科研之友
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摘要
Electromagnetic emission (EME) signals generated by tensile fracture of four different types of polymers and three different carbon fibre types are presented and discussed. A suitable set-up for the detection of the electric field component of EME generated by fracture of solids is proposed. Basic theoretical considerations are made about the coupling between these field components and the capacitive sensors used to directly measure the short ranged and low frequency (kHz-MHz) electric fields emitted by the generation of free surface charges and their spatial movement as dictated by the vibrational motion of the crack walls. Special focus is put on solids with low conductivity, where the influences of the material on the emitted fields is small and the detected electric signals almost solely depend on the source dynamics and the sensor characteristics. Analysis of the influence of the acquisition circuit is presented. The discussion of the electric signals emitted by tensile fracture of carbon fibres and polymer specimens comprises the influences of the material properties on the signals as well as correlations between the signals and the crack dynamics, including the crack propagation velocities.
- 出版日期2017-3
