• 제목/요약/키워드: Newton-Raphson Method

검색결과 500건 처리시간 0.039초

Newton-Raphson법 기반의 적응 망각율을 갖는 RLS 알고리즘에 의한 원격센서시스템의 시변파라메타 추정 (Time Variant Parameter Estimation using RLS Algorithm with Adaptive Forgetting Factor Based on Newton-Raphson Method)

  • 김경엽;지석준;곽려혜;이준탁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.1680-1681
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    • 2007
  • This paper deals with RLS algorithm using Newton-Raphson method based adaptive forgetting factor for a passive telemetry RF sensor system in order to estimate the time variant parameter to be included in RF sensor model.

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현장실측에 의한 조도계수 산정의 불확실도 평가 (Uncertainty Analysis in Estimation of Roughness Coefficient Using the Field Measurement Data)

  • 김지성;이찬주;김원
    • 한국수자원학회논문집
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    • 제40권10호
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    • pp.801-810
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    • 2007
  • 본 연구에서는 현장에서 실측된 유량 및 수위로부터 산정된 조도계수의 오차를 분석하고 그 타당성과 한계를 검토하였다. 자연 하천흐름을 등류로 가정하여 산정된 조도계수는 저유량 규모에서 부등류로 계산된 조도계수와 큰 차이를 나타내었으며, 이는 속도수두의 차이보다 평균 단면적, 동수반경 등 단면정보에 크게 영향을 받았다. 상대적으로 긴 구간에서 홍수량 규모의 평균 조도계수 산정에서는 구간 상하류만의 수위 자료를 이용하여 조도계수를 산정하는 수정 Newton-Raphson 방법이 구간 내 다수의 실측 수위로 산정된 평균 조도계수와 비교하여 효율적이고 정확한 해를 제공하였다. 현장 실측으로 조도계수를 산정할 경우, 수위 및 유량 측정오차로 인하여 홍수기보다 저유량 규모에서 산정된 조도계수의 불확실도가 증가되지만 이로 인하여 발생되는 수심 및 유속의 불확실도는 유량규모와 무관하게 5% 내외의 유사한 결과가 나타남으로써 실측 수위를 이용한 조도계수 산정의 타당성을 확인하였다.

초기응력이 있는 탄성체의 선형 및 비선형해석 -플레이트 스트립을 중심으로 (Linear and Nonlinear Analysis of Initially Stressed Elastic Solid)

  • 권영두;최진민
    • 대한기계학회논문집
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    • 제12권4호
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    • pp.642-651
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    • 1988
  • 본 연구에서는 정적 혹은 동적인 하중을 받는 탄성체의 변위, 응력 등을 구할 수 있는 유한요소해석을 하였다. 이 경우에 얻어지는 대수적인 운동방정식은 비선형 적이지만 증분응력이 미소한 경우에는 선형화될 수 있다.따라서 유한요소식의 해법 도 선형적인 경우와 비선형적인 경우로 나누어 생각한다.선형문제에 대한 해법으로 는 (1) 정하중:Gauss소거법, (2) 동하중:모우드에 대한 해석 또는 Newmark의 직접적분 법을 사용했고, 비선형적인 문제에 대한 해법으로는 (1) 정하중:Newton-Raphson반복법, (2) 동하중 :Newton-Raphson 반복법에 의거한 Newmark의 직접적분법을 사용하였다. 비선형적인 문제의 풀이시에는 Newton-Raphson방법으로 반복하여 계산하면서 외력과 등가절점하중의 평형이 이루어지도록 하므로 상당히 많은 양의 계산이 필요한데, 이때 서로 종류가 다른 강성매트릭스의 수치적분시 각기 다른 차수의 Gauss-Legendre 적분 을 시도하여, 발생된 오차 및 계산시간의 변동 등을 고찰하므로써 계산량의 감소방안 을 찾아 보았다. 또한 초기응력이 균일한 경우, 선형해와 비선형해를 비교함으로써 증분응력의 영향을 무시하는 선형해석의 적용타당성을 검토하였다.

A combined finite element-Riccati transfer matrix method for free vibration of structures

  • Xue, Huiyu
    • Structural Engineering and Mechanics
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    • 제3권3호
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    • pp.245-253
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    • 1995
  • A combination of Riccati transfer matrix method and finite element method is proposed for obtaining vibration frequencies of structures. This method reduces the propagation of round-off errors produced in the standard transfer matrix method and finds out the values of the frequency by Newton-Raphson method. By this technique, the number of nodes required in the regular finite element method is reduced and therefore a microcomputer may be used. Besides, no plotting of the value of the determinant versus assumed frequency is necessary. As the application of this method, some numerical examples are presented to demonstrate the accuracy as well as the capability of the proposed method for the vibration of structures.

경쟁기법을 이용한 스튜어트 플랫폼의 순기구학 해석 (The Analysis of the Forward Kinematics Using the Competitive Method in the Stewart Platform)

  • 허성준;이형상;한명철
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.255-258
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    • 2001
  • This introduces a improved method of the forward kinematics analysis, which finds the 6DOF motions and velocities from the given six cylinder lengths in the Steward platform. The numerical method(Newton Raphson Mehotd)of the forward kinematics analysises has the disadvantage of the long calculated time. To overcome this, we propose the competitive method that determine a proper initial value. Through the competitive method, we can select a proper initial value so that the calculate time is reduced. therefore we can give the property of the real time process to the forward kinematics analysis. We show the result comparing between general Newton-Raphson method and proposed one. From the result we verify the performance of the proposed method.

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개선된 회귀착점 방법을 이용한 이방성 적층구조물의 소성해석 (Analysis of Anisotropic Plasticity of Additively Manufactured Structure using Modified Return Mapping Method)

  • 양승용;진두한;김정한
    • 한국분말재료학회지
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    • 제29권4호
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    • pp.303-308
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    • 2022
  • The plastic deformation behavior of additively manufactured anisotropic structures are analyzed using the finite element method (FEM). Hill's quadratic anisotropic yield function is used, and a modified return-mapping method based on dual potential is presented. The plane stress biaxial loading condition is considered to investigate the number of iterations required for the convergence of the Newton-Raphson method during plastic deformation analysis. In this study, incompressible plastic deformation is considered, and the associated flow rule is assumed. The modified return-mapping method is implemented using the ABAQUS UMAT subroutine and effective in reducing the number of iterations in the Newton-Raphson method. The anisotropic tensile behavior is computed using the 3-dimensional FEM for two tensile specimens manufactured along orthogonal additive directions.

유한요소법을 이용한 축대칭 구조물의 비선형 거동해석 (Analyses of Non-linear Behavior of Axisymmetric Structure by Finite Element Method)

  • 구영덕;민경탁
    • 전산구조공학
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    • 제10권2호
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    • pp.139-148
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    • 1997
  • A finite element method is programmed to analyse the nonlinear behavior of axisymmetric structures. The lst order Mindlin shell theory which takes into account the transversal shear deformation is used to formulate a conical two node element with six degrees of freedom. To evade the shear locking phenomenon which arises in Mindlin type element when the effect of shear deformation tends to zero, the reduced integration of one point Gauss Quadrature at the center of element is employed. This method is the Updated Lagrangian formulation which refers the variables to the state of the most recent iteration. The solution is searched by Newton-Raphson iteration method. The tangent matrix of this method is obtained by a finite difference method by perturbating the degrees of freedom with small values. For the moment this program is limited to the analyses of non-linear elastic problems. For structures which could have elastic stability problem, the calculation is controled by displacement.

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AESOPS 알고리즘의 고유치 반복계산식과 고유치 초기값 선정의 효율적인 개선에 관한 연구 (An Efficient Improvement of the Iterative Eigenvalue Calculation Method and the Selection of Initial Values in AESOPS Algorithm)

  • 김덕영;권세혁
    • 대한전기학회논문지:전력기술부문A
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    • 제48권11호
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    • pp.1394-1400
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    • 1999
  • This paper presents and efficient improvement of the iterative eigenvalue calculation method and the selection of initial values in AESOPS algorithm. To determine the initial eigenvalues of the system, system state matrix is constructed with the two-axis generator model. From the submatrices including synchronous and damping coefficients, the initial eigenvalues are calculated by the QR method. Participation factors are also calculated from the above submatrices in order to determine the generators which have a important effect to the specific oscillation mode. Also, the heuristically approximated eigenvalue calculation method in the AESOPS algorithm is transformed to the Newton Raphson Method which is largely used in the nonlinear numerical analysis. The new methods are developed from the AESOPS algorithm and thus only a few calculation steps are added to practice the proposed algorithm.

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뉴턴랩슨법을 이용한 효율적인 경제부하배분에 관한 연구 (A Study on the Efficient Economic Dispatch by the Newton Raphson Method)

  • 정재길;박찬모;오창근
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1993년도 하계학술대회 논문집 A
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    • pp.192-194
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    • 1993
  • This paper presents an efficient method for determining the economic dispatch of thermal generator using an alternative Jacobian matrix considering system constraints. The transmission loss is approximately expressed as a funtion of generating powers and the generalized generation factor. From this expression, the Jacobian matrix is formulated and solved by the Newton Raphson Method. In this method, the economic dispatch problem is solved rapidly without calculating the penalty factor. The proposed method has fast convergency characteristic and good accuracy. The feasibility of this method is demonstrated by means of examples.

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쉘구조물의 기하학적 비선형해석 (Geometrically Non-linear Analysis of Shell Structures)

  • 장명호;김재열;서삼열
    • 한국공간구조학회논문집
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    • 제3권4호
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    • pp.85-92
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    • 2003
  • In this work, a finite element model is presented for geometrically non-linear analysis of shell structures. Finite element by using a three-node flat triangular shell element is formulated. The non-linear incremental equilibrium equations are formulated by using an updated Lagrangian formulation and the solutions are obtained with the incremental/iterative Newton-Raphson method and arc length method. Some of results are presented for shell structures. The obtained results are in good agreement with the results available in existing literature.

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