scholarly journals Rotor Model Updating and Validation for an Active Magnetic Bearing Based High-Speed Machining Spindle

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Adam C. Wroblewski ◽  
Jerzy T. Sawicki ◽  
Alexander H. Pesch
Keyword(s):  
Transfer Functions ◽  
Model Updating ◽  
Dynamic Properties ◽  
Magnetic Bearing ◽  
Mode Shapes ◽  
Model Parameters ◽  
Successful Implementation ◽  
Fe Model ◽  
Rotor Model ◽  
Machining Spindle

This paper presents an experimentally driven model updating approach to address the dynamic inaccuracy of the nominal finite element (FE) rotor model of a machining spindle supported on active magnetic bearings. Modeling error is minimized through the application of a numerical optimization algorithm to adjust appropriately selected FE model parameters. Minimizing the error of both resonance and antiresonance frequencies simultaneously accounts for rotor natural frequencies as well as for their mode shapes. Antiresonance frequencies, which are shown to heavily influence the model’s dynamic properties, are commonly disregarded in structural modeling. Evaluation of the updated rotor model is performed through comparison of transfer functions measured at the cutting tool plane, which are independent of the experimental transfer function data used in model updating procedures. Final model validation is carried out with successful implementation of robust controller, which substantiates the effectiveness of the model updating methodology for model correction.

scholarly journals Rotor Model Updating and Validation for an Active Magnetic Bearing Based High-Speed Machining Spindle

2012 ◽  
Author(s):  
Adam C. Wroblewski ◽  
Jerzy T. Sawicki ◽  
Alexander H. Pesch
Keyword(s):  
Transfer Functions ◽  
Model Updating ◽  
Dynamic Properties ◽  
Magnetic Bearing ◽  
Mode Shapes ◽  
Model Parameters ◽  
Successful Implementation ◽  
Fe Model ◽  
Rotor Model ◽  
Machining Spindle

This paper presents an experimentally-driven model updating approach to address the dynamic inaccuracy of the nominal finite element (FE) rotor model of a machining spindle supported on active magnetic bearings. Modeling error is minimized through the application of a numerical optimization algorithm to adjust appropriately selected FE model parameters. Minimizing the error of both resonance and antiresonance frequencies simultaneously accounts for rotor natural frequencies as well as for their mode shapes. Antiresonance frequencies, which are shown to heavily influence the model’s dynamic properties, are commonly disregarded in structural modeling. Evaluation of the updated rotor model is performed through comparison of transfer functions measured at the cutting tool plane, which are independent of the experimental transfer function data used in model updating procedures. Final model validation is carried out with successful implementation of robust controller, which substantiates the effectiveness of the model updating methodology for model correction.

scholarly journals Active Magnetic Bearing Rotor Model Updating Using Resonance and MAC Error

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yuanping Xu ◽  
Jin Zhou ◽  
Long Di ◽  
Chen Zhao ◽  
Qintao Guo
Keyword(s):  
Model Updating ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Mode Shapes ◽  
Model Parameters ◽  
System Modelling ◽  
Fe Model ◽  
Resonance Frequencies ◽  
Amb System ◽  
Rotor Model

Modern control techniques can improve the performance and robustness of a rotor active magnetic bearing (AMB) system. Since those control methods usually rely on system models, it is important to obtain a precise rotor AMB analytical model. However, the interference fits and shrink effects of rotor AMB cause inaccuracy to the final system model. In this paper, an experiment based model updating method is proposed to improve the accuracy of the finite element (FE) model used in a rotor AMB system. Modelling error is minimized by applying a numerical optimization Nelder-Mead simplex algorithm to properly adjust FE model parameters. Both the error resonance frequencies and modal assurance criterion (MAC) values are minimized simultaneously to account for the rotor natural frequencies as well as for the mode shapes. Verification of the updated rotor model is performed by comparing the experimental and analytical frequency response. The close agreements demonstrate the effectiveness of the proposed model updating methodology.

Rotor Model Validation for an Active Magnetic Bearing Machining Spindle Using Mu-Synthesis Approach

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Ryan J. Madden ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Model Updating ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Successful Implementation ◽  
Mu Synthesis ◽  
Synthesis Approach ◽  
Rotor Model ◽  
Insight Into ◽  
Machining Spindle

Model-based identification and μ-synthesis are employed for model updating of the rotor for a high-speed machining spindle supported on active magnetic bearings. The experimentally validated model is compared with a nominal engineering model to identify the unmodeled dynamics. The extracted missing dynamics from the nominal rotor model provides engineering insight into an effective model correction strategy. The corrected rotor model is validated by successful implementation of a number of μ-synthesized controllers, providing robust and stable levitation of the spindle over its entire operating speed range.

Rotor Model Validation for an Active Magnetic Bearing Machining Spindle Using mu-Synthesis Approach

2012 ◽  
Author(s):  
Ryan J. Madden ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Model Updating ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Successful Implementation ◽  
Mu Synthesis ◽  
Synthesis Approach ◽  
Rotor Model ◽  
Insight Into ◽  
Machining Spindle

Model-based identification and μ-synthesis are employed for model updating of the rotor for a high-speed machining spindle supported on active magnetic bearings. The experimentally validated model is compared with a nominal engineering model to identify the unmodeled dynamics. This extracted missing dynamics from the nominal rotor model provides engineering insight into an effective model correction strategy. The corrected rotor model is validated by successful implementation of a number of μ-synthesized controllers, providing robust and stable levitation of the spindle over its entire operating speed range.

Benchmark model updating for cable stayed bridges

2021 ◽  
Author(s):  
Minghui Lai ◽  
Haiying Ma ◽  
Pingkuan Sun ◽  
José Turmo
Keyword(s):  
Model Updating ◽  
Shell Element ◽  
Element Model ◽  
Mode Shapes ◽  
Model Parameters ◽  
Fe Model ◽  
Analysis Program ◽  
Shell Elements ◽  
Benchmark Model ◽  
Cable Stayed Bridges

<p>The use of benchmark model aims to establish a model with sufficient accuracy to reflect structure performance. Its purpose is seeking differences through repeated studying on problems using common FE model. In the paper, a novel approach is proposed for the benchmark model updating of a cable stayed bridge. It is based on the interaction of numerical analysis program and FE analysis program with updating model parameters from loop iteration operation. Shell elements and beam elements are both used, and the natural vibration frequencies and mode shapes from plate-shell element model are determined. These are used to modify the parameters used in a spine-beam element model, and to simplify a complicated FE model as a benchmark model. The genetic algorithm (GA) is introduced to complete the calculation process of loop iteration. Finally, an updated benchmark model is proposed for cable stayed bridges.</p>

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

scholarly journals Damage Diagnosis in 3D Structures Using a Novel Hybrid Multiobjective Optimization and FE Model Updating Framework

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Nizar Faisal Alkayem ◽  
Maosen Cao ◽  
Minvydas Ragulskis
Keyword(s):  
Structural Damage ◽  
Model Updating ◽  
Complex Problem ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Fe Model ◽  
Modal Strain Energy ◽  
3D Structures ◽  
Multiobjective Particle Swarm Optimization ◽  
Damage Tracking

Structural damage detection is a well-known engineering inverse problem in which the extracting of damage information from the dynamic responses of the structure is considered a complex problem. Within that area, the damage tracking in 3D structures is evaluated as a more complex and difficult task. Swarm intelligence and evolutionary algorithms (EAs) can be well adapted for solving the problem. For this purpose, a hybrid elitist-guided search combining a multiobjective particle swarm optimization (MOPSO), Lévy flights (LFs), and the technique for the order of preference by similarity to ideal solution (TOPSIS) is evolved in this work. Modal characteristics are employed to develop the objective function by considering two subobjectives, namely, modal strain energy (MSTE) and mode shape (MS) subobjectives. The proposed framework is tested using a well-known benchmark model. The overall strong performance of the suggested method is maintained even under noisy conditions and in the case of incomplete mode shapes.

A Method for FE Model Updating of Coupled Vibro-Acoustic Systems Using Constrained Optimization

2013 ◽  
Author(s):  
D. V. Nehete ◽  
S. V. Modak ◽  
K. Gupta
Keyword(s):  
Finite Element ◽  
Constrained Optimization ◽  
Model Updating ◽  
Numerical Study ◽  
Element Model ◽  
Rectangular Cavity ◽  
Mode Shapes ◽  
Fe Model ◽  
Structural Dynamic ◽  
Fe Model Updating

Finite element (FE) model updating is now recognized as an effective approach to reduce modeling inaccuracies present in an FE model. FE model updating has been researched and studied well for updating FE models of purely structural dynamic systems. However there exists another class of systems known as vibro-acoustics in which acoustic response is generated in a medium due to the vibration of enclosing structure. Such systems are commonly found in aerospace, automotive and other transportation applications. Vibro-acoustic FE modeling is essential for sound acoustic design of these systems. Vibro-acoustic system, in contrast to purely structural system, has not received sufficient attention from FE model updating perspective and hence forms the topic of present paper. In the present paper, a method for finite element model updating of coupled structural acoustic model, constituted as a problem of constrained optimization, is proposed. An objective function quantifying error in the coupled natural frequencies and mode shapes is minimized to estimate the chosen uncertain parameters of the system. The effectiveness of the proposed method is validated through a numerical study on a 3D rectangular cavity attached to a flexible panel. The material property and the stiffness of joints between the panel and rectangular cavity are used as updating parameters. Robustness of the proposed method under presence of noise is investigated. It is seen that the method is not only able to obtain a close match between FE model and corresponding ‘measured’ vibro-acoustic characteristics but is also able to estimate the correction factors to the updating parameters with reasonable accuracy.

scholarly journals Parameter identification for a point-supported cross laminated timber slab based on experimental and numerical modal analysis

2020 ◽  
Author(s):  
Michael Kawrza ◽  
Thomas Furtmüller ◽  
Christoph Adam ◽  
Roland Maderebner
Keyword(s):  
Modal Analysis ◽  
Model Updating ◽  
Dynamic Properties ◽  
Element Model ◽  
Mode Shapes ◽  
Cross Laminated Timber ◽  
Numerical Studies ◽  
Robust Parameter ◽  
Updating Procedure ◽  
Sensor Positions

AbstractIn this paper, the dynamic properties of a point-supported cross-laminated timber slab are studied in order to determine the elastic material parameters on this basis. A detailed experimental modal analysis of the slab with dimensions 16.0 m x 11.0 m is performed, and seven modes including the natural frequencies, damping ratios and mode shape components at 651 sensor positions are identified. The found mode shapes are complex due to environmental influences that occurred during the two-day measurement campaign. This error is corrected by eliminating these influences. A finite element model of the slab is presented, whose parameters in terms of material properties and boundary conditions are determined by a model updating procedure. Based on the modal properties of the seven experimentally identified modes, an accurate and robust parameter set is obtained, which can be used in further numerical studies of the considered CLT to check serviceability limit criteria.

scholarly journals Damage Detection in Structures – Examples

2019 ◽  
Author(s):  
Ivan Duvnjak ◽  
Domagoj Damjanović ◽  
Natalia Sabourova ◽  
Niklas Grip ◽  
Ulf Ohlsson ◽  
...  
Keyword(s):  
Damage Detection ◽  
Damage Assessment ◽  
Model Updating ◽  
Dynamic Properties ◽  
Element Model ◽  
Mode Shapes ◽  
Modal Shape ◽  
New Methods ◽  
Before And After ◽  
Pros And Cons

<p>Damage assessment of structures includes estimation of location and severity of damage. Quite often it is done by using changes of dynamic properties, such as natural frequencies, mode shapes and damping ratios, determined on undamaged and damaged structures. The basic principle is to use dynamic properties of a structure as indicators of any change of its stiffness and/or mass. In this paper, two new methods for damage detection are presented and compared. The first method is based on comparison of normalised modal shape vectors determined before and after damage. The second method uses so-called &#119897;l-norm regularized finite element model updating. Some important properties of these methods are demonstrated using simulations on a Kirchhoff plate. The pros and cons of the two methods are discussed. Unique aspects of the methods are highlighted.</p>

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