A Review of Damping Matrix Identification Methods in Structural Dynamics

2012 ◽  
Author(s):  
Sharad Pradhan ◽  
S. V. Modak
Keyword(s):  
Model Updating ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Structural Dynamic ◽  
Identification Methods ◽  
Damping Matrix ◽  
Matrix Modeling ◽  
Stiffness Matrices ◽  
And Control ◽  
Damping Model

Damping matrix modeling and identification has important applications in many engineering fields such as vibration analysis and control, modal analysis, condition monitoring and structural dynamic modifications. A damping model should represent both the mechanism and spatial distribution of the energy loss in the system. In contrast to the mass and stiffness matrices, formulation of the damping matrix still stands as a big challenge in modeling a linear dynamic system. Several methods have been proposed in the literature to identify the damping and the parameters of a damping matrix from measurements on a vibrating system. It is felt that a review of the various approaches developed would help to compare their main features and their relative advantages or limitations to allow for choosing the most suitable method for a particular application. In view of this, this paper presents a review of the methods of damping identification in general, but with more emphasis on the methods developed in the framework of finite element model updating.

Identification of non-proportional viscous damping matrix of beams by finite element model updating

2016 ◽  
Vol 24 (11) ◽  
pp. 2134-2148 ◽  
Author(s):  
Subhajit Mondal ◽  
Sushanta Chakraborty
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Random Noise ◽  
Current Method ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Viscous Damping ◽  
Damping Matrix ◽  
Stiffness Matrices

A methodology has been proposed to estimate non-proportional viscous damping matrix of beams from measured complex eigendata using finite element model updating technique. Representation of damping through a proportional damping matrix ignoring the complexity of eigenvectors may not be appropriate when external damping devices are employed. The current literature of determination of non-proportional damping matrix demands measurement of a large number of complex modes which is extremely difficult in practice. A gradient based finite element model updating algorithm implementing inverse eigensensitivity method has been presented through a series of numerically simulated cantilever beams. The method can accurately predict the non-proportional damping matrix even if the measured eigenvectors are polluted with random noise. The novelty of the current method is that it can sustain a high level of modal and coordinate sparsity in measurement. The method assumes prior determination or updating of the mass and stiffness matrices.

Substructure-Joint Based Approach to Damped FE Model Updating of Complex Assembly Structure

2012 ◽  
Vol 463-464 ◽  
pp. 1169-1174
Author(s):  
Parivash Soleimanian ◽  
Morteza H.Sadeghi ◽  
Akbar Tizfahm
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Element Model ◽  
Modal Testing ◽  
Fe Model ◽  
Complex Assembly ◽  
Modal Data ◽  
Damping Matrix ◽  
Stiffness Matrices ◽  
Assembly Structure

Model updating techniques are used to update the finite element model of a structure, so that updated model can be predicted the dynamic behavior of an actual assembly structure more accurately. Most of the model updating techniques neglects damping and so amplitudes of vibration at resonance and antiresonance frequencies cannot be predicted by using of these updated models. In dynamic design of structures predicting of these properties is necessary. This paper presents a new technique to create an accurate finite element (FE) updated model of complex assembly structures consisting of substructures and real joint by considering damping of them. Given the fact that modal testing of real joints (such as bolt with some washers) are almost impossible. The updated model of assembly structure is obtained in four steps. In the first step, mass and stiffness matrix of substructures, joint and assembly structure are updated using modal data and Eigen-sensitivity approach. In the second step, damping of assembly structure is identified using complex modal data and updated mass and stiffness matrices which are obtained in first step. In the third step, the effect of damping of joint on frequency response functions (FRFs) extracted from updated model was shown. In the forth step, damping matrix of joint is updated by using FRF-based model updating method and finally damped updated model of assembly structure compared with measured data.

Structural Dynamic Modifications Using Damped Updated Finite Element Model Updating

2013 ◽  
Author(s):  
V. Arora
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Fe Model ◽  
Structural Damping ◽  
Structural Dynamic ◽  
Structural Modifications ◽  
Damping Matrix ◽  
Fe Model Updating

An accurate finite element model of a structure is essential for predicting reliably its dynamic characteristics. Such a model can be used to predict the effects of structural modifications for dynamic design of the structure. These structural 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 vibration amplitudes. This paper deals with the basic formulation of finite element model updating method having identified structural damping matrix, and its use for structural dynamic modifications. A case involving actual measured data for the case of F-shaped test structure, which resembles the skeleton of a drilling machine is used to evaluate the effectiveness of FE model updating method incorporating identified structural damping matrix for accurate prediction of the vibration levels and thus its use for structural dynamic modifications. Design modifications in terms of mass and stiffener modifications are introduced to evaluate the effectiveness updated model incorporating damping matrices for structural dynamic modifications. It has been concluded that the FE model updating incorporating identified structural damping matrix can be used for structural dynamic modifications with confidence.

A new method for finite element model updating in structural dynamics

2010 ◽  
Vol 24 (7) ◽  
pp. 2137-2159 ◽  
Author(s):  
J.L. Zapico-Valle ◽  
R. Alonso-Camblor ◽  
M.P. González-Martínez ◽  
M. García-Diéguez
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Dynamics ◽  
Model Updating ◽  
Element Model ◽  
New Method ◽  
Finite Element Model Updating
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