IN-SERVICE IDENTIFICATION OF NON-LINEAR DAMPING FROM MEASURED RANDOM VIBRATION

2002 ◽  
Vol 255 (3) ◽  
pp. 549-554 ◽  
Author(s):  
D.V. IOURTCHENKO ◽  
M.F. DIMENTBERG
Keyword(s):  
Random Vibration ◽  
Service Identification ◽  
Non Linear ◽  
Linear Damping

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.

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.

The Maximum Transient Resonance Response of Rotating Blades With Regard to Centrifugal Force and Non-Linear Damping Effects

1997 ◽  
Author(s):  
Horst D. Irretier
Keyword(s):  
Centrifugal Force ◽  
Natural Frequencies ◽  
Linear Change ◽  
Rotating Blades ◽  
Operation Process ◽  
Non Linear ◽  
Linear Damping ◽  
Pass Through ◽  
Run Up ◽  
Approximate Formulas

During the operation process in many types of fluid flow machines the rotating blades pass through various resonances e.g. during run-up or run-down or other transient conditions. Therefore, for the high cycle fatigue problem of the blades it might be important to consider the transient vibratory response of the blades during these passages through resonance and to get knowledge about the occuring maximum vibratory stresses. In the paper, approximate formulas are presented which allow the estimation of the maximum transient response of the blades. Thereby, the influence of the change of the natural frequencies due to the increasing or decreasing centrifugal force field during the run-up or run-down, respectively, is taken into consideration. Basically, the approximate formulas are based on a linear change of the natural frequencies versus time and on a linear viscous type of damping. Extensions to account for parabolic changes which are more realistic for centrifugal effects and for non-linear damping models e.g. friction damping or turbulence damping are discussed.

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