응력근사해법(應力近似解法)을 이용한 평면(平面)트러스구조물(構造物)의 형상최적화(形狀最適化)에 관한 연구(?究)

이규원,유희중,Lee, Gyu Won,You, Hee Jung 대한토목학회 1993 대한토목학회논문집 Vol.13 No.2

본(本) 연구(?究)에서는 분할기법(分割技法)을 이용하여 평면(平面)트러스구조물(構造物)의 형상최적화(形狀最適化)를 시도(試圖)하였다. 본(本) 연구(?究)의 제(第)1단계(段階)(Level 1)에서는 다른 연구(?究)와 달리 응력제약(應力制約)을 감도해석(感度解析)에 효율적(效率的)이라고 알려진 설계공간법(設計空間法)에 의해서 부재응력근사화(部材應力近似化)를 하므로서 비선형최적화문제(非線形最適化問題)가 선형계획문제(線形計劃問題)로 변환(變換)되어 해(解)를 효율적(效率的)으로 구할 수 있고 또한 감도해석(感度解析)을 위한 구조해석수(構造解析數)를 줄일 수 있다. 목적함수(目的?數)는 구조물(構造物)의 중량(重量)이 최소(最小)가 되도록 중량함수(重量?數)를 택하였다. 제약조건식(制約條件式)으로는 허용응력(許容應力), 좌굴응력(挫屈應力), 변위제약(變位制約) 및 설계변수(設計變數) 상하한치제약(上下限値制約)을 부과(附課)하였고 다(多) 재하조건(載荷條件)을 고려(考慮)하여 최적화문제(最適化問題)를 형성(形成)하였다. 제(第)2단계(段階)(Level 2)에서는 설계변수(設計變數) 및 조정변수(調整變數)를 절점좌표(節點座標)로 하고 목적함수(目的?數)로는 중량함수(重量?數)로 하여 최적화문제(最適化問題)를 형성(形成)하였다. 절점좌표(節點座標)만을 설계변수(設計變數)로 하므로서 무제약최적화문제(無制約最適化問題)로 형성(形成)되므로 최적화(最適化) 과정(過程)이 용이(容易)하다. 본(本) 연구(?究)의 제(第)1단계(段階)에서는 부재응력(部材應力)을 근사화(近似化)하여 단면(斷面)을 최적화(最適化)하고 제(第)2단계(段階)에서는 형상(形狀)만 최적화(最適化)하는 분할기법(分割技法)을 트러스구조물(構造物)에 적용(適用)한 결과 본(本) 연구(?究)는 트러스구조물(構造物)의 형태(形態), 제약조건식(制約條件式)에 구애받지 않고 최적해(最適解)에 부재응력근사화(部材應力近似化)로 인하여 효율적(效率的)으로 수렴(收斂)하였고 또한 타(他)의 연구(?究)와 거의 동일(同一)한 연구(?究) 결과(結果)를 얻었으며 형상최적화(形狀最適化)로 트러스구조물(構造物)의 중량(重量)을 5.4% - 15.4% 까지 감소(減少)시켰다. In this research, configuration design optimization of plane truss structure has been tested by using decomposition technique. In the first level, the problem of transferring the nonlinear programming problem to linear programming problem has been effectively solved and the number of the structural analysis necessary for doing the sensitivity analysis can be decreased by developing stress constraint into member stress approximation according to the design space approach which has been proved to be efficient to the sensitivity analysis. And the weight function has been adopted as cost function in order to minimize structures. For the design constraint, allowable stress, buckling stress, displacement constraint under multi-condition and upper and lower constraints of the design variable are considered. In the second level, the nodal point coordinates of the truss structure are used as coordinating variable and the objective function has been taken as the weight function. By treating the nodal point coordinates as design variable, unconstrained optimal design problems are easy to solve. The decomposition method which optimize the section areas in the first level and optimize configuration variables in the second level was applied to the plane truss structures. The numerical comparisons with results which are obtained from numerical test for several truss structures with various shapes and any design criteria show that convergence rate is very fast regardless of constraint types and configuration of truss structures. And the optimal configuration of the truss structures obtained in this study is almost the identical one from other results. The total weight couldbe decreased by 5.4% - 15.4% when optimal configuration was accomplished, though there is some difference.

L.R.B를 사용한 다경간 연속 STEEL BOX GIRDER교의 온도변화와 종방향거동에 관한 연구

조동영(Cho Dong Young),임삼규(Lim Sam Kyu),유희중(You Hee Jung) 대한토목학회 2003 대한토목학회 학술대회 Vol.2003 No.10

고속철도차량 부품의 TBO 산정을 위한 분석 사례

윤차중(Yun Cha-Jung),조유희(Cho You-Hee),최덕호(Choi Deuck-Ho),유양하(Ryu Yang-Ha),소진섭(So Jin-Sub) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

The high-speed train(KTX) was operated in domestic since 2004 and 4years have been passed since then. At the beginning most of the KTX component maintenance period was followed by the France SNCF. It was settled by the TBO(Time Between Overhauls). But the environment and operation condition are different form each other, so the TBO maintenance period can be different in some component. Therefore new TBO is necessary based on our own circumstances. This paper introduces failure analysis case on some components to set TBO in domestic. KTX-RCM(Reliability Centered Maintenance System), MICS(Maintenance Information Computer System) and KOVIS(KORAIL ERP System) Data was investigated.

多段階 分割技法에 의한 鐵塔構造物의 形狀最適化에 관한 硏究

柳熙仲 湖南大學校 1996 호남대학교 학술논문집 Vol.17 No.2

직병렬 복합구조의 요소로 사용되기에 적합한 병렬 로봇 모듈이 조사되었다. Branch당 하나의 구동 조인트를 갖는 3개의 직렬 branch로 구성된 3 자유도의 병렬 구조 모듈(3-3-1,1,1)이 기구설계와 성능 측면의 관점에서 가장 적합한 구조로 선택되었다. 각각의 직렬 branch는 선단에 spherical 조인트를 기저에 1 자유도를 갖는 구동 조인트를 그리고 하나의 1 자유도를 갖는 수동 조인트를 사용하는 것이 가장 적합한 선택임이 보여졌다. In this research, configuration design optimization of planar tower structure has been tested by using multi-level decomposition technique. In the first level, the weight function has been adopted as objective function in order to minimize structures. For the design constraint, allowable stress, buckling stress constraint under multi-loading condition and upper and lower constraints of the design variable are considered. The nonlinear programming problem was transferred into the linear programming problem which is effective in view of calculation by the approximation of the member stress using design space approach which has been proved to be efficient to the sensitivity analysis. In the second level, the nodal point coordinates of the planar tower structure are used as coordinating variable and the objective function has been taken as the weight function. By treating the nodal point coordinates as design variable, unconstrained optimal design problems are easy to solve. In the multi-level, decomposition method which optimize the section areas in the first level and optimize configuration variables in the second level was applied to the planar tower structure. The optimal configuraion of the planar tower structures obtained in this study is almost the identical one from other results. Therefore it can be concluded that multi-level decomposition technique proposed in this research is helpful to the economical design of the large scale planar towers.

Rock Bolt의 길이 및 配置가 地下構造物의 支保效果에 미치는 影響

유희중,조기옥 호남대학교 산업기술연구소 1997 산업기술연구논문집 Vol.4 No.-

본 실험적 연구는 Rock Bolt의 길이와 배치간격이 지하 구조물의 지보효과에 미치는 영향을 고찰하기 위하여, 시공 중인 터널공사의 실물을 대상으로 실험을 수행하였다. 실험은 8개소의 장소를 선정하여 4종류로 모델화하였고, 각 모델은 암질이 유사한 2개소를 묶어 상호 비교할 수 있도록 하였으며, Rock Bolt의 길이와 간격을 동일 또는 상이하게 배치하여 각 모델별로 분석이 가능토록 하였다. 연구결과 Rock Bolt의 길이가 길어질수록 넓게 배치할 수 있었으나, 일정 수량 이상의 배치는 Bolt수량의 증가만큼 지보효과를 높일 수 없었다. 또한 같은 강도의 암질이라 할지라도, 절리의 방향과 위치에 따라 Rock Bolt의 Bolting 방향과 시공시기가 지보효과에 상당한 영향이 있는 것으로 판단되어, 앞으로 이 분야에 대한 연구가 있어야 할 것으로 사료된다. In this research, reinforcing fects of the length and the space of rock bolt on the underground structure was investigated through field test at the tunnelling work sites. In this test, 8 test sites were selected and modelized of 4 groups. Each group was consisted of 2 rock masses with equal quality to facilitate comparison of the reinforcing effects of length or space of the rock bolt. As a results, the length of rock bolt should be determined by the consideration of rock mass quality and tunnel width. The space of rock bolt could be increased as the length of rock bolt. The more rock bolts were installed, the more the tunnel was reinforced, the more the reinforcing effect of each rock bolt was diminished. Even if the strength of rock mass are equal, it was found that reinforcing effects are varied with the orientation and the installation time of rock bolts and with the orientation and the location of joints. So the continuous study on the rock bolting system with these variables is more desirable.

許容 方向法에 의한 트러스 構造物의 最適 設計에 관한 硏究

유희중 호남대학교 1990 호남대학교 학술논문집 Vol.11 No.2

In the study, optimize effectively the sections of the truss which takes the multi-loading condition, and the allowable stress, buckling stress, displacement constraints into consideration. The algorithm of this study is made up of sectional optimization using the Feasible Direction Method. The results of this study acquired by beenning applied to structural model of the truss a as follow; 1. It is verified that the algorithm of the study effectively converges, independent of the applied various constraints. 2. The algorithm applied in this study converges independent of the initial value. 3. The algorithm applied in this study converges very rapidly at the optimun solutions in iteration with out oscillation phenomenon is all case. 4. Even though there might be a little defference acoording to the design condition the weight of the truss can be decreaced considerably.

탄소섬유판의 보강 폭 및 길이가 RC보의 휨거동에 미치는 영향

柳熙仲 호남대학교 산업기술연구소 2001 산업기술연구논문집 Vol.9 No.-

최근 손상된 구조물의 내하력 증강이 탁월하고, 단위 면적 당 접착면적이 작아 콘크리트 모체의 통기성이 뛰어나다고 알려진 탄소섬유판을 이용한 보강 공법이 많이 이용되고 있으나, 이에 대한 연구는 매우 부족한 실정이다. 따라서 본 연구에서는 탄소섬유판의 보강 길이와 폭이 RC보의 휨보강 효과에 미치는 영향을 실험적으로 검토한 결과 다음과 같은 결론을 얻었다. 탄소섬유판은 인장철근과 같이 RC보의 인장응력을 부담하고 그 보강율의 증가에 따라 RC보의 휨내력이 증가함을 알 수 있어 탄소섬유판에 의한 보강공법은 유효한 것으로 확인되었다. 탄소섬유판으로 보강한 RC보의 최대 하중은 보강하지 않은 RC보와 비교하면 보강율이 증가함에 따라 최대 하중이 거의 선형적으로 증가하였으며 보의 중앙에서 보강율의 증가에 따라 휨성능이 개선되었다. 탄소섬유판의 보강폭과 보강길이에 따른 휨성능을 비교하면 보강길이 보다는 보강폭의 증가에 따라 더 큰 영향을 받음을 알 수 있었다. A strengthening method using Carbon Fiber Reinforced Plate which increase the durability significantly and has good ventilation for the adhesive area per unit area is small is recently used. In this study, we experimentally examine the effect of strengthening length and width of Carbon Fiber Reinforced Plate on flexural Strengthening of RC beams. The result are as followings. Carbon Fiber Reinforced Plates share tensile stresses of RC Beams like Tensile reinforcements as a ratio of strengthening is increased. Flexural strength is increased. So a strengthening method using Carbon Fiber Reinforced Plate is confirmed to be available. In comparison with maximum loads of RC Beams with strengthening Carbon Fiber Reinforced plates and without strengthening Carbon Fiber Reinforced plates. The results are as follows. As ratios of strengthening are increased, maximum loads are increased almost linearly. So as ratios of strengthening are increased at center of beams, flexural capacities are made better. In comparison with the flexural capacity of strengthening width of C.F.R.P and strengthening length of C.F.R.P. an strengthening width is more effective than strengthening length.

다목적 함수를 갖는 트러스 구조물의 퍼지 최적화

유희중 湖南大學校 1997 호남대학교 학술논문집 Vol.18 No.2

This study aims at the analysis, utlity and application of this research from the results on optimization of the truss structure having the muliti-objective function of volume and displacement which is conflicting each other in properties and the constraint which is including uncertainties by using fuzzy theory. In the formulation of optimum problems the design variablesare taken as the cross sectional areas, volume is taken as the first objective function and displacement conflicting with the first objective functionas the second objective function and the constraints consist of the fuzzy stress constraints of the 2-member, 7-member, and 10-member truss structures. The optimum solutions of 3-type truss structures are gained from applying weighting method using feasible direction method. The numerical results of the algorithm in this research is numerically tested for 3-type truss structures can be summerized as follows; Without regrading to the types and shapes of truss structures, the numbers of loading and the constraint conditions are converged within four cycle optimum solutions. The user can choose the one optimum solution in practices as obtaining the optimum solutions according to the α-cut, displacement weight and volume weight. The optimal procedure of this study can be applied optimum design of complex structures having various sagment structures.

二次 計劃法에 의한 트러스 構造物의 最適 設計에 관한 硏究

柳熙仲 호남대학교 1991 호남대학교 학술논문집 Vol.12 No.2

In the study, optimize effectively the section of the truss which takes the multi-loading condition, and the allowable stress, bucking stress, displacement constraints into consideration. The algorithm of this study is made up of sectional optimization using the Quadratic Programing Method. The results of this study acquired by beenning applied to structural model of the truss are as follows : 1. The algorithm applied in this study converges indipendent of the initial value. 2. Comparing algorithm of this study with other algorithms the result of objective function make little difference. 3. The algorithm applied in this study converges very rapidly at the optimun solutions in iteration with out oscillation phenomenon is all case . 4. Optimizing section, the weight of structure could be considerably reduced. therefore section optimization introduced by this study can be used for the economical design.

H-形鋼 斷面性向을 考廬한 트러스의 多目的 函數 퍼지最適化에 관한 硏究

유희중,조동영 호남대학교 산업기술연구소 1997 산업기술연구논문집 Vol.5 No.-

구조물의 최적설계문제에 퍼지이론을 이용한 구조물의 최적화는 최적화문제에 불확실성이 포함되어야 하므로 일반적인 구조물의 최적화에 비하여 최적화문제의 형성이 복잡하다. 또한 최적화문제가 형성되었다고 해도 서로 상충되는 여러개의 목적함수를 동시에 고려해서 최적화문제의 해를 구해야 하므로 최적화 과정이 단일목적함수를 고려한 구조물의 최적화에 비하여 매우 복잡하다. 따라서 본 연구에서는 다른 연구와 달리 구조물의 최적설계에 실제 생산되고 있는 H-형강의 단면 성향을 고려하였으며, 또한 구조물을 구성하는 재료의 특성치가 분명하지 않으므로 해서 설계에서 발생할 수 있는 불확실성을 포함한 트러스 구조물의 최적화를 시도하였다. 본 연구에서는 최적화를 효과적으로 수행하기 위하여 설계변수로 부재단면적을 취하고, 목적함수는 서로 상반되는 체적과 변위를 제1목적함수, 제3목적함수로 하였다. 제약조건은 퍼지량인 응력 제약조건을 고려한 최적화문제를 형성하여 허용방향법에 의한 다목적함수 퍼지 최적화기법으로 최적해를 구하였으며, 2부재, 7부재의 트러스 구조물에 적용한 결과, 본 연구의 알고리즘은 적용성, 타당성 및 효율성이 있다고 사료된다. The structural optimization using fuzzy theory to the optimum design of the structure should include uncertainties in the optimizing problem. Therefore, in this case the optimizing problems are structures. Also although the optimizing problems are made, they should be solved by simultaneously considering several objective functions that are individually different. So the process of this optimization is very complex, compared to that of the optimization considering a single objective function. Accordingly, thsi study distinctively considered the sectional properties of H shape steel actually being produced for the optimum design of the structure and tried the optimization of truss structures including uncertainties that can happen in design due to the ambiguity of the specific value composing one structure. In this study, to effectively execute the optimization, the section areas of member were taken as the design variables and the objective functions took volume and displacement being contrary to each other as the first objective function and the second one. As restraint conditions formed the optimizing problems considering stress restraint conditions, the optimum was obtained by the fuzzy optimization method of multiple-purpose function in allowable direction method. As a result of applying to truss structure of the 2 member and 7 member, the algorithm of this research was for the applicability, propriety and effciency.