• 대한조선학회논문집
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• 제56권5호
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• pp.427-438
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• 2019

It was important to estimate the full-scale operating performance including actual RPM and engine power of a ship since the operation efficiency during a voyage could be evaluated from the values. In the previous research, an entire voyage was simulated by following recorded speeds obtained from AIS and full-scale measurement data. Although reasonable tendencies were observed in the estimated speed, actual RPM, and engine power, it was impossible for them to be completely corresponded with the measured values due to the difference between actual operation and mathematical model. In this paper, alternative approaches to cope with the speed, actual RPM, and engine power were suggested by following the given speed, RPM, and power respectively. After entire voyages were simulated according to a given value, the effects of the value on the estimated performance were investigated. And, it was confirmed that the appropriate approach could be differently chosen according to the aim of the simulation or given value.

• 항공우주시스템공학회지
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• 제17권1호
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• pp.97-105
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• 2023

항공용의 센서 포드는 비행체 기동조건에서 유도된 비행 하중에 대하여 정적 구조시험을 통한 구조 건전성을 검증해야 한다. 이를 위해 센서 포드 전 구조체의 정하중 시험장비 개발이 필수적으로 요구된다. 본 논문에서는 시험요구도를 기본으로 정적 구조시험의 구성 및 시험 구조물, 시험체 구속장치, 하중 인가장치, 제어 및 계측장비 등의 설계, 제작, 조립 및 검증에 대한 방법과 절차들을 확보하였다. 결론적으로 센서 포드의 정하중 시험 및 데이터 획득을 성공적으로 수행하였으며, 시험장비의 신뢰성도 함께 입증하였다.

• 대한조선학회논문집
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• 제55권1호
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• pp.37-44
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• 2018

To understand the dynamic characteristics of the vessel with hydroelastic response, it is very important to estimate the dynamic modal parameters such as mode shapes, natural frequency, and damping ratio. These dynamic modal parameters of full scale ship are a priori unknowns, hence to be estimated directly based upon the full scale measurement data. In this paper, dynamic modal parameters were extracted by signal processing of acceleration and strain data measured from a large container ship whose loading capacity is 9400TEU. The mode shapes of the vibrating hull were identified using the proper orthogonal decomposition and the vibration response of hull was decomposed into its modal magnitudes. Natural frequencies of specific modes were derived via Fourier transform of these modal magnitude. Also, the free decay signal of the vibrating hull was obtained through the random decrement technique and the damping ratio was estimated with accuracy.

• 연구논문집
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• 통권30호
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• pp.59-65
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• 2000

The objective of experimental study is to apply simultaneous measurement by PIV(Particle Image Velocimetry)to high_speed flow characteristics within Ginseng washing machine. Three different kinds of flow rate(15,20,27 $\ell$/min)are selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. Instantaneous velocity distribution, time-mean velocity distribution and velocity profiles are represented quantitatively at the full-scale region for the deeper understanding of the flow characteristics in Ginseng washing machine.

• 대한조선학회 특별논문집
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• 대한조선학회 2017년도 특별논문집
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• pp.80-87
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• 2017

This paper is related to structural assessment considering the hydroelastic response of ultra large container ships, especially from whipping (bow or stern impacts) and from springing (resonance). In general, whipping contributes both to increased fatigue and extreme loading, while springing does mainly contribute to increased fatigue loading. To evaluate the hydroelastic response quantitatively with high accuracy, numerical code considering hydro-structure coupling was applied and fatigue strength of a 13,100 TEU class containership was verified. The segmented model test and full scale measurement were also needed to assess the effect of whipping and springing on the fatigue and extreme capacity in more realistic way and for verification of the numerical tools. With reference to class rule, fatigue assessment considering springing effect and extreme assessment considering whipping effect were introduced.

• Wind and Structures
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• 제4권3호
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• pp.247-260
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• 2001

In the last three decades several comprehensive field measurement programs have produced significant insight into the wind effects on low-rise structures. The most notable and well published of these efforts are measurements being collected at the Wind Engineering Field Laboratory (WERFL) at Texas Tech University, measurements on low-rise structures in Silsoe, England and measurements on groups of low-rise structures collected in Aylesbury, England. Complementary to these efforts, an additional full-scale field investigation program has recently collected meteorological, pressure, strain and displacement data on a low-rise structure in Southern Shores, North Carolina. To date over seventy-five hundred data sets have been collected at the Southern Shores site in a variety meteorological conditions up to and including hurricane-force winds. This paper provides details of the system, its development, and preliminary assessment of its performance. A description of the field site, the instrumented structure, and the instrumentation system is provided. In addition, an example of the data collected during three hurricanes is presented. The primary goal of this paper is to provide the reader with the necessary technical details to appropriately interpret data from this experiment, which will be presented in future publications currently under development.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.82-83
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• 2011

본 논문에서는 3경간 연속 사장교에 설치 된 계측장비에서 2010년 태풍 곤파스 당시 계측한 바람 및 교량응답 자료를 바탕으로 사장교의 버페팅 응답을 평가하였다. 계측 된 바람자료에서 스펙트럼 분석을 수행하고 그 결과를 버페팅 해석에 반영하여 실교량 거동을 예측하였다. 예측 된 교량의 거동은 실제 계측 된 값과 유산한 결과를 나타내었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.401-414
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• 2010

Top Base Foundation(TBF) is a stabilization method for light weight structures particularly in the soft ground. It is widely used for the increment of bearing capacity and restraining settlement of foundations when the bearing capacity of ground is not enough. However, when the design values from exiting Japanese standard are compared with the observation values from the field measurement, the bearing capacity of exiting standard estimated smaller For this reason, it is necessary to establish more reasonable prediction technique considering to understand the behavior of TBF in soft ground. In this study, 1/5 scale model tests were performed in the laboratory. Also, full scale tests were carried out in order to investigate the behavior of TBF with various shapes. In addition, about 100 sites measurement data were evaluated to investigate the behavior of TBF in various ground conditions. Based on the results of the model tests and field measurement data, it was possible to establish more reasonable the bearing capacity equation of TBF considering various N-value of soil, the effect of underground water and failure shapes.

• 한국추진공학회지
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• 제13권6호
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• pp.17-23
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• 2009

정확한 추력 및 비추력 특성을 파악하기 위하여 액체로켓엔진용 연소기에 추가적으로 임시 노즐확장부를 장착함에 있어, 그 열/구조적 건전성을 파악하였다. 이 열/구조적 건전성은 재질 및 차폐막(TBC)의 두께 효과를 살펴봄으로써 검토하였다. TBC가 없는 경우에는 열/구조적 건전성을 유지할 수 없음을 파악할 수 있었다. TBC의 두께에 따라서 노즐확장부 벽면에서의 최대온도는 많이 감소하였다. 노즐확장부를 steel로 제작하는 경우에는 TBC를 적용해야만 연소시험동안 확장부의 열/구조적 건전성이 보장될 것으로 예상된다.

• Wind and Structures
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• 제17권6호
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• pp.609-627
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• 2013

The Yingxian wooden tower in China is currently the tallest wooden tower in the world. It was built in 1056 AD and is 65.86 m high. Field measurements of wind speed and wind-induced response of this tower are conducted. The wind characteristics, including the average wind speed, wind direction, turbulence intensity, gust factor, turbulence integral length scale and velocity spectrum are investigated. The power spectral density and the root-mean-square wind-induced acceleration are analyzed. The structural modal parameters of this tower are identified with two different methods, including the Empirical Mode Decomposition (EMD) combined with the Random Decrement Technique (RDT) and Hilbert transform technique, and the stochastic subspace identification (SSI) method. Results show that strong wind is coming predominantly from the West-South of the tower which is in the same direction as the inclination of the structure. The Von Karman spectrum can describe the spectrum of wind speed well. Wind-induced torsional vibration obviously occurs in this tower. The natural frequencies identified by EMD, RDT and Hilbert Transform are close to those identified by SSI method, but there is obvious difference between the identified damping ratios for the first two modes.