Transient Resonance Oscillations of a Turbine Blade with regard to Non-Linear Damping Effects

2000 ◽  
Vol 80 (S2) ◽  
pp. 287-288
Author(s):  
H. Irretier ◽  
D. Balaschov
Keyword(s):  
Turbine Blade ◽  
Non Linear ◽  
Linear Damping ◽  
Transient Resonance ◽  
Damping Effects ◽  
Resonance Oscillations

Transient Resonance Oscillations of a Mechanical System With Regard to Non-Linear Damping Effects

1999 ◽  
Author(s):  
Horst Irretier ◽  
Dmitri Balashov
Keyword(s):  
Mechanical System ◽  
Single Degree Of Freedom ◽  
Aerodynamic Damping ◽  
Dissipative Effects ◽  
First Approximation ◽  
Resonance Response ◽  
Non Linear ◽  
Linear Damping ◽  
Transient Resonance ◽  
Resonance Oscillations

Abstract Transient, forced vibrations of a mechanical system are considered. Dissipative effects such as material damping, aerodynamic damping and damping at interfaces are taken into account. For the modeling of these effects the set of isolated weakly non-linear single degree of freedom oscillators with damping dependent non-linearities is used. The superposition of their responses approximates the resulting response of the system. The justification of this assumption is discussed. The Krylov-Bogoljubov asymptotic method is applied for the investigation of the transient resonance response. Numerical calculations are provided to demonstrate the validity of the Krylov-Bogoljubov first approximation.

scholarly journals Transient Stress Response of a Turbine Blade Under Non-Linear Damping Effects

1990 ◽  
Author(s):  
J. S. Rao ◽  
N. S. Vyas
Keyword(s):  
Stress Response ◽  
Turbine Blade ◽  
Strain Amplitude ◽  
Numerical Technique ◽  
Rotor Speed ◽  
Transient Stress ◽  
Damping Characteristics ◽  
Non Linear ◽  
Linear Damping ◽  
Transient Operations

A numerical technique to compute the stress response of a turbine blade with non-linear damping characteristics, during transient operations of the rotor has been proposed. Damping is defined as a function of vibratory mode, rotor speed and strain amplitude. The technique is illustrated by computing the stress-levels at instantaneous resonant rotor speeds for a typical step-up operation of a turbomachine.

scholarly journals SIMULATION OF NON-LINEAR CHARACTERISTICS INFLUENCE DYNAMIC ON VERTICAL RIGID GYRO ROTOR RESONANT OSCILLATIONS

2018 ◽  
Vol 6 ◽  
pp. 1094-1100
Author(s):  
Zharilkassin Iskakov
Keyword(s):  
Nonlinear Damping ◽  
Resonant Peak ◽  
Rotor Vibration ◽  
Vibration Isolators ◽  
Unbalanced Rotor ◽  
Absolute Motion ◽  
Non Linear ◽  
Linear Damping ◽  
Simulation Results ◽  
Resonance Oscillations

The influence of viscous linear and cubic nonlinear damping of an elastic support on the resonance oscillations of a vertical rigid gyroscopic unbalanced rotor is investigated. Simulation results show that linear and cubic non-linear damping can significantly dampen the main harmonic resonant peak. In non-resonant areas where the speed is higher than the critical speed, the cubic non-linear damping can slightly dampen rotor vibration amplitude in contrast to linear damping. If linear or cubic non-linear damping increase in resonant area significantly kills capacity for absolute motion, then they have little or no influence on the capacity for absolute motion in non-resonant areas. The simulation results can be successfully used to create passive vibration isolators used in rotor machines vibration damping, including gyroscopic ones.

scholarly journals Non-linear damping for scattering-passive systems in the Maxwell class

2020 ◽  
Vol 53 (2) ◽  
pp. 7458-7465
Author(s):  
Shantanu Singh ◽  
George Weiss ◽  
Marius Tucsnak
Keyword(s):  
Passive Systems ◽  
Non Linear ◽  
Linear Damping

Energy Balancing Method to Identify Nonlinear Damping of Bolted-Joint Interface

2016 ◽  
Vol 693 ◽  
pp. 318-323 ◽  
Author(s):  
Xin Liao ◽  
Jian Run Zhang
Keyword(s):  
Dry Friction ◽  
Harmonic Excitation ◽  
Joint Interface ◽  
Damping Factor ◽  
Viscous Damping ◽  
Bolted Joint ◽  
Energy Balancing ◽  
Stick Slip ◽  
Non Linear ◽  
Linear Damping

The interface of bolted joint commonly focuses on the research of non-linear damping and stiffness, which affect structural response. In the article, the non-linear damping model of bolted-joint interface is built, consisting of viscous damping and Coulomb friction. Energy balancing method is developed to identify the dry-friction parameter and viscous damping factor. The corresponding estimation equations are acquired when the input is harmonic excitation. Then, the vibration experiments with different bolted preloads are conducted, from which amplitudes in various input levels are used to work out the interface parameters. Also, the fitting curves of dry-friction parameters are also obtained. Finally, the results illustrate that the most interface of bolted joint in lower excitation levels occurs stick-slip motion, and the feasibility of the identification approach is demonstrated.

scholarly journals Machine Learning for Turbulence Model Development Using a High-Fidelity HPT Cascade Simulation

2017 ◽  
Author(s):  
Jack Weatheritt ◽  
Richard Pichler ◽  
Richard D. Sandberg ◽  
Gregory Laskowski ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Evolutionary Algorithm ◽  
Turbine Blade ◽  
A Priori ◽  
Model Development ◽  
Boussinesq Approximation ◽  
High Pressure Turbine ◽  
Stress Strain ◽  
Non Linear ◽  
Anisotropy Tensor

The validity of the Boussinesq approximation in the wake behind a high-pressure turbine blade is explored. We probe the mathematical assumptions of such a relationship by employing a least-squares technique. Next, we use an evolutionary algorithm to modify the anisotropy tensor a priori using highly resolved LES data. In the latter case we build a non-linear stress-strain relationship. Results show that the standard eddy-viscosity assumption underpredicts turbulent diffusion and is theoretically invalid. By increasing the coefficient of the linear term, the farwake prediction shows minor improvement. By using additional non-linear terms in the stress-strain coupling relationship, created by the evolutionary algorithm, the near-wake can also be improved upon. Terms created by the algorithm are scrutinized and the discussion is closed by suggesting a tentative non-linear expression for the Reynolds stress, suitable for the wake behind a high-pressure turbine blade.

The Analysis of Automotive Door Seal Energy Consumption

2011 ◽  
Vol 80-81 ◽  
pp. 714-718
Author(s):  
Yun Kai Gao ◽  
Da Wei Gao
Keyword(s):  
Energy Consumption ◽  
Elastic Force ◽  
Bernoulli Equation ◽  
Analysis Model ◽  
Damping Force ◽  
Total Energy Consumption ◽  
Linear Elastic ◽  
Non Linear ◽  
Linear Damping ◽  
Simplified Analysis

The seal deformation of automotive door is caused by the door compression forces, including non-linear elastic force and non-linear damping force. The working principles of them are analyzed and a new simplified analysis model is built. Based on the Bernoulli equation and the law of conservation of mass, the mathematical models are established to calculate energy consumption of the seal system. According to the analysis results, the energy consumption of non-linear elastic force and non-linear damping force are respectively 84% and 16% of the total energy consumption of the seal system. At last, the calculation data is compared with the test data and the error is less than 5%, so the calculation method proposed in this paper is observed to be accurate.

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