• Title/Summary/Keyword: 과도 응답 해석

Search Result 358, Processing Time 0.028 seconds

Transient response and performance of a three-dimensional straight fin (3차원 직선핀의 과도응답 및 성능)

  • 오원균;조진호;서정일;조종철
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.13 no.4
    • /
    • pp.753-763
    • /
    • 1989
  • The transient response of a three-dimensional straight fin of constant cross sectional area and perimeter with unequal top, bottom, left, right and tip surface convection coefficients is analyzed using separation variables and Laplace transforms when the fin base is subjected to a step change in temperature. The three-dimensional effects of fin dimensions and unequal fin surface convection coefficients on the fin performance which is expressed in terms of the heat flowrates through the fin base are investigated, and errors in one-dimensions and unequal fin surface coefficients. Typical results are represented in tabular and graphical forms.

A Study on Simplified Sloshing Impact Response Analysis for Membrane-Type LNG Cargo Containment System (LNG 화물창 단열구조의 슬로싱 충격응답 간이해석법에 관한 연구)

  • Nho, In-Sik;Ki, Min-Seok;Kim, Sung-Chan
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.48 no.5
    • /
    • pp.451-456
    • /
    • 2011
  • To ensure structural integrity of membrane type LNG tank, the rational assessment of the sloshing impact responses of tank structures should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the resulting structural responses show very complex behaviors accompanied with fluid structure interaction. So it is not easy to estimate them accurately and immense time consuming calculation process would be necessary. In this research, a simplified method to analyse the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was studied. The proposed technique based on the concept of linear combination of the triangular response functions which are the transient responses of structures under the unit triangular impact pressure acting on structures. The validity of suggested method was verified through the example calculations and applied to the dynamic structural response analysis of a real Mark III membrane type insulation system using the sloshing impact pressure time histories obtained by model test.

A Domain-Dependent Question-Answering System (이벤트 탐색을 사용하는 일정 영역 질의 응답 시스템의 구현)

  • Chang, Du-Seong;Oh, Jong-Hun;Choi, Key-Sun
    • Annual Conference on Human and Language Technology
    • /
    • 2001.10d
    • /
    • pp.414-421
    • /
    • 2001
  • 본 논문에서는 한정된 영역을 대상으로 하는 질의응답 시스템에서 사용자의 질의를 해석하고 적당한 대답을 생성하기 위해 백과사전이나 일반사전 등과 같은 지식원에서 추출된 구조화된 지식을 사용하는 과정을 기술한다. 질의응답을 위하여 지식원은 그 단락의 의미에 따라 구조화되고 각 단락은 논리형식으로 변환되었으며, 논리형식 내 각 개체들은 사전 정의문에 따라 확장되었다. 이 구조화된 지식은 입력된 자연언어 질의문에서 질의의 의도를 추출하고, 질의에 포함되어 있는 지식에 의미속성을 부착하기 위해 사용된다. 지식원의 논리형식 변환을 위해 한국어의 논리형식이 도입되었으며, 사용된 지식원은 우리말 큰사전과 계몽백과사전의 30여개 질병정의문이다.

  • PDF

Commonsense Graph Path Learning Model for OpenBook Question and Answering (오픈북 질의응답을 위한 상식 그래프 경로 학습 모델)

  • Lim, Jungwoo;Oh, Donsuk;Jang, Yoonna;Yang, Kisu;Lim, Heuiseok
    • Annual Conference on Human and Language Technology
    • /
    • 2020.10a
    • /
    • pp.71-75
    • /
    • 2020
  • 오픈북 질의응답 문제는 올바른 정답을 고르기 위해 사람들끼리 공유하고 있는 상식정보가 필요한 질의로 이루어져있다. 기계가 사람과 달리 상식 정보를 이용하여 결론을 도출하는 상식 추론을 하기 위해서는 적절한 상식 정보를 논리적으로 사용하여야 한다. 본 연구에서는 적절한 상식정보의 선택과 논리적 추론을 위하여, 질의에 대한 Abstract Meaning Representation (AMR) 그래프를 이용하여 적절한 상식 정보를 선택하고 그의 해석을 용이하게 만들었다. 본 연구에서 제안한 상식 그래프 경로 학습 모델은 오픈북 질의응답 문제에서 대표적 언어모델인 BERT의 성능보다 약 7%p 높은 55.02%의 정확도를 달성하였다.

  • PDF

Wave Responses and Ship Motions in a Harbor Excited by Long Waves(I) (항만내 파도응답과 계류선박의 운동해석(I))

  • I.H. Cho;Hang-S. Choi
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.29 no.2
    • /
    • pp.38-47
    • /
    • 1992
  • The motion response of a ship moored in a rectangular harbor excited by long waves has been studied theoretically and experimentally. Within the framework of potential theory, matched asymptotic expansion techniques are exployed to analyze the problem. The fluid domain is divided into the ocean and the harbor regions for the analysis of wave response in a harbor without ship. The wave responses in both the ocean and the harbor sides are solved first independently in terms of Green's functions, which are the solutions of the Helmholtz equation satisfying appropriate boundary conditions. Slender body approximations are used to obtain the velocity jumps across the ship, which are associated with the symmetric motion modes of the ship. Unknowns contained in each solution are finally determined by matching at an intermediate zone between two neighboring regions. Theoretical results predict the ship motion qualitatively well. The main source of quantitative discrepancies is presumably due to real fluid effects such as separation at the harbor entrance and friction on harbor boundaries.

  • PDF

Characteristics Analysis of Pilot Operated Pressure Control Valve (파이로트 구동용 압력제어밸브의 특성 해석)

  • 윤소남;최영호;함영복;김광영
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2002.10a
    • /
    • pp.725-728
    • /
    • 2002
  • In this Paper, a mathematical model describing the dynamics of pilot operated pressure control valve was derived. A attempt to analyze the Parameters(seat diameter, cone angle, spring stiffness, control volume) which relate to the performance of the object valve was carried out. Simulation using AMESim as a simulation tool was operated, and verified the validity of our simulation by means of comparison our simulation results with an experimental results of the pilot operated pressure control valve.

  • PDF

A Study on Reconstructing Impact Forces of an Aircraft Wing Using Impact Response Functions and Regularization Methods (충격응답함수와 조정법을 이용한 항공기 날개의 충격하중 복원 연구)

  • 박찬익
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.34 no.8
    • /
    • pp.41-46
    • /
    • 2006
  • The capability for reconstructing impact forces of an aircraft wing using impact response functions and regularization methods were examined. The impact response function which expresses the relation between the structure response and the impact force was derived using the information on mass and stiffness data of a finite element model for the wing. Iterative Tikhonov regularization method and generalized singular value decomposition method were used to inverse the impact response function that was generally ill-posed. For the numerical verification, a fighter aircraft wing was used. Strain and deflection histories obtained from finite element analysis were compared with the results calculated using impact response functions. And the impact forces were reconstructed with the strain histories obtained from finite element analysis. The numerical verification results showed that this method can be used to monitor impact forces on aircraft structures.

Fast Simulation of Output Voltage for High-Shock Piezoresistive Microaccelerometer Using Mode Superposition Method and Least Square Method (모드중첩법 및 최소자승법을 통한 고충격 압저항 미소가속도계의 출력전압 해석)

  • Han, Jeong-Sam;Kwon, Ki-Beom
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.36 no.7
    • /
    • pp.777-787
    • /
    • 2012
  • The transient analysis for the output voltage of a piezoresistive microaccelerometer takes a relatively high computation time because at least two iterations are required to calculate the piezoresistive-structural coupled response at each time step. In this study, the high computational cost for calculating the transient output voltage is considerably reduced by an approach integrating the mode superposition method and the least square method. In the approach, data on static displacement and output voltage calculated by piezoresistive-structural coupled simulation for three acceleration inputs are used to develop a quadratic regression model, relating the output voltage to the displacement at a certain observation point. The transient output voltage is then approximated by a regression model using the displacement response cheaply calculated by the mode superposition method. A high-impact microaccelerometer subject to several types of acceleration inputs such as 100,000 G shock, sine, step, and square pulses are adopted as a numerical example to represent the efficiency and accuracy of the suggested approach.

Transient Analysis of General Dispersive Media Using Laguerre Functions (라게르 함수를 이용한 일반적인 분산 매질의 시간 영역 해석)

  • Lee, Chang-Hwa;Kwon, Woo-Hyen;Jung, Baek-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.22 no.10
    • /
    • pp.1005-1011
    • /
    • 2011
  • In this paper, we present a marching-on-in-degree(MOD) finite difference method(FDM) based on the Helmholtz wave equation for analyzing transient electromagnetic responses in a general dispersive media. The two issues related to the finite difference approximation of the time derivatives and the time consuming convolution operations are handled analytically using the properties of the Laguerre functions. The basic idea here is that we fit the transient nature of the fields, the flux densities, the permittivity with a finite sum of orthogonal Laguerre functions. Through this novel approach, not only the time variable can be decoupled analytically from the temporal variations but also the final computational form of the equations is transformed from finite difference time-domain(FDTD) to a finite difference formulation through a Galerkin testing. Representative numerical examples are presented for transient wave propagation in general Debye, Drude, and Lorentz dispersive medium.

Dynamic Analysis of Very Large Floating Structure Using Beams on Elastic Foundation (탄성지지된 보를 이용한 초대형 부유구조물의 동적해석)

  • Hong, Sang-Hyun;Im, Yu-Bin;Kim, Jung-Myung;Lee, Jong-Seh
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2011.04a
    • /
    • pp.723-726
    • /
    • 2011
  • 전 세계적으로 사회기반시설 및 신재생 에너지 생산을 위한 공간부족 문제를 해결하기 위하여 초대형 부유구조물에 대한 관심이 증가하고 있다. 다양한 사용분야에 대한 안정성 확보를 위해 파랑하중에 의한 동적 응답과 부유체의 강성 대비 길이 효과로 인해 발생할 수 있는 특이 거동에 대한 분석이 필요하다. 초대형 부유구조물의 경우 중앙부에 비해 양끝 단에서 과도한 응답이 발생하며, 이를 해결하기 위해 입사파가 들어오는 초대형 부유구조물의 단부에 부착되는 다양한 감요장치(anti-motion device)가 제안되어지고 있다. 초대형 부유구조물에 감요장치가 적용될 경우 입사파에 의한 동적 파압을 감소시켜 구조물의 전반적인 응답을 줄여줄 수는 있지만 감요장치의 질량이 클 경우 오히려 끝단의 응답을 증폭시킬 수 있다. 본 논문에서는 양단 자유 경계조건의 탄성지지된 보를 이용하여 초대형 부유구조물의 길이와 끝단에 부착된 감요장치의 질량으로 인한 영향을 분석하였다.

  • PDF