scholarly journals Improvement of and Parameter Identification for the Bimodal Time-Varying Modified Kanai-Tajimi Power Spectral Model

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Huiguo Chen ◽  
Ting Zhong ◽  
Guocui Liu ◽  
Junru Ren
Keyword(s):  
Power Spectrum ◽  
Parameter Identification ◽  
Ground Motion ◽  
Spectral Model ◽  
Time Varying ◽  
Engineering Structures ◽  
Filtering Method ◽  
Power Spectral ◽  
Identification Technique ◽  
Earthquake Accelerograms

Based on the Kanai-Tajimi power spectrum filtering method proposed by Du Xiuli et al., a genetic algorithm and a quadratic optimization identification technique are employed to improve the bimodal time-varying modified Kanai-Tajimi power spectral model and the parameter identification method proposed by Vlachos et al. Additionally, a method for modeling time-varying power spectrum parameters for ground motion is proposed. The 8244 Orion and Chi-Chi earthquake accelerograms are selected as examples for time-varying power spectral model parameter identification and ground motion simulations to verify the feasibility and effectiveness of the improved bimodal time-varying modified Kanai-Tajimi power spectral model. The results of this study provide important references for designing ground motion inputs for seismic analyses of major engineering structures.

Nonstationary Probabilistic Seismic Response Analysis of Nonlinear Soil Profile under Bidirectional Dynamic Loading

2012 ◽  
Vol 193-194 ◽  
pp. 949-953
Author(s):  
Xiao Dong Pan ◽  
Jia En Zhong ◽  
Chao Chao He
Keyword(s):  
Spectral Density ◽  
Seismic Response ◽  
Ground Motion ◽  
Power Spectral Density ◽  
Soil Profile ◽  
Response Analysis ◽  
Time Varying ◽  
Seismic Response Analysis ◽  
Dynamic Reliability ◽  
Power Spectral

In this paper, according to the characteristics of near-fault earthquakes, combined with the strong ground motion attenuation law in China, the nonstationary power spectrum of bidirectional ground motion input is obtained through random vibration analysis. By introducing the pseudo excitation algorithm, the evolutionary power spectral density (PSD) of acceleration at the engineering bedrock is handled as the nonstationary pseudo input, and the Hardin-Drnevich hyperbolic model is utilized to take into account the nonlinearity of soil layer. On this basis, finite element method in the time domain and frequency domain are used for seismic response analysis of soil profile. Values including various time-varying power spectral density of the dynamic response, time varying RMS and time-dependent reliability at different threshold can be obtained by calculating, which provides a basis for the analysis of the foundation dynamic reliability assessment.

scholarly journals Fully Nonstationary Spatially Variable Ground Motion Simulations Based on a Time-Varying Power Spectrum Model

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Huiguo Chen ◽  
Yingmin Li ◽  
Junru Ren
Keyword(s):  
Power Spectrum ◽  
Ground Motion ◽  
Response Spectrum ◽  
Power Spectra ◽  
Response Spectra ◽  
Simulation Method ◽  
Time Varying ◽  
Time Frequency ◽  
Response Characteristics ◽  
Spectrum Model

By analyzing the evolutionary spectrum method for multivariate nonstationary stochastic processes, a simulation method for fully nonstationary spatially variable ground motion is proposed based on the Kameda time-varying power spectrum model. This method can properly simulate nonstationary spatially variable ground motion based on a target response spectrum. Two numerical examples, in which the Kameda time-varying power spectra are calculated for different conditions, are presented to demonstrate the capabilities of the proposed method. In the first example, the nonstationary spatially variable ground motion that satisfies the time-frequency characteristics and response characteristics of the original ground motion is simulated by identifying the parameters of the given time-varying power spectrum. In the second example, the ground motion that satisfies the design response spectra is simulated by defining the parameters of the time-varying power spectrum directly. The results demonstrate that the method can effectively simulate nonstationary spatially variable ground motion, which implies that the proposed method can be used in engineering applications.

Dynamic Modeling and Analysis of Mechanical Snubbing

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Parameter Identification ◽  
Small Range ◽  
Time Varying ◽  
Isolation System ◽  
Modeling And Analysis ◽  
Modeling Analysis ◽  
Time Varying Parameter ◽  
Identification Technique ◽  
Passive Isolation ◽  
Force Displacement

This paper presents four alternate models of varying complexity to examine mechanical snubbing in elastomeric isolators. Although the modeling, analysis, and experimentation presented is limited to snubbing of elastomeric isolators, the models are generic and can be adapted to other snubbing mechanisms as well, such as friction snubbing. Two of the four models presented in this paper use the Bouc–Wen model in order to capture hysteresis and gradual stiffening behavior, which is generally exhibited by elastomeric snubbing systems. The other two models are relatively simplistic and do not account for a time-varying parameter to model significant hysteresis. However, these two models can still be useful for applications with a small range of excitation frequencies and for applications where the snubbing design needs to incorporate an abrupt transition in stiffness. A parameter identification technique is used to determine the variables associated with each model. The parameter identification technique is based on the use of an optimization algorithm associated with the force–displacement characterization. All four models presented in this paper capture the coupled dynamics of the isolation system and the snubbing system and are, therefore, a significant improvement upon the currently used models. The models presented are expected to facilitate the design and analysis of a passive isolation system in conjunction with the design of the snubbing system and the base frame supporting the snubbing system.

A performance enhanced time-varying morphological filtering method for bearing fault diagnosis

Measurement ◽  
2021 ◽  
Vol 176 ◽  
pp. 109163
Author(s):  
Bingyan Chen ◽  
Dongli Song ◽  
Weihua Zhang ◽  
Yao Cheng ◽  
Zhiwei Wang
Keyword(s):  
Fault Diagnosis ◽  
Time Varying ◽  
Filtering Method ◽  
Bearing Fault ◽  
Bearing Fault Diagnosis ◽  
Morphological Filtering ◽  
A Performance

Simulating and analyzing artificial nonstationary earthquake ground motions

1982 ◽  
Vol 72 (2) ◽  
pp. 615-636
Author(s):  
Robert F. Nau ◽  
Robert M. Oliver ◽  
Karl S. Pister
Keyword(s):  
Difference Equations ◽  
Kalman Filters ◽  
Ground Motions ◽  
Structural Response ◽  
Model Parameters ◽  
Time Varying ◽  
Nonparametric Method ◽  
Linear Difference Equations ◽  
Earthquake Ground Motions ◽  
Earthquake Accelerograms

Abstract This paper describes models used to simulate earthquake accelerograms and analyses of these artificial accelerogram records for use in structural response studies. The artificial accelerogram records are generated by a class of linear linear difference equations which have been previously identified as suitable for describing ground motions. The major contributions of the paper are the use of Kalman filters for estimating time-varying model parameters, and the development of an effective nonparametric method for estimating the variance envelopes of the accelerogram records.

Identification of Parameters in Hereditary Systems

1995 ◽  
Author(s):  
Ferenc Hartung ◽  
Janos Turi ◽  
Terry L. Herdman
Keyword(s):  
Parameter Identification ◽  
Delay Equations ◽  
Neutral Equations ◽  
Piecewise Constant Arguments ◽  
Piecewise Constant ◽  
Identification Of Parameters ◽  
State Dependent ◽  
Identification Technique ◽  
Numerical Performance

Abstract In this paper we study the numerical performance of a parameter identification technique, based on approximation by equations with piecewise constant arguments, on various classes of hereditary systems. The examples considered here include delay equations with state-dependent delays and neutral equations.

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