Explicit Finite Element Models of Friction Dampers in Forced Response Analysis of Bladed Disks

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Dynamic Properties ◽  
Forced Response ◽  
Response Analysis ◽  
Contact Interactions ◽  
Contact Interface ◽  
Bladed Disks ◽  
Explicit Finite Element ◽  
Friction Dampers

A generic method for analysis of nonlinear forced response for bladed disks with friction dampers of different designs has been developed. The method uses explicit finite element modeling of dampers, which allows accurate description of flexibility and, for the first time, dynamic properties of dampers of different designs in multiharmonic analysis of bladed disks. Large-scale finite element damper and bladed disk models containing 104−106 degrees of freedom can be used. These models, together with detailed description of contact interactions over contact interface areas, allow for any level of refinement required for modeling of elastic damper bodies and for modeling of friction contact interactions. Numerical studies of realistic bladed disks have been performed with three different types of underplatform dampers: (i) a “cottage-roof” (also called “wedge”) damper, (ii) seal wire damper, and (iii) a strip damper. Effects of contact interface parameters and excitation levels on damping properties of the dampers and forced response are extensively explored.

Explicit Finite Element Models of Friction Dampers in Forced Response Analysis of Bladed Discs

2007 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Dynamic Properties ◽  
Forced Response ◽  
Response Analysis ◽  
Contact Interactions ◽  
Contact Interface ◽  
Explicit Finite Element ◽  
Friction Dampers ◽  
Time Dynamic

A generic method for analysis of nonlinear forced response for bladed discs with friction dampers of different design has been developed. The method uses explicit finite element modelling of dampers, which allows accurate description of flexibility and, for the first time, dynamic properties of dampers of different design in multiharmonic analysis of bladed discs. Large-scale finite element damper and bladed disc models containing 104–106 DOFs can be used. These models, together with detailed description of contact interactions over contact interface areas, allow for any level of refinement required for modelling of elastic damper bodies and for modelling of friction contact interactions. Numerical studies of realistic bladed discs have been performed with three different types of underplatform dampers: (i) a ‘cottage-roof’ (called also ‘wedge’) damper; (ii) seal wire damper; and (iii) a strip damper. Effects of contact interface parameters and excitation levels on damping properties of the dampers and forced response are extensively explored.

High Fidelity Transient Forced Response Analysis of Mistuned Bladed Disks Under Complex Excitation and Variable Rotation Speeds

2020 ◽  
Author(s):  
Jing Tong ◽  
Chaoping Zang ◽  
Evgeny Petrov
Keyword(s):  
Large Scale ◽  
Rotation Speed ◽  
Dynamic Properties ◽  
Spectral Composition ◽  
Forced Response ◽  
Mode Shapes ◽  
Response Analysis ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Amplitude Amplification

Abstract An effective method is developed for the efficient calculation of the transient vibration response for mistuned bladed disks under complex excitation and varying rotation speeds. The method uses the large-scale finite element modelling of the bladed disks allowing the accurate description of the dynamic properties of the mistuned bladed disks. The realistic distributions of the excitation forces are considered, which resulted in the multiharmonic excitation loads. The transient response calculation is based on the analytically derived expressions for the transient forced response and the effective method used for the model reduction. The effects of the varying rotation speed on the natural frequencies and mode shapes of the mistuned bladed disk and its effects on the amplitude and the spectral composition of the loading are allowed for. The different functions of the rotation speed variation can be analyzed. Numerical studies of the transient forced response and the amplitude amplification in mistuned bladed disks are performed when the resonance regimes are passed during gas-turbine engine acceleration or deceleration. The effects of different types of excitation force and mistuning on transient amplitude amplification are illustrated by a large number of the computational results and comparative analysis. These results and analysis of transient forced response are shown on an example of a realistic mistuned bladed disk.

Method for Direct Parametric Analysis of Nonlinear Forced Response of Bladed Disks With Friction Contact Interfaces

2004 ◽  
Vol 126 (4) ◽  
pp. 654-662 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Parametric Analysis ◽  
Large Scale ◽  
Normal Load ◽  
Forced Response ◽  
Finite Element Models ◽  
Contact Interface ◽  
Friction Contact ◽  
Bladed Disks ◽  
Interface Parameters ◽  
Contact Parameters

An effective method for direct parametric analysis of periodic nonlinear forced response of bladed disks with friction contact interfaces has been developed. The method allows, forced response levels to be calculated directly as a function of contact interface parameters such as the friction coefficient, contact surface stiffness (normal and tangential coefficients), clearances, interferences, and the normal stresses at the contact interfaces. The method is based on exact expressions for sensitivities of the multiharmonic interaction forces with respect to variation of all parameters of the friction contact interfaces. These novel expressions are derived in the paper for a friction contact model, accounting for the normal load variation and the possibility of separation-contact transitions. Numerical analysis of effects of the contact parameters on forced response levels has been performed using large-scale finite element models of a practical bladed turbine disk with underplatform dampers and with shroud contacts.

Analysis of Forced Response for Bladed Disks Mistuned by Material Anisotropy Orientation Scatters

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Chaoping Zang ◽  
Yuanqiu Tan ◽  
E. P. Petrov
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
High Accuracy ◽  
Forced Response ◽  
Response Analysis ◽  
High Fidelity ◽  
Fe Model ◽  
Material Anisotropy ◽  
Bladed Disks ◽  
Bladed Disk

A new method is developed for the forced response analysis of mistuned bladed disks manufactured from anisotropic materials and mistuned by different orientations of material anisotropy axes. The method uses (i) sector finite element (FE) models of anisotropic bladed disks and (ii) FE models of single blades and allows the calculation of displacements and stresses in a mistuned assembly. A high-fidelity reduction approach is proposed which ensures high-accuracy modeling by introducing an enhanced reduction basis. The reduction basis includes the modal properties of specially selected blades and bladed disks. The technique for the choice of the reduction basis has been developed, which provides the required accuracy while keeping the computation expense acceptable. An approach for effective modeling of anisotropy-mistuned bladed disk without a need to create a FE model for each mistuning pattern is developed. The approach is aimed at fast statistical analysis based on Monte Carlo simulations. All components of the methodology for anisotropy-mistuned bladed disks are demonstrated on the analysis of models of practical bladed disks. Effects of anisotropy mistuning on forced response levels are explored.

Method for Analysis of Nonlinear Multiharmonic Vibrations of Mistuned Bladed Disks With Scatter of Contact Interface Characteristics

2005 ◽  
Vol 127 (1) ◽  
pp. 128-136 ◽  
Author(s):  
E. P. Petrov ◽  
D. J. Ewins
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Forced Response ◽  
Finite Element Models ◽  
Linear Vibration ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Interface Characteristics ◽  
Blade Frequency

An efficient method for analysis of nonlinear vibrations of mistuned bladed disk assemblies has been developed. This development has facilitated the use of large-scale finite element models for realistic bladed disks, used hitherto in analysis of linear vibration, to be extended for the analysis of nonlinear multiharmonic vibration. The new method is based on a technique for the exact condensation of nonlinear finite element models of mistuned bladed disks. The model condensation allows the size of the nonlinear equations to be reduced to the number of degrees of freedom where nonlinear interaction forces are applied. The analysis of nonlinear forced response for simplified and realistic models of mistuned bladed disks has been performed. For a practical high-pressure bladed turbine disk, several types of nonlinear forced response have been considered, including mistuning by (i) scatter of underplatform dampers, (ii) shroud gap scatter, and (iii) blade frequency scatter in the presence of nonlinear shroud interactions.

Method for Analysis of Nonlinear Multiharmonic Vibrations of Mistuned Bladed Discs With Scatter of Contact Interface Characteristics

2004 ◽  
Author(s):  
E. P. Petrov ◽  
D. J. Ewins
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Nonlinear Vibrations ◽  
Forced Response ◽  
Finite Element Models ◽  
Contact Interface ◽  
Linear Vibration ◽  
Interface Characteristics ◽  
Blade Frequency

An efficient method for analysis of nonlinear vibrations of mistuned bladed disc assemblies has been developed. As a result, this development has facilitated the use of large-scale finite element models for realistic bladed discs, as used hitherto in analysis of linear vibration, to be extended for the analysis of nonlinear multiharmonic vibration. The new method is based on a technique for the exact condensation of nonlinear finite element models of mistuned bladed discs. The model condensation allows the size of the nonlinear equations to be reduced to the number of degrees of freedom where nonlinear interation forces are applied. The analysis of nonlinear forced response for simplified and realistic models of mistuned bladed discs has been performed. For a practical high-pressure bladed turbine disc, several types of nonlinear forced response have been considered including: (i) mistuning by scatter of underplatform dampers; (ii) mistuning by shroud gap scatter; (iii) mistuning by blade frequency scatter in the presence of nonlinear shroud interactions.

Advanced Modelling of Underplatform Friction Dampers for Analysis of Bladed Disc Vibration

2006 ◽  
Author(s):  
E. P. Petrov ◽  
D. J. Ewins
Keyword(s):  
Large Scale ◽  
Dynamic Models ◽  
Normal Load ◽  
Forced Response ◽  
Response Analysis ◽  
Finite Element Models ◽  
Structural Dynamic ◽  
Stick Slip ◽  
Friction Dampers ◽  
Inertia Forces

Advanced structural dynamic models for both wedge and split underplatform dampers have been developed. The new damper models take into account inertia forces and the effects of normal load variation on stick-slip transitions at the contact interfaces. The damper models are formulated for the general case of multiharmonic forced response analysis. An approach for using the new damper models in the dynamic analysis of large-scale finite element models of bladed discs is proposed and realised. Numerical investigations of bladed discs are performed to demonstrate the capabilities of the new models and an analysis of the influence of the damper parameters on the forced response of bladed discs is made.

Effects of Damping and Varying Contact Area at Blade-Disk Joints in Forced Response Analysis of Bladed Disk Assemblies

2005 ◽  
Vol 128 (2) ◽  
pp. 403-410 ◽  
Author(s):  
E. P. Petrov ◽  
D. J. Ewins
Keyword(s):  
Large Scale ◽  
Normal Load ◽  
Forced Response ◽  
Response Analysis ◽  
Finite Element Models ◽  
Bladed Disks ◽  
Contact Conditions ◽  
New Approach ◽  
Bladed Disk ◽  
Unilateral Contacts

An approach is developed to analyze the multiharmonic forced response of large-scale finite element models of bladed disks taking account of the nonlinear forces acting at the contact interfaces of blade roots. Area contact interaction is modeled by area friction contact elements which allow for friction stresses under variable normal load, unilateral contacts, clearances, and interferences. Examples of application of the new approach to the analysis of root damping and forced response levels are given and numerical investigations of effects of contact conditions at root joints and excitation levels are explored for practical bladed disks.

Advanced Modeling of Underplatform Friction Dampers for Analysis of Bladed Disk Vibration

2006 ◽  
Vol 129 (1) ◽  
pp. 143-150 ◽  
Author(s):  
E. P. Petrov ◽  
D. J. Ewins
Keyword(s):  
Large Scale ◽  
Dynamic Models ◽  
Normal Load ◽  
Forced Response ◽  
Response Analysis ◽  
Bladed Disks ◽  
Structural Dynamic ◽  
Stick Slip ◽  
Bladed Disk ◽  
Inertia Forces

Advanced structural dynamic models for both wedge and split underplatform dampers have been developed. The new damper models take into account inertia forces and the effects of normal load variation on stick-slip transitions at the contact interfaces. The damper models are formulated for the general case of multiharmonic forced response analysis. An approach for using the new damper models in the dynamic analysis of large-scale finite element models of bladed disks is proposed and realized. Numerical investigations of bladed disks are performed to demonstrate the capabilities of the new models and an analysis of the influence of the damper parameters on the forced response of bladed disks is made.

scholarly journals Forced Response Analysis of High-Mode Vibrations for Mistuned Bladed Disks With Effective Reduced-Order Models

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Yongliang Duan ◽  
Chaoping Zang ◽  
E. P. Petrov
Keyword(s):  
Dynamic Properties ◽  
Forced Response ◽  
High Mode ◽  
Mode Shapes ◽  
Response Analysis ◽  
Fe Model ◽  
Computationally Efficient ◽  
Bladed Disks ◽  
Accurate Analysis ◽  
Bladed Disk

This paper is focused on the analysis of effects of mistuning on the forced response of gas turbine engine bladed disks vibrating in the frequency ranges corresponding to higher modes. For high modes considered here, the blade aerofoils are deformed during vibrations and the blade mode shapes differ significantly from beam mode shapes. A model reduction technique is developed for the computationally efficient and accurate analysis of forced response for bladed disks vibrating in high-frequency ranges. The high-fidelity finite element (FE) model of a tuned bladed disk sector is used to provide primary information about dynamic properties of a bladed disk, and the blade mistuning is modeled by specially defined mistuning matrices. The forced response displacement and stress amplitude levels are studied. The effects of different types of mistuning are examined, and the existence of high amplifications of mistuned forced response levels is shown for high-mode vibrations: in some cases, the resonance peak response of a tuned structure can be lower than out-of-resonance amplitudes of its mistuned counterpart.

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