Publication detail

# INTERNAL FRICTION IN MAGNESIUM COMPOSITES BY RESONANCE SPECTROSCOPY

TOFEL, P. ŠIKULA, J.

Original Title

INTERNAL FRICTION IN MAGNESIUM COMPOSITES BY RESONANCE SPECTROSCOPY

English Title

INTERNAL FRICTION IN MAGNESIUM COMPOSITES BY RESONANCE SPECTROSCOPY

Type

conference paper

Language

en

Original Abstract

We have analyzed magnesium composites structure by internal friction at sample resonance frequency. The first, second and third resonance signal was measured by FFT. Results measured on two identical samples of magnesium composites, denoted as H01 and H02 are presented. We have applied aging process on sample H02 by liquid nitrogen at temperature 77 K, where the sample was dipped for 15 minutes. The differences of damped harmonic motion parameters for three harmonic signals were fitted by standard equation for damped harmonic motion. The forced vibrations amplitudes for the first harmonic signal are similar for both samples. We can see in our case that the amplitude of the forced vibrations of both samples is the lowest for the second harmonic signal. Sample H02 has much higher amplitude for the third harmonic signal then sample H01. Amplitude of third harmonic signal increases due to ageing. If we compare the values of vibration damping coefficients for different harmonics then we found that the maximum increasing is obtained for the first harmonic signal. Sample H02 has much bigger value of the vibration damping coefficient for the first harmonic signal than sample H01. The other values of vibration damping are similar for both samples for the second and the third harmonic signal.

English abstract

We have analyzed magnesium composites structure by internal friction at sample resonance frequency. The first, second and third resonance signal was measured by FFT. Results measured on two identical samples of magnesium composites, denoted as H01 and H02 are presented. We have applied aging process on sample H02 by liquid nitrogen at temperature 77 K, where the sample was dipped for 15 minutes. The differences of damped harmonic motion parameters for three harmonic signals were fitted by standard equation for damped harmonic motion. The forced vibrations amplitudes for the first harmonic signal are similar for both samples. We can see in our case that the amplitude of the forced vibrations of both samples is the lowest for the second harmonic signal. Sample H02 has much higher amplitude for the third harmonic signal then sample H01. Amplitude of third harmonic signal increases due to ageing. If we compare the values of vibration damping coefficients for different harmonics then we found that the maximum increasing is obtained for the first harmonic signal. Sample H02 has much bigger value of the vibration damping coefficient for the first harmonic signal than sample H01. The other values of vibration damping are similar for both samples for the second and the third harmonic signal.

Keywords

ultrasonic, non-destructive, internal friction

RIV year

2008

Released

26.11.2008

Publisher

Marta Kořenská and Luboš Pazdera

Location

Brno, Czech Republic

ISBN

978-80-7204-610-2

Book

6th Workshop NDT 2008

Pages from

118

Pages to

121

Pages count

4

BibTex

```
@inproceedings{BUT29217,
author="Pavel {Tofel} and Josef {Šikula}",
title="INTERNAL FRICTION IN MAGNESIUM COMPOSITES BY RESONANCE SPECTROSCOPY",
annote="We have analyzed magnesium composites structure by internal friction at sample resonance frequency. The first, second and third resonance signal was measured by FFT. Results measured on two identical samples of magnesium composites, denoted as H01 and H02 are presented. We have applied aging process on sample H02 by liquid nitrogen at temperature 77 K, where the sample was dipped for 15 minutes. The differences of damped harmonic motion parameters for three harmonic signals were fitted by standard equation for damped harmonic motion. The forced vibrations amplitudes for the first harmonic signal are similar for both samples. We can see in our case that the amplitude of the forced vibrations of both samples is the lowest for the second harmonic signal. Sample H02 has much higher amplitude for the third harmonic signal then sample H01. Amplitude of third harmonic signal increases due to ageing. If we compare the values of vibration damping coefficients for different harmonics then we found that the maximum increasing is obtained for the first harmonic signal. Sample H02 has much bigger value of the vibration damping coefficient for the first harmonic signal than sample H01. The other values of vibration damping are similar for both samples for the second and the third harmonic signal.",
address="Marta Kořenská and Luboš Pazdera",
booktitle="6th Workshop NDT 2008",
chapter="29217",
howpublished="electronic, physical medium",
institution="Marta Kořenská and Luboš Pazdera",
year="2008",
month="november",
pages="118--121",
publisher="Marta Kořenská and Luboš Pazdera",
type="conference paper"
}
```