• 한국소음진동공학회논문집
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• 제13권4호
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• pp.300-307
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• 2003

This paper presents the multi-mode noise reduction of smart panels of which passive piezoelectric shunt damping is introduced. For the piezoelectric shunt damping, a passive shunt circuit composed of inductors and a load resistor is connected to the piezoelectric patch mounted on the panel structure. An electrical impedance model is introduced for the system based on the measured electrical impedance, and the criteria for maximum energy dissipation at the shunt circuit is used to find the optimal shunt parameters. For multi-mode shunt damping, the shunt circuit is modified by the introduction of a block circuit. Also the optimal location of the piezoelectric patch is studied by finite element analysis in order to cause the maximum admittance from the patch for each mode of the structure. An acoustic test is performed for the panels and a remarkable noise reduction is obtained in multiple modes of the panel structure.

• 한국안전학회지
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• 제21권3호
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• pp.94-100
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• 2006

The goal of this study is to show the way to increase the safety of deteriorated PSC beam bridges by the to-box reinforcing method. This method is to change the open girder section into the closed box section by connecting bottom flanges of neighboring PSC girders with the precast panels embedding PS tendons at the anchor block. The box section is composed of three concrete members with different casting ages, RC slab, PSC beam, precast panel. This different aging requires a time-dependent analysis considering construction sequences. Reliability index and failure probability are produced by the AFOSM reliability analysis. Transversely five schemes and longitudinally two schemes are considered. The full reinforcing scheme, transversely and longitudinally, shows the highest reliability index, but it requires more cost for retrofit. The partial reinforcing scheme 4, 4-1 are recommended in this study as the economically best scheme.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.68-74
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• 2001

In the drawing of large size automotive panels, elastic deflection of die components is induced by the contact force between them. The deflection is nonuniform and locally distributed, and results in nonuniform material flow. In order to arrange such a nonuniform die gap, a correcting operation, so called die spotting, is inevitable, which requires trial and error works and consuming time. A prediction of the bending deflection prior to a try-out must be useful to reduce the die spotting time. In this study, drawing process of a front fender is simulated first. and the deflection of the blank holder is calculated from the contact force imposing on th blank holder. The balance block heights ensuring a uniform deflection are optimized by the analysis and design of experiments.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.249-254
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• 2000

The contact forces between die components for the drawing of large size automotive panels introduce elastic deflections of the die components. Due to the deflections, the gap between blank holder and die varies locally resulting in nonuniform material flow. Such a nonuniform die gap usually requires correcting operation, so called die spotting, which is time consuming trial and error process. To reduce the die spotting time, the optimization of the blank holder bending deflection is needed. In this paper, we implemented an analysis procedure to predict the blank holder deflection. The analysis procedure and design of experiments techniques are applied to the optimization of balance block heights. The optimization results can be used as guidelines in actual die spotting process.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 가을 학술발표회 논문집
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• pp.337-344
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• 2001

The application of mechanically stabilized earth wall(MSEW) with segmental front panel has been increasing in highway construction due to its cost-effectiveness. However, some failures during construction have been reported and many field engineers are reluctant to select this method for important structure. One of the main reasons may be that there is no moderate specification for design and construction of MSEW yet. This paper discussed the main results of analysis on a case of block-type segmental retaining wall in highway construction. Based on the results, some recommendations on design and construction method of MSEW are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.508-514
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• 2005

This paper is concerned with the active vibration control of a grid structure equipped with piezoceramic sensors and actuators. The grid structure is a replica of the solar panel commonly mounted on satellites, which contains complex natural mode shapes. The multi input and multi output positive position feedback controller is considered as an active vibration controller for the grid structure. A new concept, the block-inverse technique, is proposed to cope with more modes than the number of actuators and sensors. This study also deals with the stability and the spillover effect associated with the application of the multi-input multi-output positive position feedback controller based on the block inverse technique. It was found that the theories developed in this study are capable of predicting the control system characteristics and its performance. The new multi-input multi-output positive position feedback controller was applied to the test structure using a digital signal processor and its efficacy was verified by experiments..

• Structural Engineering and Mechanics
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• 제34권3호
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• pp.335-350
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• 2010

Out of plane behaviors of walls and infills are investigated in this paper, using rigid block concepts. Walls and infills are sometimes separated from top beams because of in plane movement of the walls and crumbling mortar layers under the top beams. Therefore, sufficient strength should be supplied to hold them against out of plane forces. Such walls are studied here under some real and scaled earthquakes, regarding their out of plane behavior. Influences of some reinforcements, connecting the walls to frames or perpendicular walls, are also studied. It is shown that unreinforced walls of regular sizes (3 m high and 4.5 m long) are normally unstable in the earthquakes. However, performing some reinforced bars that connect them to adjacent elements- frames or perpendicular walls - stabilizes them. Eventually, it is concluded that supplying 3 reinforced bars at 1/4, 2/4 and 3/4 of the panel's height stabilizes the walls in the assumed earthquakes. In this regard, for 20 cm and 35 cm thick walls ${\Phi}$18mm and ${\Phi}$20mm bars are to be used, respectively. For walls with other configurations, the forces and required areas of the reinforcements can be determined by the developed method of this paper.

• 대한조선학회논문집
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• 제36권3호
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• pp.122-133
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• 1999

완성되어진 블록을 이용한 탑재의 과정에서 발생하는 블록 경계간의 판재 겹쳐짐 현상, 과도한 간격 및 단차의 발생현상은 선박의 건조비용과 공수를 증가시키는 요인이 된다. 본 논문에서는 블록의 조립 및 탑재에 관한 시뮬레이션 시스템을 제안하고 이중 조립에 관한 시뮬레이션을 용접순서에 따라 용접변형 및 자중을 고려하여 유한요소해석을 ANSYS를 이용하여 수행하였다. 용접에 의한 변형은 실험에 의한 변형량을 이용한 등가강성에 따른 등가 하중을 사용하여 탄성적인 해석법을 수행하여 예측하였으며 선체 이중저 평블록을 패널 조립법에 근거한 조립순서에 따라 시뮬레이션을 수행하였다. 시뮬레이션을 통한 변형으로부터 조립순서에 따른 중간 제품의 형상의 변화에 의한 강성의 변화에 기인한 변형량의 차이를 확인 할 수 있었으며, 자중의 효과를 반드시 고려하여야 함을 확인 할 수 있었다.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1037-1044
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• 2005

This paper is concerned with the active vibration control of a grid structure equipped with piezoceramic sensors and actuators. The grid structure is a replica of the solar panel commonly mounted on satellites, which contains complex natural mode shapes. The multi-input and multi-output positive position feedback controller is considered as an active vibration controller for the grid structure. A new concept, the block-inverse technique, is proposed to cope with more modes than the number of actuators and sensors. This study also deals with the stability and the spillover effect associated with the application of the multi-input multi-output positive position feedback controller based on the block-inverse technique. It was found that the theories developed in this study are capable of predicting the control system characteristics and its performance. The new multi-input multi-output positive position feedback controller was applied to the test structure using a digital signal processor and its efficacy was verified by experiments.

• 패션비즈니스
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• 제22권4호
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• pp.30-46
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• 2018

The purpose of the study was to suggest certain measurements of the skirt block pattern drafting process for the Korean female fashion models, with the aim to improve its fit. For this purpose, the study carried out an analysis of the lower body features of a dress form developed for the study. This form was representative of Korean female fashion models' body features. The study performed a cross-sectional analysis at waist and hip levels and measured the angles from the frontal and lateral silhouettes of the dress forms. The comparisons of the skirt block patterns developed through draping by the use of 2 types of the dress forms developed and existed and through drafting according to the current patternmaking method have led to noticeable findings in terms of implementation of the skirt block drafting process for the Korean female fashion models. The results of the study are as follows: (1) the vertical lengths between the levels at the front waist point and the side waist point in the patterns are 0.7cm; (2) the vertical length between the levels at the front waist point and the back waist point in the back panel is 0.7cm; (3) the horizontal lengths between the perpendicular line from the side hip point and the side waist point in patterns are within a range of 2.0 to 2.2cm; (4) the horizontal length between the original and the adjusted back waist points moved into the waist line, in a range of 0.0 to 1.0cm, differs whether the center back line would be folded or sewn.