Publication

Modeling and simulation of an impact test using wavelets, analytical solutions and finite elements

Pierre Vandergheynst
2001
Journal Articles

Abstract

An instrumented falling weight impact test is thoroughly investigated in two cases, that of a rebound and that of a rupture in the sample. First, the force signal is analyzed with four methods: the continuous wavelet transform (with different wavelets: derivatives of a Gaussian and Morlet's), the Gabor transform, the Wigner Ville transform and the classical Fourier analysis. It is shown how a proper use of the time frequency methods allows to precisely detect the discontinuities in the signal, the moment of rupture, if any, and the frequencies that are excited at the impact. In a second part, modal and stress analyses are carried out, both by an analytical method and by finite element computations. The results confirm those obtained in the first part and agree with experimental findings.

Official source

https://infoscience.epfl.ch/entities/publication/c5bd60b3-c5d1-4b42-97ea-c4ce730b6b80

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Pierre Vandergheynst
2001
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/c5bd60b3-c5d1-4b42-97ea-c4ce730b6b80

About this result

Related concepts (32)

Time–frequency analysis

In signal processing, time–frequency analysis comprises those techniques that study a signal in both the time and frequency domains simultaneously, using various time–frequency representations. Rather than viewing a 1-dimensional signal (a function, real or complex-valued, whose domain is the real line) and some transform (another function whose domain is the real line, obtained from the original via some transform), time–frequency analysis studies a two-dimensional signal – a function whose domain is the two-dimensional real plane, obtained from the signal via a time–frequency transform.

Wavelet

A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases or decreases, and then returns to zero one or more times. Wavelets are termed a "brief oscillation". A taxonomy of wavelets has been established, based on the number and direction of its pulses. Wavelets are imbued with specific properties that make them useful for signal processing. For example, a wavelet could be created to have a frequency of Middle C and a short duration of roughly one tenth of a second.

Time–frequency representation

A time–frequency representation (TFR) is a view of a signal (taken to be a function of time) represented over both time and frequency. Time–frequency analysis means analysis into the time–frequency domain provided by a TFR. This is achieved by using a formulation often called "Time–Frequency Distribution", abbreviated as TFD. TFRs are often complex-valued fields over time and frequency, where the modulus of the field represents either amplitude or "energy density" (the concentration of the root mean square over time and frequency), and the argument of the field represents phase.

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Modeling and simulation of an impact test using wavelets, analytical solutions and finite elements

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