Reduction-Based Model Updating of a Scaled Offshore Platform Structure

This paper attempts to develop a reduction-based model updating technique for jacket offshore platform structure. A reduced model is used instead of the direct finite-element model of the real structure in order to circumvent such difficulties as huge degrees of freedom and incomplete experimental data that are usually civil engineers' trouble during the model updating. The whole process consists of three steps: reduction of FE model, the first model updating to minimize the reduction error, and the second model updating to minimize the modeling error of the reduced model and the real structure. According to the performance of jacket platforms, a local-rigidity assumption is employed to obtain the reduced model. The technique is applied in a downscale model of a four-legged offshore platform where its effectiveness is well proven. Furthermore, a comparison between the real structure and its numerical models in the following model validation shows that the updated models have good approximation to the real structure. Besides, some difficulties in the field of model updating are also discussed.

[1]  W. A. Benfield,et al.  Vibration Analysis of Structures by Component Mode Substitution , 1971 .

[2]  H. Du,et al.  Improved Inverse Eigensensitivity Method for Structural Analytical Model Updating , 1995 .

[3]  Nicholas A J Lieven,et al.  DYNAMIC FINITE ELEMENT MODEL UPDATING USING SIMULATED ANNEALING AND GENETIC ALGORITHMS , 1997 .

[4]  S. Rubin.  Improved Component-Mode Representation for Structural Dynamic Analysis , 1975 .

[5]  Alex Berman,et al.  Mass Matrix Correction Using an Incomplete Set of Measured Modes , 1979 .

[6]  E. Wilson,et al.  Dynamic analysis by direct superposition of Ritz vectors , 1982 .

[7]  J. D. Collins,et al.  Statistical Identification of Structures , 1973 .

[8]  W. Hurty.  Dynamic Analysis of Structural Systems Using Component Modes , 1965 .

[9]  Hamid Ahmadian,et al.  Parameter Selection Strategies in Finite Element Model Updating , 1997 .

[10]  Pc Pandey,et al.  Multilayer perceptron in damage detection of bridge structures , 1995 .

[11]  Yong Lu,et al.  A two-level neural network approach for dynamic FE model updating including damping , 2004 .

[12]  Rongming Lin,et al.  A new eigensolution of structures via dynamic condensation , 2003 .

[13]  R. Hintz.  Analytical Methods in Component Modal Synthesis , 1975 .

[14]  A. Berman,et al.  Improvement of a Large Analytical Model Using Test Data , 1983 .

[15]  Lambros S. Katafygiotis,et al.  Application of a Statistical Model Updating Approach on Phase I of the IASC-ASCE Structural Health Monitoring Benchmark Study , 2004 .

[16]  Mehdi Setareh,et al.  USING COMPONENT MODE SYNTHESIS AND STATIC SHAPES FOR TUNING TMDS , 1992 .

[17]  Mehmet Imregun,et al.  Finite element model updating using frequency response function data: I. Theory and initial investigation , 1995 .

[18]  M. Friswell,et al.  THE CONVERGENCE OF THE ITERATED IRS METHOD , 1998 .

[19]  John E. Mottershead,et al.  Model Updating In Structural Dynamics: A Survey , 1993 .

[20]  G. Visweswara Rao.  Dynamic Condensation and Synthesis of Unsymmetric Structural Systems , 2002 .

[21]  Mehmet Imregun,et al.  Finite element model updating using frequency response function data. II. Case study on a medium-size finite element model , 1995 .

[22]  Hamid Ahmadian,et al.  Generic element matrices suitable for finite element model updating , 1995 .

[23]  R. Fox,et al.  Rates of change of eigenvalues and eigenvectors. , 1968 .

[24]  Lambros S. Katafygiotis,et al.  Bayesian spectral density approach for modal updating using ambient data , 2001 .

[25]  Chih-Chen Chang,et al.  Selection of training samples for model updating using neural networks , 2002 .

[26]  Zu-Qing Qu,et al.  Model Order Reduction of Viscously Damped Vibration Systems Using Accelerated Iterative Dynamic Condensation , 2005 .

[27]  L. Katafygiotis,et al.  Tangential‐projection algorithm for manifold representation in unidentifiable model updating problems , 2002 .

[28]  Edward J. Kuhar,et al.  Dynamic Transformation Method for Modal Synthesis , 1974 .

[29]  Z. Qu,et al.  New Structural Dynamic Condensation Method for Finite Element Models , 1998 .

[30]  T. K. Kundra,et al.  Comparative study of model updating methods using simulated experimental data , 2002 .

[31]  Lambros S. Katafygiotis,et al.  Bayesian modal updating using complete input and incomplete response noisy measurements , 2002 .

[32]  R. Guyan.  Reduction of stiffness and mass matrices , 1965 .

[33]  Menahem Baruch.  Methods of Reference Basis for Identification of Linear Dynamic Structures , 1984 .

[34]  David C. Zimmerman,et al.  Correcting finite element models using a symmetric eigenstructure assignment technique , 1990 .

[35]  Philip D. Cha,et al.  Enforcing Structural Connectivity to Update Damped Systems Using Frequency Response , 2002 .

[36]  R. Lin,et al.  Improvement on the iterated IRS method for structural eigensolutions , 2004 .

[37]  Nicholas A J Lieven,et al.  Measuring and Improving Neural Network Generalization for Model Updating , 2000 .

[38]  Mauro J. Atalla,et al.  On model updating using neural networks , 1996 .

[39]  Mario Paz,et al.  Modified Dynamic Condensation Method , 1986 .

[40]  J. Beck,et al.  Updating Models and Their Uncertainties. I: Bayesian Statistical Framework , 1998 .

[41]  Chih-Chen Chang,et al.  Adaptive neural networks for model updating of structures , 2000 .

[42]  Ri Levin,et al.  DYNAMIC FINITE ELEMENT MODEL UPDATING USING NEURAL NETWORKS , 1998 .

[43]  Wei-Xin Ren,et al.  Structural Finite Element Model Updating Using Ambient Vibration Test Results , 2005 .

[44]  Mauro J. Atalla,et al.  Model updating using neural networks , 1996 .

[45]  Chung Bang Yun,et al.  Substructural identification using neural networks , 2000 .

[46]  J. Beck,et al.  UPDATING MODELS AND THEIR UNCERTAINTIES. II: MODEL IDENTIFIABILITY. TECHNICAL NOTE , 1998 .

[47]  M. Bampton,et al.  Coupling of substructures for dynamic analyses. , 1968 .

[48]  Pierre Léger,et al.  Generation of load dependent Ritz transformation vectors in structural dynamics , 1987 .

[49]  M. P. Singh,et al.  Modal Synthesis Method for General Dynamic Systems , 1992 .

[50]  Y. G. Tsuei,et al.  Direct Component Modal Synthesis Technique for System Dynamic Analysis , 1989 .

[51]  F. Hemez,et al.  Updating finite element dynamic models using an element-by-element sensitivity methodology , 1993 .

[52]  Tae W. Lim,et al.  Submatrix approach to stiffness matrix correction using modal test data , 1990 .

[53]  M. Friswell,et al.  Model reduction using dynamic and iterated IRS techniques , 1995 .

[54]  Ki-Ook Kim,et al.  Convergence Acceleration of Iterative Modal Reduction Methods , 2001 .

[55]  Luis E. Suarez,et al.  Dynamic condensation method for structural eigenvalue analysis , 1992 .

[56]  R. L. Citerley,et al.  Application of Ritz vectors for dynamic analysis of large structures , 1985 .