• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.131-138
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• 2002

The fuel handling machine handles the core assembly in refueling period of the reactor, it is necessary to predict the motion and structural integrity of it. The kinetic analysis of the fuel handling machine was carried out for the refueling motion. The reaction forces at the joints of machine were calculated with IDEAS code considering the weight of the machine and the loading force of the core assembly, Also, the structural analysis for the machine modeled by lumped-mass and beam elements was performed by using ANSYS code. The stresses and deformations were calculated for the equivalent static force based on the kinetic analysis and the seismic loads. The calculated displacements and stresses are quite low compared with allowable limits.

• Applied Biological Chemistry
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• 제20권1호
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• pp.147-155
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• 1977

본도(本稻)에 심층추비(深層追肥)를 하여 초기무효분벽(初期無效分蘗)을 억제(抑制)하고 유효경비율(有效莖比率)을 높여 생육후기(生育後期)까지 지속적(持續的)인 질소공급(窒素供給)으로 수량증수(收量增收)를 위하여 품종(品種)은 동일(統一)과 진흥(振興), 토양(土壤)은 식양토(埴壤土)와 사양토(砂壤土), 배수조건(排水條件)은 무배수(無排水) 배수(排水)로 구분(區分)하여 질소질비료(窒素質肥料)를 표준시비(표층추비)標準施肥(表層追肥)와 대비(對比)하여 추비비율(追肥比率)을 50%액비(液肥), 50%단자비(團子肥) 80%단자비(團子肥)로 하여 출수(出穗) 35일전(日前) 12cm의 토양(土壤)깊이로 심층추비(深層追肥)하여 얻은 결과(結果)를 요약(要約)하면 다음과 같다. 1. 가) 생육시기별(生育時期別) 경수변화(莖數變化)를 보면 진흥(振興)은 표층추비(表層追肥)에서 경수(莖數)가 급격(急激)히 증가(增加)하다가 감소경향(減少傾向)도 심(甚)하여 유효경비율(有效經比率)이 낮으며 심층추비(深層追肥)에서는 경수(莖數)의 증감(增減)이 완만(緩慢)하여 유효경비율(有效經比率)이 현저(顯著)하게 높았다 나) 통일(統一)에서는 진흥(振興)처럼 표층추비(表層追肥)와 심층추비간(深層追肥間)의 경수증감(莖數增減)의 폭(幅)이 크지않으나 80%단자심층추비(團子深層追肥)는 유효경비율(有效經比率)이 $83{\sim}93%$로 가장 높았다. 다) 진흥(振興)에서 80%단자심층추비(團子深層追肥)는 시비량(施肥量)이 많은 것 같다. 라) 유효경비율(有效經比率)은 통일(統一)보다 진흥(振興)이 높은 경향(傾向)이다. 2. 주당총립수(株當總粒數)는 심층추비(深層追肥)로 증가(增加)하였으며 입수(粒數)가 증가(增加)할수록 등숙비율(登熟比率)은 감소(減少)하는 경향(傾向)이다. 3. 진흥(振興)에서 심층추비(深層追肥)로 지엽(止葉)의 길이가 길며 수량(收量)과는 유의(有意)한 정(正)의 상관(相關)을 보였다. 4. 심층추비(深層追認)는 수확기(收穫期) 고(藁)중의 질소함량(窒素含量)을 증가(增加) 시켰으며 수량(收量)과도 정(正)의 상관(相關)이 있었다. 5. 조고비율(粗藁比率)이 심층추비(深層追肥)로 증가(增加)하였으며 통일(統一)보다 진흥(振興)이 높았다. 6.정조(精粗收量)은 80%단자심추(團子深追)>50%단자심추(團子深追)>50%액심추(液深秋)>표층추비(表層追肥)의 순(順)으로 심층추비(深層追肥)의 효과(效果)가 있었으며 증수요인(增收要因)으로는 표층추비(表層追肥)에 비(比)하여 유효경비율(有效經比率)의 증가(增加) 및 수수증가(穗數增加)와 진당총립수(振當總粒數)의 증가(增加)로 본다. 7. 토양별(土壤別) 심층추비효과(深層追肥效果)는 통일(統一)은 사양토(砂壤土)에서 진흥(振興)은 식양토(埴壤土)에서 증수(增收)하였다. 8. 통일(統一), 진흥(振與) 다같이 식양토(壇壞土)에서는 80%단자심층추비(鬪子深層追肥)를 제외(除外)하고는 무배수(無排水)에서 증수(增收)하였다. 9. 본(本) 실험실시중(試驗實施中) 출수기(出穗期) 등숙기(登熟期)에 저온(低溫)이 계속(繼續)되어 통일(統一)에서 등숙비율(等熟比率)이 낮았으나 표층추비(表層追肥)에 대(對)한 증수효과(增收效果)는 진흥(振興)보다 통일(統一)이 높았다.

• Structural Engineering and Mechanics
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• 제30권3호
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• pp.369-382
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• 2008

An oscillator of two lumped masses linked through a vertical spring moves forward in the horizontal direction, initially at a certain height, over a horizontal Euler beam and descends on it due to its own weight. Vibration of the beam and the oscillator is excited at the onset of the ensuing impact. The impact produced by the descending oscillator is assumed to be either perfectly elastic or perfectly plastic. If the impact is perfectly elastic, the oscillator bounces off and hits the beam a number of times as it moves forward in the longitudinal direction of the beam, exchanging its dynamics with that of the beam. If the impact is perfectly plastic, the oscillator (initially) sticks to the beam after its first impact and then may separate and reattach to the beam as it moves along the beam. Further events of separation and reattachment may follow. This interesting and seemingly simple dynamic problem actually displays rather complicated dynamic behaviour and has never been studied in the past. It is found through simulated numerical examples that multiple events of separation and impact can take place for both perfectly elastic impact and perfectly plastic impact (though more of these in the case of perfectly elastic impact) and the dynamic response of the oscillator and the beam looks noisy when there is an event of impact because impact excites higher-frequency components. For the perfectly plastic impact, the oscillator can experience multiple events of consecutive separation from the beam and subsequent reattachment to it.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1991년도 춘계학술대회논문집; 한국해사기술연구소, 대전; 1 Jun. 1991
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• pp.153-158
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• 1991

Recently, demands on light weight, high strength, and low noise or vibration have led to the design of complicated structural systems. Although finite elements [1], mode synthesis [2], and statistical energy analysis [3] can be used to compute the dynamic response of such systems, the structural complexity has made the interpretation of the results of such analysis difficult. Many researchers in dynamic analysis have sought to further develop existing theories or develop alternate methods to obtain greater insight in the behavior of large massive primary systems (P systems) with connected light secondary systems (S systems). Some recent research includes work by Sackman and Kelly [4], Sackman et al.[5], Der Kiureghian et al.[6], and Igusa and Der Kiureghian [7-9] who have combined mode synthesis concepts, matrix algebraic theory, and perturbation methods for characterizing weakly-coupled structural systems. A major limitation of these works are that they are limited to lumped mass S systems. In this paper, the general ideas in the Refs.[4-9] are used to study continuous S systems and the method to reduce the complexity, studied in the works by Igusa, Achenbach, and Min [10,11], is developed into the frequency window method.

• 한국전산구조공학회논문집
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• 제22권3호
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• pp.251-258
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• 2009

개념설계단계에서 전투차량은 크게 화력성능, 기동성능과 체계의 물리적 특성으로 나누어진다. 본 연구에서는 전투차량체계를 구성하는 3가지 특성 중 화력성능의 최적화로 제한한다. 체계의 개념설계 단계에서 화력성능에 영향을 미치는 주요 인자로 파괴효과에 직접적인 영향을 주는 탄의 중량과 원거리 사격을 고려한 최대사거리를 분석대상으로 선정하였다. 최대 사거리 분석을 위하여 강내탄도와 강외탄도해석은 질량 집중 모델, Le Duc모델과 질점탄도모델을 사용하여 분석하였다. 실험계획법과 회귀분석으로 반응표면식을 구성하고 선정된 인자를 반응표면법으로 최적화하였다.

• 센서학회지
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• 제22권5호
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• pp.364-368
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• 2013

Vibrational energy harvester based on piezoelectricity has been expected to be the dominant energy harvesting technology due to the advantages of high conversion efficiency, light weight and small size, night operation, etc. Its commercialization is just around the corner but the integration with power management electronics should be solved in advance. In this paper, therefore, fully-integrated design environment for piezoelectric energy harvesting systems is presented to assist co-design with the power management electronics. The proposed design environment is capable of analyzing the energy harvester including the package-induced damping effects and simulating the device and its power management electronics simultaneously. When the developed design environment was applied to the fabricated device, the simulated resonant frequency matched well with the experimental result with a difference of 2.97% only. Also, the complex transient response was completed in short simulation time of 3,001 seconds including the displacement distribution over the device geometry. Furthermore, a full-bridge power management circuit was modeled and simulated with the energy harvester simultaneously. Therefore the proposed, fully-integrated design environment is accurate and fast enough for the contribution on successful commercialization of piezoelectric energy harvester.