approved system for ac current measurement were calibrated according to IEC 60060. The scale factor and linearity were determined by comparison with the reference measuring system. Measurements of temperature rise due to the rated current was also investigated to analyze a temperature effect. One of the main goals was the determination of the measurement uncertainty of the shunt. The expanded uncertainty of the scale factor for the complete measuring system was satisfied with the STL(Short-circuit Testing Liaison) guide recognized tentatively.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.184-187
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• 2004

The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.

• 한국소음진동공학회논문집
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• 제21권10호
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• pp.967-974
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• 2011

The direct and indirect PFBEM(power flow boundary element method) for the treatment of the 3 dimensional multi-domain problems are proposed to predict the acoustic energy density in medium to high frequency ranges. In the proposed method, the equation is derived in a matrix form by considering coupled relationships of the power flow at the interface of given domains. The proposed method can successfully obtain the analytical solutions for the problems of coupled cubes and the small-scale reverberant chamber. Then the experiment is carried out to obtain STL(sound transmission loss) by using small-scale reverberant chamber and the results are compared with analysis results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.884-889
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• 1994

In this work, rapid prototyping and three dimensional finite element analysis are simltaneously applied to design metal forming processes. Rapid prototyping is a new prototyping technology which producess three dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus (SLA) which is the most widely-used rapid prototyping system is introduced to manufacture the die set. To prepare STL file generally, mesh data which are in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are effectively connected. The die sets are manufactured using SLA prototypes, and matal forming experiments are carried out using them. Comparing experiments results with analyses, the processes can be predicted and designed successfully.

• 한국정밀공학회지
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• 제17권7호
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• pp.181-188
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• 2000

The objective of this research is to develop an efficient reverse engineering method of 3-dimensional compound surfaces for raped prototyping process. As a first step, several image processing techniques were applied to the measured data obtained using laser scanner. And the boundary information of the compound surface were extracted to divide the surface into several separate regions. As a next step, the Delaunay triangulation method were applied to reconstruct the surface based on the measured data and the boundary information. Finally, the STL file were created for the rapid prototyping process. Required simulations and experiments were performed and the results were analyzed to show the effectiveness of the proposed methods.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.102-109
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• 1999

Reverse engineering is a technique that helps designers to quickly generate computer interpretable data from existing physical objects. It can be used for generating CAD data from a mechanical part of high precision, or generating computer animation characters from physical mock-ups. We developed a low precision reverse engineering system that is composed of surface/solid generation software and a contact type commercial 3D digitizer. A unique point sampling procedure has been devised to easily form solid topology from the sampled data. It was also shown that STL data for rapid prototyping was successfully generated from the solid.