• 제목/요약/키워드: Experiment of Full-Scale Model

검색결과 87건 처리시간 0.026초

심해 저층트롤망의 수중형상에 관한 모형실험 (A model experiment on the underwater shape of deepsea bottom trawl net)

  • 박광제;이주희;김형석;정순범;오택윤;배재현
    • 수산해양기술연구
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    • 제42권3호
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    • pp.134-147
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    • 2006
  • A model experiment using circulation water channel was carried out to investigate the dynamic characteristics of bottom trawl net which can be used in sea mount of North Pacific. Hydrodynamic resistance and shape variation according to the flow velocity and angle of hand rope transformation for net were measured, and experimental value was analyzed as the value of full-scale bottom trawl net. The results summarized are as follows; At the $30^{\circ}$ of angle of hand rope to net, hydrodynamic resistance varied from 0.5kgf to 2.68kgf as the flow velocity increased between 0.31m/s and 0.92m/s, and formula of hydrodynamic resistance for the model net was $F_m=3.04\;{\cdot}\;{\upsilon}^{1.53}$. At the fixed angle of hand rope, Net height was low and Net width was high according to the increase of flow velocity, and in addition, vertical opening was low and Net width was high by the increase of angle of hand rope at the fixed flow velocity. At the $30^{\circ}$ of angle of hand rope to net, net opening area was $0.214m^2$ as flow velocity was 0.61m/s, and formula of net opening area for the model net was $S_m=-0.22{\upsilon}+0.35$. At the $30^{\circ}$ of angle of hand rope to net, catch efficiency seemed to be highest as $0.319m^3/s$ of filtering volume at the 0.76m/s(51kt's) of flow velocity. Shape variation of net showed the gradual laminar transform for the variation of flow velocity but there needed some improvements due to the occurrence of shortening at the ahead of wing net.

Drift displacement data based estimation of cumulative plastic deformation ratios for buildings

  • Nishitani, Akira;Matsui, Chisa;Hara, Yushiro;Xiang, Ping;Nitta, Yoshihiro;Hatada, Tomohiko;Katamura, Ryota;Matsuya, Iwao;Tanii, Takashi
    • Smart Structures and Systems
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    • 제15권3호
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    • pp.881-896
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    • 2015
  • The authors' research group has developed a noncontact type of sensors which directly measure the inter-story drift displacements of a building during a seismic event. Soon after that event, such seismically-induced drift displacement data would provide structural engineers with useful information to judge how the stories have been damaged. This paper presents a scheme of estimating the story cumulative plastic deformation ratios based on such measured drift displacement information toward the building safety monitoring. The presented scheme requires the data of story drift displacements and the ground motion acceleration. The involved calculations are rather simple without any detailed information on structural elements required: the story hysteresis loops are first estimated and then the cumulative plastic deformation ratio of each story is evaluated from the estimated hysteresis. The effectiveness of the scheme is demonstrated by utilizing the data of full-scale building model experiment performed at E-defense and conducting numerical simulations.

Flexural Behavior of High-Strength Concrete Beams Confined with Stirrups in Pure Bending Zone

  • Jang, Il-Young;Park, Hoon-Gyu;Kim, Yong-Gon;Kim, Sung-Soo;Kim, Jong-Hoe
    • International Journal of Concrete Structures and Materials
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    • 제3권1호
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    • pp.39-45
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    • 2009
  • The purpose of this study is to establish flexural behavior of high-strength concrete beams confined in the pure bending zone with stirrups. The experiment was carried out on full-scale high-strength reinforced concrete beams, of which the compressive strengths were 40 MPa and 70 MPa. The beams were confined with rectangular closed stirrups. Test results are reviewed in terms of flexural capacity and ductility. The effect of web reinforcement ratio, longitudinal reinforcement ratio and shear span to beam depth ratio on ductility are investigated. The analytic method is based on finite element method using fiber-section model, which is known to define the behavior of reinforced concrete structures well up to the ultimate state and is proven to be valid by the verification with the experimental results above. It is found that confinement of concrete compressive regions with closed stirrups does not affect the flexural strength but results in a significantly increased ductility. Moreover, the ductility tends to increase as the quantity of stirrups increases by reducing the spacing of stirrups.

Performance of bridge structures under heavy goods vehicle impact

  • Zhao, Wuchao;Qian, Jiang;Wang, Juan
    • Computers and Concrete
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    • 제22권6호
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    • pp.515-525
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    • 2018
  • This paper presents a numerical study on the performance of reinforced concrete (RC) bridge structures subjected to heavy goods vehicle (HGV) collision. The objectives of this study are to investigate the dynamic response and failure modes of different types of bridges under impact loading as well as to give an insight into the simplified methods for modeling bridge structures. For this purpose, detailed finite-element models of HGV and bridges are established and verified against the full-scale collision experiment and a recent traffic accident. An intensive parametric study with the consideration of vehicle weight, vehicle velocity, structural type, simplified methods for modeling bridges is conducted; then the failure mode, impact force, deformation and internal force distribution of the validated bridge models are discussed. It is observed that the structural type has a significant effect on the force-transferring mechanism, failure mode and dynamic response of bridge structures, thus it should be considered in the anti-impact design of bridge structures. The impact force of HGV is mainly determined by the impact weight, impact velocity and contact interface, rather than the simplification of the superstructure. Furthermore, to reduce the modeling and computing cost, it is suggested to utilize the simplified bridge model considering the inertial effect of the superstructure to evaluate the structural impact behavior within a reasonable precision range.

Hybrid RANS and Potential Based Numerical Simulation for Self-Propulsion Performances of the Practical Container Ship

  • Kim, Jin;Kim, Kwang-Soo;Kim, Gun-Do;Park, Il-Ryong;Van, Suak-Ho
    • Journal of Ship and Ocean Technology
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    • 제10권4호
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    • pp.1-11
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    • 2006
  • The finite volume based multi-block RANS code, WAVIS developed at MOERI is applied to the numerical self-propulsion test. WAVIS uses the cell-centered finite volume method for discretization of the governing equations. The realizable $k-{\epsilon}$ turbulence model with a wall function is employed for the turbulence closure. The free surface is captured with the two-phase level set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. The propeller forces are obtained using an unsteady lifting surface method based on potential flow theory. The numerical procedure followed the self-propulsion model experiment based on the 1978 ITTC performance prediction method. The self-propulsion point is obtained iteratively through balancing the propeller thrust, the ship hull resistance and towing force that is correction for Reynolds number difference between the model and full scale. The unsteady lifting surface code is also iterated until the propeller induced velocity is converged in order to obtain the propeller force. The self-propulsion characteristics such as thrust deduction, wake fraction, propeller efficiency, and hull efficiency are compared with the experimental data of the practical container ship. The present paper shows that hybrid RANS and potential flow based numerical method is promising to predict the self-propulsion parameters of practical ships as a useful tool for the hull form and propeller design.

하수처리장의 고도처리 upgrading 설계와 공정 최적화를 위한 다변량 통계분석 (Design of a Wastewater Treatment Plant Upgrading to Advanced Nutrient Removal Treatment Using Modeling Methodology and Multivariate Statistical Analysis for Process Optimization)

  • 김민정;김민한;김용수;유창규
    • Korean Chemical Engineering Research
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    • 제48권5호
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    • pp.589-597
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    • 2010
  • 하수처리 시스템에서의 생물학적 영양염류 기준이 강화됨에 따라, 표준활성슬러지공법으로 운전 중인 하수처리장의 고도처리 공법으로의 개보수 필요성이 증가하고 있다. 그러나 실제 하수처리 시스템에서의 다양한 유입조건 및 운전조건의 복잡한 반응 구성으로 인해 실험을 통하여 개보수된 고도처리공법의 최적조건을 찾는 것은 쉽지 않은 일이며, 이는 많은 시간과 비용을 소모하여 비효율적이다. 따라서 본 연구에서는 활성슬러지공정모델(ASMs)을 기반으로 한 하수처리장의 모델링 및 시뮬레이션 기법을 통하여 하수처리장의 고도처리공법으로의 upgrading 설계를 수행하며, 이를 통계적이며 체계적으로 접근하기 위해 반응표면분석법(Response surface method)을 통한 고도처리공법의 설계 최적화를 수행하였다. 또한 실규모 하수처리장에서의 운전 최적화를 위해서는 하수처리의 동력학적 매개변수에 대한 정확한 분석이 수행되어야 한다. 본 연구에서는 다변량 통계분석 기법인 부분최소승자법(PLS)을 통하여 하수처리 시스템의 동력학적 매개변수 간의 상관관계를 파악하며, 고도처리공법 하수처리장의 운전 결과에 가장 큰 영향을 미치는 매개변수를 도출하였다. 본 연구를 통해 하수처리장의 고도처리공법 upgrading 설계 및 운전 최적화를 위한 방법론을 제시하였으며, 이를 통하여 설계시간 및 경비 절감 등 고도처리공법으로의 고효율적인 개보수가 가능할 것으로 예상된다.

제주도 연안 정치망 조업시스템 개발에 관한 연구 3. 구조개량을 위한 각멍어구 모형실험 (Studies on the Development of the Fishing System of Set Net in the Coast of Jeju Island 3. The Mode| Experiment of Fyke Net for Construction Improvement)

  • 김석종;구명성
    • 수산해양기술연구
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    • 제40권1호
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    • pp.37-46
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    • 2004
  • 제주도 연안 정치망 조업 시스템 개량과 개발분야에서 연안해역에서 널리 사용되고 있는 각망어구의 구조개량을 위한 기초연구로서 현재 사용되고 있는 실물망을 1/20로 축소하여 개량된 입구 구조를 갖춘 모형 어구 8종류를 제작하고, 실험 수조에서 고등어 어군을 이용하여 모형 어구에 대한 어군의 입 ${\cdot}$ 출망 행동을 관찰 분석하였는데, 그 결과는 다음과 같다. 1. 원통그물내에서의 어군의 행동 패턴은 원형 모양으로 한쪽 원통그물내에 체류하는 행동과 긴 타원형 모양으로 좌 ${\cdot}$ 우 원통그물내를 왕복 유영하는 행동패턴으로 분류할 수 있었다. 2. 모형 어구 내에서의 고등어 어군의 평균 유영 속도는 원통 그물 중간 부분에서 24.9cm/sec, 오른쪽 원통그물내에서 12.6cm/sec, 입구에서 32.0cm/sec였다. 3. 어군의 입망율은 경과 시간 60초일 때 표준 모형 어구에서는 47%였고, 깔대기 그물이 길이가 35cm 의 모형 어구에서는 40%로 나타났는데, 양자의 차이는 7% 정도로 그다지 크지 않았다. 4. 어군의 출망율은 경과 시간 60초일 때 표준 모형 어구에서는 69%였고, 깔대기 그물의 길이가 35cm 의 모형 어구에서는 10%로 나타났는데, 양자의 차이는 59% 정도로 그 폭이 컸다. 5. 어군의 잔여율은 경과 시간 60초일 때 표준 모형 어구에서는 31%였고, 깔대기 그물의 길이가 35cm의 모형 어구에서는 90%로 나타났는데, 양자의 차이는 59% 정도였다.

Identification of acrosswind load effects on tall slender structures

  • Jae-Seung Hwang;Dae-Kun Kwon;Jungtae Noh;Ahsan Kareem
    • Wind and Structures
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    • 제36권4호
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    • pp.221-236
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    • 2023
  • The lateral component of turbulence and the vortices shed in the wake of a structure result in introducing dynamic wind load in the acrosswind direction and the resulting level of motion is typically larger than the corresponding alongwind motion for a dynamically sensitive structure. The underlying source mechanisms of the acrosswind load may be classified into motion-induced, buffeting, and Strouhal components. This study proposes a frequency domain framework to decompose the overall load into these components based on output-only measurements from wind tunnel experiments or full-scale measurements. First, the total acrosswind load is identified based on measured acceleration response by solving the inverse problem using the Kalman filter technique. The decomposition of the combined load is then performed by modeling each load component in terms of a Bayesian filtering scheme. More specifically, the decomposition and the estimation of the model parameters are accomplished using the unscented Kalman filter in the frequency domain. An aeroelastic wind tunnel experiment involving a tall circular cylinder was carried out for the validation of the proposed framework. The contribution of each load component to the acrosswind response is assessed by re-analyzing the system with the decomposed components. Through comparison of the measured and the re-analyzed response, it is demonstrated that the proposed framework effectively decomposes the total acrosswind load into components and sheds light on the overall underlying mechanism of the acrosswind load and attendant structural response. The delineation of these load components and their subsequent modeling and control may become increasingly important as tall slender buildings of the prismatic cross-section that are highly sensitive to the acrosswind load effects are increasingly being built in major metropolises.

보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법 (Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation)

  • 권오병
    • Asia pacific journal of information systems
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    • 제19권3호
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

스위스 Grimsel Test Site에서 수행된 FEBEX 현장시험에 대한 수치해석적 연구 (Numerical analysis of FEBEX at Grimsel Test Site in Switzerland)

  • 이창수;이재원;김건영
    • 터널과지하공간
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    • 제30권4호
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    • pp.359-381
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    • 2020
  • 벤토나이트 완충재에서의 열-수리-역학적 복합거동을 예측하기 위해 TOUGH2-MP/FLAC3D 시뮬레이터를 기반으로 개발된 Barcelona basic 모델(BBM) 해석모듈의 현장 적용성을 검토하고자 국제공동연구 DECOVALEX-2019 Task D에 참여하여 스위스 Grimsel Test Site의 현장시험(full-scale engineered barriers experiment, FEBEX) 모델링을 수행하고 현장시험에서 계측된 히터 파워, 온도, 상대습도, 응력, 포화도, 함수율 그리고 건조밀도를 계산 값과 비교하였다. 수치해석을 이용하여 시간에 따른 히터 파워와 온도 변화는 전반적으로 잘 재현되었지만, 히터 1과 히터 2에서의 파워 차이를 계산할 수는 없었으며 이를 개선하기 위해서는 FEBEX 터널 주변에 분포하는 황반암과 시험장치 및 벤토나이트 블록의 설치 공정을 반영할 필요가 있을 것으로 판단된다. 상대습도 변화와 분포 역시 전반적으로 잘 모사되었으나, 수치해석에서 히터 부근에서의 재포화과정이 상대적으로 빠르게 진행된 것으로 보아 수리모델에 대한 일부 수정이 필요할 것으로 보인다. 현장시험에서는 벤토나이트 완충재와 암반 사이에 틈이 존재하지만 수치해석에서는 완벽하게 접촉하고 있는 것으로 가정하였기 때문에 운영 초기의 응력 변화는 다소 차이를 보였지만, 전반적으로 유사한 경향을 보이는 것으로 나타났다. 해체 이후 측정한 포화도, 함수율, 그리고 건조밀도의 분포 역시 전반적으로 잘 재현되었지만, 건조밀도가 터널 중심과 히터부근에서 조금 크게 계산되어 벤토나이트 블록의 투수계수가 상대적으로 작은 값으로 반영되어 포화도와 함수율이 작게 계산된 것으로 보이며, 이를 개선하기 위해서는 건조밀도에 따른 투수계수 모델에 일부 수정이 필요할 것으로 판단된다. 본 연구의 결과를 토대로 수치모델을 수정하고 추가적인 연구를 수행한다면, 보다 나은 해석 결과와 벤토나이트 완충재에서의 THM 복합거동을 좀 더 현실적으로 예측할 수 있을 것으로 판단된다.