On the Effects of Blade-Disk Interface Mistuning on the Response of Integrated Bladed Rotors

2013 ◽  
Author(s):  
Javier Avalos ◽  
Raghavendra Murthy ◽  
X. Q. Wang ◽  
Marc P. Mignolet
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Element Model ◽  
Nonparametric Modeling ◽  
Bladed Disks ◽  
Structural Coupling ◽  
Disk Interface ◽  
Mass Matrices ◽  
Significant Attention

The response of blades in bladed disks can be represented as a sum of modal contributions from their cantilevered modes and a component induced by the motion of the disk and its interface with the blades. This last contribution referred to here as the disk-induced blade motions is generally considered to be tuned when performing mistuning analysis of bladed disks. Yet, as most of the blade properties, its structural coupling to the disk is likely to be uncertain, for example due to variations in thickness at the blade filet. One thus expects a mistuning of the interface stiffness and mass matrices in particular. The effect of this mistuning on the blade response, which does not appear to have received significant attention, is the focus of the present investigation. A Craig-Bampton methodology is introduced to highlight the disk-blade interface and a mistuning modeling of its stiffness matrix is introduced following the nonparametric modeling method. The analysis with various mistuning models is carried out on a 15-blade impeller finite element model at several resonances. It is found that a small mistuning of the disk-induced blade does not alter notably the mistuned response of the blades.

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.

A Complaint Mechanism with Freedom Degrees of One Movement and Two Rotations

2014 ◽  
Vol 551 ◽  
pp. 444-447
Author(s):  
Sheng Lin ◽  
Xi Kong ◽  
Chun Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Degrees Of Freedom ◽  
Compliant Mechanism ◽  
Element Model ◽  
Theory Analysis ◽  
The Finite Element Model

Based on the method of Freedom and Constraint Topology (FACT), a compliant mechanism with 3 degrees of freedom is designed. The 3 DOF are one movement and two rotations, which belongs to Case 3, Type 2. The whole stiffness matrix of the compliant mechanism is obtained. The finite element model is established for statics analysis. The results of theory analysis and finite element method are closed.

scholarly journals Stiffness and Elastic Deformation of 4-DoF Parallel Manipulator with Three Asymmetrical Legs for Supporting Helicopter Rotor

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jialin Song ◽  
Yang Lu ◽  
Yongli Wang ◽  
Yi Lu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Elastic Deformation ◽  
Stiffness Matrix ◽  
Parallel Manipulator ◽  
Element Model ◽  
Helicopter Rotor ◽  
Elastic Deformations ◽  
The Finite Element Model ◽  
Type Composite

The stiffness and elastic deformation of a 4-DoF parallel manipulator with three asymmetrical legs are studied systematically for supporting helicopter rotor. First, a 4-DoF 2SPS + RRPR type parallel manipulator with two linear SPS type legs and one RRPR type composite leg is constructed and its constraint characteristics are analyzed. Second, the formulas for solving the elastic deformation and the stiffness matrix of the above mentioned three asymmetrical legs are derived. Third, the formulas for solving the total stiffness matrix and the elastic deformation of this manipulator are derived and analyzed. Finally, its finite element model is constructed and its elastic deformations are solved using both the derived theoretical formulas and the finite element model. The theoretical solutions of the elastic deformations are verified by that of the finite element model.

scholarly journals Vibration-based damage localization and quantification in a pretensioned concrete girder using stochastic subspace identification and particle swarm model updating

2019 ◽  
Vol 19 (2) ◽  
pp. 587-605 ◽  
Author(s):  
Alessandro Cancelli ◽  
Simon Laflamme ◽  
Alice Alipour ◽  
Sri Sritharan ◽  
Filippo Ubertini
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Particle Swarm ◽  
Element Model ◽  
Subspace Identification ◽  
Reduced Order ◽  
Stochastic Subspace Identification ◽  
Modal Properties ◽  
Pretensioned Concrete

A popular method to conduct structural health monitoring is the spatio-temporal study of vibration signatures, where vibration properties are extracted from collected vibration responses. In this article, a novel methodology for extracting and analyzing distributed acceleration data for condition assessment of bridge girders is proposed. Three different techniques are fused, enabling robust damage detection, localization, and quantification. First, stochastic subspace identification is used as an output-only method to extract modal properties of the monitored structure. Second, a reduced-order stiffness matrix is reconstructed from the stochastic subspace identification data using the system equivalent reduction expansion process. Third, a particle swarm optimization algorithm is used to update a finite element model of the bridge girder to match the extracted reduced-order stiffness matrix and modal properties. The proposed approach is first verified through numerically simulated data of the girder and then validated using experimental data obtained from a full-scale pretensioned concrete beam that experienced two distinct states of damage. Results show that the method is capable of localizing and quantifying damages along the girder with good accuracy, and that results can be used to create a high-fidelity finite element model of the girder that could be leveraged for condition prognosis and forecasting.

A reduced passive constrained layer damping finite element model based on the modified improved reduced system method

2017 ◽  
Vol 21 (2) ◽  
pp. 758-783
Author(s):  
Wei Li ◽  
Yansong He ◽  
Zhongming Xu ◽  
Zhifei Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Deformation Theory ◽  
Element Model ◽  
Constrained Layer Damping ◽  
Finite Element Software ◽  
System Method ◽  
Mass Matrices ◽  
Mode Truncation ◽  
Passive Constrained Layer Damping

This paper proposed a new reduced passive constrained layer damping finite element model. The passive constrained layer damping structure is a sort of sandwich plate made up of a viscoelastic core sandwiched between two elastic faces. The model is built by combining the first shear deformation theory with the Golla-Hughes-McTavish model that takes the frequency dependence of the viscoelastic material property into consideration. Due to the Golla-Hughes-McTavish model, the stiffness, damping and mass matrices are at least doubled, which requires a large amount of calculation. Then, a modified improved reduced system method is proposed to reduce the order of the model. Finally, the proposed reduced model is compared to the Guyan reduction, the mode truncation and the improved reduced system models by two numerical examples. It demonstrates that the proposed modified improved reduced system method is obviously superior to the other three classical methods and the presented passive constrained layer damping model with the Golla-Hughes-McTavish model is an effective and accurate sandwich model, which can be applied to the finite element software.

Prediction of Modal Characteristics due to Design Change

1997 ◽  
Author(s):  
Tong Y. Yi ◽  
Parviz E. Nikravesh
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Element Model ◽  
Vibration Characteristics ◽  
Original Structure ◽  
Design Change ◽  
Modal Data ◽  
Modal Characteristics

Abstract This paper presents a method for predicting modal characteristics of a structure that is considered to undergo a design change. It is assumed that for the original structure the modal data is available either as a complete or as an incomplete set. Based on the available modal data and the known data on the design change, this paper discusses methodologies for determining the vibration characteristics of the modified structure. By considering practical situations, the emphasis of this paper is on structures for which a finite element model, and hence a stiffness matrix, is not available.

Elastic-Plastic Finite Element Analysis for the Head-Disk Interface With Fractal Topography Description

2002 ◽  
Vol 124 (4) ◽  
pp. 775-784 ◽  
Author(s):  
K. Komvopoulos ◽  
N. Ye
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Equivalent Stress ◽  
Magnetic Layer ◽  
Element Model ◽  
Real Surface ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Elastic Plastic ◽  
Plastic Deformation Behavior

An elastic-plastic contact analysis based on a finite element model and real surface topographies was performed to elucidate the evolution of deformation at the head-disk interface. The topographies of the head and disk surfaces were represented by an equivalent profile generated using a modified two-variable Weierstrass-Mandelbrot function, with fractal parameters determined from images of head and disk surfaces. A region of the equivalent rough surface profile was selected for analysis based on topography scale considerations and contact simulation results. The evolution of plasticity and the likelihood of cracking in the overcoat and the magnetic layer are interpreted in light of results for the subsurface von Mises equivalent stress, equivalent plastic strain, and maximum first principal stress. The finite element model provides insight into the elastic-plastic deformation behavior of the layered medium in terms of the thickness, mechanical properties, and residual stress in the carbon overcoat.

scholarly journals Direct image-based micro finite element modelling of bone tissue

2020 ◽  
Vol 329 ◽  
pp. 03072
Author(s):  
Oleg Gerasimov ◽  
Nikita Kharin ◽  
Viktoriya Yaikova ◽  
Evgeniy Statsenko ◽  
Tatyana Baltina
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Element Model ◽  
Direct Image ◽  
Data Simulation ◽  
Plane Element ◽  
Calculation Results ◽  
The Finite Element Model ◽  
Tomography Data

In the paper, a method for the direct image-based creation of the finite element model from images is presented. Image information is taken into account during the calculation of the element stiffness matrix. In this case, material heterogeneity can be included directly in the finite element model. For this purpose, the hypothesis about the correlation between pixel values and elastic properties was used. Four nodes plane element was built. The element can be used with the quantitative phase or scanning electron images and computed tomography data. Simulation for bone data performed. The influence of pixel on the error estimate was studied. The method to parallelize the calculation of the stiffness matrix is presented. As an example, a slice of bone was used in the calculation. Results for average stress distribution for the origin and improved mesh are presented.

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