scholarly journals Effect of Intentional Mistuning on Dynamic Characteristics of a Energy Turbomachine Bladed Disk

2021 ◽  
Vol 2096 (1) ◽  
pp. 012012
Author(s):  
O V Repetckii ◽  
V V Nguyen
Keyword(s):  
Dynamic Characteristics ◽  
Critical Value ◽  
Forced Response ◽  
Design Stage ◽  
Nominal Mass ◽  
Bladed Disk ◽  
Maximum Value ◽  
Engine Excitation ◽  
Low Order

Abstract In this article the effect intentional mistuning of an axial turbomachine bladed disk has been analyzed in order to reduce forced response due to low-order engine excitation. The maximum value of forced response of turbomachine rotor’s blades with mistuning parameters is usually much more than the value of the tuned rotors. An increase level mistuning of this critical value actually leads to a decrease magnifications of the forced response. Thus, the actual work has been introducing some degree of intentional mistuning in the design to achieve these purposes. The effectiveness of intentional mistuning has been researched at the design stage of the bladed disk in the energy turbomachines, which is introduced into the rotor’s design by changing the nominal mass of the blades in harmonic models.

scholarly journals DYNAMIC CHARACTERISTICS ANALYSIS OF BLADED DISK TURBOMACHINES BASED ON INTENTIONAL MISTUNING

2020 ◽  
pp. 61-70
Author(s):  
Oleg Repetckii ◽  
◽  
Van Vinh Nguyen ◽  
Keyword(s):  
Dynamic Characteristics ◽  
High Reliability ◽  
Forced Response ◽  
Rotor Blades ◽  
Design Stage ◽  
Bladed Disk ◽  
Rotor Design ◽  
Urgent Task ◽  
Characteristics Analysis ◽  
Engine Excitation

To increase technical level of energy turbomachine in modern turbomachinery, high reliability and durability of structures are required in the design, manufacture and operation of turbomachine. Any change geometry, mass, material properties of the bladed disk of turbomachine in the design is called mistuning parameters. With a small value of mistuning blades can significantly increase amplitude, displacement or stresses of the blades structures. So, analysis influence of the effect mistuning parameters on the dynamic characteristics in the field of turbomachine is an important and urgent task. This article analyzes the effect intentional mistuning of the axial bladed disk turbomachine in order to reduce forced response due to low-order engine excitation. The maximum value forced response of rotor blades turbomachine with mistuning parameters is usually much more than that of the tuned rotors. An increase level mistuning of this critical value actually leads to a decrease magnifications of the forced response. Thus, the actual work has been introducing some degree of intentional mistuning in the design to achieve these purposes. In this paper, we study the effectiveness of intentional mistuning at the design stage bladed disk turbomachine, which is introduced into the rotor design by changing the nominal mass of the blades in harmonic Формаls.

A Reduced Order Model for Transient Analysis of Bladed Disk Forced Response

2005 ◽  
Author(s):  
J. P. Ayers ◽  
D. M. Feiner ◽  
J. H. Griffin
Keyword(s):  
Transient Analysis ◽  
Critical Value ◽  
Forced Response ◽  
Reduced Order Model ◽  
Transient Effects ◽  
Order Model ◽  
Reduced Order ◽  
Bladed Disk ◽  
Vibratory Response ◽  
Acceleration Rate

A method for predicting the vibratory response of bladed disks under high engine acceleration rates is developed. The method is based on the Fundamental Mistuning Model, an existing reduced order model for predicting the steady-state vibratory response. In addition, a criterion is developed for a critical engine acceleration rate, above which transient effects play a large role in the response. It is shown that military engines operate at acceleration rates above this critical value and therefore transient effects are important in practice.

Probabilistic Vibration Analysis of a Mistuned Integrally Bladed Disk

2014 ◽  
Vol 891-892 ◽  
pp. 726-731
Author(s):  
Guang Xia Chen ◽  
Jian Fu Hou
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Probabilistic Approach ◽  
Forced Response ◽  
Computational Time ◽  
Fe Model ◽  
Reduced Order ◽  
Bladed Disk ◽  
Model Size

Abstract. The objective of this paper is to probabilistically evaluate the effects of mistuned sectors on the dynamic characteristics of an integrally bladed disk (blisk). Small blade to blade physical variation in a disk is termed as mistuning. In this study, the dynamic characteristics of the perfectly tuned blisk were firstly analysed as a baseline. Secondly, a probabilistic approach is used for the mistuning analysis of a blisk. A reduced-order method named as the subset of nominal modes (SNM) was used to generate modes for a mistuned blisk from a cyclic perfectly tuned FE model without creating the full model. Furthermore, as only the modes with natural frequencies close to the modes of interest were considered, a relatively shorter computational time and a much smaller model size than a full blisk model is used. Therefore, the dynamic characteristics of the forced response for random mistuned blisks were obtained.

A Comparative Study on the Dynamic Characteristics of Bladed Disks With Piezoelectric Network and Piezoelectric Shunt Circuit

2016 ◽  
Author(s):  
Jiuzhou Liu ◽  
Lin Li ◽  
Pengcheng Deng ◽  
Chao Li
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Energy Analysis ◽  
Vibration Suppression ◽  
Forced Response ◽  
Bladed Disks ◽  
Electromechanical Systems ◽  
Bladed Disk ◽  
Engine Order ◽  
Shunt Circuit

This paper is meant to contribute a further investigation of the dynamic characteristics of the bladed disks with piezo-network and piezo-shunt circuit. The non-engine-order (NEO) excitation is taken into account from a practical point of view, and the mechanisms of vibration suppression of the two electromechanical systems are explained by means of the modal analysis and the energy analysis. First of all, the dynamic equations are derived based on a lumped parameter electromechanical model, and a normalizing process is used to make the analysis results more general. After the modal analysis of the electromechanical systems, the vibration suppression effect is analyzed when the bladed disk is excited by the engine-order (EO) excitation and the NEO excitation respectively. Then, an energy analysis of the electromechanical systems is performed to understand the dynamic behaviors of the systems better. Finally, the effect of reducing the amplitude magnification of the mistuned bladed disk is investigated. The research results turn out that the electrical natural frequencies (induced by electrical elements) of the system with piezo-shunt circuit are dense, while those of the system with piezo-network are not. When the system is excited by an EO excitation, the energy dissipated by resistors in the shunt circuit is slightly more than that in the network. However, the former is much less than the latter when the system is excited by an NEO excitation. A statistical analysis has been performed and proved that both the piezo-shunt circuit and the piezo-network can compensate the amplitude magnification of the forced response induced by mistuning, and the piezo-network has a better performance when the bladed disk is excited by an NEO excitation.

Probabilistic Method to Compute the Optimal Slip Load for a Mistuned Bladed Disk Assembly With Friction Dampers

1990 ◽  
Vol 112 (2) ◽  
pp. 214-221 ◽  
Author(s):  
S. Chen ◽  
A. Sinha
Keyword(s):  
Probabilistic Method ◽  
Critical Value ◽  
Forced Response ◽  
Statistical Linearization ◽  
Friction Dampers ◽  
Analytical Technique ◽  
Bladed Disk ◽  
Optimal Value ◽  
Bladed Disk Assembly ◽  
Friction Joint

In this paper, an analytical technique has been developed to compute the statistics of forced response of a mistuned bladed disk assembly with friction dampers (blade-to-blade or blade-to-ground). The method is based on the statistical linearization approach and predicts the probability distribution function of a blade’s amplitude. The validity of this technique has been corroborated by comparison with the results from numerical simulations. Using this technique, the optimal value of the slip load at the friction joint has been computed to minimize the probability that a blade’s amplitude will exceed a critical value.

A Reduced-Order Model for Transient Analysis of Bladed Disk Forced Response

2005 ◽  
Vol 128 (3) ◽  
pp. 466-473 ◽  
Author(s):  
J. P. Ayers ◽  
D. M. Feiner ◽  
J. H. Griffin
Keyword(s):  
Transient Analysis ◽  
Critical Value ◽  
Forced Response ◽  
Reduced Order Model ◽  
Transient Effects ◽  
Order Model ◽  
Reduced Order ◽  
Bladed Disk ◽  
Vibratory Response ◽  
Acceleration Rate

A method for predicting the vibratory response of bladed disks under high engine acceleration rates is developed. The method is based on the Fundamental Mistuning Model, an existing reduced order model for predicting the steady-state vibratory response. In addition, a criterion is developed for a critical engine acceleration rate, above which transient effects play a large role in the response. It is shown that military engines operate at acceleration rates above this critical value and therefore transient effects are important in practice.

A Method for Use of Cyclic Symmetry Properties in Analysis of Nonlinear Multiharmonic Vibrations of Bladed Disks

2004 ◽  
Vol 126 (1) ◽  
pp. 175-183 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
High Efficiency ◽  
Equations Of Motion ◽  
Linear Part ◽  
Forced Response ◽  
Mode Shapes ◽  
Solution Technique ◽  
Disk Model ◽  
Sector Model ◽  
Bladed Disk ◽  
Symmetry Properties

An effective method for analysis of periodic forced response of nonlinear cyclically symmetric structures has been developed. The method allows multiharmonic forced response to be calculated for a whole bladed disk using a periodic sector model without any loss of accuracy in calculations and modeling. A rigorous proof of the validity of the reduction of the whole nonlinear structure to a sector is provided. Types of bladed disk forcing for which the method may be applied are formulated. A multiharmonic formulation and a solution technique for equations of motion have been derived for two cases of description for a linear part of the bladed disk model: (i) using sector finite element matrices and (ii) using sector mode shapes and frequencies. Calculations validating the developed method and a numerical investigation of a realistic high-pressure turbine bladed disk with shrouds have demonstrated the high efficiency of the method.

scholarly journals Redesign of a High-Pressure Compressor Blade Accounting for Nonlinear Structural Interactions

2014 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
Sèbastien Cochon ◽  
François Garcin
Keyword(s):  
High Pressure ◽  
Forced Response ◽  
Compressor Blade ◽  
Design Stage ◽  
Blade Design ◽  
Early Integration ◽  
Nonlinear Structural ◽  
High Pressure Compressor ◽  
Structural Interactions ◽  
Pressure Compressor

Recent numerical developments dedicated to the simulation of rotor/stator interaction involving direct structural contacts have been integrated within the Snecma industrial environment. This paper presents the first attempt to benefit from these developments and account for structural blade/casing contacts at the design stage of a high-pressure compressor blade. The blade of interest underwent structural divergence after blade/abradable coating contact occurrences on a rig test. The design improvements were carried out in several steps with significant modifications of the blade stacking law while maintaining aerodynamic performance of the original blade design. After a brief presentation of the proposed design strategy, basic concepts associated with the design variations are recalled. The iterated profiles are then numerically investigated and compared with respect to key structural criteria such as: (1) their mass, (2) the residual stresses stemming from centrifugal stiffening, (3) the vibratory level under aerodynamic forced response and (4) the vibratory levels when unilateral contact occurs. Significant improvements of the final blade design are found: the need for an early integration of nonlinear structural interactions criteria in the design stage of modern aircraft engines components is highlighted.

Investigation on the Robustness of Rotor/Stator Contact Interactions with Respect to Small Mistuning

2021 ◽  
Author(s):  
Florence Nyssen ◽  
Alain Batailly
Keyword(s):  
Degrees Of Freedom ◽  
Design Stage ◽  
Contact Interactions ◽  
Reduced Basis ◽  
Amplification Factors ◽  
Bladed Disk ◽  
Nonlinear Amplification ◽  
Rotor Stator Interaction ◽  
Bending Modes ◽  
The Impact

Abstract In this work, the impact of small mistuning on rotor/stator contact interactions is investigated. First, a detailed study of a rotor/stator interaction between the first bending modes and the second engine order is presented in the tuned case. Then, a numerical investigation on the effect of mistuning on the studied rotor/stator contact interaction is carried out. In particular, a stochastic analysis is performed to evaluate the robustness of the interaction with respect to the mistuning level. Simulations are conducted using a reduced order model (ROM) of an industrial bladed disk that combines both physical degrees of freedom (along blades tip for contact treatment) and modal coordinates. Mistuning is introduced in the tuned ROM by means of a modified version of the component mode mistuning method that allows to keep physical degrees of freedom within the reduced basis. Nonlinear amplification factors, i.e. the amplification factors in the context of contact nonlinearities, are compared with their linear counterparts, the latter are computed using a linear forcing on each blade using a two nodal diameters traveling wave excitation on the mistuned and the tuned bladed disk. The comparison between the linear and nonlinear amplification factor for each sample highlights that no correlation exists between a mistuning pattern leading to high amplifications in a linear context or when contact nonlinearities are taken into account. Therefore, dedicated analyses on the effect of mistuning should be undertaken with contact nonlinearities considerations at the design stage especially if intentional mistuning is considered.

The Effect of Non-Uniform Aerodynamic Loading on the Blade Responses

2007 ◽  
Author(s):  
Abdelgadir M. Mahmoud ◽  
Mohd S. Leong
Keyword(s):  
Turbine Blades ◽  
Forced Response ◽  
Flow Section ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Bladed Disk ◽  
Aerodynamic Loading ◽  
Bladed Disk Assembly ◽  
Flow Generator ◽  
Inlet Flow Distortion

Turbine blades are always subjected to severe aerodynamic loading. The aerodynamic loading is uniform and Of harmonic nature. The harmonic nature depends on the rotor speed and number of nozzles (vanes counts). This harmonic loading is the main sources responsible for blade excitation. In some circumstances, the aerodynamic loading is not uniform and varies circumferentially. This paper discussed the effect of the non-uniform aerodynamic loading on the blade vibrational responses. The work involved the experimental study of forced response amplitude of model blades due to inlet flow distortion in the presence of airflow. This controlled inlet flow distortion therefore represents a nearly realistic environment involving rotating blades in the presence of airflow. A test rig was fabricated consisting of a rotating bladed disk assembly, an inlet flow section (where flow could be controlled or distorted in an incremental manner), flow conditioning module and an aerodynamic flow generator (air suction module with an intake fan) for investigations under laboratory conditions. Tests were undertaken for a combination of different air-flow velocities and blade rotational speeds. The experimental results showed that when the blades were subjected to unsteady aerodynamic loading, the responses of the blades increased and new frequencies were excited. The magnitude of the responses and the responses that corresponding to these new excited frequencies increased with the increase in the airflow velocity. Moreover, as the flow velocity increased the number of the newly excited frequency increased.

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