scholarly journals Approximate Power Spectral Density of the Response of a Nonlinear System to Stationary Random Excitation

1962 ◽  
Vol 34 (12) ◽  
pp. 2001-2001
Author(s):  
Thomas G. Butler
Keyword(s):  
Nonlinear System ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Random Excitation ◽  
Power Spectral ◽  
Approximate Power

scholarly journals Power Spectral Density Conversions and Nonlinear Dynamics

1994 ◽  
Vol 1 (4) ◽  
pp. 349-356 ◽  
Author(s):  
Mostafa Rassaian
Keyword(s):  
Nonlinear System ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Spectral Response ◽  
Damping Ratio ◽  
Random Excitation ◽  
Isolation System ◽  
Power Spectral ◽  
Alternative Approach ◽  
Stiffness And Damping

To predict the vibration environment of a payload carried by a ground or air transporter, mathematical models are required from which a transfer function to a prescribed input can be calculated. For sensitive payloads these models typically include linear shock isolation system stiffness and damping elements relying on the assumption that the isolation system has a predetermined characteristic frequency and damping ratio independent of excitation magnitude. In order to achieve a practical spectral analysis method, the nonlinear system has to be linearized when the input transportation and handling vibration environment is in the form of an acceleration power spectral density. Test data from commercial isolators show that when nonlinear stiffness and damping effects exist the level of vibration input causes a variation in isolator resonant frequency. This phenomenon, described by the stationary response of the Duffing oscillator to narrow-band Gaussian random excitation, requires an alternative approach for calculation of power spectral density acceleration response at a shock isolated payload under random vibration. This article details the development of a plausible alternative approach for analyzing the spectral response of a nonlinear system subject to random Gaussian excitations.

scholarly journals Simulation of Pavement Random Excitation Based on Harmonic Superposition Method

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Kehui Ma ◽  
Yongguo Zhang ◽  
Xü Zhen
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Ride Comfort ◽  
Random Excitation ◽  
Superposition Method ◽  
Generation Model ◽  
The Road ◽  
Power Spectral ◽  
Control Research ◽  
The Relationship

The road input model is very important in the analysis of vehicle ride comfort and handling stability. Based on the analysis of the relationship between the spatial frequency power spectral density and the time power spectral density of the road, the road signal generation model is established. The simulation is carried out under different vehicle speeds, and the B and C-level random road time excitation signals are generated. The power spectral density is used to compare the simulation results of the model with the road classification standard. The experimental results show that the results are accurate and can provide reliable excitation signals for vehicle control research.

Damage Localization Based on Power Spectral Density Analysis

2007 ◽  
Vol 347 ◽  
pp. 589-594 ◽  
Author(s):  
Sheng En Fang ◽  
Ricardo Perera ◽  
Maria Consuelo Huerta
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Large Scale ◽  
Damage Identification ◽  
Random Excitation ◽  
Rc Beam ◽  
Engineering Structures ◽  
Damage Location ◽  
Power Spectral ◽  
Aluminum Beam

An environmental excitation having random characteristics may be more effective and cost-efficient than other excitation means for non-destructive damage identification purpose on most of the large-scale engineering structures under operation. In general, many existing damage indexes are constructed based on the modal properties derived firstly from the power spectral density (PSD) analysis of the structures under random excitation. However, the derivation procedures for the modal parameters usually introduce some extra errors into the indexes. This paper aims to propose a simple and feasible damage location index (DLI) constructed directly derived from the analysis results of the structural response PSD. The performance of DLI was verified using an aluminum beam with fixed ends and an experimental reinforced concrete (RC) beam under free boundary condition. Our results show that the damage location of the aluminum beam can be determined via the plot of DLI value by selecting the peaks with the amplitudes exceeding a predefined threshold value in both single- and multi-damaged scenarios. And the index may also predict the possible damage zones in the RC beam experimentally tested.

scholarly journals Power spectral density analysis for nonlinear systems based on Volterra series

2021 ◽  
Author(s):  
Penghui Wu ◽  
Yan Zhao ◽  
Xianghong Xu
Keyword(s):  
Nonlinear System ◽  
Nonlinear Systems ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Random Vibration ◽  
Volterra Series ◽  
Harmonic Excitation ◽  
Random Load ◽  
Vibration Prediction ◽  
Power Spectral

AbstractA consequence of nonlinearities is a multi-harmonic response via a mono-harmonic excitation. A similar phenomenon also exists in random vibration. The power spectral density (PSD) analysis of random vibration for nonlinear systems is studied in this paper. The analytical formulation of output PSD subject to the zero-mean Gaussian random load is deduced by using the Volterra series expansion and the conception of generalized frequency response function (GFRF). For a class of nonlinear systems, the growing exponential method is used to determine the first 3rd-order GFRFs. The proposed approach is used to achieve the nonlinear system’s output PSD under a narrow-band stationary random input. The relationship between the peak of PSD and the parameters of the nonlinear system is discussed. By using the proposed method, the nonlinear characteristics of multi-band output via single-band input can be well predicted. The results reveal that changing nonlinear system parameters gives a one-of-a-kind change of the system’s output PSD. This paper provides a method for the research of random vibration prediction and control in real-world nonlinear systems.

Fuzzy Modeling of Multi-Degree-of-Freedom Power Spectral Density Systems

2009 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Montasser Tahat ◽  
Hussien Al-Wedyan ◽  
Kudret Demirli ◽  
Saad Mutasher
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Fuzzy Modeling ◽  
Degree Of Freedom ◽  
Power Spectral
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