Uncertainty analysis of an offshore jacket-type platform using a developed numerical model updating technique

Abstract To investigate the dynamic behavior of a complex system, an accurate updated finite element (FE) model is essentially required. Numerical model updating, which is performed based on valid experimental data, is imprecise without taking the related uncertainties into account. In this study, both structural and parametric uncertainties are considered within model updating of an offshore jacket platform through time history analysis for the first time. The experimental test is implemented employing a shake table and a scaled hydro-elastic model of the case study. For updating the FE model, a three-step updating procedure is implemented through eight distinct scenarios. In the first step, three unknown structural parameters are calibrated over ten distinct groups of elements in the FE model by using particle swarm optimization algorithm (PSO). In the second step, the damping matrix coefficients are also updated through the optimization process. In the third step, the model form error is considered utilizing four mathematical functions to decrease the parametric uncertainty and improve the FE model accuracy. Based on the results, by employing the proposed methodology, approximately 98 percent fitness is observed between the experimental and updated numerical model. According to the results, not only reducing both structural and parametric uncertainties is essential, but also calibrating the damping matrix for updating a numerical model and improving the FE model accuracy is of great importance. The developed methodology, which is applied to a sophisticated structural system, is strongly recommended for updating the systems that existence of an accurate updated numerical model is vital.

[1]  H. Nevzat Özgüven,et al.  A new method to determine dynamically equivalent finite element models of aircraft structures from modal test data , 2012 .

[2]  Rodrigo Astroza,et al.  Effects of model uncertainty in nonlinear structural finite element model updating by numerical simulation of building structures , 2018, Structural Control and Health Monitoring.

[3]  G. Najafian.  Probability models for offshore structural response due to Morison wave loading: Part II: Inertia-only and total responses , 2007 .

[4]  John E. Mottershead,et al.  The sensitivity method in finite element model updating: A tutorial (vol 25, pg 2275, 2010) , 2011 .

[5]  Yu Hong,et al.  Experimental model updating using frequency response functions , 2016, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[6]  Sondipon Adhikari,et al.  Lancaster’s Method of Damping Identification Revisited , 2002 .

[7]  Ismail Farajpour,et al.  Error and Uncertainty Analysis of Inexact and Imprecise Computer Models , 2013, J. Comput. Civ. Eng..

[8]  Masoud Sanayei,et al.  Significance of Modeling Error in Structural Parameter Estimation , 2001 .

[9]  Alireza Mojtahedi,et al.  Establishment of a hybrid Fuzzy–Krill Herd approach for novelty detection applied to damage classification of offshore jacket-type structures , 2018, Journal of Marine Science and Technology.

[10]  Saeed Eftekhar Azam,et al.  Steel railway bridge fatigue damage detection using numerical models and machine learning: Mitigating influence of modeling uncertainty , 2020 .

[11]  A. O'Hagan,et al.  Bayesian calibration of computer models , 2001 .

[12]  P. G. Bakir,et al.  Sensitivity-based finite element model updating using constrained optimization with a trust region algorithm , 2007 .

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

[14]  James M. W. Brownjohn,et al.  Dynamic Assessment of Curved Cable-Stayed Bridge by Model Updating , 2000 .

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

[16]  A. Mojtahedi,et al.  Structural control of a fixed offshore structure using a new developed tuned liquid column ball gas damper (TLCBGD) , 2019, Ocean Engineering.

[17]  Vikas Arora,et al.  Finite element model updating with damping identification , 2009 .

[18]  A. Mojtahedi,et al.  Experimental investigation of TARMAX model for modeling of hydrodynamic forces on cylinder-like structures , 2011 .

[19]  G. Najafian,et al.  Probability models for offshore structural response due to Morison wave loading Part I: Drag-only response , 2007 .

[20]  Erick I. Saavedra Flores,et al.  Bayesian updating of complex nonlinear FE models with high-dimensional parameter space using heterogeneous measurements and a batch-recursive approach , 2019 .

[21]  Joel P. Conte,et al.  A dual adaptive filtering approach for nonlinear finite element model updating accounting for modeling uncertainty , 2019, Mechanical Systems and Signal Processing.

[22]  Anil K. Chopra,et al.  Dynamics of Structures: Theory and Applications to Earthquake Engineering , 1995 .

[23]  Russell C. Eberhart,et al.  A new optimizer using particle swarm theory , 1995, MHS'95. Proceedings of the Sixth International Symposium on Micro Machine and Human Science.

[24]  Thomas H. Dawson.  Offshore Structural Engineering , 1983 .

[25]  Jack W. Baker,et al.  Using model error in response history analysis to evaluate component calibration methods , 2019, Earthquake Engineering & Structural Dynamics.