Wavelet Analysis of Impact Energy Absorption.
Tomoko Endo, Susumu SAKAKIBARA · TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C · 1999
In a drop mass test, in which a weight falls onto a piece of silicon gel, the displacement and acceleration of the weight have been measured. The amount of energy absorbed by the gel is determined by the mass of the weight times the area, enclosed by a curve drawn by the data on the displacement-acceleration plane. In this convenient method to study energy absorption properties of such materials, contamination of noise is unavoidable due to its experimental set Up. In this paper, we show that wavelet analysis can be used to reduce noise in a simple way, and to effectively extract information contained in the data. The cut off level is determined by the assumption that the underlying data is expected to be reasonably smooth. We discuss the validity of our method and the reliability of the results. We also discuss that the phase characteristics of the mother wavelet, rather than the cut off characteristics of the associated filter, may have strong effects on the smoothed data, and hence on the determination of the energy absorption.