Abstract

Electromagnetic emission (EME) testing and acoustic emission (AE) testing are applied to investigate the failure of a brittle, dielectric material under mechanical load. A setup for three point flexure tests comprising simultaneous monitoring of EME and AE was used to induce fracture of epoxy resin specimens. The influences of the orientation and the distance of the crack surface on the detectable EME signals are the subjects of investigation. As EME sensor a capacitive sensor was used. Tests with an artificial test source are carried out to characterize the system response of the sensor, the attached amplifier and acquisition cards as well as the included bandpass filters. We propose an EME source based on the surface charge density modelled at the position of the fracture plane. Results of finite element method modelling of the EME source are compared to experimental results and show very good agreement. The experimental results show a clear directional character of the emitted electromagnetic field and a strong dependence of the detected signals amplitude on source-sensor distance. A significant influence of the measurement chain on the detected electromagnetic signals bandwidth was found. Furthermore it is shown that the electromagnetic signals consist of three contributions originating from different source mechanisms. These are attributed to the separation and relaxation of charges during crack growth and to the vibration of the charged crack surfaces.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.