Finite element model updating of damped structures using vibration test data under base excitation

Yuan, Zhao Xu; Yu, Kai

doi:10.1016/j.jsv.2014.11.041

Cited by 24 publications

(14 citation statements)

References 26 publications

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“…FRF-based methods provide more data suitable for model updating as compared with modal methods [15][16][17]. In this regard, reference is made to Esfandiari et al [16] who worked on the development of quasi linear sensitivity equation using FRF as metric, Sipple and Sanayei [18] who presented a method based on numerical sensitivities, and Yuan and Yu [19] who conducted two stage model updating based on vibration data of base excitation.…”

Section: Introductionmentioning

confidence: 99%

Finite element model updating using strain-based power spectral density for damage detection

Pedram

Esfandiari

Khedmati

2016

Struct. Control Health Monit.

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In this paper a new sensitivity-based finite element (FE) model updating method using spectral density of strain as metric is introduced, which is applicable for damage detection and structural health monitoring purposes. Derivation of the sensitivity equation is exact without any need for approximation. A set of incompletely measured natural frequencies and damping loss factors of the damaged structure is used to deal with incomplete measurement without implementation of the FE model reduction or data expansion algorithms. The insights provided from the distribution of the spectral strain energy among the elements in the intact model are used for selection of excitation location. The solution to the developed sensitivity equation is achieved by linear least square and imposing unprejudiced side constraints on the design variables. The proposed method is successfully examined on the FE model of a 3D truss and frame structure and is capable of localization and quantification of damage. The method is robust against measurement, natural frequency, and mass modeling error.

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Section: Introductionmentioning

confidence: 99%

Finite element model updating using strain-based power spectral density for damage detection

Pedram

Esfandiari

Khedmati

2016

Struct. Control Health Monit.

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“… developed a method based on a vector of discrepancy between analytical and experimental FRF data obtained from measured data in master DOFs and estimated data in pseudo master DOFs by a reduced model iteratively. Yuan and Yu proposed a model updating method for damped structures exposed to base excitation utilizing a complex form of transfer function. Wang et al .…”

Section: Introductionmentioning

confidence: 99%

Structural model updating using incomplete transfer function and modal data

Farshadi

Esfandiari

Vahedi

2016

Struct Control Health Monit

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Structural damage detection by non-destructive techniques has been investigated widely by researchers in recent years, and several response-based Structural Health monitoring techniques have been developed. In this paper, a vibration-based damage detection algorithm through model updating utilizing incomplete frequency response function and modal data is presented. First, a modified sensitivity equation is presented to relate the changes of mode shapes to the changes of unknown structural parameters. Then, the developed equations are used to correlate changes of frequency response functions to the changes of structural parameters. Parameter estimation is conducted through least square solution of sensitivity equations. In order to prove the capability of the proposed method for structural damage detection purpose, a numerical example using error contaminated data is presented. Results exhibit robustness of method against measurement and mass modeling errors. KEYWORDS damage detection, frequency response function, modified modal method, sensitivity equation | INTRODUCTIONEvery structure may experience changes in structural properties during its design life because of the occurrence of several conditions such as extreme loading, earthquake, strong wind, erosion, and fatigue. Even if a structure is managed to withstand such changes, it is crucial to investigate its integrity. To ensure this objective, many algorithms have recently been developed to detect the location and severity of structural damages and evaluation of its safety. The basic principle of damage detection algorithms is because damage can cause detectable changes in structural response.A general classification of damage identification techniques refers to types of data used to detect damage including static and dynamic data. Most common dynamic features are modal data including mode shapes, [1,2] natural frequencies, [3,4] strain energy, [5] transfer function parameters, [6] measured modal flexibility, [7,8] frequency response function (FRF), [9][10][11][12] time domain structural responses, [13][14][15] or a combination of these features. [16,17] Damage detection by model updating is the process of modification of structural parameters to minimize discrepancy between response of structure and numerical model. The response residual can be minimized by various approaches. [18][19][20] Because model updating is an inverse problem and the relationship between structural parameters and measured response is inherently nonlinear, methods known as sensitivity-based approaches are developed to simplify solving this problem through linearization of equations. [21] Model updating using FRF improves predictive capabilities of updating procedure through providing large amount of information and has been used by some researchers. [22][23][24] One of the main advantages of using FRFs data in sensitivity-based model updating algorithm is avoiding propagation of errors in parameter estimation. [25,26] By sensitivity-based approaches, FRF residual is minimized to eval...

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“…e identification of damping matrix can be performed separately, through the well-established methods proposed in literature [27,28], once the inertial and elastic parameters have been updated. A "two-step" approach, that updates stiffness and the mass matrices first and then updates damping matrix, is often adopted in literature since it is usually more reliable [29].…”

Section: Formulation Of the Mass And Stiffness Matrix Updatingmentioning

confidence: 99%

An Updating Method for Finite Element Models of Flexible‐Link Mechanisms Based on an Equivalent Rigid‐Link System

Belotti

Caracciolo

Palomba

et al. 2018

Shock and Vibration

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This paper proposes a comprehensive methodology to update dynamic models of flexible-link mechanisms (FLMs) modeled through ordinary differential equations. The aim is to correct mass, stiffness, and damping matrices of dynamic models, usually based on nominal and uncertain parameters, to accurately represent the main vibrational modes within the bandwidth of interest. Indeed, the availability of accurate models is a fundamental step for the synthesis of effective controllers, state observers, and optimized motion profiles, as those employed in modern control schemes. The method takes advantage of the system dynamic model formulated through finite elements and through the representation of the total motion as the sum of a large rigid-body motion and the elastic deformation. Model updating is not straightforward since the resulting model is nonlinear and its coordinates cannot be directly measured. Hence, the nonlinear model is linearized about an equilibrium point to compute the eigenstructure and to compare it with the results of experimental modal analysis. Once consistency between the model coordinates and the experimental data is obtained through a suitable transformation, model updating has been performed solving a constrained convex optimization problem. Constraints also include results from static tests. Some tools to improve the problem conditioning are also proposed in the formulation adopted, to handle large dimensional models and achieve reliable results. The method has been experimentally applied to a challenging system: a planar six-bar linkage manipulator. The results prove their capability to improve the model accuracy in terms of eigenfrequencies and mode shapes.

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Finite element model updating of damped structures using vibration test data under base excitation

Cited by 24 publications

References 26 publications

Finite element model updating using strain-based power spectral density for damage detection

Finite element model updating using strain-based power spectral density for damage detection

Structural model updating using incomplete transfer function and modal data

An Updating Method for Finite Element Models of Flexible‐Link Mechanisms Based on an Equivalent Rigid‐Link System

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