Decomposition and Analysis of Non-Stationary Dynamic Signals Using the Hilbert Transform

2008 ◽  
Author(s):  
Michael Feldman
Keyword(s):  
Hilbert Transform ◽  
Time Domain ◽  
Instantaneous Frequency ◽  
Decomposition Method ◽  
Initial Signal ◽  
Time Modeling ◽  
Stationary Signals ◽  
A New Technique ◽  
The Time Domain ◽  
The Hilbert Transform

This paper describes a new technique, called the Hilbert Vibration Decomposition method, dedicated to decomposition of non-stationary wideband dynamic signals. Using the Hilbert transform in the time domain, we extract a number of elementary oscillating components of the initial signal, who’s both the instantaneous frequency and envelope can vary in time. Modeling examples of decomposition of non-stationary signals are included.

Non-Linear Spring and Damping Forces Estimation During Free Vibration

1995 ◽  
Author(s):  
Michael Feldman ◽  
Simon Braun
Keyword(s):  
Free Vibration ◽  
Hilbert Transform ◽  
Time Domain ◽  
Free Vibration Analysis ◽  
Single Degree Of Freedom ◽  
Non Linear ◽  
Linear Spring ◽  
The Time Domain ◽  
The Hilbert Transform ◽  
Vibrating Systems

Abstract A method for dynamic analysis of sophisticated nonlinear single-degree-of-freedom systems, based on the Hilbert transform in the time domain is described. Using the Hilbert transform together with the proposed method for system identification, we obtain both instantaneous modal parameters together with non-linear force characteristics during free vibration analysis under impulse excitation without long resonance testing. Using the Hilbert transform in the time domain is a new method of studying linear and non-linear vibrating systems exposed to impulse or shock inputs.

Feasibility of Describing Joint Nonlinearity in Exhaust Components With Modal Iwan Models

2014 ◽  
Author(s):  
Daniel R. Roettgen ◽  
Matthew S. Allen ◽  
Dan Osgood ◽  
Stuart Gerger
Keyword(s):  
Hilbert Transform ◽  
Instantaneous Frequency ◽  
Exhaust System ◽  
Degree Of Freedom ◽  
Bolted Joints ◽  
Automotive Exhaust ◽  
Small Frequency ◽  
Frequency Shifts ◽  
Slip Regime ◽  
The Hilbert Transform

Segalman recently proposed a model for joint nonlinearity in a built up structure in which each mode is treated independently (orthogonality is assumed to be preserved) and with an Iwan model added to each modal degree of freedom to capture the nonlinearity of all of the joints that are active in that mode. Recent works have shown that this type of model can faithfully describe the nonlinearity in simple laboratory structures and in simulations of structures with several Iwan joints in the micro-slip regime. This work explores the validity of these concepts for more complicated structures, each of which is part of a production automotive exhaust system. Where possible, factory gaskets were used and the bolted joints were tightened per the manufacturer’s specifications. Tests were performed on different subassemblies of the exhaust using a modal hammer to excite the structure and accelerometers to measure its response. Mayes & Allen’s ZEFFT algorithm was used to determine which modes were behaving nonlinearly. Then an algorithm based on the Hilbert transform was used to extract the instantaneous frequency and damping for the modes of interest and to fit the behavior to a modal Iwan model. The results show several modes that exhibit small frequency shifts and damping that changes by as much as a factor of two over the range of forces that were employed.

First-Passage-Time Modeling of Transport in Fractured Rock

1995 ◽  
Vol 412 ◽  
Author(s):  
M. W. Becker
Keyword(s):  
Time Domain ◽  
Breakthrough Curve ◽  
Fractured Rock ◽  
First Passage Time ◽  
Tracer Tests ◽  
Passage Time ◽  
Matrix Diffusion ◽  
Rock Matrix ◽  
Time Modeling ◽  
The Time Domain

AbstractThis paper presents theory intended for the design and interpretation of tracer tests in fractured rock. The objective is to provide an understanding of experiments in which particulate and solute tracers are injected simultaneously. In such experiments, it is expected that the solute tracer will diffuse into the rock matrix, while the particulates will be confined to the fractures. The theory allows information about matrix diffusion to be extracted from the breakthrough curve. Furthermore, it can accommodate tests in which a non-ideal source is used, and where some of the withdrawn fluid is re-injected. The solution is performed in Laplace space and transformed to the time domain using a commercial spreadsheet.

scholarly journals A Generalized Demodulation and Hilbert Transform Based Signal Decomposition Method

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Zhi-Xiang Hu ◽  
Wei-Xin Ren ◽  
Zuo-Cai Wang ◽  
Yue-Ling Jing ◽  
Xia Yang
Keyword(s):  
Hilbert Transform ◽  
Decomposition Method ◽  
Signal Decomposition ◽  
Dynamic Strain ◽  
Cable Stayed Bridge ◽  
Multicomponent Signal ◽  
Frequency Components ◽  
Echolocation Signal ◽  
The Hilbert Transform ◽  
Strain Signal

This paper proposes a new signal decomposition method that aims to decompose a multicomponent signal into monocomponent signal. The main procedure is to extract the components with frequencies higher than a given bisecting frequency by three steps: (1) the generalized demodulation is used to project the components with lower frequencies onto negative frequency domain, (2) the Hilbert transform is performed to eliminate the negative frequency components, and (3) the inverse generalized demodulation is used to obtain the signal which contains components with higher frequencies only. By running the procedure recursively, all monocomponent signals can be extracted efficiently. A comprehensive derivation of the decomposition method is provided. The validity of the proposed method has been demonstrated by extensive numerical analysis. The proposed method is also applied to decompose the dynamic strain signal of a cable-stayed bridge and the echolocation signal of a bat.

Sign in / Sign up

Export Citation Format

Share Document