Prediction Capabilities of Damped Updated Finite Element Models

2011 ◽  
Author(s):  
Vikas Arora
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Dynamic Properties ◽  
Detailed Comparison ◽  
Element Model ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Complex Frequency ◽  
Structural Modifications ◽  
The Finite Element Model

Model updating techniques are used to correct the finite element model of a structure using experimental data such that the updated model more correctly describes the dynamic properties of the structure. One of the applications of such an updated model is to predict the effects of making modifications to the structure. These modifications may be imposed by design alterations for operating reasons. Most of the model updating techniques neglect damping and so these updated models can’t be used for accurate prediction of complex frequency response functions (FRFs) and complex mode shapes. In this paper, a detailed comparison of prediction capabilities of parameter-based and non parameter-based damped updated methods for structural modifications is done. The suitability of paramter-based and non parameter-based damped updated models for predicting the effects of structural modifications is evaluated by laboratory experiment for the case of an F-shape test structure. It is concluded that parameter-based damped updated models are likely to perform better in predicting the effects of structural modifications.

Dynamic Test and Analysis of Concrete Filled Steel Tube Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2843-2847
Author(s):  
Li Xian Wang ◽  
Sheng Kui Di
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Yellow River ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Element Model ◽  
Steel Tube ◽  
Acceleration Signal ◽  
The Finite Element Model

Based on random vibration theory, virtual response is obtained from the measured acceleration signal of Yantan Yellow River Bridge of Lanzhou under ambient excitation, Yantan Yellow River bridge's modal parameters were identified by using the peak picking and stochastic subspace identification, analyzed from theoretical and experimental aspects, compared with the finite element model results and verified the reliability of recognition results. The identified dynamic properties can be served as the basis in the finite element model updating, damage detection, condition assessment and health monitoring of the bridge.

Modal Analysis of Helical Milling Unit

2012 ◽  
Vol 482-484 ◽  
pp. 2454-2459 ◽  
Author(s):  
Xu Da Qin ◽  
Cui Lu ◽  
Qi Wang ◽  
Hao Li ◽  
Lin Jing Gui
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Element Model ◽  
Helical Milling ◽  
Mode Shapes ◽  
Three Dimensional Model ◽  
Working Principle ◽  
The Finite Element Model

Based on the analysis of the working principle and structure characteristics of helical milling unit, the prototype’s three-dimensional model was built, the prototype’s finite element modal analysis was conducted, and the first 6 natural frequencies and their mode shapes were obtained. The finite element model is experimentally validated by comparing finite element and experimental modal’s parameters. This paper investigates the dynamic properties of prototype, and provides theoretical references for the subsequent dynamic analysis and structural optimization.

scholarly journals Finite Element Model Updating of Reinforced Concrete Beams with Honeycomb Damage

2012 ◽  
Vol 58 (2) ◽  
pp. 135-151 ◽  
Author(s):  
Z. Ismail
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Significant Loss ◽  
Reinforced Concrete Beams ◽  
Finite Element Model Updating ◽  
Finite Element Models ◽  
The Finite Element Model

Abstract A method of detecting honeycombing damage in a reinforced concrete beam using the finite element model updating technique was proposed. A control beam and two finite element models representing different severity of damage were constructed using available software and the defect parameters were updated. Analyses were performed on the finite element models to approximate the modal parameters. A datum and a control finite element model to match the datum test beams with honeycombs were prepared. Results from the finite element model were corrected by updating the Young’s modulus and the damage parameters. There was a loss of stiffness of 3% for one case, and a loss of 7% for another. The more severe the damage, the higher the loss of stiffness. There was no significant loss of stiffness by doubling the volume of the honeycombs.

Parameter Identification of Complex Structures Using Finite Element Model Updating Techniques

2015 ◽  
Author(s):  
Dimitrios Giagopoulos ◽  
Alexandros Arailopoulos
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Complex Geometry ◽  
Element Model ◽  
Mode Shapes ◽  
Cad Model ◽  
Modal Characteristics ◽  
Acceleration Time Histories ◽  
The Finite Element Model

In this work, an integrated reverse engineering strategy is presented that takes into account the complete process, from the developing of CAD model and the experimental modal analysis procedures to computational effective model updating techniques. Modal identification and structural model updating methods are applied, leading to develop high fidelity finite element model of geometrically complex and lightweight bicycle frame, using acceleration measurements. First, exploiting a 3D Laser Scanner, the digital shape of the real bike frame was developed and the final parametric CAD model was created. Next the finite element model of the frame was created by using quadrilateral shell and hexahedral solid elements. Due to complex geometry of the structure, the developed model consists of about one million degrees of freedom. The identification of modal characteristics of the frame is based on acceleration time histories, which are obtained through an experimental investigation of its dynamic response in a support-free state by imposing impulsive loading. A high modal density modal model is obtained. The modal characteristics are then used to update the finite element model. Single and multiobjective structural identification methods with appropriate substructuring methods, are used for estimating the parameters (material properties and shell thickness properties) of the finite element model, based on minimizing the deviations between the experimental and analytical modal characteristics (modal frequencies and mode shapes). Direct comparison of the numerical and experimental data verified the reliability and accuracy of the methodology applied.

scholarly journals Dynamic Model Updating Using Virtual Antiresonances

2004 ◽  
Vol 11 (3-4) ◽  
pp. 351-363 ◽  
Author(s):  
Walter D’Ambrogio ◽  
Annalisa Fregolent
Keyword(s):  
Finite Element ◽  
High Frequency ◽  
Model Updating ◽  
Element Model ◽  
Mode Shapes ◽  
Finite Element Model Updating ◽  
Frequency Error ◽  
Modal Expansion ◽  
Modal Data ◽  
The Finite Element Model

This paper considers an extension of the model updating method that minimizes the antiresonance error, besides the natural frequency error. By defining virtual antiresonances, this extension allows the use of previously identified modal data. Virtual antiresonances can be evaluated from a truncated modal expansion, and do not correspond to any physical system. The method is applied to the Finite Element model updating of the GARTEUR benchmark, used within an European project on updating. Results are compared with those previously obtained by estimating actual antiresonances after computing low and high frequency residuals, and with results obtained by using the correlation (MAC) between identified and analytical mode shapes.

Model structure correction and updating of aeroengine casings using fictitious mass modifications

2005 ◽  
Vol 219 (1) ◽  
pp. 19-30 ◽  
Author(s):  
H Shahverdi ◽  
C Mares ◽  
J E Mottershead
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Mode Shapes ◽  
Combined Model ◽  
Shell Elements ◽  
Turbine Casing ◽  
The Finite Element Model

In this paper the results of a finite element model updating exercise, carried out on closely axisymmetric aeroengine casings, are presented. The correction of the combustion chamber outer casing (CCOC) model is considered and, after assembly with the turbine casing (TC), the quality of the resulting combined model is investigated. The dynamics of both casings is characterized by pairs of close modes, which may be separated by fictitious point mass modifications. The natural frequencies and mode shapes of the fictitiously modified CCOC are determined from receptances obtained from the CCOC in its original (unmodified) configuration. The modifications are shown to improve the understanding of both the CCOC and the system formed by connecting the CCOC to the TC. A particular problem is revealed when model updating is applied to the CCOC. An analysis of the mode shapes locates a modelling error on an inner shell of the structure but it is found that the finite element model is unable to be parameterized for the correction of two pairs of wrongly ordered predicted modes. This can only be achieved by firstly correcting the ‘structure’ of the model itself. The main error is found to be a geometrical inaccuracy, and, when this is put right, the sequence of the modes is corrected. Model updating is then applied to the thickness of certain shell elements and the CCOC is found to be in excellent agreement with measured data, as is the complete model formed from the two models of the CCOC and the TC together.

scholarly journals Sensitivity Analysis of the Influence of Structural Parameters on Dynamic Behaviour of Highly Redundant Cable-Stayed Bridges

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
B. Asgari ◽  
S. A. Osman ◽  
A. Adnan
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Structural Parameters ◽  
Element Model ◽  
Structural Behavior ◽  
Model Tuning ◽  
The Finite Element Model ◽  
Cable Stayed Bridges

The model tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics of cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however, the results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the analytical model of cable-stayed bridges. This paper presents a model updating algorithm for highly redundant cable-stayed bridges that can be used as an iterative manual procedure. The updating parameters are selected through the sensitivity analysis which helps to better understand the structural behavior of the bridge. The finite element model of Tatara Bridge is considered for the numerical studies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating the finite element model of cable-stayed bridges. The new aspects regarding effective material and structural parameters and model tuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges.

A Parallel Solution Strategy for Finite Element Models

1996 ◽  
Author(s):  
Jordan J. Cox ◽  
Jeffrey A. Talbert ◽  
Eric Mulkay
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Decomposition Methods ◽  
Finite Element Models ◽  
Unique Contribution ◽  
Matrix Equations ◽  
Parallel Solution ◽  
The Finite Element Model ◽  
Parallel Fashion

Abstract This paper presents a method for naturally decomposing finite element models into sub-models which can be solved in a parallel fashion. The unique contribution of this paper is that the decomposition strategy comes from the geometric features used to construct the solid model that the finite element model represents. Domain composition and domain decomposition methods are used to insure global compatibility. These techniques reduce the N2 behavior of traditional matrix solving techniques, where N is the number of degrees of freedom in the global set of matrix equations, to a sum of m matrices with n2 behavior, where n represents the number of degrees of freedom in the smaller sub-model matrix equations.

Application of a FRF Based Model Updating Technique for the Validation of Finite Element Models of Components of the Automotive Industry

1995 ◽  
Author(s):  
Stefan Lammens ◽  
Marc Brughmans ◽  
Jan Leuridan ◽  
Ward Heylen ◽  
Paul Sas
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Automotive Industry ◽  
Stiffness Matrix ◽  
Model Updating ◽  
Dynamic Stiffness ◽  
Element Model ◽  
Model Parameters ◽  
Finite Element Models ◽  
Analytical Dynamic

Abstract This paper presents two applications of the RADSER model updating technique (Lammens et al. (1995) and Larsson (1992)). The RADSER technique updates finite element model parameters by solution of a linearised set of equations that optimise the Reduced Analytical Dynamic Stiffness matrix based on Experimental Receptances. The first application deals with the identification of the dynamic characteristics of rubber mounts. The second application validates a coarse finite element model of a subframe of a Volvo 480.

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