An Electromagnetic Emission SIgnal Generated by A Moving Crack in Solids

An Electromagnetic Emission SIgnal Generated by A Moving Crack in Solids

článek ve sborníku ve WoS nebo Scopus

čeština

When a stress is applied to the solids (rocks or tiles) cracks creation can be detected by signals of an acoustic and electromagnetic emission. The experimental study has been performed on rock samples. Two metallic layers have covered the tested devgices to create metal-insulator-metal structure. During the process of the crack generation the electric charges appeared at the face of the cracks. The electric dipole system is a source of voltage induced on metal electrodes. Using Shockley-Ramo thoerem, the differential equation for induced voltage is derived. We found that voltage on measuring capaciotr is directly proportional to the dipole width and its active area. The recorded electric signal is superposition of crack walls :self: vibration given by crack length and vibration due to an ultrasonic wave given by sample dimensions. The electromagnetic signal precedes the acoustic emission response and time delay corresponds to the difference of propagation velocities of sound and electromagnetic radiation in the sample. The simultaneous investigation of acoustic and electromagnetic emission signals enable us to localise the crack position in solids.

nondestructive testin, noise, nonlinearity

KOKTAVÝ, P., ŠIKULA, J., KOKTAVÝ, B.

2003

1. 1. 2003

CNRL

Brno

80-238-9094-8

Noise and Non-linearity Testing of Modern Electronic Components

134

139

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